Ethellent thtart Marthter Dan! Do you need any thpare electrodeth? I’ve a Jacob’th ladder and a lightning rod lying about that are thtill good for a few thouthand voltth or tho.
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Ethellent thtart Marthter Dan! Do you need any thpare electrodeth? I’ve a Jacob’th ladder and a lightning rod lying about that are thtill good for a few thouthand voltth or tho.
Why thank you Ig0r, but those Jacob'th Ladderth (uhum, sorry, got something stuck in my throat, hack that's better) scare me silly.
Read the story of the capacitor plague.Quote:
Originally Posted by jugglindan
https://en.m.wikipedia.org/wiki/Capacitor_plague
Thanks Cliff, that was an interesting read. I don't know when the amp was manufactured, but at least I now know it's possible for the cap to fail catastrophically all by itself, and there may not be anything else wrong. Fortunately I haven't started tearing down the amp for parts (I got distracted testing a chorus/vibrato pedal by playing shimmery ambient stuff), so attempting a fix is possible.Quote:
Originally Posted by Cliff Rogers
DC
Can we please get Ig0r an avatar.....Quote:
Originally Posted by Ig0r
I’m voting for ....
http://2.bp.blogspot.com/-b8q9DWe-IO...ankenstein.PNG
Or
http://bestsimilar.com/img/movie/thumb/5b/15615.jpg
Definitely Marty Feldman. That's a great movie.
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There it’s thertainly a family rethembelenth, I think he ith (partth of) my thecond couthin theveral timeth removed.
Wathte not want not, ath the old thaying goeth.
What hump?
So we are making profiles for all our multiple personalities now? Oh boy, things are going to get crowded in here.
This is what happens when @FrankenWashie is lax on changing the WiFi password periodically.Quote:
Originally Posted by Sonic Mountain
Ig0r isn't a multiple personality. Just multiple people.Quote:
Originally Posted by Sonic Mountain
Im sure he’ll limp off back into the shadows of the lab before long. There’s only so much lithping the keyboard can soak up.....Quote:
Originally Posted by Sonic Mountain
I'm surprised he can type, what with the 4 thumbs, 3 index fingers and the repurposed monkey toes.
A monkey paw sure helped Bob Log. I wonder if Ig0r can play like that.
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I had to google Bob Log... found some YT videos...Quote:
A monkey paw sure helped Bob Log. I wonder if Ig0r can play like that.
That's eight minutes of my life I'll never get back.
I saw him live a couple of times. His shows in person have a certain energetic charm, but I don't listen to his CDs. There's only so much frenetic slide guitar by a man wearing a helmet and singing into an old telephone mic that I can take.Quote:
Originally Posted by McCreed
Back to the original topic, I did some suck-it-and-see-engineering just now. Stuck a disk piezo transducer to the bottom of a small wooder crate and plugged it into my THR set to the bass amp sim. The output was low (no pre-amp) but the audio quality was apparent. Rather than the satisfying thump I am aiming for, I got something more akin to a tap, or a knock, with just a little bit of click mixed in. I don't even think EQ would help (I maxed the amp bass and adjusted mid and treble) since the low frequencies didn't appear to be there to start with. Maybe a different wooden box would help, or wearing boots instead of socks.
To compare, I then hooked the broken 6" sub driver up as a microphone and gave the cone a light tap. From the amp came the rich resonant thumpa thumpa I was looking for with this project. I tested again with the Sanyo speaker I got for the mini amp project, and again, a nice thump from the amp. It was not as rich as the sub driver, but it was still in the ballpark. The piezo wasn't in the ballpark. It wasn't in the car park. I don't even think it was in the right part of town.
I now understand why many of the DIY foot drum designs I looked at use a speaker as the transducer. In this application, more or less faithful reproduction of the vibrations isn't really the goal.
Good to know. I have a couple of old speakers kicking around somewhere, maybe I should dig one out before I try playing around on the weekend
OK - so here's one I built with my brother last time I was in Canberra. Haven't wired it up - hence front cover not sitting properly. Also need to clear coat it and chamfer the edges a little.
That looks awesome Brendan. Very close to the sort of thing I am working towards. I know it's not wired up, but what are you using inside as the microphone? Have you tested with temporary wiring? How does it sound?
DC
Does that affect the dimensions for the box Dan?Quote:
Originally Posted by jugglindan
Good question. At first I thought it wouldn't, since the 150mm width would be enough for a 4" speaker, or maybe a 5" depending on the timber thickness and internal dimensions. But I am now wondering how much height will be needed. I know speaker drivers vary a lot in depth. Today I will look up dimensions of some of the speakers I might use and get back to you.Quote:
Originally Posted by FrankenWashie
DC
OK, I have a 5" speaker that has a diameter of 135mm once I include the metal surround. That will easily fit into the 150mm width even if the wood was no more than 6 or 7mm thick. But the speaker is 50mm high (measured with digital calipers). So it's too big, especially the taper from 50mm to 40mm plan. I am happy to keep the box as is, and obtain a smaller diameter speaker. Or the box could have 10mm added to the height (tapering 60 to 50mm). That's getting pretty big though, so maybe keep it as is and I will get a smaller speaker if the piezo doesn't sound right.
