Probably resurrecting something old and tired and I see lots of posts in the archives here about this but I wanted to take a tiny bit of a different approach.
CMOYBB isn't new but fairly new to me. Got my first one a couple months ago. Since then I've built probably 7 or 8 and sold a few and kept a few to play mad scientist with.
Right now I'm dealing with two different voltage configurations. I have one CMOYBB with 9v mains and another with 18v mains.
Configs and opamps I have tried so far:
OPA2227 - This is stock with the JDSLabs v2.0.3
MUSES01 with 9v and 18v
OPA627 with Brown Dog Single to Dual Adapter at 9v and 18v
AD8620 at 9v
MUSES02 - doesn't work in the CMOYBB. Don't know why. I have multiple, authentic ones and it just doesn't work.
My favorite? Tough to say.
Perhaps it is the MUSES01 at 18v. And it could be a toss up with the OPA627 at 18v.
If you factor in EVERYTHING such as cost, ease of construction, obtaining parts, sound, configuration I have to give the nod to the AD8620 though. They can be bought from Brown Dog pre- manufactured for about the same as buying a chip from Digikey, paying shipping, buying an adapter from Brown Dog and soldering and shipping.
Where's the fun in that though? I like soldering my owns chips on the adapters. Anyway an AD8620 can be run easily from a 9v CMOYBB as just a drop in replacement. It's way cheaper than a MUSES01. Regarding overall cost two 9v rechargeable batteries aren't cheap in Japan (where I live) and then you must buy a larger wall wart (18-24v) if you opt to charge in place. Since mine is usually strapped to an iPod (4th generation iMod iPod) it's a pain to unstrap and an even bigger pain to remove the two batteries in the tin which barely fit. Wall wart is a must.
CMOYBB is a great amp, fun to play with, a fantastic conversation piece and it can be suited to taste by opamp rolling. As I build these in the future for sale or gifts I'm going to stock them with AD8620's. Nothing wrong with the stock chip though, although I'm sure they add it to keep the price point lower.
Right now I'm working my way through an OPA627 which initially sounded great then the next day sounded awful, then after just cranking it up and letting the cans sit sounds much better after a few hours of that. It opened back up or something. Really spacious sound, high end is a bit subdued and soundstage a little compressed compared to MUSES or AD8620. But the mids are spot on. Vocals are buttery smooth and bass licks dead on.
Edited by Deterministic NL - 6/18/14 at 4:11pm