Hi - I´m planning to build a mic system for my accordeon, and I think I may need some help to design a pre amp circuit.
The plan is to use 3 electret mic capsules on the treble side of the accordeon, and 2 on the bass side. The mics will be wired to a pre-amp/mixer/battery box that can be velcro´d on to the outside. I want to have 2 separate output channels, one for each side, so I will need one set of 3 imputs mixed to one channel, and one set of 2 inputs mixed to the other channel. I will need to use preset resistors to trim the levels of each mic to compensate for differences in sensitivity, and I want to have one volume control for each channel. Of course, all this needs to be in quite a small circuit. With that in mind, I´m thinking I might have to make do with one pre-amp for each channel, with a pot to control the gain, and just use a resistor mixer, with presets, to mix the different mics to each pre-amp. Would that be a bad idea bearing in mind the fairly low impedance of the mics though? Should I use another tranistor pre-amp stage for each mic before mixing?
Any help appreciated,
Wilf
The plan is to use 3 electret mic capsules on the treble side of the accordeon, and 2 on the bass side. The mics will be wired to a pre-amp/mixer/battery box that can be velcro´d on to the outside. I want to have 2 separate output channels, one for each side, so I will need one set of 3 imputs mixed to one channel, and one set of 2 inputs mixed to the other channel. I will need to use preset resistors to trim the levels of each mic to compensate for differences in sensitivity, and I want to have one volume control for each channel. Of course, all this needs to be in quite a small circuit. With that in mind, I´m thinking I might have to make do with one pre-amp for each channel, with a pot to control the gain, and just use a resistor mixer, with presets, to mix the different mics to each pre-amp. Would that be a bad idea bearing in mind the fairly low impedance of the mics though? Should I use another tranistor pre-amp stage for each mic before mixing?
Any help appreciated,
Wilf