Well.... Summer's over, I'm back at college and I just finished the project I've been contemplating for 5 months. It's a cute little red Marshall-style amp. Same controls as a plexi with the addition of a SS/tube rect. switch and a post PI master volume on the back panel. Two EL84's at about 250 volts so it's doing about 12 watts. Not that it's a big problem to only have 12 watts. It still does 115 dB through its matching 112, complete with an old creamback Celestion. It sounds incredible for old-style Cream tunes or Hendrix. Not to mention I won't go deaf quite as soon and I can have my sound without the rest of the band complaining!! I'd love to have someone in the Nashville area give their opinion. Or... Someone else build one and see for yourself! Incredible! JT My amp is really just a Marshall model 1987 50 watt circuit (like you can find on the net) modified in a few small ways.... 1. Change 1m resistors in PI to 470k- makes it more like an 18watt Marshall circuit from back in the day. 2. Replace the EL34's with EL84's- similar tube, two very different power ratings. 3. Use a 6ca4 (EZ81 european) for rectification and put the diodes on a switch so that they'll bypass the tube.- As for the bias, the EL84 seems to be pretty tolerant of varying plate and bias voltages plus the plate voltage on my amp is very low- I'd really like it to be 100 volts higher so it would be less brown and more plexi-ish. However-Right now it sounds very much like Clapton's sound with Cream. I can't complain!! 4. EL84's need very little signal to overdrive so I did one mod that counteracts this in two ways. Replace the 220k grid resistors with a dual 100k audio taper pot. Connect the bias supply to one end, grids to the wipers and drive from the PI to the other terminals. This loads the PI more (less drive) and splits the load when turned down (even less drive) 5. Changed bias supply to have far less neg. voltage but a wider range of adjustment. I was trying to avoid just having another cathode biased amp. I was really trying to preserve most of the elements of the marshall so that I could get that exact sound but at lower volume. I think this answers most of the questions. BTW, How would I draw a schematic to post here or anywhere? What program would I use? When I wired up the switch I just soldered a pair of 1n4007's to the plates of the ez81 and soldered the cathodes (of the tube to one pole and diode to the other pole) to a spst switch. This effectively put the ez81 out of circuit since the diodes conduct a lot sooner than the tube. I was originally worried about the need for a bias change but my the change in plate voltage is only about 15-20volts, depending on the bias setting. You could always use a dpdt switch and have a seperate high-value bias pot be switched in parallel with the existing pot, giving you two bias settings with one bias circuit. whatever the case, the plate voltage is hovering around 250. With the thing channel linked and dimed out with my HS-2 equipped strat in the bridge position, driving a single reissue creamback, It's putting out about 18 watts. (Highly distorted) I've found that I can get clapton-type sounds by using the bridge pickup and the same settings as above. I'd love to hear it with an ES-335! Using just the bright channel at about half to 3/4 volume I can get old Van Halen sounds. My personal favorite, however is using a 4-knob tube driver into a delay into the amp- channels linked and volumes maxed. Turn the presence down all the way and pretend you know how to play "Cliffs of Dover!" About that presence and brightness thing- to make it a little darker I put a .001 uf cap across the feedback resistor. I also decide that the caps I was using on the PI driver were funky and replaced them with old .039 uf caps- This seemed to make sense because- 1. the R/C load of the PI is different because of the dual-ganged 100k master volume pot. 2. THe .022 uf caps I had there previously looked cheap and had no epoxy around them- They're the silver 600v ones from Javanco in Nashville, if any of you techs care to give your opinion. Steve- I do hot switch the rect and the amp doesn't seem to mind- no thump, no bias jump, and cathode current stays around the same level each way. Where would you bias a pair of EL84's? It seems to sound good around 40 ma a pair, but this is for old Grommes el84's that spent the whole summer in a cathode-biased amp running at 450 volts B+. (they're pretty durable!) They don't seem to mind the current and I've had the cathode current above 40ma already. When I can afford it I'll try the Sovteks. The master volume (which I rarely use) is a daul ganged 100k pot set up to replace the 220k bias resistors. The wipers are tied to the el84's grids. This thing is still stinkin' loud!! I took it to a music store today and had a session guy asked about it. He kinda did a double take when he saw this tiny little amp the looked exactly like his super lead. It's not boxy looking like Budda's 18 watt amp. People seem to be hungry for this type of amp. I see no reason why anyone (EJ included) would want any more volume than this thing has!! I'm flattered by the response I'm getting from my little project. Thanks, guys! P.S. Did I mention that I just turned 19 and I think I've found what I really want to do with a good portion of my life?!