Dc offset on usamps axtu 1000

[tomat]

i have a problem with this hybrid amp, i measure 1 volt dc output on right channel speaker output,what can cause this?

thanks

 

[tomat]

Anybody can help? Thanks

 

[Perry Babin]

I didn't reply because I know nothing about the amp.

Does it produce clean audio on the channel with DC offset?

 

[tomat]

thank you,i'm not try to connect to the loudspeaker yet,i'm just measure at the speaker output terminal

 

[amc32]

Don't use a speaker as of yet,grab an O'scope and view the signal with no load and/or speaker.

 

[tomat]

thank you,i feel strange with the relay,it works too soon,after i turned on the amp,only 2 or 3 seconds the relay starts to work,it placed after the capacitor from the tubes to transistor circuit (amplifier circuit)

 

[Perry Babin]

Do you have DC offset before the relay clicks?

 

[tomat]

yes,about 150mv,and then +/- 1 volt after the relay clicks.
thanks a lot

 

[Perry Babin]

Unless someone has some hands on experience with this amp (or something similar), I think you'll have to compare one channel to the other to see where the DC is being introduced into the circuit.

 

[finbar]

I know this is an old thread but I have just gone through adjusting the DC offset on a USAMPS AX TU1000C.
Greg at U.S. Amps got me squared away, he was very approachable and helpful.
A multi-meter, screwdriver and allen-wrench did the job.
I powered up the amp with no input or load and let it sit for 20 minutes.
I adjusted the pots (small increments) while monitoring the offset to <100mV at the speaker terminals.
The pic is of my amp, pots circled.
If your board is different and/or you need direction I highly recommend Greg.
No more turn-off pop 😀