Hi, I am new to tube amps and have bought a cheap Chinese amp as somewhere to start. I have been listening to it for a couple of weeks and I'm very pleased with the sound.
What I don't like is the nasty pcb that everything is mounted onto and would like to junk the board and hard-wire it. I have managed to draw most of the cct after a start from a cct that MOAMPS drew some time back.
What I would like to know is, what the (20k I think) trimmer from pin 7 to ground of the input valves is for and how to measure its effect?
Any other (non obscene) comments for any of the other parts in the cct would be most appreciated..cheers..
What I don't like is the nasty pcb that everything is mounted onto and would like to junk the board and hard-wire it. I have managed to draw most of the cct after a start from a cct that MOAMPS drew some time back.
What I would like to know is, what the (20k I think) trimmer from pin 7 to ground of the input valves is for and how to measure its effect?
Any other (non obscene) comments for any of the other parts in the cct would be most appreciated..cheers..
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The pot is AC balance, for maximum of 2'nd order distortion cancellation.
Nice drawing!
What software did you use?
Nice drawing!
What software did you use?
Wavebourn said:
OK, so you would need an oscilloscope to set that?
I used express PCB (free) but had to draw the valves. (could not use eagle at all)..
A picture of the inside, I expect the large capacitors I fitted are showing my non understanding (ignorance) of tube amps...
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Hi, audio1st
I have a question: is it a poor quality PCB or you like more point-to-point wire?
I'm curiouse to see a picture of the original PCB, can you post one?
I have a question: is it a poor quality PCB or you like more point-to-point wire?
I'm curiouse to see a picture of the original PCB, can you post one?
Makeover finished, hardest part was removing the last bit of hum.
The 330ohm resistor where the feedback connects to, had to be earthed via the pot ground. My thanks to SY for his earth suggestion on another thread that allows me to connect the case to a safety earth without causing ground loop hum...PS sounds great..😀
The 330ohm resistor where the feedback connects to, had to be earthed via the pot ground. My thanks to SY for his earth suggestion on another thread that allows me to connect the case to a safety earth without causing ground loop hum...PS sounds great..😀
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