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JohnH
23-11-2020, 10:13 AM
As doc pointed out that there is actually an amplifier section on this forum I thought I should start a build thread in the right place!

First attempt at a tube amp build, but I'm assuming it won't be my last.

The build is a 5E3, using mojotone wiring layout and instructions.

The caps arrived yesterday, and I have resistors and a chassis in the post. I haven't ordered tubes, tube sockets or input jacks/misc hardware yet because I have to look through my stash to see what I already have - I definitely have 9 pin shields and sockets and a new 12AX7, and am pretty sure I have a 12AY7 too.

I thought I'd try to keep track of the cost, just out of interest more than anything. I don't think any of us take up DIY because we are trying to save money, but it's still good to know what it comes to.

So far - including postage - it's cost:

$120 for the chassis (https://modulusamplification.com/Tweed-Deluxe-Style-Head-Chassis-P5411536.aspx)
$41 for tonnes of wire and resistors (lots more than I need, so hard to gauge actual cost there)
$80 for capacitors

https://i.imgur.com/zszbOtQ.jpg

Marcel
23-11-2020, 02:29 PM
Yay !! ... Welcome to the club. The pain you go through now will wash away when your newly built amp barks at you for the first time... I know it did for me on my AC18W scratch amp build.

Yeah, caps and resistors are pretty cheap when compared to tubes and transformers...

DrNomis_44
23-11-2020, 02:55 PM
A total of $241.00 actually sounds quite reasonable, given that a vintage 5E3 in reasonably decent condition would maybe cost ten times that, as Marcel said, I would like to welcome you to the DIY guitar amp club, I hope you have lots of fun building your 5E3, and if you need help, we're all here for you.


Which reminds me, I need to start doing some more work on my DIY Soldano SLO 50 amp head, I've decided that next year I will get back into doing some DIY electronics, because I have a few projects I'm itching to start working on, I'm done with futzing with my guitars.

Simon Barden
23-11-2020, 04:03 PM
Just been looking at valve prices, and they've seem to have gone up considerably since the last time I looked, which was maybe two years ago. Got some of the new Electro-Harmonix 7502 valves on order. These are supposed to be a proper recreation of the original 7502 valves, not just low noise 12AX7s badged as them. We shall see if they make any difference to the performance of my new (used) Fender 68 Custom Reverb Deluxe, which is quiet (no mains hum), but I'm sure it could be a bit quieter on the hiss front. I'm not supposed to have it until my birthday on the 29th Nov, but I have had to do a bit of testing just to make sure it works. The trem/vib circuit needs adjusting as it is rather clicky with no guitar signal going through when turned on. Unfortunately, RoHS regs mean that the European amps have a solid state vibrato board added, as the CdS opto coupler on the US versions isn't allowed over here any more. I know Cadmium is pretty toxic, but there's been enough used in Ni-Cad batteries over the years that one small opto-coupler that isn't going to get thrown away wouldn't do much harm. Interesting to note that Fender still fit the valve that's part of the bypassed circuit!

DrNomis_44
23-11-2020, 04:28 PM
I recently bought four 500g bargain grab bags of bits and pieces from my local Jaycar Electronics shop, they each cost me Au$9.99, anyway, once I got them home from the shops I opened them up and went through each bag's contents, in one of the bags I found a new and still in the box Electroharmonix EL34 tube/valve, which I might use to make a single-ended guitar amp like an AX84 High Octane next year, or, if I can buy a second Electroharmonix EL34 from Evatco, they might be matched well enough for use in my Soldano SLO 50 build.

38145

Brand new and still in it's box.


I do understand that it's unlikely that two EH EL34 tubes in separate boxes will be closely matched enough for use in a guitar amp, unless I get lucky.

JohnH
23-11-2020, 04:48 PM
Thanks guys, I'm looking forward to it. And good score on that tube, doc!

I almost certainly have some power tubes in my collection, but I figure like you say there's unlikely to be a matched pair in there anywhere, so I'll have to buy those. The tubes and transformers are going to add a fair bit to the price, and hardware all adds up. Still it'll be interesting to see what it comes in at price wise.

I'm hoping the power tubes can somehow be squeezed in as an xmas present, ha ha.

Keen to see how you go on the SLO 50 - it's on my wish list for future builds

DrNomis_44
23-11-2020, 05:39 PM
Thanks guys, I'm looking forward to it. And good score on that tube, doc!

I almost certainly have some power tubes in my collection, but I figure like you say there's unlikely to be a matched pair in there anywhere, so I'll have to buy those. The tubes and transformers are going to add a fair bit to the price, and hardware all adds up. Still it'll be interesting to see what it comes in at price wise.

I'm hoping the power tubes can somehow be squeezed in as an xmas present, ha ha.

Keen to see how you go on the SLO 50 - it's on my wish list for future builds


First item on my parts shopping-list is a new and properly-rated power transformer for my Soldano SLO 50 build, I've got a suitable one saved on my wishlist on my account with Evatco, it's going to cost me roughly about Au$200.00 or so, but I reckon it's worth it for the safety-factor alone, I don't really trust the insulation in the original power transformer I made for it.

JohnH
24-11-2020, 10:24 AM
First item on my parts shopping-list is a new and properly-rated power transformer for my Soldano SLO 50 build, I've got a suitable one saved on my wishlist on my account with Evatco, it's going to cost me roughly about Au$200.00 or so, but I reckon it's worth it for the safety-factor alone, I don't really trust the insulation in the original power transformer I made for it.

You made your own?

Transformers blow my mind to be honest - like capacitors, they seem magical. They definitely add to the cost of the build. I'd have to check again on my home computer, but I think the PT and OT together (plus postage) will be about $250

DrNomis_44
24-11-2020, 12:51 PM
You made your own?

Transformers blow my mind to be honest - like capacitors, they seem magical. They definitely add to the cost of the build. I'd have to check again on my home computer, but I think the PT and OT together (plus postage) will be about $250


Yep, I took a power transformer from a defunct reel-to-reel tape recorder, pulled it apart so that I had a cardboard bobbin and a set of iron laminations left after removing all the windings out of it, then with the help of a small book called Design Your Own Coils And Transformers, I did some maths to work out how many turns of enameled copper wire I needed for the primary and secondary windings, then I re-wound the transformer according to my calculations, surprisingly it did work first time and the voltages were close to what I wanted.

Marcel
24-11-2020, 01:30 PM
AU$250 incl postage for 2 transformers = BARGAIN.!!

I had a customer come in with a Lexicon Signature 284 that wanted it modified from USA 120VAC to Aussie 240VAC... Transformer had to be custom made by Voltran in Melbourne... Cost AU$280 plus shipping, and then add my time to fit it (and get rid of some hum issues due dud 25yo caps)... But damn, it is a very nice sounding class A tube amp at the end...

JohnH
25-11-2020, 03:58 PM
AU$250 incl postage for 2 transformers = BARGAIN.!!

I had a customer come in with a Lexicon Signature 284 that wanted it modified from USA 120VAC to Aussie 240VAC... Transformer had to be custom made by Voltran in Melbourne... Cost AU$280 plus shipping, and then add my time to fit it (and get rid of some hum issues due dud 25yo caps)... But damn, it is a very nice sounding class A tube amp at the end...

Oof, that is expensive. I feel like transformers are going to provide a world of intrigue and wallet emptying in the near future, ha ha

jonwhitear
25-11-2020, 04:41 PM
I built a stereo valve amp several years ago, and got the transformers from Edcor in the USA. Shipping’s takes a while, but at the time the we’re very competitive. Don’t know how they stack up now with the current exchange rate, or indeed if they make units suitable for a guitar amp, but they might be worth checking out.

JohnH
26-11-2020, 10:08 AM
I built a stereo valve amp several years ago, and got the transformers from Edcor in the USA. Shipping’s takes a while, but at the time the we’re very competitive. Don’t know how they stack up now with the current exchange rate, or indeed if they make units suitable for a guitar amp, but they might be worth checking out.

Good to know - I'll check them out!

JohnH
29-11-2020, 09:09 AM
Just put in an order for some more parts, so am updating the running cost:

$120 for the chassis
$41 for tonnes of wire and resistors
$80 for capacitors
$47 for turret board, stand offs, assorted hardware, and an iec socket

JohnH
09-12-2020, 04:23 PM
Have managed to organise a whole set of tubes for Xmas, which is exciting. I still need the transformers and a few other odds and ends before I can start the build, but on track to start mid-Jan when the kids are away.

