B1 Buffer Preamp

Ex-Moderator R.I.P.
Joined 2005
found I had a nice trafo
and also have some macthed LDR

so I hope its ok to try and build Nelson's B1 buffered LDR volume control :rolleyes:
 

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when the interconnects are fitted at both ends, the grounding resistors at both the Source end and the Receiver end have virtually no effect. On this basis while listening to Audio the grounding resistors can be ANY High value. 10M if they are available cheap would do.

When one or other end of the interconnect is open then the game changes. If you do this hot (power on) then lower values would probably be better.
If you ALWAYS make or break connections when powered down, then high values are not a problem.
 
Guys, I'm puzzled

Been rolling caps on my b1, everything was fine.
Recently I ve turned it on and had massive hum- had to switch off immediately.
Next day I did check everything, reconnected wires. Everything was fine . Used it for some time.
Few days ago I put my system on and notices weak music goes along with much louder hum. If I increase volume- hum increases.

Strange, cause everything seems to be normal.

10uf caps placed outboard- russian mbgo 2. 1uf is russian 71-4...

What can be the cause of the problem.

P.S. device running off the battery.
 
Guys, I'm puzzled

Been rolling caps on my b1, everything was fine.
Recently I ve turned it on and had massive hum- had to switch off immediately.
Next day I did check everything, reconnected wires. Everything was fine . Used it for some time.
Few days ago I put my system on and notices weak music goes along with much louder hum. If I increase volume- hum increases.

Strange, cause everything seems to be normal.

10uf caps placed outboard- russian mbgo 2. 1uf is russian 71-4...

What can be the cause of the problem.

P.S. device running off the battery.
Same problem faced by one of my friend. Issues seemed to be the Russian made PIO cap itself. On measurement it was found leaking DC into signal. It was only one channel.