Hi....
I think i finished my power amp design. I would like to hear your comments. this is my first one, so i would like to know what mistakes i made. I intend to use it as a stand alone guitar power amp so i can learn a bit about preamps...
A few considerations:
- the B+ is lower than usual. That was on purpose. I had this power supply here that i wanted to use. This is was the starting point of the design. FYI, the power supply itself, which is not shown, has two 470u smothing capacitors (this used to be a laser power supply), so i should have very little ripple. also i am using a bridge rectifier capable of driving 30Amp.
- the valves I am using came out of an old RCA amplifier i acquired. The whole thing cost me $10...and i learned a hell of a lot by using it. That explains the choice of cathodyne with 6CG7 tubes. I figured if used an LTP PI with those tubes, gain would be way to low. The simulation shows that at full volume i still should be able to drive the output tubes into clipping (not by a lot though).
- I tried to be careful with blocking distortion and distortion of the PI, i am not sure if i exaggerate a bit, but still....
- for the biasing i will be using a regular 24V power supply you can find at radio shack. Would that be ok?
also, if you guys could consider power ratings on the resistors and voltage rating on the capacitors, i would appreciate as well...
Thanks a lot
I think i finished my power amp design. I would like to hear your comments. this is my first one, so i would like to know what mistakes i made. I intend to use it as a stand alone guitar power amp so i can learn a bit about preamps...
A few considerations:
- the B+ is lower than usual. That was on purpose. I had this power supply here that i wanted to use. This is was the starting point of the design. FYI, the power supply itself, which is not shown, has two 470u smothing capacitors (this used to be a laser power supply), so i should have very little ripple. also i am using a bridge rectifier capable of driving 30Amp.
- the valves I am using came out of an old RCA amplifier i acquired. The whole thing cost me $10...and i learned a hell of a lot by using it. That explains the choice of cathodyne with 6CG7 tubes. I figured if used an LTP PI with those tubes, gain would be way to low. The simulation shows that at full volume i still should be able to drive the output tubes into clipping (not by a lot though).
- I tried to be careful with blocking distortion and distortion of the PI, i am not sure if i exaggerate a bit, but still....
- for the biasing i will be using a regular 24V power supply you can find at radio shack. Would that be ok?
also, if you guys could consider power ratings on the resistors and voltage rating on the capacitors, i would appreciate as well...
Thanks a lot
Im sure that this amp will play. No serious problem I can see. However I would suggest a 1M resistor from the grid of the input tube to ground. As it is, the volume control not only sets the AC level into the amp but controls the grid bias as well. Even better would be the resistor plus a series cap in the 1 ufd range between the volume control and the grid.
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