Helo,guys ! How can I control DC offset of STK 403 , I have an Yamaha-rx-v357 and all STK have 1 V DC offset on output, otherwise sound is clear if protection is deactivated...
I've found on Google : "I found that the +/- Pre voltages were very important in setting the DC offset on the output."
I've found on Google : "I found that the +/- Pre voltages were very important in setting the DC offset on the output."
We would need to see the circuit it is used in. DC offset is/should be independent of any DC supply voltages and should always be near zero even in circuits with no adjustment.
It sounds like something else is going tbh.
I think this needs moving to a new thread of its own which I will do 🙂
Edit... done.
It sounds like something else is going tbh.
I think this needs moving to a new thread of its own which I will do 🙂
Edit... done.
Here are all errors ...
DC:37% -I don't know how to control DC offset of STK 403, it is 1 V in my case
PS:16%-I don't know how to solve- all voltages seems to be ok, I don't know exactly what does it mean
THM: 490% 5 FAN-I know how to solve
IMP:6 PL:255%-I know how to solve
DC:37% -I don't know how to control DC offset of STK 403, it is 1 V in my case
PS:16%-I don't know how to solve- all voltages seems to be ok, I don't know exactly what does it mean
THM: 490% 5 FAN-I know how to solve
IMP:6 PL:255%-I know how to solve
Attachments
I would just concentrate on the voltages around the STK. The supply voltages being slightly low will make no difference (and doesn't indicate a problem).
Are all four outputs showing the same DC offset. That is L, SL, R and SR.
If so then I think you have to look at more obscure reasons. Perhaps there is some high frequency oscillation occurring, perhaps being fed to the chips from the preamp stages.
That really needs a scope to check.
You could try either shorting out the mute transistors (C to E) for one of the chips and seeing if that brings the offset to zero. If it does then you have some unwanted signal causing the offset.
Are all four outputs showing the same DC offset. That is L, SL, R and SR.
If so then I think you have to look at more obscure reasons. Perhaps there is some high frequency oscillation occurring, perhaps being fed to the chips from the preamp stages.
That really needs a scope to check.
You could try either shorting out the mute transistors (C to E) for one of the chips and seeing if that brings the offset to zero. If it does then you have some unwanted signal causing the offset.
I suspect that only only channel may be acting up, but since they are all combined via 47k resistors into PRD you will have to test DC levels on each power amplifier output to see which one is the culprit, and then investigate further there.
Only if multiple channels turn out to have the exact same DC offset, I would suspect something like a bad ground connection.
Only if multiple channels turn out to have the exact same DC offset, I would suspect something like a bad ground connection.