I've got a Punch 125.2 with a gain control that i believe to be out of tolerance. There is about a 1 k ohm difference between the gain controls for each channel when both are turned into their max or minimum positions. Is that difference in ohm load going to cause any huge problems?I can get equal output from either channel, I just have to turn one up a lot higher than the other to acheive the same output. I'll probably just change them both out as they look to have been abused by the previous owner.
It probably has a linear resistive element. To make sure, set the pot to the center position and measure the resistance from the wiper to either leg. If they're approximately the same, it's a linear taper pot. This needs to be done with the pots out of the board.
There should be a 909 and a 270 ohm resistor (values used in older amps) for each gain section. Check them to make sure they're in tolerance. If any of the components (including the pot) are out of tolerance, it could account for the difference in the gain at the maximum setting. If the pot is the culprit, I'd expect the gain at the minimum setting to be precisely the same.
I attached a typical Rockford gain control circuit.
Mouser stocks Piher pots and will likely have a suitable replacement.
There should be a 909 and a 270 ohm resistor (values used in older amps) for each gain section. Check them to make sure they're in tolerance. If any of the components (including the pot) are out of tolerance, it could account for the difference in the gain at the maximum setting. If the pot is the culprit, I'd expect the gain at the minimum setting to be precisely the same.
I attached a typical Rockford gain control circuit.
Mouser stocks Piher pots and will likely have a suitable replacement.
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