I searched but could not find an answer. Does a single version of the OPA2107 exist? I've discovered that this is my favorite opamp in Cmoys, but if there is no single equivalent, then I cannot use it in a Pimeta. Any other similar sounding opamps that aren't too current/voltage hungry for a portable? I have the impression that the OPA2604 sounds somewhat similar, but requires higher voltage. Also, for some reason (maybe inside my head), I didn't like the OPA2227 as much and found the AD8620 too bright.

Thanks,
George

There doesn't appear to be a direct equivalent single version of the 2107.

You have some options.

You can build an adapter that would let you use 1/2 of another 2107.Sijosae has a simple method that requires modifying two sockets. This is probably the only way you could truly have a symmetrical ground channel. You waste half the chip, but it's not super-expensive compared to the only other audio grade laser trimmed, unity-gain stable DIFET part BB has to offer in a single opamp - the opa627.

http://www.headphoneamp.co.kr/bbs/zb...desc=asc&no=71

Since the ground channel isn't as critical, you could use some other opamp there. Using a mismatched ground channel in a buffered amp is a reasonable compromise - it really only needs to be essentially as fast and with similar bandwidth.

You don't hear the ground channel the same way you hear the other channels, but I have heard that some combinations of mismatched opamps in ground-channel amps can actually sound pretty good.

What single opamps do you have on hand? There is probably a configuration available that sounds pretty good.

Ah yes the Good Old OPA-2107! This is a nice smooth opamp however there are no singel versions because better performance and sound can be had in the OPA-627. While the OPA-2107 has a unique sound The marketing Guys at Burr Brown was looking at the 2101 as a way to bring there then New DI-FET Technoligy to a Dual opamp.

The OPA604 and its Dual version the OPA-2604 are not similer to the 2107. the 2604 is not Di-FET and has stability problems the 2107 do not have.

Sonicaly the closest Dual is the AD712, AD-711 is the Dual version.

I suspect you will find the sound differences between different opamps in a Pimeta is less than in a CMOY and while you might not have found OPA2227 or similar desirable in a CMOY L/R position, the single-channel equivalent, OPA227 or similar may do fine in the Pimeta ground position if not AD8610.

My PIMETA has 637s in LR and a 227 in the ground channel. I couldn't hear a difference in swapping the ground channel, so I went with the 227 to increase battery life a little. I just built a tread, and I have a hornet for portable use, so I think my PIMETA is gonna get the desktop treatment (back to 627 in ground for the hell of it, stacked buffers, bandwidth resistor, class A bias)

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There are a few other opamp options that seem to get overlooked, the OPA606 and the OPA602. Both are DiFET, unity gain stable, and their datasheets recommend them for audio purposes.