disassembled
Well-known member
Yep folks just like the title asked. I am looking for the schematic for the 20/20 power amp. Not for any particular reason but I just like having access to it incase I have to perform repairs or mods in the future.
To anyone that has opened their 20/20 amp:
Did you notice that either of the output trannies were loose? This was the case with me so I tried tightening up the screws underneath but they were already tight. It turned out the screw head was too small for the hole drilled into the chassis causing it to not be secured properly. I put a washer around the screws to give them a chance to grab the outside of the chassis which made it look a little ugly but stopped any potential rattles.
Another thing I noticed was that the tube mounting board seemed flimsy when removing or installing tubes. Has anyone has serious trouble with theirs?
Other than that, the circuit layout is very nice, there's tons of room, the cooling system works well, and the component selection seems pretty robust (1/2 watt resistors all around instead of the usual 1/4 watt). This amp seems like it would be extremely easy to work on.
Possible mods: Adjustable Bias (maybe, not too sure. Kind of debating whether it is necessary), tranny choke, and switchable deep mod (this mod is so simple it's rediculous). The deep mod can be made switchable by the Tri but I am not sure if the sonic advantages are worth it.
That's all for now.
To anyone that has opened their 20/20 amp:
Did you notice that either of the output trannies were loose? This was the case with me so I tried tightening up the screws underneath but they were already tight. It turned out the screw head was too small for the hole drilled into the chassis causing it to not be secured properly. I put a washer around the screws to give them a chance to grab the outside of the chassis which made it look a little ugly but stopped any potential rattles.
Another thing I noticed was that the tube mounting board seemed flimsy when removing or installing tubes. Has anyone has serious trouble with theirs?
Other than that, the circuit layout is very nice, there's tons of room, the cooling system works well, and the component selection seems pretty robust (1/2 watt resistors all around instead of the usual 1/4 watt). This amp seems like it would be extremely easy to work on.
Possible mods: Adjustable Bias (maybe, not too sure. Kind of debating whether it is necessary), tranny choke, and switchable deep mod (this mod is so simple it's rediculous). The deep mod can be made switchable by the Tri but I am not sure if the sonic advantages are worth it.
That's all for now.
