The Amp Garage

Omar, thanks for the kind words. :) I didn't try the Rich mod in this amp, but I had previously added it to another amp (a cathode biased 18W clone). It worked perfectly (although a post-PI MV just doesn't suit that amp at all). I decided on Marshall's own version because it's used in several of the...

Looks great. I see you went for a later model - split cathode on V1, cathode bypass cap on V2, etc. That'll have a fair bit of gain, but I know why you want the MV. :) I added one to a plexi conversion and I just thought I'd mention a tip I discovered when adding the post-PI MV: there's a perfectly ...

Interesting - I'm going to temporarily wire in a simple post-PI MV on my Liverpool to see how useful it is.

OIC. I'll bear these tone stack changes bear that in mind when tweaking. After more playing through the two cabs, I think the amp sounds *far* better through the 4x12. The G12M25 in the open-back combo cab has a bit of sizzle riding on top of the 50-100% cranked tone - there's none with the 4x12. An...

I don't know if this FX loop would work effectively or not in a wreck...and in this location. Well, I'm guessing that the Wreck's PI is distorting, because it's quite similar to the 18Wer's PI and it's getting a hefty signal from stage 3, plus the favourite MV for this amp is the post-PI MV like th...

I gather that they're made in France, so I'm hoping to find them cheaper over here than they are in the USA...

So do any other European builders know a source? Preferably with online ordering?

Great work :) You've answered a lot of questions on the Komet differences. I may put some into my next project which is an Express from an old Traynor. I've also been wondering about some of KOC's ideas in the Wreck. Power Scaling works great (I have a London Power Studio). I've made up the kit for ...

Interesting - which one do you call the "tone cap"? So far I've been sticking to the Tele - to see where I am on the "too bright" thing mentioned in other threads. Will get an ES-335 and a LP Jr out tomorrow. I've now tried the amp through a 4x12 (G12H) and the combo's own 1x12 (G12M) open-back cab ...

Thanks for the kind words, Chris. I was expecting to have to trouble shoot some oscillation, but lucked out.

This weekend I'll recheck my tone stack wiring. It was a head-scratcher for a while and I might have misread something. But I will take your advice and stick to these values for a while.

Big thanks to Mark Abbott for the very clear Liverpool drawing. My 18W version is now complete and it worked first time. Which was nice! :) No oscillations and no undue noise (FWIW, I kept the WEM's original heater wiring loom, OT, PT and valve layout 100% as-is). I used a simple ground bus. I'm sti...

Interesting reading. I think Doug H is right. If this was a production-line amp, it'd be sensible to talk about making a clone. But if it had been a production line amp, I'll bet the basic design would have had to be 'detuned' to cover every eventuality and component/tolerance variations. There's so...

Thanks Mark A. I've just now rounded up values from .001 to .022, so I should be all set for experimenting... once I get the amp up and running. This is the most complex circuit I've done yet, and I'm hoping the oscillation gremlins and SNAFU pixies stay away.

Hey Mark - thanks for the info. I'm rather "theory-lite" :) so your explanation helps shed light on this part of the circuit. I'd never seen anything like it in other 'classic' schematics. And you've persuaded me to rewire the turretboard a bit so these components will be a bit easier to change. I g...

Hi guys - just thought I'd stop lurking and say "Hi" and thanks for providing a great resource :) I'm about halfway through converting an old and trashed 2xEL84 WEM combo into an 18W Liverpool. I'm using Mark's hand-drawn schematic (thanks, Mark!), and making a layout on a 2-row ex-Ministry of Defen...