I'm looking at building a newer version of my ultralight aircraft headset amps. It supports music as well as voice. I want quality here.
My previous version all ran off of 12v. It used a very powerful OPA634 unity gain amp chip, which due to its low gain and sigficant output impedance was surrounded with a TL082 to make it put out a regulated voltage. The center point was created by another OPA634/TL082 rather than a cap because I ran calcs and the impedance really does appear to affect the bass response. It would be loaded with 2 headsets in parallel, 32 ohm I think.
So I wonder if this whole thing is even such a good idea. For one, OPA634 is an expensive chip. Second thing that comes to mind is I don't have a lot of protection against overvoltage spikes, makes me think maybe I should switch to a 5v regulated bus which is needed for the logic in the new design anyways. In 5v I can get rail-to-rail amps too.
I guess there's always the LM386 chip. That thing always seemed to be pretty crummy in general to me though. Too low of a gain for an external feedback loop and aren't they kinda noisy? Without feedback compensation the impedance can mess with freq response, and I might have to readjust the volume when adding the load of a second headset which I find far too inconvenient.
Any recommendations on what the best circuit would be? Is there a cheap but powerful and quality headset amp out there that I'm missing?