Gates SA-39B A few problems

[vinvol]

Hello
I recently have replaced all the caps in the machine, and installed good tubes, and it finally makes sounds. But the unit has a few issues.

1. The sound is distorted when I tweak the input pot over 10AM direction. Below 10AM, the sound is OK, but the compression does not occur(no VU movement when the input signal is too low, which is natural)
The current pot(attenuator) is not original one and someone replaced it before. It is written 2 x 100k (4k7). I am wondering if this modified pot can be the cause or something else.

2. I have seen someone replaced the pot with a modern pot. Can anyone recommend any high end replacement pot?

3. When I turn on the unit, it makes pops and noises. After for some period of time of power on, the noise disappears. Is this because of the tubes or can other parts be the cause?

FYI:
- I checked L1 : 445v in and 419v out.  so the power is OK.
- The neon blub in the back is working OK.

Thanks,
VV

 

[beatnik]

the original schematic also calls for a 100k dual pot ( R1A and R1B)

you could try bypassing the pot and see if compression is happening

regarding the noise and pops, i presume it's tube related