A friend of mine sent this to me today. I thought I would pass it along as I really love the way these amps sound and I think you will too. I'll leave this up for a few days, if someone else can host it after that would be great.
I would have used the 2 x 220k resistors as a dual pot for the master volume, and a filter choke instead of the 150 dropper resistor between the plate (output transformer primary centre tap) and screen grids - a 9w flourescent light ballast works well for a cheap and effective choke filter by the way - got to have that choke - old skool me
bajaman
There's room for improvement on this one. It's basically an AC15 with a lot of oomph. It's sort of new, very portable and people are raving about it. Did I say cool tone?
I don´t know why, but for some subjective personal reasons I would prefer this design: http://www.drtube.com/schematics/marshall/4001m86.gif
At least in 1984/1985 it was so....today I would add/change some little details - For example remove the tone-control between the first and second stage and place it later in the signal path.....
The OOP-Amplifier looked like this:
analogguru
There´s a sucker born every minute - and too many of them end up in the bootweak pedal biz.
I would have used 2 EL84 without feedback - but the trend/demand from the customers this time was more to the Fender deluxe reverb. They want it - they got it - the difference is marginal. The speaker was more important... the first "Retro"- blue celestion:
A 12" Celestion G12 Vintage 30 speaker
The next amp I want to do will likely have EL84s - mostly because I'm not used to them. Nearly every small amp I own uses 6V6s, so I'm wanting to hear the difference between the two.
I just finished my first prototype for my 12K5 DI amp - it's sounding pretty rockin', I'll get something put up when I get the thing assembled in a chassis - it's living on a breadboard right now. Imagine something kinda like the H&K Cream Machine, except designed for 12v operation with space charge tubes.
I had no problem downloading from rapidshare, so I will not be hosting them - If you still cannot download tby tomorrow, let me know and I will send them to you.
Cheers
bajaman
You can use the same trannie for EL84 and 6V6. I would wire tube sockets parallel for both tubes, it's not much effort and the tube type can be swapped with ease. For the use of 6V6 the 47k in the phase splitter must be decreased too (the 6V6s need a stronger input signal).
The TT uses a R/C combi to generate the floating BIAS for both tubes, I would alter this to a split R/C combi for each tube (less interaction and a bit better sound).
You can use the same trannie for EL84 and 6V6. I would wire tube sockets parallel for both tubes, it's not much effort and the tube type can be swapped with ease. For the use of 6V6 the 47k in the phase splitter must be decreased too (the 6V6s need a stronger input signal).
do you know an amp that already does that? could you link a schematic if you know one?