Also got a new Hakko FX888D soldering station, which is a pretty big improvement on my $20 Jaycar one

Simon Barden
09-12-2020, 04:51 PM
Looks great! A worthwhile investment.

artyone
10-12-2020, 02:16 AM
In reply to an earlier posting within this thread about matched output tubes they don't necessarily need to be matched and a little research, beyond all the superstition that the world will fall apart if they aren't, is worth the effort.
Basically the criteria for basic matching is really basic and tubes can be all over the place in other ways and even a randomnly picked set of tubes that are at least new and/or NOS new will be close enough together that using them as a pair in a push pull amp ain't at all not a bad idea.
The thing is that the slight mismatch in the proprietary way of matching tubes could actually result in some quite useful sonic characteristics and the more on to it boutique builders will actually put a nice big wire wound pot between either the cathodes in a cathode biased amp or between the negative voltage feed on a... you guessed it, grid biased amp (doesn't need to be a wire wound pot here though as it's just voltage) so that two tubes working at different power levels can be brought a little closer together with the point being equalising the amount of DC sitting on the opposing windings of the primary of a OT.

Look into it as in reality you're already setting up measuring cathode currents and voltages anyway and these possibilities just make it a bit wider what we can do there.

Simon Barden
10-12-2020, 02:35 AM
However if the valves are too far adrift, then they could have very different plate dissipation values (unless you compensate for that within the circuit by allowing for individual bias adjustment so they match within normal tolerances), and so quite different power outputs. Which means that the mains hum on the DC to the power valves isn't cancelled out that well, so the amp could put out a lot of hum. You can counter this by better filtering of the DC to the power valves, but this isn't standard.

McCreed
10-12-2020, 05:23 AM
Also got a new Hakko FX888D soldering station, which is a pretty big improvement on my $20 Jaycar one

That looks like a good soldering station, and def a step up from a basic "stick"!

If you haven't already, I would recommend getting a chisel tip for it. A pencil tip (usually provided as the stock tip) will still be challenging to heat up the back of a pot no matter how high you set the temp on the base.

FWIW, my station is a 48w Duratech (Jaycar brand) and has served me well for over 10 years. Not as flash as the Hakko (password protected heat setting???) but I think it was $99 back then, up to $119 now.

OK... now go melt some lead!!!

JohnH
10-12-2020, 05:55 AM
If you haven't already, I would recommend getting a chisel tip for it.

One step ahead of you! ha ha.

I bought a few chisel tips at the same time, as everyone seemed to recommend them. I got some extra stock tips too, because it's a good size for pedal PCBs.

JohnH
02-05-2021, 08:31 AM
I've had a bit of a break from guitar/pedal/amp related activities, but I'm back to working on this amp.

I was mostly held up waiting for tubes at xmas, and then assorted hardware. It was much cheaper to buy all the nuts and bolts in bulk (and now I have heaps spare), but the shipping took forever. So, while I'd hoped to have a crack at this build in my post-xmas holiday, I didn't get the hardware til early feb!

Now I have everything except the faceplates, so I can start wiring it up.

https://i.imgur.com/xuVujif.jpg

McCreed
02-05-2021, 11:41 AM
Good to see this back in production.
Have you made a cabinet for this yet? I can't remember back that far... :o

JohnH
02-05-2021, 02:29 PM
Cabinet is high on the list of jobs to attend to before wiring is complete - the studio space is used by the kids all the time, so I don't want the amp sitting out where they could touch it, and don't have anywhere to hide it. So, having a head cabinet to screw it back into when I'm not working on it seems the safest option.

I almost have enough ply just sitting around, but need quite. I also don't have any cabinet hardware, so the plan is to buy a small sheet of ply plus handle, corners, feet and tolex next pay. I don't think it will take long to put together, based on the experience with the 2 x 12 I built. This will be much smaller!

Simon Barden
02-05-2021, 02:44 PM
Don’t forget either some metal vent grille material or some moulded plastic vents. You don’t want it overheating, as valves can put out quite a bit of heat. Keep too much of that inside the head and those electrolytic caps will dry out very quickly.

JohnH
02-05-2021, 02:49 PM
Oh yes, well spotted. I'm going to put a metal grill on the back, but need a friend to powdercoat it. I was tempted to put side vents in too, but wasn't sure if that was over kill?

Simon Barden
02-05-2021, 03:01 PM
I’d put a vent at the top and bottom of the rear panel, to allow for natural convection current cooling. Only really need to side vent if you can only fit one vent in the rear. Even then, you’d really want low and high vents. On a bigger valve amp, say 50W+, I’d be thinking about a top vent as well, but rear only should be fine on a 5E3.

McCreed
03-05-2021, 07:27 AM
I don't think it will take long to put together, based on the experience with the 2 x 12 I built.

Ahh, that's right! I thought I remembered something somewhere sometime about you and a cabinet!

That did come together quickly and nicely too. (just checked the old thread)

JohnH
03-05-2021, 10:18 AM
Thanks McCreed! I'm pretty happy with how the cab came out, and definitely happy with the sound.

I think I need to build a 1x12 though - I had to lug the 2x12 up a steep flight of stairs in a warhouse/studio last month and honestly it was terrible, ha ha ha

McCreed
03-05-2021, 12:05 PM
I think I need to build a 1x12 though - I had to lug the 2x12 up a steep flight of stairs in a warehouse/studio last month and honestly it was terrible, ha ha ha

Yes, one reason I really like my Fender Tone Master Deluxe Reverb... 10.4kg!
Plenty loud enough for me, and sounds bloody brilliant.

And who thought a studio on the second floor without a lift was a good idea????

Simon Barden
03-05-2021, 02:44 PM
You could always swap out the heavy V30s (4.7kg each) for some neodymium magnet speakers. I like the Celestion Neo Creambacks. Weighs almost nothing in comparison (1.9kg each). Make two 1x 12” cabs and put the V30s in these as they’d be far more manageable. That would make the cab 5.6kg lighter, a considerable weight saving. Though if the cab chassis is really heavy, then you probably wouldn't notice much difference. Just a thought as you’ll probably be buying one new speaker anyway.

JohnH
03-05-2021, 08:08 PM
And who thought a studio on the second floor without a lift was a good idea????

Well, to be fair it is an artist's studio/gallery, so they probably weren't expecting people to drag amps and cabs to their exhibitions, ha ha ha


You could always swap out the heavy V30s (4.7kg each) for some neodymium magnet speakers. I like the Celestion Neo Creambacks. Weighs almost nothing in comparison (1.9kg each). Make two 1x 12” cabs and put the V30s in these as they’d be far more manageable. That would make the cab 5.6kg lighter, a considerable weight saving. Though if the cab chassis is really heavy, then you probably wouldn't notice much difference. Just a thought as you’ll probably be buying one new speaker anyway.

Good thinking Simon, I'll check them out

Simon Barden
03-05-2021, 08:13 PM
Other neo speakers are available from Celestion and other makes like Eminence. They aren't cheap because neodymium is more expensive than a standard ceramic ferrite magnet (though you need less of it). On a par with the cheaper alnico speakers.

The Neo Creamback has a nice sound, less mid-forward than the V30s. Less efficient at 97dB vs 100dB for 1W input, but that does mean you can turn the amp volume up just that little bit more. Still go nice and loud though if necessary.

JohnH
19-05-2021, 02:15 PM
I've been a bit slack at posting progress pics, but I've managed to get quite a lot done. The amp is pretty much all wired up - I'm just waiting on the faceplates to arrive so I can connect the IEC socket.

I've glued the headshell together, but haven't routed the roundover on the outside edges, or attached the internal bracing. I haven't got the tolex or other hardware for the shell yet either, so I can't do much more there.

Once all that's done I just need to buy a variac and build a current limiter and I can begin startup procedures!

An update on the cost tally:
$120 for the chassis
$41 for wire and resistors
$80 for capacitors
$47 for turret board, stand offs, assorted hardware, and an iec socket
$163 for tubes
$30 for timber for the head

Andy40
20-05-2021, 03:17 AM
Hey John, Thanks for the updates. I think I ended up costing about $900 - $1000 in the end with all the bits including speaker, transformer, cabinet, tolex, grill cloth and the cabinet hardware. I wasn't trying to spare expenses though.

