Liverpool power supply (Ginger pics)

[UR12]

Ok guys I am confused. Mark or Chris (or anyone else), if you could shed some light on this I would appreciate it. I am looking to start a Liverpool build and after searching every post regarding the liverpool I can't seem to connect the stuff I'm seeing in the Pics of Ginger with the power supply layouts and schematics available so here are a couple of questions.

1) What is the 3rd switch used for next to the power and standby switch?
Is this some kind of 1/2 power thing??

2) What is the pot and jack used for on the back of the amp. Line out?

3) Does anyone know the values of the 2 ten watt resistors. I can see one being the 50 ohm cathode bias resistor but what is the other used for?

I hope to build an Exact clone of Ginger and I understand the Preamp is the same but the power supply looks like a monster. I am going to try and duplicate the PS board and layout if I can.

Thanks

[Chris G]

Hi Dana,
I must admit I have no clue as to the answer to those questions!!!
only suggestions and they are:

The 3rd switch could be a 1/2 power switch, but couldn't it also be a polarity switch.This was the first amp he did from scratch.that wasn't built on an existing platform.

The pot on the back would almost certainly be a line out with level control......what else could it be

As for the resistors, The pics are a little too out of focus,maybe the extra resistor could couple with the extra switch to change the cathode bias resistor to a different level.


Sorry I couldn't be of more help!!!
Chris G

[UR12]

Hi Dana,
I must admit I have no clue as to the answer to those questions!!!
only suggestions and they are:

The 3rd switch could be a 1/2 power switch, but couldn't it also be a polarity switch.This was the first amp he did from scratch.that wasn't built on an existing platform.

The pot on the back would almost certainly be a line out with level control......what else could it be

As for the resistors, The pics are a little too out of focus,maybe the extra resistor could couple with the extra switch to change the cathode bias resistor to a different level.


Sorry I couldn't be of more help!!!
Chris G

If it was a polarity switch wouldn't it be a SPDT switch instead of a SPST??

Are you saying Ginger was the first Liverpool that Ken built?? WOW! Is this the only one that had the extra switch? Sorry to ask so many questions.

Being a self biased amp it would be a pretty easy to power scale a Liverpool. That could get a little interesting................

[Chris G]

Hi Dana,

I had read(and maybe I'm wrong on this) That Ginger was the first Trainwreck amp built for a Guy named Casper, who was playing John Lennon in the very first Beatlemania(sp?)Production.He left his ac-30's at home,IIRC This would have been the early 80's.

Maybe that switch is set up like a Matchless dc-30, giving you the choice of the resistors,for a hi/low type settings.

Chris

[UR12]

Hi Dana,

I had read(and maybe I'm wrong on this) That Ginger was the first Trainwreck amp built for a Guy named Casper, who was playing John Lennon in the very first Beatlemania(sp?)Production.He left his ac-30's at home,IIRC This would have been the early 80's.

Maybe that switch is set up like a Matchless dc-30, giving you the choice of the resistors,for a hi/low type settings.

Chris

Chris

I found an excerpt from Ken's self Bio that explains things just as you said. It appears that Ginger was the first Liverpool and that it was made sometime in late 1982 and early 1983 for a guy named Casper McCloud. (Ginger was Casper's Wife's name) I checked the DC30 and the switching arangement that Matchless used and they use a DPDT switch. It would appear that if this is Ken's version of a 1/2 power switch he did it a little differently. I have sent Mark Abbot an email and will see what his opinion is on the matter. It just seems peculiar that this hasn't come up before. At least from what I have been able to determine with various searches.

Thanks for the replies and let me know if you come up with anything else.

[LeftyStrat]

I'm glad this thread came up. I've been toying with the idea of a two channel 18/36 watt amp w/ the half power switch, and combining a wreck-style preamp with a Marshall 18 watt preamp (not sure whether to do a tmb, lite, or ef86).

