Neve 1290 Questions - Vintage Design

[Rob Flinn]

Duka

Your box looks mighty fine.

Its strange that you are getting hum on one channel. My version has no noticeable hum on either channel.

Looking at your pictures, I would have swapped the position of the mains transformer & PSU board. This would have got the transformer slightly further away from the audio stuff. The position of the transformer is more likely to give you a problem like this than where the PSU board is placed.

 

[dukasound]

[quote author="Rob Flinn"]Duka

Your box looks mighty fine.

Its strange that you are getting hum on one channel. My version has no noticeable hum on either channel.

Looking at your pictures, I would have swapped the position of the mains transformer & PSU board. This would have got the transformer slightly further away from the audio stuff. The position of the transformer is more likely to give you a problem like this than where the PSU board is placed.[/quote]
Yes when I move transformer I lost hum, but I cant locate it on the other place.
Duka

 

[Tekay]

Very nice!
Put the transformer in a separate box outside the unit? Or shield it very well!
For bias I think 80-81mA through the primary windings is fine.

 

[dukasound]

[quote author="Tekay"]Very nice!
Put the transformer in a separate box outside the unit? Or shield it very well!
For bias I think 80-81mA through the primary windings is fine.[/quote]
Thanks Thomas
If I understand to measure 80-81mA through of output transformer primary. Can I desolder one wire from primary and put meter in series?
Control on zero, no signal :?: :?: :?:

 

[Bauman]

Hey Duka! Nice!
You are working hard as I can see

congrats!
Fabio

 

[maxwall]

Wow,

I've been away from this thread for a little while.....

Duka that is really a great studio rack piece now. splendid work.

 

[pmroz]

.
Duka,
I think CJ suggested (or was it PRR?) to put a tuna can around toroid.
You saw this i bet. Works very well... cut a small slot for wires.
Also must clean it thoroughly... like soak overnight in dish soap.