Definitely give some thought into replacing the ceramic 5W 270 Ohm resistor with a 10Wone. It reduces the heat a lot.

I also put in a bleed resistor to make it much safer to work on the amp so I don't have to keep bleeding the caps every time I need to work on it.

JohnH
20-05-2021, 06:55 AM
Thanks for the tips Andy!

I did actually put in a 10W resistor, based on the same advice I'd read in another forum.

I think I forgot to mention too, while I was ordering parts I decided to swap from the mojotone layout to the Rob Robinette one:

40613

Simon Barden
20-05-2021, 05:24 PM
I certainly think the Robinette one is a lot safer electrically, with the live going through the fuse and then the switch. The Mojotone one has the live fused and the neutral switched, which works but is effing unsafe in my eyes! It may be original, but original doesn't always mean good!

The Mojotone also has a pointless ground switch shown, which is there only for appearances sake as it doesn't actually work, with a capacitor used for looks only. Your chassis probably has a hole cut for it though. Some people use the switch to add in a negative feedback option. https://robrobinette.com/5e3_Modifications.htm#Switched_Negative_Feedback

JohnH
21-05-2021, 06:53 AM
Yeah, I did a lot of reading which led me to the same conclusion. I'll have to get some pics this weekend, but I've got the live and neutral both switched, and obviously deleted the unnecessary ground switch and capacitor.

I realised after it arrived that the chassis has an IEC hole large enough for a socket with inbuilt fuse, so I think I will use one of those. It removes some extra wires and frees up another hole in the front of the chassis.

I'm keen to try the negative feedback option, but wanted to build it stock first so I can concentrate on making it work before I start changing anything. The chassis I have has the ground switch hole, but it also has a few extra holes at the rear, so there's lots of options for adding things later if needed

JohnH
04-07-2021, 06:40 PM
Finally got the faceplate and wired in the iec socket.

I went through the rob robinette start up procedure (although to be fair I was a bit lazy and didn't build a light bulb limiter).

Voltages seemed ok so I plugged in a guitar. It sounds great but started red plating, so stopped and did voltages again and it seems I accidentally skipped V2 pin 7, which should be 17v but gives me 3v

Bit too tired to figure it out tonight. Will post pics and voltages later for anyone who has any ideas

JohnH
04-07-2021, 06:53 PM
I can't edit that last post for some reason, but I should add heaters measured 6.1 across the pins, not referenced to ground.

I did have a bit of a weird thing measuring the heaters though. I measured the high voltage secondaries with black probe on the chassis and red probe on the pin (and got a stable reading of 350) but when I did the same for the heaters it just kept rising way past the 3v I expected (I took the probe off when it hit 45v because it freaked me out). Measuring across the pins gave me 6.1 which seems reasonable but I didn't think I'd get a runaway reading with the black probe to ground?

Is that just me missing something obvious?

JohnH
04-07-2021, 06:54 PM
Oh, now it looks like my voltages have disappeared lol. I'll try again tomorrow, ha ha ha

DrNomis_44
04-07-2021, 07:51 PM
Oh, now it looks like my voltages have disappeared lol. I'll try again tomorrow, ha ha ha


Were you measuring the voltages with the black probe firmly connected to the chassis?, if so, could be that the mains fuse blew for some reason, I'd investigate that if that's the case.

Just had a quick look at the Rob Robinette eyelet board layout you posted, and it appears that both the power amp ground-bus and the preamp ground-bus don't have any ground wires going to the chassis, which might be why you're getting funny voltage readings, but then-again I might be mistaken.

JohnH
04-07-2021, 08:06 PM
Were you measuring the voltages with the black probe firmly connected to the chassis?, if so, could be that the mains fuse blew for some reason, I'd investigate that if that's the case.

Just had a quick look at the Rob Robinette eyelet board layout you posted, and it appears that both the power amp ground-bus and the preamp ground-bus don't have any ground wires going to the chassis, which might be why you're getting funny voltage readings, but then-again I might be mistaken.

Oh, no sorry - I meant that I'd posted the voltages but the post has disappeared!

I'll post them again now

JohnH
04-07-2021, 08:12 PM
Voltages, for those interested:

Wall voltage - 246V

Filiments - 6.1 V

B+1 - 368
B+2 - 332
B+3 - 241

Rectifier
Pin 2 - 8 - 4.7V across the pins
Pin 4 - 350
Pin 6 - 350

V1
1 -120
2 -
3 - 2
4 - fil
5 - fil
6 - 120
7 -
8 - 2
9 - fil

V2
1 - 155
2 -
3 - 3
4 - fil
5 - fil
6 - 193
7 - 3
8 - 45
9 - fil

V3
1 -
2 - fil
3 - 365
4 - 334
5 -
6 -
7 - fil
8 - 22


V4
1 -
2 - fil
3 - 365
4 - 334
5 -
6 -
7 - fil
8 - 22

JohnH
04-07-2021, 08:13 PM
I'm using this voltage chart to check against:

40934

Simon Barden
04-07-2021, 08:59 PM
I can't edit that last post for some reason, but I should add heaters measured 6.1 across the pins, not referenced to ground.

I did have a bit of a weird thing measuring the heaters though. I measured the high voltage secondaries with black probe on the chassis and red probe on the pin (and got a stable reading of 350) but when I did the same for the heaters it just kept rising way past the 3v I expected (I took the probe off when it hit 45v because it freaked me out). Measuring across the pins gave me 6.1 which seems reasonable but I didn't think I'd get a runaway reading with the black probe to ground?

Is that just me missing something obvious?

Is the heater negative side connected to ground? If not the differential voltage can remain constant but the voltages relative to ground will float and could read up to almost any voltage present in the amp. If it's not grounded, then it either needs grounding or you need both sides of the feed tied to ground through their own same-value resistors or a more complex circuit that adds about 20v dc to the ac voltage, which can reduce heater-induced hum. You don't want the circuit floating as you can then exceed the maximum heater to cathode voltage and damage the valves.

DrNomis_44
05-07-2021, 09:11 AM
At a glance, the voltages on the valve pins do look pretty normal, or pretty much what you'd expect, so, looking good so far, if the power transformer doesn't have a center-tap wire for the 6.3V AC heater supply for valves V1 to V4, you can make a virtual center-tap by using two resistors of same value, say 100 Ohms, connected as per this diagram:

40940


Sometimes the heater-supply is deliberately made to float at a voltage above chassis ground in order to reduce the heater-cathode voltage so that no short-circuit or leakage occurs, from memory, the maximum heater-cathode voltage rating for a 12AX7 is about 100V or so, but I could be wrong, in any case, the maximum heater-cathode voltage should not be exceeded.

JohnH
05-07-2021, 10:02 AM
Ah, that's good to know Doc.

I'm actually wondering if the red glow is even unusual. I've never looked closely at a power tube operating normally, and these pics from Rob Robinette's site make me wonder if all I'm seeing is cathode glow. For some reason I just assumed that the only glow would come from the little bits at the top (which I assumed were the heaters, but honestly don't know).

My tubes:

https://i.imgur.com/hTgiQtY.jpg
https://i.imgur.com/aDReu6V.jpg

Pics from Rob's site:

40947
40948

JohnH
05-07-2021, 10:03 AM
I tried getting a pic in the dark, but this was the best I could do...

https://i.imgur.com/ztIiHpq.jpg

DrNomis_44
05-07-2021, 10:42 AM
I tried getting a pic in the dark, but this was the best I could do...

https://i.imgur.com/ztIiHpq.jpg

That red glow from the center of the tubes/valves is the filaments, or heaters glowing, which is normal, in order for a tube/valve to operate properly, the cathode needs to be heated so it glows a dull orange colour, when this happens electrons will boil-off the surface of the cathode much like water-vapour boils-off the surface of boiling water.

If you see a blue-coloured fluorescence on the inside of the glass envelope of the 6V6 power tubes while they are operating, that's normal and is caused by a phenomenon known as secondary emissions, basically the electrons from the cathode hit the anode with enough force to knock other electrons out of their orbits.


On the other hand, if you see the anode of one of the 6V6 power tubes glowing a cherry red colour, that's called "Red-Plating" and it indicates that the 6V6 tube is conducting too much current.

JohnH
05-07-2021, 10:48 AM
Excellent! In that case the amp is a total success, and I was worrying for nothing, ha ha. Thanks doc.

