Before I explain what I did, I want to first say that I am well aware that I may have voided the warranty on my amp and that's not something that I'm worried about. Now for the explanation:
I searched to no avail and couldn't find any information on how to adjust the gain on the J&M Rokker 250W amp, so I decided to see if I could locate the adj. gain control potentiometers or pots on my own amp. I removed the six screws on top, removed the lid and there they were; two orange pots labeled CH1/Left and CH2/Right. Before making any adjustments I took note of the current position of each pot, so that I could return them to their original positions if necessary. CH1 was turned all the way clockwise and CH2 was turned approximately 95% clockwise. I tried various settings and did not notice any change at all in sound quality. I even tried moving the input level switch for preamp/speaker on the left side of the amp to both positions when making the changes. I found that moving the switch to the speaker position caused a ticking sound to be emitted through the speakers. However, the ticking sound is almost completely filtered out when the switch is placed back in the preamp position as received from J&M. Needless to say folks, I believe that this is as good as it gets with this amp. I just wanted to share this information in case someone else was thinking of trying this. Here are a few pics of the amp's internals.
I searched to no avail and couldn't find any information on how to adjust the gain on the J&M Rokker 250W amp, so I decided to see if I could locate the adj. gain control potentiometers or pots on my own amp. I removed the six screws on top, removed the lid and there they were; two orange pots labeled CH1/Left and CH2/Right. Before making any adjustments I took note of the current position of each pot, so that I could return them to their original positions if necessary. CH1 was turned all the way clockwise and CH2 was turned approximately 95% clockwise. I tried various settings and did not notice any change at all in sound quality. I even tried moving the input level switch for preamp/speaker on the left side of the amp to both positions when making the changes. I found that moving the switch to the speaker position caused a ticking sound to be emitted through the speakers. However, the ticking sound is almost completely filtered out when the switch is placed back in the preamp position as received from J&M. Needless to say folks, I believe that this is as good as it gets with this amp. I just wanted to share this information in case someone else was thinking of trying this. Here are a few pics of the amp's internals.
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