Hi friends,
i am restoring Revox E36 (half track 9/19) for my friend. I have a problem with some disturbing (it looks like some impulse interferences and hum) in the signal. But in one channel only ... second channel is without interfering noises ... there is only a little hum.
What can be a source of mentioned interfering sounds?
Exist possibility, that tube(s) ECC83 could be a source ?
Thanks for ideas ...
Regards Peter
i am restoring Revox E36 (half track 9/19) for my friend. I have a problem with some disturbing (it looks like some impulse interferences and hum) in the signal. But in one channel only ... second channel is without interfering noises ... there is only a little hum.
What can be a source of mentioned interfering sounds?
Exist possibility, that tube(s) ECC83 could be a source ?
Thanks for ideas ...
Regards Peter
Impulse noise is usually external to an audio equipment via the mains but if one channel only is picking this up then it could be internal due to a fault condition .
If you think its the ECC83 then remove it and refit to check contacts if not try another tube in its place.
Lots of possibilities -changes of values of components etc but try that first.
If you think its the ECC83 then remove it and refit to check contacts if not try another tube in its place.
Lots of possibilities -changes of values of components etc but try that first.
Hi Duncan2 🙂
I didn't have any other ECC83 here (new). So I tried to exchange the 3 ECC83 between each other. No significant change.
But one thing is strange: the supply voltage of the preamp is greatly increased (about 230 V on the first stage of the playback preamplifier). It almost seems that all the tubes are weak (decrease in cathode emission) and draw a small current ... and thanks to that the supply voltage is high.
It is true that here in the Czech Republic we have now 230 V and not 220 (as many years ago) ... but that would increase the secondary voltage only slightly (less than 5%).
Peter
I didn't have any other ECC83 here (new). So I tried to exchange the 3 ECC83 between each other. No significant change.
But one thing is strange: the supply voltage of the preamp is greatly increased (about 230 V on the first stage of the playback preamplifier). It almost seems that all the tubes are weak (decrease in cathode emission) and draw a small current ... and thanks to that the supply voltage is high.
It is true that here in the Czech Republic we have now 230 V and not 220 (as many years ago) ... but that would increase the secondary voltage only slightly (less than 5%).
Peter
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