A problem with audio on the gpm-02 is that original audio come out too low when mixed with cart audio. The audio circuit on gpm-02 vs earlier revs differs in the R7 value of 43K (instead of 100K).
Whats the best way of adjusting to the right level?
I am planning to add a slide resistor of 100K (physically limited to max at 70K ohm) in line after the 43K resistor so that the value would span from 43K to 113K.
Another way to adjust would be to change the values of R4 and R5 coming out of the cpu.
I don't even know yet if my initial plan will work, but it seems logical that it will.
By changing R7, am I in that way lowering the impedance of the circuit and if so, could it be harmful in any way?
Couldn't find any mod on this issue (it seems to me that the general discussions on mixing audio regards either the NES and powerpak or changing the cart level itself).
Whats the best way of adjusting to the right level?
I am planning to add a slide resistor of 100K (physically limited to max at 70K ohm) in line after the 43K resistor so that the value would span from 43K to 113K.
Another way to adjust would be to change the values of R4 and R5 coming out of the cpu.
I don't even know yet if my initial plan will work, but it seems logical that it will.
By changing R7, am I in that way lowering the impedance of the circuit and if so, could it be harmful in any way?
Couldn't find any mod on this issue (it seems to me that the general discussions on mixing audio regards either the NES and powerpak or changing the cart level itself).