DC
Hmmm... I am pondering how to go about this.
if we make it more wedge shaped, the you might over come the depth issue some what. But we will still end up wit a chunky enclosure.
Out of interest what size piezo did you test?
I agree that the box shouldn't get any larger. The speaker I have is just too large (it's a 5"). I can get a generic 4" speaker from Jaycar for $5. It will easily fit into the current planned dimensions. I was just at Jaycar today getting some parts for my current pedal and amp builds. I should have picked up one of the speakers.
The piezo I tested is a 3cm disk. It probably wasn't a totally fair test though, as the box was a bit dinky, making it hard to stomp with my foot. A lot of people use piezo mics in these, so it should work. The box Brendan built looks too small to house a speaker, so I suspect it has a piezo inside.
Nothing as yet - hence why I'm following intently. Didn't want to stuff it up with a couple of dinky piezo's and haven't really revisited to see alternatives...Quote:
Originally Posted by jugglindan
Ah, I see. Well, I am happy to be the guinea pig :)Quote:
Originally Posted by Brendan
There are three main designs I have seen: piezo, speaker, and a pickup mounted close to a metallic object under the stomping surface. I will try the first two.
I've got an old p bass pickup kicking around - may see if I can rig that up inside without a full commit.
Great. I think I linked to a design or two like that back on page 1 or 2. I would be very interested to see how it works out, even though I don't have any spare pickups laying around. I like that it is less likely to need a preamp while I am pretty much committed to building a preamp into my mini amp as an optional input.Quote:
Originally Posted by Brendan
So the Lab got a bit busy this afternoon.
I needed to do some rip cutting on a large chunk of QLD Maple and some mahogany that has been laying about.
This involved passing an 8” wide board through my bandsaw, with a 20mm ripping blade on it. Slightly scary. Push sticks mandatory.
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I’m building 2 enclosures, one is more or less to the basic box specified by Jugglindan, the other is a FrankenLab twist version.
I decided to use some of the beech I had for the box sides; on the square box for DC, the ends will be Merbau, on the FL version sides and ends are beech.
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The tops will be QMaple, the key decision for being 1/4” or 1/2” top?
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I'm just wondering if the tops might be a little too thick to resonate well enough to get a good 'thump' sound. You can but see and you can always thin it down if necessary.
Whoa, that looks amazing!
And I think that the 1/4" top is more than enough. I agree with Simon it needs to allow vibrations through to the microphone on the other side. But since this is all new to me, I don't know for certain.
I should get the amp stuff wired up in the next few days to test the electrical side of things.
FrankenWashie, I see you are building your own. Do you want me to build a piezo preamp in a box to send up to you? Or do you have something suitable already?
I think that in the wedge form version, it will definitely need thinning to perhaps 1/8”, with the bigger box version it might be okay at 1/4”.Quote:
Originally Posted by Simon Barden
Waiting on some piezo discs to test that.
I’m going to see what I can cobble together to fill that function DC. I’m playing with similar bits in the franken Reso build so it’s all good experience.Quote:
Originally Posted by jugglindan
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Okay if anyone is curious as to why it takes the FrankenLab forever and a day to get anything done, here is a good example.Quote:
Originally Posted by FrankenWashie
https://uploads.tapatalk-cdn.com/202...dafe7d7bb1.jpg
We’ve got 3 or 4 differing thickness QMaple blanks to use as the skin for these two stomps. We hard right turn and slice up some rock maple into 4mm boards and laminate two together just ‘cause we got curious as to how that would sound.
We also chewed up an hour and a half because we had this idea about slicing up some merbau strips and using them as inlays in the corner of the stomp boxes, cause y’know, why not!
https://uploads.tapatalk-cdn.com/202...ed98f69b52.jpg
ps: DC where do you want your jack mounted? Front of box or side or other?
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I am simultaneously laughing at your description of getting distracted, and gawping in admiration at your workshop as glimpsed in these photos.
Jack to the rear please, just where it looks like yours is drilled.
So some progress shots, here is the DC stomp in progress
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https://uploads.tapatalk-cdn.com/202...5cf527dc92.jpg
The Lab stomp is now mostly complete, bar the piezo discs, which I have now been advised won’t get here until August. In the interim I’m going to have a crack at mounting an old pick up in it and seeing how that goes.
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Fine skills there Boss
thanks BD. It’s been a nice diversionQuote:
Originally Posted by Bakersdozen