to brianqq....I had to build a guitar amp for a musician. The hum was almost always my main problem. I don't know how much experience you have, but I silenced them all.
first tube is stage one and two.
I have disconect stage one from the ciruit.
Disonected the grid from stage two from the ciruit and grounded it.
the only time it stops is when I disconnect the plate from stage two, or pull first tube.
I have disconect stage one from the ciruit.
Disonected the grid from stage two from the ciruit and grounded it.
the only time it stops is when I disconnect the plate from stage two, or pull first tube.
Which treble pot mode reduces hum?
first tube is stage one and two.......... this is v1.....You connect the grid to ground and the hum is stop , but u 9, can not stop hum ?
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Try to use -for example- 470k grid leak resistor for U4b and temporary remove wire from U9 pot to U4b grid.
V1 is correct.
The top pot is trebble, the second is bass and last is mid.
all pots effect pitch of hum,
The trebble effects volume of hum as it is turned down
The top pot is trebble, the second is bass and last is mid.
all pots effect pitch of hum,
The trebble effects volume of hum as it is turned down
Hum may be coming from the heater supply
A simple fix may be to raise the heater winding to 30v DC
A simple fix may be to raise the heater winding to 30v DC
I completely bypass the first to stages, plugged in a guitar and it sounded fine, not much gain but fine.
Going to rip out the entire first two stages ( including the socket) and build it backwards testing it as I go.
seems if there was going to be heater hum it would still be there in some amount.
Wont add the relays back in untill its clean.
I had the 5v regulator disconected from the secondaires so not causing a problem.
Going to rip out the entire first two stages ( including the socket) and build it backwards testing it as I go.
seems if there was going to be heater hum it would still be there in some amount.
Wont add the relays back in untill its clean.
I had the 5v regulator disconected from the secondaires so not causing a problem.
When I built first a guitar amplifier, I had no idea... it was completely different from a hi-fi amplifier. Due to the higher gain, noise is heard in the speaker. And the higher the gain, the more noise becomes incredible. The tone control reacts to the amount of noise naturally, but it does not create it itself.The tube... which is the first amplification unit, can actually be a source of noise. To test and differentiate, it must be disconnected from the rest of the circuit. If there is a gain control pot... closing it will completely cut off the noise. HUM can be very loud in a sensitive guitar speaker.The filament for the tube V1...must be DC. I did this many times. The way of assembly is very, very important. Fender was an art in assembly. The type of grounding can fix silence, but you have to have a model and experience.. There are no pictures of his work.
..brianqq:.............U9 is off and it does not changeThe first stage is not effecting this at all, as stated in OP........please send picture of your project .
..brianqq:.............U9 is off and it does not changeThe first stage is not effecting this at all, as stated in OP........please send picture of your project .
We figured it out. the fact that the heaters had two taps for the different voltage, the center tap wasn't working right.
The CT was removed and we used the two 100ohm method and it worked, then elevated it with dc for good measure.
Now I need to float the ground on my power regulator and relays that is using the heaters for the in.
Not sure how to do that
The CT was removed and we used the two 100ohm method and it worked, then elevated it with dc for good measure.
Now I need to float the ground on my power regulator and relays that is using the heaters for the in.
Not sure how to do that