OK, I finished me drawering and will try to post it. The layout is of the Ampeg B25-B which in my opinion is one of the greatest sounding amps to my ears and has become the mainstay of my sound out of all my amps. I Hoffmanized the layout and made a few minor modifications which I'll number below. For the interminably bored, (like me), that actually look at this, feel free to point out any errors I've made. I'm a novice at best with schematics and until now the most complicated schematics I've tried to figure out were mostly a few single channel fenders so their could be mistakes but I've yet to find anything to be terribly erroneous by myself. Figuring out the PI and changing it to accept the 6GH8 nearly drove me to madness.
Ok, the changes:
1. I used single input instead of 4. I used the channel switch like on Sluckey,s Supro.
2. I put the bright switch ("ultra hi") on a push/pull pot with help from Sluckey. Thanks!
3. I omitted the "ultra lo" switch entirely because I simply do not like it.
4. The "shift" pot was added per Merlin's illustrations of the James Tone Stack in his preamp book.
5. PI tube was changed from a very expensive 7199 ($90- $120)to a much cheaper 6GH8 pentode/triode ($8). (Pin numbers are different.)
6. Added 470R to screens.
7. Changed bias circuit...is adjustable.
8. Wired octals to accept 6L6. The Ampeg used 7027A. Disconnect pin 1 from pin 8 if you want to use 7027. Pins 1 and 4 are internally connected on a 7027.
I'll get Visio or something comparable in the future but for now here's the drawings. I'll post them in a new reply. Hope they're legible...and correct.
Topic: Bright switch (Read 3960 times)