Obviously, I'll have to play with the PI. In addition to half power, I've thought about a pentode/triode/ultralinear switch, as well as the NF switch that the 36 watt has.

I recognize some of you guys from the 18watt board, and just wonder what you're opinions are wrt mixing up the two. Would they be too close to be versatile? Should I dump my idea of triode/pentode/UL switch in favor of a VVR?

I guess what I've been hoping for is a two channel amp w/ trainwreck for lead, and a rhythm channel with nice semi clean Marshall tones voiced for a Strat. Crunch to semi clean with nice bottom (think Wind Cries Mary).

[UR12]

I'm glad this thread came up. I've been toying with the idea of a two channel 18/36 watt amp w/ the half power switch, and combining a wreck-style preamp with a Marshall 18 watt preamp (not sure whether to do a tmb, lite, or ef86).

I'm not sure but the last time I heard people were having problems with the 1/2 power switch on the 36watter. What intrigues me is that IF the extra switch on the Liverpool is in fact a 1/2 power switch then Ken was using this as early as 1982 on his amps. Don't know if he came up with the idea but he certainly predates a lot of others.

Obviously, I'll have to play with the PI. In addition to half power, I've thought about a pentode/triode/ultralinear switch, as well as the NF switch that the 36 watt has.

Those are all cool mods but I'm not sure how much you would use the triode/ pentode mode. Seems like they came out with this years ago with mixed reviews and I haven't seen it much lately. (I live a sheltered life though) The 36watt and the 18watt really push the PI pretty hard. They are actually getting gain/ that sound, mostly from the PI and power stage. You may be hitting the PI to hard with a TW preamp and if you change the PI then you may lose a little of the Marshall sound. You might want to try playing with the 3rd gain stage 150k resistor value to lower gain going to the PI. Anyway you go this would be a compromise and you may lose a little of the Marshall or TW sound. Sounds like a good idea to try though.

I recognize some of you guys from the 18watt board, and just wonder what you're opinions are wrt mixing up the two. Would they be too close to be versatile? Should I dump my idea of triode/pentode/UL switch in favor of a VVR?

Allyn has actually dubed a name for our little group of 18watt/TW misfits. He calls us the Wrecking Crew. Kind of catchy actually I really cant answer your question regarding mixing up the two. If you could get it to work you would really have something. Each amp the 36 and the liverpool have their own distinct voicing and staging and even though the use a quad of EL84s they are a little different. I have only heard a clip of a liverpool and have never seen one. Why don't you go ahead and build it and maybe we can help tweak it as a group project.

As far as the VVR goes I have one installed in a 18watt. 18 watts is still loud and the VVR works great. Richie has tested on a 36watt and loves it. I am torn between having both a VVR and a 1/2 power switch so I will probably build my liverpool as close as I can get to the way Ken designed it and give it a listen before I make a descision on that one. I could always install it later.

I guess what I've been hoping for is a two channel amp w/ trainwreck for lead, and a rhythm channel with nice semi clean Marshall tones voiced for a Strat. Crunch to semi clean with nice bottom (think Wind Cries Mary).

Yep don't we all. That would be one nice amp...........

[krash]

I am working on just such an amp as you describe. I will be putting this in my Classic 30 chassis and recycling transformers from the C30. Basically a Liverpool-like power amp and preamp for the high-gain (with just TB tone-stack, fixed mid resistor), and the "vibrato" channel from an 18W for the "clean" channel (sans vibrato, just Vol, Tone), plus (solid-state) buffered effects loop, channel switching, and master vol (post PI).

I have a schematic so far, but have not actually started building.

I have a Princeton Reverb that has been modded for an express-type preamp and also a GDS 18W combo. Here's what I think about maybe mixing them (not having a complete Liverpool-like design, but close on the preamp). The Princeton/expressalike is very bright compared to the GDS and does not like the same speakers. In fact the darkest sounding speaker I have is on the edge of too bright with the PR and I had to put a cut control (vox-style) in it and change the "contour" resistor in the tonestack to make it just work (still tuning). I think in the end, to get an express/liverpool-type preamp to work to channel-switch with a Marshall 18W preamp (simple, lo-gain), it will take quite a bit of voicing/tweaking to get them to play nice together with the same speaker and phase inverter/power-stage coupling setup.

