> Op-amps. I came into possession of a few OPA2132PA's and a few OPA2277P'sThe OPA2132 is FET-input, whereas OPA2277 looks like bipolar input. That means the later one needs larger input bias current, which could cause too large voltage offset at the output of your amplifier.
> Power supply. I'll probably end up using batteries, simply because of all the horror stories ... about wall-supplied sources
9V should be OK. However, I don't think wall power is that dangerous. I have one off-the-shelf switch-mode wallwart, one off-the-shelf regulated linear wallwart and one simple "capacitance multiplier" filtered power supply I built myself. All of these work just fine for my audio needs. I am sure they do not provide the highest fidelity possible, but simple cmoy amp is not likely to be in that category either.
> ...which virtual ground circuit to use. I was looking at this page, particularly at the TLE2426 design.
Yes, TLE2426 alone might not be optimal solution for Grado load. A resistor divider followed with a bigger buffer than TLE2426 contains would probably be better option. These are discussed in that Tangent's article too. You might also want to check this thread, post #24 in particular.
posted 02-20-2008 06:18 PM CST (US) 
