18W Liverpool ?

[Doxie man]

I have on hand some nice 18w iron speced for a Marshall 1974X and was thinking about doing an LP with it. Anybody done this here ? how were the results ? Also.....I am NOT concerned with copying every little last drop of Ken Fisher mojo here. I just like to build amps that sound good ...could give a rat's ass if it is not an exact replica/doesnt nail the exact recording sound BS. I just like to build and am kinda' new to the TW thing though NOT new to building.

[joeboo88]

I built mine with the same type of iron, and it is really nice clean tones and is also a meant little b#%^h.
It is loud, I put in a MV and it's ok, but I like the amp better without the MV.
My amp has a bit of fizz, but I haven't looked at the amp as my grandkids is with us for a month. So I don't get much done

There are a few threads on the 18 watt Liverpool. Joecon has a build thread I constantly looked at, gathering info.
Peace,Joe

[Sappy]

Hi Doxie (and everybody else since I think this is my first post, but I lurk now and then).

I'm thinking about doing roughly the same thing: A Liverpool-ish amp, inspired by the Liverpool but not worrying about copying every last detail. In fact, I plan to tinker around and play with the circuit a fair bit.

I've got a Classictone 18W Marshall output transformer and a Heyboer 18W Marshall transformer laying around, both just staring at me accusingly for not putting is them to work yet. I've also got a selection of Power Transformers I could put to work too. (My stash of parts enviable, primarily because I buy stuff then procrastinate actually committing time to projects). Lots of irons in the fire here and I travel weekly for work.

Just to use up some stuff I have hanging around, I'm figuring on probably using the Heyboer 18W Output transformer, a Hammond 270DX Power transformer, and 6P15/SV83 output tubes since I scored a stash of the extra rugged ones pretty reasonably. They require no more than Vg2 = 200V to operate, but the slightly lower power output they have vs EL84 would suit me.

If that's not enough heretical departure from KF scripture to get the natives in "torches and pitchforks" mode - I'm also considering stuffing this into an empty Fender Super Champ XD combo cab I have, which I also scored pretty cheap.

Dad owns a machine shop and has more tools and aluminum sheet around than I'd ever need, which I have free access to, so I'll be rolling a chassis for it in the near future.

Anyway... thought I'd chime in since I'm thinking about doing a very similar project, but I don't want to hijack your thread. If you want another guy doing something similar to chime in though, just let me know.

It seems like we're on the same wavelength about the same amp and topic at the same time. I just want to use up some spare stuff I have hanging around, and end up with a great sounding amp... with departures from the design that inspired it that mostly will depend on available parts on hand, and probably my mood.

btw - Thanks to all you folks who have gathered so much information on this forum. I've lurked for a while, and learned a lot. Been a tech since 1995, and my current background is precision measurement and calibration, so hopefully I can contribute some too now that I have the bug to at least build Trainwreck(ish) stuff.

[M Fowler]

If you do a search you will find several guys building a rjguitars 15w Liverpool kit that you can get some ideas from.

Mark

[RJ Guitars]

I'm along for the ride on this thread... Curious how this iron works out.

In my build package that mark mentioned I provide some custom wound Edcor Transformers. No complaints but always curious if there is something else that will do the trick as well. I am currently working with Pacific to develop a set of trannys for an 18 watt... No results to report so far. In all cases I am using a 270-0-270 secondary... slightly less than the typical 18 watt tranny.

The Liverpool makes a great 15 watt amp with a ferocious attitude and really loud. I actually call mine 16 watts so I can market it as the "Sweet Sixteen"... but who's counting? One cool part of these builds is that they weigh half of what the 30 watt version does yet are almost as loud... cheaper to retube the output section also. Keep your preamp wiring simple because lead dress can be finicky on these. Also watch that presence control, it tends to add some random irritability at times.

[Doxie man]

I decided to just do the full blown Liverpool......glad I did

[RJ Guitars]

Nice build with near perfect marks for neatness. Lots of cool ideas to add to the Wreck build options as well.

Can we see a photo of it from the top side? I am curious if you notice any transformer coupling hum? This is what I consider the perpetual design weakness in a traditional Wreck layout. Those two big trannies in close proximity always seem to want to talk to each other. I've gotten it down to where nobody notices but never managed absolute zero in a traditional layout.

[Doxie man]

Actually this build went without a hitch. No hum....no annoying sounds. It has a touch of white/gain hiss but it's to be expected in such high gain/ sensitive circuits but it's not bad by any stretch of the imagination. I did notice this circuit is very selective to what it likes as far as speakers are concerned. My 2x12 THD semi-open back cab sounds WONDERFUL ! My other 2x12 with Celestions sounded like ASS !! I was never a big Celestion fan anyway so I loaded that cab with a pair of Texas Heat 12's from Eminence and it is much better but not quite as smooth/thick/tight as my THD cab. That cab sounds great with ANYTHING !! I do seem to notice a slight buzzy/fuzzy overtone on the overdriven notes but it's slight....still trying to eliminate that. I'm wondering if playing around with the 47pf"fizz cap and .0022uf coupler might help. I also used standard Switchcraft input jack... I'm going to use a Cliff jack there when my order arrives to fully isolate the input from the chassis Overall the amp is relatively head-ache free. I am very meticulous in my guilds and usually avoid the issues most have by simply being overly neat and careful with my lead dress I'll post a top-side pic in few for you along with a few more pics

[Doxie man]

[Doxie man]

[Doxie man]

My bias on those EL84 valves is a little hot IMO. With the 145R per pair, I'm at 101% dissipation. El84's are notorious for getting buzzy when running hot so I'm going to bias them cooler with a 180R per pair and re-check. That should drop me down in the 95% dissipation area and hopefully eliminate what little buzz on the notes I am having. GROOVE TUBES aren't exactly the best 84's out there but it's what I had at the time

[RJ Guitars]

What B+ are you running on the plates with the 145R Bias resistors? I've seen Liverpool amps running 120 or 130 Ohm bias resistors and the actual voltage measurements I've had access to have the plate B+ running from 329 to 338 volts. The Rocket amps actually run the tubes even hotter with a 50R resistor across the 4 tubes. I'll be curious what you hear as you tweak.

[Doxie man]

IMG_0040.JPG

[Doxie man]

On cathode biased circuits, you don't measure plate to ground. It's measured plate to CATHODE. Just to be clear we are talking about the same thing

[RJ Guitars]

Good Point -- The document I took those numbers from is old data from the AmpGarage archives without that specific info about the measurement point. Judging that all the other voltages listed are referenced to ground, this is most likely the case for the plate voltages on the output tubes. From what I can see this adds about 10 additional volts to the plate voltage which puts your numbers right in line with these... if the assumptions are valid otherwise of course.