DIY Trace Elliot V8 w/ 8 KT120

I managed to scrounge up:
Enormous Trace Elliot V-8 power transformer
Enormous Trace Elliot V-8 output transformer
Trace Elliot V-8 power amp printed circuit board (unpopulated)
Trace Elliot V-8 preamp printed circuit board (unpopulated)
8 KT-120 tubes

Up until now, the biggest project I ever did was 44 years ago, building a transistorized guitar amp with 1 preamp channel and 2 quasi-complimentary power sections. That was with my dad's design, supervision and test equipment, as I was a kid.

Now I really took on a really big one.

One of the real "holy grail" production bass amps (not mega-buck Boutique), perhaps even more elite than a blackline SVT or the 400-watt Hi-Watt, is the Trace Elliot V-8. It's not hand-wired on turrets like a Marshall Major or that HI Watt, but it's not machine-loaded printed circuit either. Filament wiring is off-board twisted-pair. Preamp filaments are regulated DC. This product is a few decades newer than most competition (though Fender has a nice tube bass amp now).

The Trace Elliot V8. I think only about 100 were made and few made it to the USA, and every kid in England with a V-6 really wants one. I was never into the blacklight green, and for years I thought they only made transistor amps. When Gibson took over, all their big amps would be transistor and they stopped making the v6 and v8. The V-8 had some front-panel controls for a tube compressor modelled after some classic studio gear, more to fatten up the bass without boom than control punchiness. The only weak spot was the direct-out, reputed to be noisy. It also had a cool magic-eye type tube used for adjusting bias and as a VU indicator, calibrated to indicate clean at 400 watts. Both the V-6 with 6 KT88's and the V8 with 8 KT88's were rated at 400 watts, though the V-8 made a lot more, just the first 400 were clean. Trace also made a tube preamp with the same circuit board as the V-6 preamp, but no compressor. There were also some models similar to the V-6 but with the compressor.

I'm going to use 2 or maybe even 3 larger, roomier chassis. The preamp is not too simple, and I want to make sure I get something completed. So I might put th epower supply on its own chassis, and the power amp on its own chassis, both to be mounted on the bottom of a large head cabinet, with a preamp in its own chassis mounted above...kind of like an SVT but bigger and roomier.

This SOB is going to be really heavy. It might even make more sense to make the components rack-mount.

I'm going to start on the power amp chassis and the power supply chassis, but this is going to be a long-term project to (hopefully) finish before I die or get tremors and can't play.
 
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Up until now, the biggest project I ever did was 44 years ago

The biggest (most powerful, not physical size) project I ever did was 42 years ago. It was also solid state, with an unknown maximum power output. I personally saw 1200 watts before blowing the line breaker.

I had scored a huge heat sink with 24 X 2N3773's and two fans mounted in a military scrap yard. I wired two banks of 12 paralleled transistors in a transformer driven totem pole circuit. It was powered from bridge rectified wall outlet. I usually drove it with a Kustom solid state PA amp, but I saw it fed with a 50 watt Plexi Super Lead once, and it was a deadly sound. I sold it to a rock band that used it for a PA booster for about a dozen years. With 360 amps of silicon, shorting the speaker leads just melted the speaker leads and blew the line breaker!

I have never seen a Trace V-8...or V6. It has to be deadly, the good SVT were! I hope you have some serious speakers! I am starting on a 200 to 250 watt tube amp now, but the really big one is still pretty far down the list.
 
Luckily their parts list / bill of materials has decent descriptions of the parts. LIke whenever using a production printed circuit board, there will be some issues of using the exact same board-mounted switches and pots in order to fit. I really like the built-in tube compressor, but the preamps might be a bit complicated. Of course, I COULD build the power amp on turret-board! But the truth is that this is a well-designed printed circuit, with good start grounding, and some things wired direct to the tube sockets, like the filament wires are still twisted pairs of wire, coming off the sockets at 90 degrees to the printed circuit board. Good stuff.

The Trace Elliot tube stuff has more of a following in England than here in the USA. If I don't finish the project, I'd probably have to sell it overseas in order to recoup my investment.

There's a Plitron toroidal output transformer that's rated at 500 watts, but this is the only one I've found that's comparable. And it's reduced in price, new, at British Audio Sales.
 
There's a Plitron toroidal output transformer that's rated at 500 watts,

There was a thread here about 5 years ago that mentioned some transformers listed on Plitron's surplus page for just over $100 each.. A feeding frenzy ensued and they were soon all gone. I bought two. They are rated for "400 watts at 20 Hz." The guy I talked to at Plitron thought they were made for Marshall, but never used in a production amp. Those are for the really big one. I have seen 525 audio watts flow through one of them, fed by 4 X 35LR6's running at the edge of meltdown.

