Neumann/Gefell N61V sounds like waterfall

[TillM]

Hi guys,
I’ve a N61V PSU on my table and I can’t find the fault.
The UM57 sounds like a waterfall, when I use this PSU.
A friend of mine has also the UM57 and I tested the mic with his PSU (aftermarket) and its definitely not the mic.
I changed the 1uf cap and 20uf capacitor on the transistor psu.
The other capacitors show the right values.
I also get a NOS rectifier tube.
Still the same problem.
Has anybody an idea what I could change?

Best regards
Till

 

[[silent:arts]]

Remove the TV 61 amplifier board and convert your N61V back to a N61

 

[TillM]

Thanks Volker !
I will try it and report back,
Things could be so easy.
I hope that it solves the issue.

 

[TillM]

Volker thank you so much !
Amazing ! Now it works without sounding like a waterfall!