I designed this thing when I still thought that there was some benefit to only utilizing one triode per bottle. When I realized that was not the case, I was not too happy because figuring out the best ptp layout for four valves is exponentially more difficult. See, when you lay out an amps face and decide the exact distance of the valves ,pots and inputs from eachother, what do you have in mind? You probably heard the ptp demon tempting you to take all of the pots, connect their terminals directly to eachother, solder them and hope the user can read. I basically gave into that ptp demon in a big way. And don't go thinking it stopped with the pots. After reading everything on the net about point-to-point and ideal grounding, my design just wanted to turn into a sphere. It basically did. This is not an ergonomically correct amp to any extent. As you can see, the knobs are all askew--hopelessly scattered across shabby preamp's dull, aluminum face.
And do you think that after reading all of that parannoyed, audiophile insanity I would be able to stick the power supply in the same 6-foot radius as my preamp? NO WAY!
And about that power supply...
Power supply (THE TRAIL TO INSANITY)
Cris's preamp circuit it awesome. The problem is he put very few details on construction on his page. What the hell was the B+ voltage on this thing? After a few emails he finally told me "I think it was 350v" just to shut me up.
Basically, I know nothing about hi-voltage electronics. I'm more of a chips and programs kind of electronics hobbyist. My fundamentals really leave something to be desired!!! SUDDENLY, like an angel, Fred Nachbauer reaches down from the highest point in heaven to save me...almost. I used a power supply based on Fred Nachbauer's(R.I.P.) "standalone preamp" power supply. The day after I veiwed the universe that is his site, I wnt back to study and copy the power supply, and his site was down. And it stayed down for a long time. Meanwhile, I needed a power supply. I remembered his design except for the voltage tripler part so I improvised one. When his site came back up I saw that his circuit was different than mine! The amp works, but I suspect my Im having a filtering problem. That is, I think my tripler is half-wave tripler which are harder to filter. ***UPDATE*** I give up ***UPDATE*** Major breakthrough. Turns out the heater voltage matters!! Who knew?
SUMMARY OF MAJOR MESS-UPS
1) Four triodes does not mean four 12ax7s. My design only was using half of each triode cause I swear I read that its better that way somewhere. I fixed it by bypassing the extraneous tubes and rewiring. I have yet to find a purpose for the extra room and slots--with still-powered filament leads(any ideas?)
2) Did the "right thing" and breadboarded everything first. BIG mistake. So I buy a brand new protoboard from Texas-based consumer electronics company, Radio shack. My transformers keep getting hot for some odd reason. After a week of tearing the amp apart, reading, posting on web boards, it turns out the board was full of shorts. More recently I almost blew my head off while adjusting a voltage tripler on the same breadboard (gotta get my money's worth). Then there was that time when a resistor burned a hole in it...
3) The flyback tranny incident.
4) more to come