Advice for a Newbie Mini-JTM45 Build

[bluesbreaking]

Nowadays I'm living in an apartment where I can hear my neighbor's phone vibrate... Naturally, I can't crank any larger amp, so I want to build a little JTM45. What I had in mind was taking an AX84 P1E (using a KT66 output tube) and building a JTM45 preamp to match. I know the phase inverter is an important part of the tone, so I can't really just tweak the values on the regular P1 to be closer to JTM45 specs.

My question is: can I just build a regular JTM45 preamp until I get to the power tubes and just use one power tube with the one output which would usually go to one of the KT66s?

[EFK]

Sure you can. I just built one myself, although I went more the plexi route as opposed to JTM. I can also guarantee you it will not help with your apartment situation. I don't know what these SE Marshall types are making re: output power; maybe 8 or 10 watts? It doesn't sound that much quieter than my 70s aluminum panel through the same cab. If you want to try an experiment, take a JTM or plexi or whatever and desolder one end of the PI cap feeding V5. I don;t think it matters which end you desolder, just lift one end of the cap and leave it there out of the way (this way the tube still gets its bias voltage - do NOT just ground out the grid). Now play it - yes, there's a little difference, but not much. It's easier to try this on a cathode bias amp where you can jsut quickly ground the grid and really go back and forth, but if you are looking for real low volume, you need to be looking at something that will give you no more than 1 or 2 watts max. Somewhere on the AX site, someone had a schematic for a little monster that used a 12AU7 triode (I think that's what it was) in push pull, or maybe it was a 6SN7, something like that.

BTW, there really isn;t any trick to the PI. Just build the first half of it and double the cathode resistor from 470 ohms to 820 ohms. Leave the cathode elevated w. the 10K tail, basically just omit the second side plate resistor, grid resistor and .1 cap. Works perfectly and keeps your NFB setup intact. I think this sounds a lot more "real" than just building another 100K/1.5K gain stage like some do which then forces you to alter the nfb/presence application.

[gldtp99]

The single ended 10 watter i built (w/one RCA Blackplate 6L6GC) is much too loud to play, cranked up, in my apartment--- this one has a #36 Mod preamp--- i put a MV after the tonestack (typical JCM 800 pre-PI MV) and this feeds the output tube--- so it can be dialed down to "constipated mouse fart" if wanted--- but what's the fun of that ? If always used this way, most of the amp's potential would be wasted.
The 14/7 watt (pentode/triode switch with push/pull EL84's) 2204 w/#34 Mod head i built is also much too loud, on either power setting, to use in the apartment.
But i can play my Marshall 4010 (again w/#34 mod) at home because I installed a Lar/Mar PPIMV--- at apartment-friendly vol levels the tone isn't exactly perfect--- but if i just have to play at home then it will do--- or i can wait until i go over to my shop where i can play as loud as i want to anytime of the day or night.
Tube amps running through live speaker(s) just aren't a good idea for apartment living.
A friend played the SE10 watter through a 4x12 cab when he dropped off his 2553 Silver Jub for service (hit by voltage spike onstage)--- and he was very suprised by how loud a SE 10 watter is---- he had a strange look on his face and said, "How can 10 watts be so loud ?"
Or think about an Iso Cab--- http://www.guitarcenter.com/Jet-City-Am ... 1529342.gc

[bluesbreaking]

Thanks so much for the responses! By the looks of things, I'll need to research using dual triodes as output tubes... The Firefly is the one I think you're talking about, EFK. I can't tell how the 12AU7 by itself sounds as an output tube, so I'll need to research how to make that sound more like a KT66 before going ahead.