My current design is running Edcor OPT's and a big surplus toroidal power transformer, two channels 100 to 150 watts each. I have no speakers that can eat a bigger amp, so I haven't been in a rush to make one, but the parts have been sitting on the shelf lonely for several years........someday soon.
 
Hi

Had a V4, 3 V6s, 4 V8s.
Are you doing the V-type preamp with the compression circuit, or the V pre with just gain and tone?
PCB quality let the production units down a bit - sound great, not really up to touring.
They were built to order, so every one different (I had three different logo plates).
Used the compnents at hand, so some freedons taken 'on the day'....

Do you need the schematic?
 
Hi

Had a V4, 3 V6s, 4 V8s.
Are you doing the V-type preamp with the compression circuit, or the V pre with just gain and tone?
PCB quality let the production units down a bit - sound great, not really up to touring.
They were built to order, so every one different (I had three different logo plates).
Used the compnents at hand, so some freedons taken 'on the day'....

Do you need the schematic?

This is with the compression. Man you had some nice amps. I just saw a new-looking V8 go for $3900. They didn't make many. PCBs are not turret, but they look extremely uncompromising in some ways. For instance they put relays in the circuit locations for optimum layout. Pots are typical modern small low-wattage ones.

I was surprised the V6 and V8 output transformers are the same physical size.
 

Pitticcu

Member
2019-12-17 2:18 am
V8 potential issues and spare transformers

Bumping this thread up as I have just joined as looking for advice!

I assume the V8 build project has been successful?

I have acquired one of them, specifically the one used by John Entwistle on his last ever concert with the Who in 2002, before he passed away.

I was wondering if any of you had the components list (in particular the Transformers, since I want to make sure I can source spares just in case, and I am afraid that the model may be discontinued?) and also where I can buy the components?

Also, but it would be a long term project, I would love to try to build one myself, so the schematics would also be great!

Finally, since I have read these things do happen, how long can the head resist if played whilst unloaded (no cabs attached)? Just want to make sure that, if I am moving stuff around and detach cabs and then forget about it, that I do not blow anything up if I fancy a play and the cab is not connected! One can never be too careful lol!

Thanks a lot!
 
1) not sure why you want a detailed component list if you already have a working amp !!!!!
and do not plan on building one either (not in the foreseeable future anyway)

2) Standard components (resistors, capacitors, some jacks and pots, etc.) are "generic" and can be bought over the counter.

Some are factory specific/ "proprietary" and must be sourced through them, or maybe some Distributor.

3) Power and output transformers are NOT considered "a plain Component" by any means since they are VERY specific, very expensive, custom made for the original manufacturer.

Even worse, the manufacturer usually has NO CLUE about actual design, they just order "100 OTs for the 100W amp, such and such primary and secondary impedances", etc. and let manufacturer deal with details: wire, core, turns, insulation, interlacing, etc.

So TAKE CARE OF YOUR TRANSFORMERS, PERIOD.
how long can the head resist if played whilst unloaded (no cabs attached)? Just want to make sure that, if I am moving stuff around and detach cabs and then forget about it, that I do not blow anything up if I fancy a play and the cab is not connected!
But if that were to happen to my V8, how long would it require to blow up
Nothing!!!! 1 millisecond can be enough!!!!
It is not a thermal problem where heat builds up along time until it damages somethingbut an inductive peak punching through insulation and shorting your OT forever.

So simply DO NOT
fancy a play and the cab is not connected!

Be obsessive checking the cabinet is connected and you won´t go wrong.
 

Pitticcu

Member
2019-12-17 2:18 am
Hello,

Ok I think I have not explained very well!

1) I need the list because I would like to buy some of the critical components that might be discontinued or become too difficult to find, for two reasons: spares, and also because in the future I plan on making a rep li ca for myself. I have the list of the components on the boards and the schematic, but that does not include the transformers, I do not know the model and make for them. My V8 needs maintenance, probably caps and valves, and also to check the transformer, because there is a hum coming from the speaker when raising the Master volume and gain. At the end of the day, it is 20 years old and has been use in concert...

2) yes. For the specific ones, it would be good to know how to source them and where from (Would trace Elliot of modern days be able to help / which distributors would be best)

3) sourcing a spare transformer is probably what I would really like to nail down for the reasons outlined in 1).

My observations regarding the time it takes to blow parts when head is unloaded is more general and was related to the topology of the circuit, as in: can the trace stand longer time or not, because different circuits and designs are a bit more tolerant.

I know you are right in satin to be obsessive when checking connections, but there is always the possibility a combination of factors may end my up in that situation! So I am planning ahead :)

Thanks a lot!