Paul Joppa
Moderator
Considering the age of the am, it is possible the 100uF electrolytic filter capacitor is getting old and not functioning as it should.
S.E.X monoblocks - filter caps
- Thread starter Psimon
- Start date
You live in the country of origin. The part number for that cap is likely EKMM451VSN101MQ30S.
Update:
I replaced the 100uF electrolytic filter capacitors but it made no difference. I've again checked all the joints, measured the voltages in L & R monoblocks but there's no significant differences that I can find. Resistors seem to be functioning at the right ohms.
One thing I have noticed is that when I flick the switch of the power amp, the hum starts off louder for a second or two and then settles to about half the volume.
Does that suggest anything?
Cheers,
Simon
I replaced the 100uF electrolytic filter capacitors but it made no difference. I've again checked all the joints, measured the voltages in L & R monoblocks but there's no significant differences that I can find. Resistors seem to be functioning at the right ohms.
One thing I have noticed is that when I flick the switch of the power amp, the hum starts off louder for a second or two and then settles to about half the volume.
Does that suggest anything?
Cheers,
Simon
Paul Joppa
Moderator
OK, so we've tried the easy guesses and not found the problem. Time to get more methodical.
Has the amp always hummed, or did it start doing so recently?
Does it hum when nothing is connected to the input? You will probably have to short the inputs temporarily to do this test - a shorted RCA plug is a convenient way to do this, but a clip-lead can do the job if that's all you have.
We'll do what we can to help, but there is a limit to how much help we can provide, since the circuit and most of the components are changed from the original and unknown to us. The filter choke on the top side is not original, and the center tube socket is also not in the original, though it appears to be used as a terminal strip. We may need more pictures, too. Just so you know what to expect.
Has the amp always hummed, or did it start doing so recently?
Does it hum when nothing is connected to the input? You will probably have to short the inputs temporarily to do this test - a shorted RCA plug is a convenient way to do this, but a clip-lead can do the job if that's all you have.
We'll do what we can to help, but there is a limit to how much help we can provide, since the circuit and most of the components are changed from the original and unknown to us. The filter choke on the top side is not original, and the center tube socket is also not in the original, though it appears to be used as a terminal strip. We may need more pictures, too. Just so you know what to expect.
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