Now to tolex the box and then start on the next one.

I thought I'd have the box done by yesterday, but somehow managed to order the wrong feet, handles and corners. I have no idea what I was doing, but clearly not concentrating.

DrNomis_44
05-07-2021, 10:50 AM
Excellent! In that case the amp is a total success, and I was worrying for nothing, ha ha. Thanks doc.

Now to tolex the box and then start on the next one.

I thought I'd have the box done by yesterday, but somehow managed to order the wrong feet, handles and corners. I have no idea what I was doing, but clearly not concentrating.


Have you tried plugging a guitar into the amp chassis with a speaker connected to see if the amp passes good sound?

JohnH
05-07-2021, 11:00 AM
Yeah, it sounds great. I was playing it when I noticed the red glow and assumed I'd wired something wrong

DrNomis_44
05-07-2021, 11:12 AM
Yeah, it sounds great. I was playing it when I noticed the red glow and assumed I'd wired something wrong

Was there a loud hum with the red glow?, if so, that would indicate red-plating, red-plating is usually caused by a leaky coupling capacitor on the grid of the power tube, or a loss of the -V bias supply, or sometimes by the power tube itself if it has an internal fault.


https://www.ampvalves.co.uk/red-plating-guitar-amplifier-valves/


But, if the amp is sounding really good especially if you crank it up, it should be fine.


Note that some high-power radio transmitter tubes are deliberately designed to be operated in a condition where they are red-plating.

JohnH
05-07-2021, 11:25 AM
Nah, no hum. A little bit when the tone is all the way up and the volume was up but otherwise its really quiet.

DrNomis_44
05-07-2021, 11:31 AM
Nah, no hum. A little bit when the tone is all the way up and the volume was up but otherwise its really quiet.

Sounds like your amp is working like it's supposed to.

JohnH
05-07-2021, 12:05 PM
Well, that's a relief! It's very cool to be able to play one I've built myself. It seemed impossible a year or two ago.

I think the next one will be an 18w build, but I think I'll buy a pre built head cabinet for it. It's satisfying making your own but I'm a bit too time poor at the minute

JohnH
05-07-2021, 04:24 PM
An update on the cost tally. I realised I left off the transformers before, which is a huge chunk of the cost!

$120 for the chassis
$41 for wire and resistors
$80 for capacitors
$47 for turret board, stand offs, assorted hardware, and an iec socket
$163 for tubes
$200 OT
$90 PT
$30 for timber for the head
$60 for tolex
$40 for handles, feet and corners

$871 Total

I didn't include the cost of faceplates because I actually can't remember how much they were, but say another $50 or so. The next build I'll get a chassis that comes with faceplates so it's one less thing to think about.

Also didn't include the cost of the variac, etc (because tools don't count!) and didn't include the satisfaction of the build (because it's priceless!)

JohnH
09-07-2021, 01:35 PM
Even though I still haven't really finished this build yet, I've started planning the next.

The next build will almost certainly be an 18W, but I came across this site today and now have a future goal to work to: http://c3amps.com/

It is way beyond me at the minute, but good to have something to aim for!

JohnH
15-07-2021, 03:56 PM
I realised I forgot a gut shot!

It's a bit embarassing sharing chassis shots after some of the amazing wiring jobs I've seen online. Definitely need to be neater next time...

https://i.imgur.com/zLpezPS.jpg

McCreed
15-07-2021, 06:15 PM
I realised I forgot a gut shot!

It's a bit embarassing sharing chassis shots after some of the amazing wiring jobs I've seen online. Definitely need to be neater next time...

Never mind a guts shot, I don't think we've seen the outside yet! (or haven't you got the cabinet for it yet?)

As for the soldering, I know what you mean. There are some out there that have taken soldering to an artform (I'm not one of them!).
I don't see anything that resembles wads of chewing gum in your work, so that gets points from me!

Simon Barden
15-07-2021, 07:01 PM
It's not bad at all. I've seen far worse on some boutique amp pictures.

Unless you really understand how all the circuits interact, it's probably best not to simply dress all the wires so that they all look neat and run together in straight lines, as you can easily induce a lot more noise in the amp.

Getting the heater supply wires well twisted and away from the other cabling is probably the most important thing, and it looks like you've done that.

JohnH
15-07-2021, 07:59 PM
Never mind a guts shot, I don't think we've seen the outside yet! (or haven't you got the cabinet for it yet?)

As for the soldering, I know what you mean. There are some out there that have taken soldering to an artform (I'm not one of them!).
I don't see anything that resembles wads of chewing gum in your work, so that gets points from me!

Still working on the box! The shell is made and I made a grill for the back, but haven't had a chance to wrap it in tolex yet. The only clean space I have to work in is the lounge room and the adhesive stinks, so I need to wait til no one else is home for a day lol

JohnH
15-07-2021, 08:01 PM
Thanks Simon.

I did my best with the heaters but its fiddly. Next time I think I have a better idea of how to go a out it, but we will see! Going to order a chassis for the next build tomorrow

McCreed
16-07-2021, 06:47 AM
Going to order a chassis for the next build tomorrow

So the "buy another one before the last one is finished thing" applies to amp building as well?

Good to know...
:o

JohnH
16-07-2021, 11:40 AM
So the "buy another one before the last one is finished thing" applies to amp building as well?

Good to know...
:o

It appears so! Just ordered the 18w chassis lol

Andy40
16-07-2021, 02:52 PM
A TMB??? ;)

Currently building the cabinet for mine....scheduled the build for my holidays in December this year!:cool:

JohnH
16-07-2021, 04:52 PM
A TMB??? ;)

Currently building the cabinet for mine....scheduled the build for my holidays in December this year!:cool:

Yeah, TMB! How are you going with the cabinet for yours? I'd love to see the progress

Andy40
17-07-2021, 03:18 AM
I get about an hour a week or fortnight to work on it. It's slowly coming together. I'll take some pics this weekend and post them. It seems rather big compared to a 5E3 Cab and the Cab design is soo different. Its been fun though!:)

JohnH
19-07-2021, 06:50 PM
What layout/schematic are you using? I spent ages reading through the 18 watt forum and got a bit overwhelmed lol. Ended up settling on the valvestorm layout for reasons I've since forgotten.

JohnH
19-07-2021, 06:53 PM
I spent a bit of time playing with the amp today and got to crank it more than I have previously. Its very loud, ha ha.

I thought I had a hum issue with the normal input but late in the day I swapped guitars to my pitbull LP and the hum disappeared. After a bit of playing around it seems like my Ibanez is introducing the hum, so that is a fun bit of troubleshooting for another day

Simon Barden
19-07-2021, 11:01 PM
Ibanez what? Humbuckers or single coils?

JohnH
20-07-2021, 10:28 AM
Ibanez what? Humbuckers or single coils?

Oh, should have said. Humbuckers - it's this exact guitar (http://www.dwmusic.com.au/ibanez-iron-label-rgdix6pb-surreal-black-burst-electric-guitar-used-i161008019) (an impulse buy last year while hanging out at DW with my brother)

It's a great guitar - love the shape of the neck, etc. I've never noticed a hum problem before, but then I also tend to run it through a bunch of pedals so that's not surprising

Andy40
20-07-2021, 04:12 PM
What layout/schematic are you using? I spent ages reading through the 18 watt forum and got a bit overwhelmed lol. Ended up settling on the valvestorm layout for reasons I've since forgotten.

Good question John! Not sure yet. I was a bit bamboozled too and since my birthday isn't until December I have some time to muddle through which schematic I would use.

Andy40
20-07-2021, 04:30 PM
Cabinet is coming along nicely too got the corners routed on the weekend.https://uploads.tapatalk-cdn.com/20210720/e30ea289440a8c0b4883d50f658b275a.jpghttps://uploads.tapatalk-cdn.com/20210720/c3243a0634c9e1ac2407c1540a45f000.jpghttps://uploads.tapatalk-cdn.com/20210720/7e750a29cfc56539c09e6b9639e98a34.jpg

Sent from my Pixel 4a using Tapatalk

McCreed
20-07-2021, 06:15 PM
Looking good Andy.

I should commission you to build a 1 x 12 cabinet for my Quilter Superblock US amp.

I could offer you free harmonica lessons for part payment!

