New 12w Liverpool build

[Mark]

Sorry for the confusion, when I mean adhoc, I mean an amp put together to get an idea of what the Liverpool was about.

I went with 250-0-250vac as I didn’t think the two EL-84’s would draw enough current to drop the voltage to where it should be. As with any Trainwreck build they live and die by the quality of the transformer set.

[dblgun]

I agree, the transformers have a great deal of influence on the sound of these circuits. The other important feature are the components and their implementation and layout. That being said the transformers KF used were massively over spec'd for the environment used. I think the results of this added to the uniqueness of his circuits. Although the voltages were not high compared to many other guitar amps the current capability of the television power transformers used were huge.

I'd like to see your two EL84 build. Are there photos here on the forum or could you post some? I'm always looking to see other examples. I too am always curious about the differences in Kens circuits and what they each had to offer. I have built several and no two sound exactly the same but all have something that links them together. I'm still trying to nail down what or where that is! I'd like to build a DTM in the future and am still working on some of the things that make a 6v6 Express different than EL34 versions other than just the power tubes.

[Mark]

I'd like to see your two EL84 build. Are there photos here on the forum or could you post some? I'm always looking to see other examples. I too am always curious about the differences in Kens circuits and what they each had to offer. I have built several and no two sound exactly the same but all have something that links them together. I'm still trying to nail down what or where that is! I'd like to build a DTM in the future and am still working on some of the things that make a 6v6 Express different than EL34 versions other than just the power tubes.

There was a early recording if it somewhere, though this was early in the days of the forum and I didn’t think it was worth keeping.

You say you would like to build a DTM, or do you mean DLM?

I don’t think there is a circuit of this amp around. I thing Komet had a go at building one and Dr Z made a few.

https://chasingtone.com/odds-and-ends/t ... oke-wreck/

https://youtube.com/shorts/5vKnBBy_BzM?feature=share

[dblgun]

Yes, you're right DLM. I fat fingered that and didn't catch it! I know that there is very minimal information. It would be an experiment that would probably be continuous. Certainly a good project in the future.

I am surprised that there is not more interest in the amp and KF's amps in general. It does appear to me that the interest has always been limited to a comparatively small group but even that has waned. My interest is relatively new compared to many here which may explain my continued exuberance. KF's designs were very simple while being exceedingly nuanced compared to many amps I have worked with. I guess I'm just not done with them yet...

[pedro]

Youre so right about the apparent limited interest/activity around at the moment concerning these amps. I was around on the Dumble section of the forum many years ago and spent an awful lot of time chasing that tone but didnt have any real awareness if the TWs at that time and certainly didnt appreciate what amazing amps they were/are. I built a couple of dumble type amps - an HRM and a non HRM then didnt really explore the forum any more once they were done and i was happy with them.
Having built and modded my own express last year i now realise what superb designs they were and am quite obsessed with them! I too would love to know more about the DLM circuit.

[Mark]

Trainwreck amp were popular around 2004, but the excitement did die off over the years. I get it as they are a loud amp and have been referred to as a one trick pony, but it’s a good trick. Of course you can get more tones out of them. It’s just a matter of looking at the Komet circuits and thinking about what you want.

Personally, I would put the vintage fast switch in an Express or Liverpool to get clean tones easier. I would experiment with a larger coupling cap (only attached to the vintage node) to the third stage to allow cleaner and fatter tones.

If you are thinking of building a DLM amp the transformer set is crucial to the build. The Komet DLM style amp had a huge output transformer, Hogy won’t sell the amp as it would cost as much as his other amps. I don’t think Hogy was very happy with the DLM amp.

[pedro]

That makes perfect sense Mark. I have been trying to work out how to add the fast/gradual switch to my amp without making a mess of the lead dress. I dont have a lot of space on the board and used eyelets together with the B+ wires being routed under the board. Consequently its going to make swapping the 100k plate resistor for an 82k and 22k a bit tricky. I could do it - but am a bit worried that the routing to a switch in the back panel will affect what is otherwise a very quiet noise floor with no oscillation, even when cranked.

I was also thinking of putting the fast/slow on the second stage plate but from what you say the third stage is the place to put it?

Best,
Pete.

[Mark]

Allyn Meyer use to make a solid state switch which allowed the amp to be switched between vintage and fast via a foot switch. It was a good thing, I don’t know if anyone still makes the switch. That would be the option you would be after.

[pedro]

Thanks Mark

I dont want to clog up dblguns thread any more - but quick question - would you put the fast/gradual switch on the second or third stage - i think the K60 has it on the second stage ?

Best,
Pete

[dblgun]

I added a version of a fast/gradual switch in the amp when I built and like it a lot. It does help with cleans with guitar volume minimized. It is the second mini toggle on the face of the amp and not foot switchable. I suppose a DIN connector could be added at the rear for a foot switch that would allow for activation by either control.

[pedro]

Is that on the second triode stage dblgun?

[dblgun]

Hey Pete, sorry I could have been clearer. Yes it is and I simply replaced the 68k(R7) with three resistors in series and added a .068uf cap. I think I saw a variation to the idea here on the board and played with values. Like I said, it was simple and is a nice feature that doesn't seem to have any negative effect on tone when not in use. I guess the only downside/challenge is finding a place for the switch.

Made some changes to the amp today including swapping out the P/T for a lower voltage unit. This necessitated a few additional changes to bias and PI to bring everything back in line. It didn't really have a huge impact but the amp, including 6BM8's, will see a bit less voltage which in this case is not a bad thing. I also changed out the 50pf treble cap for a bit higher value. The amp is a fraction of the volume of my Express clone but still loud through a 4x12 of Blackbacks! Lots of fun...

[Mark]

Allyn MIGHT have used a 4066 style switch, they are a 16 pin chip, and easy to work with.

[dblgun]

I suppose one option would be to make use of the unused 5v circuit to power some relays for the purpose as well. It does seem counterintuitive to the simplicity of KF's design and open up some other potential noise issues. I'm sure it could be sorted out.

[pedro]

Thanks guys

Yeah. I guess too much additional circuitry kind of takes it further away from the purity of Kens designs

I will try with a manual switch first and see how I like it

Dblgun - yes I see the string of resistors on your board and how they are tapped in between for the plate supply.

As i am mainly using my amp to record with i guess a manual switch will be fine for now. Looking forward to having the extra tones on tap

These are wonderful amps for rock - i bet yours sound amazing judging by the build quality

Best,
Pete