Scratch build head(s)...

[Dedman]

wow, that's a real eye opener Marcel. I suppose keeping corpses for parts scrounging is out of the question with so many variables.
(Sounding like the Franken lab now)

[Marcel]

We scrounge a few things that we think have a high probability of being useful.. But the workshop is only so big, and rent for a bigger place is not available....so most of the truly dead stuff goes to the dump..

Yeah, that $8k 4yo 85" plasma.... we could trick it to light up and the picture was great, but the CPU that controls the set had let go of the magic smoke inside so it didn't respond to the remote control. No replacement CPU board available due sold out months earlier.... Very sad to see it go, but very exhilarating giving it the 'Wun-too-heave-ho' at the dump...

[JohnH]

The back door of any techs workshop has little regard for any well meaning ROHS standards...

Dead $8k plasmas stacked against equally dead $100 Kogan LCD's... it's all a little sad when we fill the tandem trailer with the un-repairable gear for the once a month trip to the dump. All too often there are 3yo TV's making the journey due to the failure of a single component that is not held in stock and no longer in production... and nobody wants to pay for or is setup to do the recycling that the community at large thinks is happening. It's no longer like the old days where a toolbox full of parts (most often tubes) could fix every electronic item in the house... The things in electronics that break are so vastly different from job to job. Over the last 6 months I can count on one hand the number of times where the same exact part was used to fix more the two different jobs. I mean that we can get 5 Samsung TV's in for repair, and all can have the exact same fault, yet due to changes during manufacture maybe only 2 will use the exact same item to be fixed.... Did you know there are at least 4 different versions of the Playstation IV and not including production/manufacturing changes all have totally incompatible electronics inside...

Tube amps make a tech's life so much simpler...

I didn't realise this was the case, though it explains why so often the few friends I have who do try to get things repaired cant manage to.

[Marcel]

It is a sad story... An unseen by-product of mass production combined with built in obsolescence and a public community with a fast growing 'throw away' mindset.

To add insult to injury there is an association that most Australian and NZ based TV/microwave repair guys are members of... 10 years ago membership was well over 3000 individuals/companies, but today the number is fast going South of 400... I've never been a member as fixing domestic TV's and microwaves has up until now not been part of my skill set, and I'm still not sure if it ever will become a factor in my career...

Oh, and I got reminded today that there is actually 6 different incompatible versions of the PlayStation IV....not the 4 versions I had said previously...

[dave.king1]

We have an Asian guy local to us that repairs pretty much anything, always got guitar amps and other musical gear in there along with TVs etc.

I do hope he stays in business for the foreseeable future because the local music community depends on him and his prices are most acceptable

[tiltbell]

here is a really crappy hand drawn version of the Lucky13. I have been using this as a basic reference for my build.

[Marcel]

Certainly a bucket load of gain in the OD channel on that Lucky 13 tiltbell...also quite a bit of tone shaping in each stage too. As I'm looking to generaly build a Fenderish clean amp I'm not sure I want a Soldano tone that much as to add an extra stage or three, but others may see than need differently...

[artyone]

I did lots of amp building years and years ago with not too many actually working... duh! Though the ones that did tended towards being simple and over the years I've kinda realised why and essentially it's, for me, come down to patience and not letting ideas get ahead of curiousity and ending up with incredibly complex builds where the amount of potential tweaking to get it right would send me straight to frustration land.

Anyway, that's my story, sad but true, and I'm thinking very seriously about hauling all the gear out, I managed to sequester quite a load of choice gear, and going back in. Now that I am contemplating doing it again I'm going to make it easy on myself and what that mostly means is driving smaller amps harder in the output section because it seems that where the really nice sounds are. 6V6's, el84's etc.

On one of my very last amps, which sounds suspiciously like yours, I kinda designed this system whereby each tube in the preamp section had it's own little tagboard style etched circuit board upside down so I could solder in and out resistors and caps way easy. I had them upside down so I could read the circuit real easy and also test voltages as well.

This isn't the specific amp but a much smaller one where I used the etched board procedure as I knew such weird little radio valves would need lots of tweaking to get right... though I never got around to it.

[Marcel]

Hi Artyone... I've seen that build method often, using small PCB's to build up to a much larger project.

There is method to the madness of putting the components on the track side of the PCB, and quite often in the SMD arena that is the only way to get the job done. A few years ago I was involved in repairing gear that operated at 10GHz range which had double sided and multi layer boards for the sections that worked below 1GHz and single sided teflon/Brass PCB boards for everything above 1GHz which made life as a repair tech so much easier.

On my tube amp builds I tend to stay away from PCB's preferring instead to only use tag strips. It's seriously old school, not suitable for any kind of mass production, and easily filled with lots of wiring errors, but I like the results and I consider it to be the real 'hand wired' art form .... I can see a lot of me in every tag strip build that I don't see in a PCB or turret board based build. As the photos show even in my AC18W build that used two of one type of turret board both of these turret boards were treated as if they were only slightly more than glorified tag strips. The one big advantage that PCB and turret boards have is that they can be built to a formula, a preset construction plan that is executed in production stages which of course is ideal for mass production.

On a transistor/FET/IC build the only way to go is using a PCB. I'm hopeless at making them so it tends to be the 'pre made by others' variety that I tend to build.

In the photos are a partially complete AC18W (EL84) build that used a type of turret board as tag strips, and the 2203 clone (EL34) build that uses only old school tag strips.

This EF86/6L6 amp will get built similar.... actually, due to cost constraints I'm giving serious thought to rewiring the 2203 build and using that chassis as the basis for this "new" amp.

[artyone]

Cool Marcel, I did lots of that too, tagboard, and basically just found it cheaper and more kinda non linear I guess to etch my own boards.

I suppose when the builds sorted and works it's a easier way, the tagboards, but if it's work in progress all those places where two resistors and maybe a signal cap are all bent in and soldered... they're a bugger to change. That's all, each to his own bro!

One thing I might do, this time around, is actually shape copper foil over wooden molds and then glass it to make my own three dimensional curved and sculptural circuit boards...