I have a mini Rolls mixer, model MX-28. It's a very cute and useful product. It's very small, so I can put it on the top of a keyboard to monitor my sound. I like it a lot, but it has a flaw. When I feed it with a bass sound, it won't reproduce every details so some warmness is lost. I would like to mod it to get a better frequency response and thus a more accurate reproduction.
Here is a link to the schematic (it's public):
As you can see, it is using five BA4560 opamps. The 120pF (x8) and the 50nF (x1) capacitors are ceramic. I thought about changing the opamps for better ones, and changing the 120pF ceramic capacitors for mica's. What do you think about this ? Any suggestions for the opamps ?
Another question I have is about the power source: The unit uses 12V. Isn't it a limitation ? Aren't opamps giving better results when they're powered with 18V or 24V ?
Thanks for your help !