JohnH
20-07-2021, 06:29 PM
Looks great Andy! Now I'll be hanging out til December to watch your build, ha ha

Simon Barden
21-07-2021, 12:01 AM
Oh, should have said. Humbuckers - it's this exact guitar (http://www.dwmusic.com.au/ibanez-iron-label-rgdix6pb-surreal-black-burst-electric-guitar-used-i161008019) (an impulse buy last year while hanging out at DW with my brother)

It's a great guitar - love the shape of the neck, etc. I've never noticed a hum problem before, but then I also tend to run it through a bunch of pedals so that's not surprising

Humbuckers, so shouldn’t be noisy except with a lot of gain. Black hardware, so I’d first check for a good ground to string connection. The bridge ground wire may have been pulled and now isn’t touching a scraped bit of the bridge.

Otherwise general ground and signal connection checking. I’d probably squirt some contact cleaner in the barrel jack (looks like it has one) and check that’s done up tight.

JohnH
21-07-2021, 07:34 AM
Yeah, I assumed the bridge ground was loose, but checking it last night it seems fine.

I played around with it plugged into the amp again last night and the hum was gone. The only difference I can see between the Ibanez and the LP build is the LP has all shielded cavities, so I wonder if something was getting into the Ibanez but not into the LP (or perhaps an intermittent grounding issue with the Ibanez that wasn't immediately obvious when I looked last night).

The room I was playing in is definitely not electrically quiet - there's computers, wifi, all sorts. I turned everything off to chase the hum, but maybe one of those things was having it's own issues that day - who knows!

Rabbitz
21-07-2021, 10:21 AM
Don't forget to look outside for noise sources...

Until a couple of days ago we lived across the road from some 133kV power lines and depending on the humidity, weather and length of time since it last rained on the insulators it would make my single coil ST-1 unplayable.

JohnH
22-07-2021, 07:41 AM
Don't forget to look outside for noise sources...

Until a couple of days ago we lived across the road from some 133kV power lines and depending on the humidity, weather and length of time since it last rained on the insulators it would make my single coil ST-1 unplayable.

Good thinking! I'll keep an eye out if it happens again

JohnH
22-07-2021, 07:45 AM
Got this in the mail yesterday, so the 18w build is officially underway.

https://i.imgur.com/IZCja9b.jpg

I've decided to do two parallel builds, so I'll also be buying parts to build a Champ micro: https://robrobinette.com/Champ_Micro.htm

I want to try to build a small amp as a gift for someone for their 30th next year, so thought I'd see how the champ goes. Just as a kind of personal challenge I'm going to try to build the champ from the schematic using a mix of point to point and tag strips (we will see how it goes lol)

McCreed
22-07-2021, 08:41 AM
I want to try to build a small amp as a gift for someone for their 30th next year...

Coincidentally I too have a birthday coming up (eventually). hint hint :o

Andy40
25-07-2021, 05:26 AM
Still waiting for my chassis.....

That Champ micro project has caught my interest!

JohnH
25-07-2021, 07:08 AM
Coincidentally I too have a birthday coming up (eventually). hint hint :o

Ha ha ha ha


Still waiting for my chassis.....

That Champ micro project has caught my interest!

Any idea how long til it arrives? I still have to buy a chassis for the champ, but was thinking of getting one of those Hammond project boxes that has a steel cage

JohnH
25-07-2021, 07:10 AM
I was planning on saving myself some time on the 18w build and buying a pre-made head shell and to use the face and back plates that came with the Evatco chassis, but then last night I started thinking about tolex colours, and as invariably happens I think I've changed my mind and decided to make the shell and new plates lol

McCreed
26-07-2021, 07:14 AM
I'm not ready to take on an amp build (likely never will) but I'm planning a extension cabinet build (which I've discussed with Andy40 through PM's) but I've discovered a pattern that is common throughout anything I build.
I feel the need to have every little piece, part, wire and tiniest screw in my possession before commencing anything beyond the planning stage.

Sometimes it can't be helped due to supply issues etc, but there's something in my brain that says I need to have A to Z first!
Is it just me, or do you guys find this happening?

I've experienced this with guitar builds too but sometimes a plan change occurs mid-build and then I have no choice but to wait.
Maybe I really do have some form of OCD...

DrNomis_44
26-07-2021, 11:19 AM
I'm not ready to take on an amp build (likely never will) but I'm planning a extension cabinet build (which I've discussed with Andy40 through PM's) but I've discovered a pattern that is common throughout anything I build.
I feel the need to have every little piece, part, wire and tiniest screw in my possession before commencing anything beyond the planning stage.

Sometimes it can't be helped due to supply issues etc, but there's something in my brain that says I need to have A to Z first!
Is it just me, or do you guys find this happening?

I've experienced this with guitar builds too but sometimes a plan change occurs mid-build and then I have no choice but to wait.
Maybe I really do have some form of OCD...


I'm a bit like that too, usually I start with working-out what I want to build, then I grab some A4 printer paper and a pen, or pencil, then I write out a comprehensive list of all the parts I'll need, and then it's off to my local Jaycar Electronics shop if I'm building a pedal, or, I go online and visit the Evatco website if I'm doing any amp-building/repairing stuff, I tend to wait till I've got all the bits and pieces I need before starting the build/repair process.

DrNomis_44
26-07-2021, 11:48 AM
Got this in the mail yesterday, so the 18w build is officially underway.

https://i.imgur.com/IZCja9b.jpg

I've decided to do two parallel builds, so I'll also be buying parts to build a Champ micro: https://robrobinette.com/Champ_Micro.htm

I want to try to build a small amp as a gift for someone for their 30th next year, so thought I'd see how the champ goes. Just as a kind of personal challenge I'm going to try to build the champ from the schematic using a mix of point to point and tag strips (we will see how it goes lol)

Nice!....I'm definitely going to be following the build-process, if you ever need any help with it, let me know.

Simon Barden
26-07-2021, 03:53 PM
Sourcing parts with one or two day delivery is a lot easier here in the UK, so I normally only need the main components to hand before I start something.

JohnH
26-07-2021, 04:35 PM
I'm not ready to take on an amp build (likely never will) but I'm planning a extension cabinet build (which I've discussed with Andy40 through PM's) but I've discovered a pattern that is common throughout anything I build.
I feel the need to have every little piece, part, wire and tiniest screw in my possession before commencing anything beyond the planning stage.

Sometimes it can't be helped due to supply issues etc, but there's something in my brain that says I need to have A to Z first!
Is it just me, or do you guys find this happening?

I've experienced this with guitar builds too but sometimes a plan change occurs mid-build and then I have no choice but to wait.
Maybe I really do have some form of OCD...

Hmm, I've never really thought about it, but I don't think I'm like that at all lol. I think I build the way I paint - kind of reactive, just seeing what looks good as I go, or changing ideas as I build/read/think about it. At least when it comes to aesthetic choices - circuit design is a different thing, and I'm very envious of people who can modify a circuit on the fly.

JohnH
26-07-2021, 04:37 PM
Nice!....I'm definitely going to be following the build-process, if you ever need any help with it, let me know.

Thanks Doc! I'll definitely try to post better progress updates than I did with the 5E3.

JohnH
03-08-2021, 09:48 AM
I'm still waiting on corners and feet, but I got impatient and decided to build the rest of the box anyway.

I had read that the ivory and white tolex are hard to do because they show up all your mistakes, and it was v true lol. The corners are pretty dodgy, but they'll get covered. I accidentally tore a bit at the back, and had a whole host of other issues. It's pretty amateur hour up close, but looks good from about 1m away, ha ha

41159

DrNomis_44
03-08-2021, 10:12 AM
I'm still waiting on corners and feet, but I got impatient and decided to build the rest of the box anyway.

I had read that the ivory and white tolex are hard to do because they show up all your mistakes, and it was v true lol. The corners are pretty dodgy, but they'll get covered. I accidentally tore a bit at the back, and had a whole host of other issues. It's pretty amateur hour up close, but looks good from about 1m away, ha ha

41159


I think it looks great, the tolex will eventually get a bit dinged, and scratched-up over time anyway, so I wouldn't worry about it too much if I were you, I did all the green pool table felt covering on my tube amp head all by myself, so I know how hard it is to get the corners right, I think you did a pretty good job of it.

JohnH
03-08-2021, 10:32 AM
Yeah, I'm not really worried about it, but I did think while i was doing it that I better not give up my dayjob!

dozymuppet
03-08-2021, 10:57 AM
Looks very cool so far!

