Donor amps in the UK

[Seb C]

Hi all,

Long time lurker. I've dug through many threads via the search about donor amps, what HAD used, etc. - but a lot of it is (completely understandably) both US-centric, and refers to amps that may have been more available and affordable ten years ago. In the UK, based on my searches, finding solid old 70s-80s heavy iron is far from easy (and new transformers are really quite expensive here too). It's not just about saving a little money - there's something very appealing about taking an unloved amp and turning it into exactly what I want.

So when I do searches now, the sort of things I find that are big, affordable and valve-based are more often than not Peavey. But not the good old USA-made stuff. Lots of Valvekings and Classics, the odd 6505. Does anyone have any experience of gutting these for parts? It's all PCB stuff - so I expect pots, switches and valve bases will be no use. But for transformers, perhaps the chassis, valves, reverb tank and some hardware - is it just disappointing, under-built cheap rubbish that's not worth the effort? Or is there something in this?

Thanks!

Seb

[pdf64]

Here’s a couple of potential donors under £200 for the moment
https://www.ebay.co.uk/itm/334636605626 ... media=COPY

https://www.ebay.co.uk/itm/304508374878 ... media=COPY

[Seb C]

Thanks. I saw those. I think the Wem is solid state. The Selmer is a totally unknown quantity to me. It might be great.

But I suppose my point is more than lots that has been written about donor amps assume we can all find broken Fender Twins for not much money, and that's really not the case in the UK. But if I type "Peavey Valveking" into eBay there are about 14 options between £100-300, from 50w 1x12 combos through 100w 2x12s to half stacks. They must've made a boatload of these - so they're cheap, easy to find, and many probably still have a heap of life left in them. They're not rare or special, and nobody is going to cry if a few are cannibalised for parts.

I'm a firm believer in the saying along the lines of 'There are two kinds of fools in this world: those who say "this is old, so it must be good", and those who say "this is new, so it must be better"'. One of the biggest problems with old stuff is... it's old. So, can amps like this make decent donors, by virtue of the fact they're cheap, easily available, and not old? Or are the parts like transformers just... a bit crap?

[Stevem]

There was a period about 12 years ago where I had picked up 3 SS Univox 1-12 combo amps and built them over to point to point 15 to 25 watt tube amps.

Maybe you have this same crap still lurking around in GB to use as a resource.

[LOUDthud]

Checkout this amp over at MEF. Link: https://music-electronics-forum.com/for ... re-minimum

It's a DSP amp with a tube power amp. The DSP board is bad and Fender doesn't have any replacements. You'll have to replace all the pots and construct a new preamp. The power amp is part of the main circuit board so you may have to toss that, replace the tube sockets and re-wire.

[Seb C]

So I picked up a broken red knob "The Twin". Will attempt to revive first, then decide what to do with it...

[timrobertson100]

I’m in Denmark, but I’ve recently been picking up old Carlsbro PA5-60 amps (PA not guitar amps) from the early 70s for around £100. They were 60W 2x EL34, with really decent chassis, tubes, cabs and good iron made by Drake. I built Plexi type amps which turned out well (one here), but I’d likely do some Dumble style with the next. They seem to pop up around here regularly and no one wants them. Might be an idea to get alerts on your second hand sites for such a thing? I think there were other UK companies making similar (Simms Watts perhaps?)

[bepone]

just acquired one carlsbro PA 60W.. only for output transformer..we will see

[timrobertson100]

just acquired one carlsbro PA 60W.. only for output transformer..we will see

Nice, let us know your impressions please.
You not going to use the huge choke too?

[bepone]

just acquired one carlsbro PA 60W.. only for output transformer..we will see

Nice, let us know your impressions please.
You not going to use the huge choke too?

only OT for the moment, but PT and choke if in good condition will be used in other project ofcourse i have transformer varnish i will immediatelly soak them inside to close old holes for humidity and short circuit potential problem.. so i hope they will work for another 10 yrs min

[Seb C]

I also picked up a Smarvo. I had never heard of them, apparently also sold as a Divinity Ashton (never heard of that, either!). Best I could find online is that it's some sort of copy of a modern Marshall. 100w 2x12, 4xEL34. Two channels - clean with boost, overdrive with two different gain settings and voicings. Op amp driven reverb (quad op amp send, LM324 based, 4558 for recovery) with a pathetically tiny spring tank. Was sold as working. It was not working! One bad EL34, had taken out a couple of 1R/2W cathode resistors. All fixed for under £1, running as a 50w for now.

Power transformer seems pretty awesome for projects - enough juice to run 4xEL34 and 4x 12AX7, bias tap, another winding that's used to make +/- 15v for the op amps. OT has 4, 8 and 16 ohm taps.

Speakers say G12/65 - which makes me think Celestion, but baskets don't look Celestion and no visible branding. They sound pretty good.

So lots to harvest and all for... £23. Plus £10 postage. Bargain!