I should begin actually building in a week or two. I'll let you know how it goes.

[Richie]

If i were to use the power setting option,i would go after the VVR type control. over the half power switch any day..

As for what some of you are describing..I built an 36 watter, that was a blend of both the express and 18 watt channel amp. Called it the TREX.

Somewhere i have a layout of that amp. Also i think Mark Huss drew up a tweaked version he built of this amp,with a schematic. Since these are a bit different than just a clone of an amp.. kinda melds a wreck ,and a 18 watt marshall channel.

But i agree, that looks like a sort of half power switch on the Ginger.

Later on, after i clear up a few other things, i may get to working on a Liverpool.. my Wreck is in sort of Limbo right now,thill i have some of the other amps built and out of the way.. Then back to the Express.. and another couple modified versions. The Heyboer 36 watt transformer set ought to work great for one of these type amps.


Richie

[LeftyStrat]

I have an old Dynaco A-470 (4k3 primary) that I originally wanted to use for a stereo, but I've never been able to snag a companion for it, so I thought it might be nice with a quad of el84's. Unfortunately, I don't believe I have any suitable iron for the PT. A local tube store here in Seattle closed recently, and he was selling off his considerable stock of transformers for a dollar a pound. I picked up a bunch of great stuff, but most of the PT's have a higher voltage than what el84's like.

I have an old Acoustic 165 tube amp with the half power switch 60/100 (they just lift the cathodes on two tubes). It doesn't make that much difference in overall volume (ears bleeding vs ears bleeding and puking), the difference is more about headroom and possibly beefier bass response.

The trick with the half power is that you have to bias it in half-power mode, since the voltage creeps up when the tubes are disconnected, otherwise you'll bias it too hot.

[Richie]

The trick with the half power is that you have to bias it in half-power mode, since the voltage creeps up when the tubes are disconnected, otherwise you'll bias it too hot

You've got that right.. if not you'll have a tube cooker

Richie

[krash]

Richie, I'm very interested in your TREX design.

Do you care to share? How does it sound? Do you have schematic or layout? Maybe that's what I need to do with my C30.

Thanks-

[LeftyStrat]

There's a schem and layout on Mark Huss' web site:

http://www.mhuss.com/18watt/schematics/

[UR12]

Mark Abbott sent me an email this morning and I just thought I would share a little of his insight. Mark said that the only two Liverpools he had seen did not have the 1/2 power switch or the line out on the back. It would appear then that Ken only included the 1/2 power switch and line out on Ginger or maybe some of his amps. Makes me wonder how successful it was or why he decided to delete it. I am going to go ahead and build Ginger with the extra switch and Line out. I got a PS board mocked up today and thought I would share it. It's not as fuzzy as the Ginger pics. I'll try and get the layout and updated version of mark's schematic posted soon.

[UR12]

Well After a few days more of staring at blurry pics of Ginger and Mark Abbott's schematic, I finally came up with what 'I think' is the wiring layout for the PS board. The third switch IS a 1/2 power switch there are two resistor/cap combinations in parallel and one is clearly going to the third switch and the switch grounds one end. I don't have a clue why Ken would have used a 25 watt resistor in one cathode circuit and a 10 watt in the other. The 25w 130ohm / 220mfd cathode bias resistor and cap goes to the two outer tubes for 18w mode and the 10w 130ohm /220mfd cathode bias resistor/cap goes to the middle two tubes and is switched in and out via the front panel switch.

I have drawn up the wiring diagram and added the extra components to Marks Power amp schematic. If anyone sees anything that needs to be changed please let me know.

Note:Use at your own risk. I haven't tested this yet.......