Rabbitz
03-08-2021, 02:07 PM
Meh, if anyone asks chalk it up to "battle-damage" or to be trendy "relicing" :D

Simon Barden
03-08-2021, 02:53 PM
It's pretty amateur hour up close, but looks good from about 1m away, ha ha

41159

It looks good from over 10000 miles away!

McCreed
03-08-2021, 04:34 PM
Looks good John.
There's a reason I am doing my 1 x 12 cabinet with stain and poly!

I have also publicly stated "I'm going for a rustic look" so that automatically allows me a lot of grace!

Simon Barden
03-08-2021, 05:00 PM
Maybe some straw thatch and a few beams?

JohnH
04-08-2021, 06:41 AM
Looks good John.
There's a reason I am doing my 1 x 12 cabinet with stain and poly!

I have also publicly stated "I'm going for a rustic look" so that automatically allows me a lot of grace!

We did our kitchen with a 'rustic' aesthetic for the same reason. My dad was helping with the tiling, and kept scoffing when we'd say we were going for rustic, but afterwards he admitted it allowed a lot of leeway and made the whole thing a lot less stressful, ha ha ha

JohnH
23-12-2021, 12:49 PM
Man, it's been awhile since I've been on the forum!

We got hit with lockdown a week after I last posted, and I haven't had a chance to work on any 'for fun' projects since (that home-schooling/wfh combo really hits hard)

I figure the Xmas break is a good time to finish this 18W build (though I realised an order for parts I made in August never turned up, and I didn't notice because life was so chaotic! - they're re-posting it, so hopefully it will be here soon)

https://i.imgur.com/jjxq2U1.jpg

https://i.imgur.com/Jevp2ou.jpg

McCreed
23-12-2021, 06:34 PM
Good to see you back at it John!

Marcel
24-12-2021, 04:00 PM
Hey John,

Was admiring your handy work in the pic you posted, and found a point of concern. The tabs on your big electrolytic cap in the photo seem a bit to close for comfort to the chassis. It may be a optical illusion but I thought I'd mention it, particularly as the -ve will be earth but the two +ve terminals will be at something near 400VDC. In my books the greater the distance they can be from the chassis the better. It may be a simple a fix as rotating the cap in its mount until the +ve terminals are as far away from the chassis as attainable.

Simon Barden
24-12-2021, 04:51 PM
A good point well made, Marcel.

Simon Barden
24-12-2021, 04:53 PM
It's probably worth taking a few more photos of the wiring so far, in case anyone can spot anything else that needs attention whilst it's easy to rectify.

Simon Barden
24-12-2021, 05:00 PM
E.g. when soldering the turrets, I'd space out the transformer-end electrolytic cap from the 5W resistor next to it. That resistor will get warm, and electrolytics will dry out faster when warm. Make sure that resistor is well off the board and has as much space around it as possible.

JohnH
25-12-2021, 03:10 PM
Good call Marcel, though in this case it's an optical illusion - here's a better pic (I can't space them further from the chassis than this)

https://i.imgur.com/5rjWQmL.jpg

Will definitely post build pics as I go. Nothing is soldered on the turret board yet, and the legs of the components haven't been trimmed - I'm just setting them out to make sure the layout works (I'm working from the Valvestorm 18W TMB layout, but have an 18W turret board with slightly different layout, so I'm taking it slow to make sure my adjustments still match the valvestorm schematic)

JohnH
25-12-2021, 03:21 PM
It just occurred to me it may not have been an optical illusion, but possibly I took the photo before I tightened everything up!

In any case, suggestions and observations are always welcome; I want to build it as well and as safely as possible!

Marcel
26-12-2021, 04:49 AM
Yes, it it hard to know the state of play in any photo unless you are told so all you can do is make an observation...

That last pic looks fine in my books. Keep the blob soldering to a minimum and you should be sweet.

JohnH
04-01-2022, 06:21 AM
I just had this super fun parcel arrive in the post (ordered from here) (https://www.aliexpress.com/item/10000349668429.html?spm=a2g0o.productlist.0.0.3eae 66a65jNMlP&algo_pvid=f953cac9-52aa-4d08-b21a-dc1c8b245b70&algo_exp_id=f953cac9-52aa-4d08-b21a-dc1c8b245b70-0&pdp_ext_f=%7B%22sku_id%22%3A%2220000000180682717%2 2%7D&pdp_pi=-1%3B181.93%3B-1%3BAUD+204.83%40salePrice%3BAUD%3Bsearch-mainSearch).

I only ordered it a week ago, so it came quite quickly. It was a bit of a gamble, as the dimensions on the site don't show the cut out size for the faceplates. Thankfully it looks like it's a perfect fit - I might just need to get faceplates that are 5mm taller than the ones that came with the chassis, but I was going to get new plates anyway so that's not a huge drama.

https://i.imgur.com/6phJx3r.jpg

JohnH
12-01-2022, 10:59 AM
Just double checking (as transformer wiring continues to confuse me), will this wiring work if I have one of these 120v indicator lights (https://au.element14.com/dialight/656-1105-303f/led-indicator-panel-12-7mm-red/dp/2673632)?

The transformer I have has 120 and 240 v primaries, and so far I haven't found a 240 v light that I like the look of.

I realised I should have labelled my drawing better, but I hope it makes sense? Indicator on the left, dpst switch on the right.

https://i.imgur.com/2RvN0wc.jpg

Simon Barden
12-01-2022, 03:45 PM
Have you first checked with a meter that the primary is one single tapped winding rather than two separate sets of windings? You need the primary to act as a voltage divider for it to work at all, but if the windings are separate, then it won't.

Assuming the windings are all connected, there's something inside of me that says it's wrong to do it like that, but I can't think of any logical reason why (for the moment at least).

Surely it's more a case of finding a suitable 240v bulb to fit a 120v holder? I'm sure Fender don't use different jewel lights for their 120v and 240v versions, just different bulbs inside them.

JohnH
12-01-2022, 04:58 PM
Thanks Simon - I'll double check with a meter tomorrow.

I'm sure I've read of someone else doing it like this, but I can't find it again (and I don't trust my memory)

Happy to keep looking for a nice 240v light if necessary, and obviously I can also wire in one I don't like as an interim until I find one I do!

Simon Barden
12-01-2022, 05:17 PM
I know this is in the UK but here are a number of different coloured jewel lights to fit a standard Fender bulb holder along with a 230/240v bulb:

https://www.hotroxuk.com/amplifier-parts-service-equipment-294-0/amplifier-jewel-7475-0.html

Or maybe you want something very different? However I'd expect most jewel lights are threaded to screw into that standard bulb holder.

McCreed
12-01-2022, 05:41 PM
I know this is in the UK but here are a number of different coloured jewel lights to fit a standard Fender bulb holder along with a 230/240v bulb:

https://www.hotroxuk.com/amplifier-parts-service-equipment-294-0/amplifier-jewel-7475-0.html

Or maybe you want something very different? However I'd expect most jewel lights are threaded to screw into that standard bulb holder.

There are both metric and imperial threaded lamp holders, so you obviously need the appropriately threaded jewel.
I can't remember what the diameter and thread count is for the imperial (Fender) ones now. It's been many years since I dealt with the lamps and jewels.

A lot of modern amps have switched to LED now. Which is kind of sad, but I guess the way of "progress".
I know they'll use an LED that changes colour to discern between stand-by and on.
NOT that you want an LED on a vintage-style hand-wired amp!!! I was just pointing it out...

JohnH
13-01-2022, 08:33 AM
Ahh, excellent, thanks guys.

I do like the fender lights, but don't like the Marshall ones. I was looking to see if there was an alternative neon/LED similar to the Marshall one but, well, nicer. The only one's I liked were the 120v ones I linked to above.

I didn't realise you could get 240 v bulbs for the fender lamp holders. That probably solves it for me tbh.

Simon Barden
13-01-2022, 05:22 PM
If you can get them as standard in the UK, I can't see any reason why you can't get them easily in Australia.

Marcel
16-01-2022, 07:41 AM
Technically your drawing can be correct. As was pointed out the primary 240vac winding needs to be one winding with a 120vac tap.... or two 120vac winding's that need a bridge between them.

