circuitry

I have an instrument with a very complex onboard preamp circuit that needs some TLC. Does anyone have a recommendation for someone to tackle this in the DC DMV area? I'd really like to go with a well-vetted expert for this. It's vintage and has sentimental value, so I need to get this right the...

Recently I've noticed a buzz when my bass is plugged in. It is constant whether or not I'm touching the strings and I've figured out that it's not an issue from the amp or battery. It's an Ibanez SR405. My preferred tone is when the switch is in "power tap" (facing away from me) with the balance...