[CBMC]

I was wondering how difficult it is to make a meta42 both able to run on batterys and able to run on a regulated wall wart? What differences are there from making just battery and making battery and wall-wart power? I am new at headphone amp building and fairly new at circuit board building but really need my amp to have both.

 

[PeterR]

Remembering that there was a very similar question not too long ago, I wanted to link you to that thread, but then realized that you had started that one as well...
I thought your question had been answered there, so maybe you could be a little more specific?

 

[CBMC]

You ever just read something and forget you ever read it, probably not. Sorry for that, I am a moron. Couple of other questions, which I know has probably been anwsered on this forum before. What is the best way to hook up (2) 9 volt batterys? Series or parallel? Second has to do with the opa637 opamps. Will 2 9volt batterys power this amp sufficiantly? Lastly, is a 25 volt rated cap in the C1 space large enough for the opa637?

 

[PeterR]

Quote:

What is the best way to hook up (2) 9 volt batterys? Series or parallel?

Depends on what you're trying to achieve. Two batteries in parallel will give you the same voltage but twice the battery life, in series you get twice the voltage but the Ah rating of a single battery. Usually you'll connect them in series to get the higher voltage.
Quote:

Second has to do with the opa637 opamps. Will 2 9volt batterys power this amp sufficiantly?

Don't have first hand experience with these. According to tangent the 627/637 will need 12V to perform their best, so with two 9V batteries in series (=18V) you should be fine.
Quote:

Lastly, is a 25 volt rated cap in the C1 space large enough for the opa637?

The voltage rating is ok, but isn't the critical factor.
See http://www.tangentsoft.net/audio/meta42/advice.html