A point to note about your switch. For it to have both active and neutral pass thru it the switch MUST have a physical barrier between any active and neutral terminals. By physical barrier it can just be a bit of plastic or other non-conductive material that runs all the way down the center of the switch..... If you can use a screwdriver or bare piece of wire and can make a short circuit type contact between any of your intended active and neutral terminals then your switch is definitely not suitable to switch both active and neutral at the same time. Despite any rating labels No physical barrier means it can only be used to switch one or the other but NEVER both..... To add insult to injury in Australia if a no physical barrier main power switch is discovered to be the possible cause of a house fire all insurance companies are well within their rights to refuse any resultant claim, and decent fire investigators know to look for such things.

JohnH
16-01-2022, 10:19 AM
That's really good to know, thanks Marcel (where would I be without you!)

I actually didn't know those switches existed - I assume you mean one like this? - https://au.rs-online.com/web/p/toggle-switches/8610298

McCreed
16-01-2022, 05:00 PM
I just had this super fun parcel arrive in the post (ordered from here) (https://www.aliexpress.com/item/10000349668429.html?spm=a2g0o.productlist.0.0.3eae 66a65jNMlP&algo_pvid=f953cac9-52aa-4d08-b21a-dc1c8b245b70&algo_exp_id=f953cac9-52aa-4d08-b21a-dc1c8b245b70-0&pdp_ext_f=%7B%22sku_id%22%3A%2220000000180682717%2 2%7D&pdp_pi=-1%3B181.93%3B-1%3BAUD+204.83%40salePrice%3BAUD%3Bsearch-mainSearch).

I only ordered it a week ago, so it came quite quickly. It was a bit of a gamble, as the dimensions on the site don't show the cut out size for the faceplates. Thankfully it looks like it's a perfect fit - I might just need to get faceplates that are 5mm taller than the ones that came with the chassis, but I was going to get new plates anyway so that's not a huge drama.

https://i.imgur.com/6phJx3r.jpg

I don't know how I missed this!
That's a way cool looking enclosure. Now I really get the purple mica tele build!

(you're going to need a purple tolex extension cabinet now)

Marcel
16-01-2022, 08:27 PM
That's really good to know, thanks Marcel (where would I be without you!)

I actually didn't know those switches existed - I assume you mean one like this? - https://au.rs-online.com/web/p/toggle-switches/8610298

Yes, The switch in the link complies due the barrier between the two sets of spade terminals.

JohnH
17-01-2022, 05:36 AM
(you're going to need a purple tolex extension cabinet now)

I've been seriously thinking about it!


Yes, The switch in the link complies due the barrier between the two sets of spade terminals.

Excellent, thanks Marcel. I'll make sure I get one

JohnH
21-06-2022, 08:39 AM
What's the saying - perfect is the enemy of done? Well that is totally what I've been doing with this build. I literally have everything on hand to wire it up but kept getting held up fiddling around with faceplate designs because I don't like the ones that came with the chassis.

I decided that was crazy, and am back at it.

43269

JohnH
21-06-2022, 08:47 AM
A colleague picked up a fantastic 1961 Vibralux and it led me down a bit of a rabbit hole, but it's got me planning a vibrochamp build. I already have the sockets, switches, and caps/resistors on hand, as well as most of the pots and a tag board I think will work.

I figure an upcoming birthday might be a solution to sourcing some or all of the more expensive tubes/transformers/chassis

43270

Simon Barden
21-06-2022, 02:18 PM
I have an 82 Vibro Champ and TBH, it’s a bit ‘meh’. A lot is down to the 8” speaker. It has got an upgraded WGS alnico speaker in it as the original was terrible and broke up and made farting noises at any reasonable volume. However, it’s designed for a 4 ohm load, so finding a single 10” or 12” could be hard. 2x10” maybe if using an original style output transformer?

Really could do with some built-in reverb IMO, which I’d much prefer to having tremolo.

Simon Barden
21-06-2022, 02:25 PM
I can’t see an output transformer in that layout diagram, and all the originals certainly have one.

JohnH
22-06-2022, 08:24 AM
That's good to know Simon. It seems from what I've been reading that the speakers make a huge difference (unsurprisingly)

I'm not sure what you mean about the layout missing the OT? The wires are either side of the 6V6, unless I'm misunderstanding you?

It definitely isn't the clearest layout though. From what I was reading the circuit never changed, so sometimes layouts fail to mention things like filter cap values or OT values because they are always the same as the original.

I haven't actually gone through the schematic and layout to check yet, but will work from the schematic in any case

43272

JohnH
22-06-2022, 08:36 AM
I should also mention that I'm not particularly interested in getting an amazing playing amp from the vibrochamp build, but really want to have a small relatively simple amp circuit to play around with.

I'm treating the amp builds the same way I have been treating the pedal builds - each one should be more complex than the last, or teach me something new. So, the vibrochamp is pretty simple in terms of components but it has the vibrato and if I build it into a larger box I have room to play around - make a list of amp mods and just work my way through.

For example, I'd like to add reverb. Not because I think it'll sound amazing, but because I'd like to understand reverb circuits better - what are the options, how do they work, how are they each different, what will or won't work with this circuit and why, etc

If I end up with an ok amp at the end, then great! But I have heaps of amps now and really just want to understand the circuits better. I figure worst case I make an awful amp but learn some things, then can strip it down for parts for future builds

Simon Barden
22-06-2022, 04:00 PM
If you can’t see that what should be an output transformer on the Triode schematic is a capacitor symbol (one of the big filter caps) and that there are only output wires to it, no input ones (so it’s not just a misused symbol), then can I suggest that for safety’s sake you probably need to read up more on valve circuits, so you get to the point where you can. They are not things to take lightly.

Not being fully up on circuit design is OK if you are assembling a good kit with clear instructions, but if that Triode diagram was supplied with a kit, then it’s bad and dangerous. So you first need to know the difference between good and bad.

Referring back to the original schematics is definitely good, so try going through the Triode schematic following the Fender schematic and see how close they are and where the Triode goes wrong.

Don’t take this the wrong way. I just don’t want you blowing yourself up or electrocuting yourself!

For a small amp, I’d personally either go Tweed champ (a bit more character to the sound IMO) or a Princeton circuit of some sort. I’ve always liked Princetons whenever I’ve played one.

JohnH
23-06-2022, 07:13 AM
Sorry, but I still don't understand why you think there isn't an OT on that triode layout - there is a 20/20/20 cap can (unlabelled, as I mentioned in a previous post, and which you seem to be suggesting is being used as the symbol for an output transformer?) and there's an OT.

There isn't a picture of the output transformer, but the rubber grommets for the OT wires are either side of the 6V6 with wires clearly shown and labelled. As lots of layouts are set out this way that doesn't seem unusual?

I only picked the layout because others seem to have had good success (with the caveat that the layout is unclear on what filter cap and OT values to use, and has an easy to miss connection on the speed pot). As I've already mentioned, I haven't had a chance to go through the schematic to check but a quick look seems to confirm that the cap can in the layout is the 3 x 20uF 450V caps from the fender schematic.

As this is for a *future* build I'm not particularly concerned about going through it now; will get the 18W build up and running first.

Simon Barden
23-06-2022, 04:11 PM
OK I see what you mean. My faulty interpretation. Grommets, not caps. Suddenly it all makes sense.

I just find it weird that the OT isn’t even shown in a dotted outline (or similar) though.

Simon Barden
23-06-2022, 04:59 PM
I think I'd add a couple of sockets so that the 4 ohm tap could be used as well. If you want to make it an 'authentic' Vibro Champ, then it should be a 4 ohm speaker

JohnH
25-06-2022, 06:49 PM
Yeah I agree Simon, multiple OT taps are definitely more useful. I'm pretty sure I saw a vibrochamp OT with 4, 8 and 16 Ohm taps, but didn't bookmark it. I'll have a proper look once I start buying parts/planning.

I got the 18W build all wired up, mostly. I ran out of heat shrink, and also realised I didn't actually have a 240V indicator after all that, so I've ordered those but it means I haven't wired the power switch, IEC socket or OT/speaker jacks.

I've gone through it twice against the layout, and once against a schematic with a highlighter. It seems ok, but I'll wait a week and go back through it with fresh eyes (and will also double check solder joins and look for stray whiskers of wire I may have missed)

Interested to see how it goes, as I don't think I've done the best job at getting short wire runs which are also routed most appropriately.

https://i.imgur.com/fjnV26r.jpg

https://i.imgur.com/bZmdQqm.jpg

Marcel
25-06-2022, 07:23 PM
Nice work... Looks awesome....

