Amp sounds horrible

[fossilshark]

Ive been working on this build for a few months and i just got sound out of it. Theres absolutely no sound (no noise no ambience) coming out of the speakers until i play a note then it kind of sags and fades out. I thought mabey there wasnt enough signal but my distortion pedal had no effect. The weirdest part, when i turn it off you can heard my hands on the string and the feedback for a split second and it shuts off. Does this sound like the plate voltage is too low? Ill take some readings and post them here.

[fossilshark]

When i measure the voltage it wont stop rising

[p2pAmps]

Detailed pictures would be helpful

[uki]

Also the schematic of the amp can help !

[hesamadman]

Does it act as if there is a heavy noise gate? Like if you barely hit the strings there is no sound but if you pluck them good there is a sound but with a very fast decay?

[pompeiisneaks]

As others have mentioned, if we don't know what 'kind' of amp and don't have a schematic, it becomes impossible to even guess intelligently.  Also, pictures of the amp will help us look for things in the schematic that don't match on the actual amp.

[MFowler]

You need to go over your schematic/layout against your amp to see if it is wired correctly and measure every resistor. I usually check resistor values with DMM before I wire them in and when I don't I find that I have mistakenly inserted a 100 ohm for a 100k (example) and no sound or gated sounded happens.


Hello Phil (pompeiisneaks)


Mark

[pompeiisneaks]

You need to go over your schematic/layout against your amp to see if it is wired correctly and measure every resistor. I usually check resistor values with DMM before I wire them in and when I don't I find that I have mistakenly inserted a 100 ohm for a 100k (example) and no sound or gated sounded happens.


Hello Phil (pompeiisneaks)


Mark

I see you've come over to the dark side :)  or is this the light?  I'm not so sure lol

[fossilshark]

I made a dummy, plate voltage was too high. I was using the wrong transformer line for tha plate voltage

[pompeiisneaks]

Is this some kind of multi tapped Transformer?  usually the highest voltage output is the one for the plates.  ? 

~Phil

[fossilshark]

Yes its really weird theres a 700v line with a few center taps with different voltages like 280v and 390v

[pompeiisneaks]

OH ok, gotcha, possibly an UL transformer, I think they do have two sets of taps for UL mode or some such.