Hi all, I have a pending issue to address.
Recently I diy a tube preamp wif a matching tube rectifier power supply. I used this combo on my existing old Sansui amp.
It seems like the amp relay un-triggered(protection led blinking) as it sensed dc on the preamp pre-out stage.
Hence do I have any solution to rectify this issue? Meaning that I able to block any dc from pre-out stage of the tubes entering the power amp stage?
Tks for the feedback.
Recently I diy a tube preamp wif a matching tube rectifier power supply. I used this combo on my existing old Sansui amp.
It seems like the amp relay un-triggered(protection led blinking) as it sensed dc on the preamp pre-out stage.
Hence do I have any solution to rectify this issue? Meaning that I able to block any dc from pre-out stage of the tubes entering the power amp stage?
Tks for the feedback.
Yes it a published circuit diagram of the M7.
Unaware of uploading the diagram though.
If the circuit is otherwise sound, there may be a turn-on transient from the preamp that the amplifier sees.
I've always added muting at the outputs of tube preamps, in the form of a normally closed relay that shorts
the outputs to ground. It's run by a 555 timer that enables the output after 30 seconds (or more).
Another option instead of the above would be significantly reducing the size of the output coupling capacitors.
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Difficult to tell from a fuzzy picture, but it looks like a 3.3uF output cap with a 1M ground leak resistor. This could put out a significant voltage for quite a lot of seconds after switching on, even with the slow start of a valve rectifier. Change the resistor to 100k and see if that fixes it.
Yes, or decrease the cap size by a similar factor, which may also improve the sound.
What's the amplifier's input impedance?
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