Is there a difference between the VTA driver board for the ST-70 and the ST-120?
I am starting to get some popping and volumn jumps in the right channel of VTA-120 with the step attenuator and when I touched the knob the other night, it made a loud hum. So, I am thinking about removing the step attenuator completely and upgrading to the new CCS VTA driver board with the lower gain 12AU7 tubes. With my current preamp, I can only get to about 9 o'clock before I am almost at full volumn.
I saw someone had a modern VTA driver board for an ST-70 for sale on eBay, but it was removed from an upgraded ST-70. So, if I was to purchase this board, what changes would be required to make it work on an VTA-120?
Lastly, could the hum and jumping in volume be a bad solder connection on my step attenuator?