First off, hi, I'm poly-p man. I'm a geek that's mostly into software stuff like Linux/etc. and also low-level hardware stuff. I also have a unlying passion for music.The last two make a great combination for buiding a headphone amp, obviously 
. I took interest in the cmoy amp because of it's small size, relatively high quality, and low price. I'm looking to build one, but of course I want to follow some of the tweaks, because I want as good a quality as I can get. Of course, going down this road, I have some questions.
Just a note: I have done significant work with hardware, such as designing/building (relatively) simple circuits, and a lot of soldering work, but never before have I really done audio hardware work (except for replacing the cables on my headphones when they died). This amp will be my first endeavor into that field.
1. Op-amps. I came into possession of a few OPA2132PA's and a few OPA2277P's (don't ask, don't tell), all 8-pin DIP. There are tons of reviews everywhere for the 132's, and I'll probably try to get those to work first. However, I have had a bear of a time finding people's opinions on the 277. Anyone tried these out?
2. Power supply. I'll probably end up using batteries, simply because of all the horror stories I've found (here in particular) about wall-supplied sources and their noise levels. However, will one 9v battery be good enough for the amps listed above? Can I just swap in a second (in series) if I decide (in the future) to upgrade to a 627/637? Also, I'm not quite sure which virtual ground circuit to use. I was looking at this page, particularly at the TLE2426 design. However, it says that the output current is pretty limited. Will that be enough to supply my circuit (one of: the two above listed amps or a pair of 627/637's)? Should I go with another design?
I think that's all I'm really confused about right now - I might have more questions later, of course .
I'm trying to drive a pair of Grado SR-60's, btw.
thanks,
poly-p man
posted 02-20-2008 04:24 PM CST (US) 
