Hello everyone, first post. I have a new to me CSP2+ it sounds great. The person I bought it from sent new tubes with it. (3) 6n1p-ev and1 Mullard GZ34. Got some questions. The output controls if I turn them to the 2nd position I get a very noticeable hum, right and left channels. The input controls need to be at least 2 positions different to balance. I'm running a pc with tidal and a ifi DAC. I've tried both inputs. Is this something normal? Or should I give the new tubes time? Thanks

Very good advice above from Juan. Also, pay attention to cable placement. Three out of four times I've had hum problem it has been cured by routing all power and signal cables carefully as far from each other as possible. Even with shielded cables I would get hum at times with some placement.

Thanks everyone for the advice. I will try each step and keep everyone updated.

Most run the input pots high. With most tube combinations, I run mine in the CSP3 at 8. I also run the outputs usually at 8. This will vary according to build, tubes and tastes. Before I upgraded to Jupiter caps and Steve did a mod to make different output tubes work without overloading (mine was one of the first CSP3s), I ran the output pots more like 5-7. The point being ....you should be able to run with much higher gains with minimal to almost no hum.

When you changed around the 6N1Ps did you also rotate the input, or just switch the output positions. I am pretty sure I have gotten channel imbalances with the input being a little off, and any tube can be noisy, especially if it is failing. Rectifiers as much as any can create various levels of hum.

If your system was balanced before, it should be pretty close with the CSP if the tubes and cables are good and suit the setting.

Good luck!

Another? Where is the best source for tube? Thanks

Sent some pics to Steve of the amps interior. & just ordered new set of tubes. Its a start.
Vashod 3x 6N1P-EV
Mullard GZ34