For some reason, I am getting no voltage on pin 6 of both V1 and V2 (cathodes) and hence no signal. From pin 8 of V2 forward, there is no problem with the amp. I have replaced the wire, the resistors, the cap, the tubes, and still no signal. Help...
Ya, it looks like you have your cathodes and plates swapped - pin 6 on V1 connects to the first board component on the right which goes to ground. On 12A*7 type tubes : 1,6 - plates ; 2,7 - grid ; 3,8 - cathode.
KT66 wrote:Ya, it looks like you have your cathodes and plates swapped - pin 6 on V1 connects to the first board component on the right which goes to ground. On 12A*7 type tubes : 1,6 - plates ; 2,7 - grid ; 3,8 - cathode.
Also, if you used shielded cable on your input, be sure that the braid is trimmed back at least 1/8-1/4" from the inner conductor, then heat shrink it.
Some cables have a conductive layer over the inner conductor insulation to prevent noise.
If yours has this it must be trimmed back or it can short the input to ground.
Structo wrote:Also, if you used shielded cable on your input, be sure that the braid is trimmed back at least 1/8-1/4" from the inner conductor, then heat shrink it.
Some cables have a conductive layer over the inner conductor insulation to prevent noise.
If yours has this it must be trimmed back or it can short the input to ground.
You guys are great! Thanks. The amp sounds great,but I am getting some hum from the V1, V2 Filaments. I think I will experiment with feeding the filaments from above and see if that quells the noise. It is only audible if I put the gain above 1:00PM and crank the Master at 10:00.
I will definitely strip back the wire more and heat shrink it. First i want to get rid of the hum and then I will do a majo clean up and post some pics and clips....
768]http://i169.photobucket.com/albums/u223 ... G_3083.jpg[/img]