My only comment/observation - Looks to me that you have used Jaycar hookup wire everywhere. While it is easy to work with it is also NOT rated for many of the higher voltages found in a tube amp, mostly due to the plastic insulation being too thin.... That being the case I'd go find a small roll of 650V rated stranded wire and replace any wire that typically has more than 20VDC on it. Keeping wires apart from each other and the chassis will for the short term have the same effect.

JohnH
25-06-2022, 08:14 PM
Good call Marcel, but thankfully its not jaycar wire!

I used this 600V rated wire from tube depot: https://www.tubedepot.com/products/20-ga-tin-plated-aerospace-grade-tefzel-wire

Its nice to use - the insulation doesn't melt when you're soldering

JohnH
17-07-2022, 05:57 PM
The indicator light came in the mail yesterday, so I finished the wiring.

Got myself all set up to test voltages tonight - plugged in the variac and light bulb limiter, jewellery off, thick rubber mat down on the floor, voltage charts and schematics out, DMM at the ready, lined up all my tubes aaaaand... I don't have a rectifier tube.

I swear I bought one, so maybe it's just hiding somewhere, but I've ordered one in any case.

Sigh.

On the plus side I also got a vibro champ eyelet board in the mail

https://i.imgur.com/phtqpTV.jpg

JohnH
17-07-2022, 06:10 PM
I also decided today that I need a smaller cab for my 5E3. I think I may have mentioned I was thinking about it before, but it's such a great amp it'd be nice to be able to take it to jam with people, but the only cabs I have are the 2 x 12 I built and the Laney 4 x 12. Both are way to heavy to cart around (the 2 x 12 sounds fantastic though).

I have enough ivory tolex left over, so I'm just thinking about speaker options. A 10" speaker would make a cab the same width as the amp head, which could be nice. I think I'll add small legs to it, like the Ibanez tubescreamer I have. It puts the speaker at a nice height, and looks great.

If you haven't seen the tubescreamer before, it is a great little amp. You can check it out here (https://downtownmusicsydney.com.au/products/ibanez-tsa5tvr-tube-screamer-1x8-5-watt-tube-guitar-amp-combo).

(Here's a pic)
43325

DrNomis_44
18-07-2022, 06:32 PM
I also decided today that I need a smaller cab for my 5E3. I think I may have mentioned I was thinking about it before, but it's such a great amp it'd be nice to be able to take it to jam with people, but the only cabs I have are the 2 x 12 I built and the Laney 4 x 12. Both are way to heavy to cart around (the 2 x 12 sounds fantastic though).

I have enough ivory tolex left over, so I'm just thinking about speaker options. A 10" speaker would make a cab the same width as the amp head, which could be nice. I think I'll add small legs to it, like the Ibanez tubescreamer I have. It puts the speaker at a nice height, and looks great.

If you haven't seen the tubescreamer before, it is a great little amp. You can check it out here (https://downtownmusicsydney.com.au/products/ibanez-tsa5tvr-tube-screamer-1x8-5-watt-tube-guitar-amp-combo).

(Here's a pic)
43325



I totally love the retro-look of that, really cool, can't wait to hear a demo of your 5E3, looks like I'm going to have to seriously look into building a Tweed 5E3 for myself, cause I love the raw breakup tone you can get from driving them, very bluesy sounding.

JohnH
21-07-2022, 07:15 PM
It lives! And, I have to say, it sounds bloody great. I spent an hour noodling around on it, and can see why people like these so much.

I could crank it a bit too as I was home alone, and don't seem to have any hum issues or oscillations.

https://i.imgur.com/NJF1mDe.jpg

https://i.imgur.com/33WRNKb.jpg

Simon Barden
21-07-2022, 07:36 PM
Hooray and well done! It looks great.

Is a sound demo forthcoming?

McCreed
22-07-2022, 06:39 AM
Looks great. Hope it sounds great too!

With that colour, it should be a "Prince-ton" (get it???)

Trevor Davies
22-07-2022, 06:51 AM
+ 1 for looking great. I'm in awe. What great skills to have.

Marcel
22-07-2022, 04:45 PM
Very nice, almost professional looking... Just needs a "JohnH" logo in the corner...lol

Yeah, 15W EL84 tube amps to my ears are super nice cranked... plus you can play them wound up to 10 and still be able to hear things afterwards...

Simon Barden
22-07-2022, 05:26 PM
Yeah, 15W EL84 tube amps to my ears are super nice cranked... plus you can play them wound up to 10 and still be able to hear things afterwards...

What?
djfdjkjkd

McCreed
23-07-2022, 07:28 AM
Very nice, almost professional looking... Just needs a "JohnH" logo in the corner...lol

Yeah, 15W EL84 tube amps to my ears are super nice cranked... plus you can play them wound up to 10 and still be able to hear things afterwards...

I thought this was 5E3/6V6 build??? What did I miss?

Simon Barden
23-07-2022, 07:39 AM
The bit where he finished that Deluxe combo and moved on to an EL84 amp head.

McCreed
23-07-2022, 08:23 AM
The bit where he finished that Deluxe combo and moved on to an EL84 amp head.

LOL! Thanks Captain O! :o
I'll need to pay closer attention (or not be too lazy to reread through entire threads).

Marcel
24-07-2022, 07:15 AM
Uummm.. I could be mistaken but to my eyes the pic of the completed amp bottles shows half a 12AX7,two EL84's as finals, a filter cap and rectifier bottle..... If they are 6V6's the photo has some optical size distortion going on as they don't look like any in my 45y in the electronics/tube repair game that I have seen before.

McCreed
24-07-2022, 09:30 AM
Uummm.. I could be mistaken but to my eyes the pic of the completed amp bottles shows half a 12AX7,two EL84's as finals, a filter cap and rectifier bottle..... If they are 6V6's the photo has some optical size distortion going on as they don't look like any in my 45y in the electronics/tube repair game that I have seen before.

Marcel, you are correct. They are EL84's. I was just confused because the thread started out as a 5E3 build.

JohnH
24-07-2022, 01:59 PM
Hooray and well done! It looks great.

Is a sound demo forthcoming?

I'll definitely try a demo. I'm not a very confident guitarist, so I'm always a bit hesitant to share anything, but I should get over that anxiety really


Looks great. Hope it sounds great too!

With that colour, it should be a "Prince-ton" (get it???)

Ah ha ha


+ 1 for looking great. I'm in awe. What great skills to have.

Thanks! I couldn't have done it a few years ago, and I still have an awful lot to learn, but it's been a lot of fun.


Yeah, 15W EL84 tube amps to my ears are super nice cranked... plus you can play them wound up to 10 and still be able to hear things afterwards...

Agreed! (I think my wife agrees too, ha ha)


Marcel, you correct. They are EL84's. I was just confused because the thread started out as a 5E3 build.

Yeah, sorry, I figured I'd roll all future builds into the same thread - it's probably a slightly confusing way to do it...

JohnH
24-07-2022, 02:05 PM
I'm really enjoying it - the normal channel is good but the TMB channel is great, and sounds giant with my low tuned guitars. Very glad I decided to build this circuit.

I'm still thinking about a build for my brother's birthday, and am considering building another of these for him. I think it would suit his playing style, and he has requested purple tolex, so at least I know I can buy a pretty good pre-built box for it!

I also have tubes already, plus I bought extras of all the parts so lots of the small parts are on hand. I'll keep thinking about it though so if anyone has ideas for something else worth building, feel free to make suggestions. Ideally I'd like it to be a build where the faceplates and chassis are easily available - I don't mind making a cab, but I don't think I have the time or brain space to DIY the entirety of the build.

JohnH
16-08-2022, 11:15 AM
Well, I'm sorted for the next little while!

The first of two packages - most of the large parts for the next two builds - another 18W TMB (pretty much exactly the same as the last one), and a Slucky Revibe (which is very well documented here: Slucky revibe (https://sluckeyamps.com/revibe/revibe.pdf))

I've been thinking about a revibe build for a while but was put off by the complexity. It's a well documented build though and I've read so many build threads now that I think I'm cautiously confident, particularly if I go slow, re-read the threads, and ask lots of questions.

Vibrochamp also still in the works, but I need to figure out what I'm still missing for that one.

https://i.imgur.com/dusxCyY.jpg