[ppl]

Ether is great nd Bias them with a current source.

 

[tangent]

Since aggressive sound is your problem, go with the OPA627. If you wanted to go AD, and you're not running from batteries, AD843 would be a better choice than the 8620, since the 843 is smoother than the 8620.

 

[cello]

woah, just looking up these on newark, they're damn expensive. Which of these should I get?
http://www.newark.com/NewarkWebComme...OPA627&x=0&y=0

 

[cello]

also, how would you compare the smoothness of the sound of one of these nicer op-amps in a meta42 to that of the PPA with a similar op-amp? Someone once said that I should consider building a PPA to solve this problem. Is it worth it, or will the new op-amp really make a pretty big difference?

 

[Voodoochile]

The PPA is another beast alltogether. Yes, it's a big step up from the META- in all respects.

The OPA627s would make a fairly big change in the character of your amp.

If the money seems large, try the AD744 before. It's similar in price to the OPA2132, and I like it better, at least in the META. Try it, and if it produces the effect (or lack thereof) you are after, then search for 'AD744' for the posts regarding driving your buffers from the 744's compensation pin. It's an easy mod, and I have loved the results. No need to bias to class A with this. I am still on the fence between my long-standing favorite OPA637 and the AD744. Check it out before you embark on a PPA, at the very least. It might even meet your needs as well as the 627, at a significantly smaller outlay.

Edited for horrid typing.

 

[dokebi]

In most cases I didn't like the 627/637 much. Way to sterile and flat sounding. In one instance I tried the 8620 but that didn't really satisfy me either. It sounded grainy. Something with sound in between those two would be perfect. Unfortunately I haven't found it yet.

 

[cello]

I still don't entirely know which of these op-amps I should get... (check the link to a newark search for 'OPA627' on the previous page). I'm a bit of a noob with DIY stuff, and so I don't know whether I'm supposed to get the AP, or the AU, or whatever...

 

[myself, aka me]

OPA627AP, and you want two of those. The difference between AP and AU is that one is a single 8 pin DIP and the other an SO-8, which fits on those pads on the bottom of the META42.

 

[tangent]

The AU is also a single-channel chip, so it does not work on the SO-8 pads on the META42. You'd need a Brown Dog SO-8 op-amp adapter to use the UA chip with the META42.