[Andrea]

I haven't had the opportunity to try these (or the OPA552) yet, but I continue to be intrigued. I'm waiting to find out a decent cmoy derivative on ebay to stick 'em in

To anyone who has tried them, how do they sound used as "buffers with gain" ? Do they truly compete with (or better) a op-amp + buffer configuration, as on paper one would expect? How refined sounding are they?

 

[Andrea]

bump!

 

[Garbz]

Ummm try them? There are countless different opamps out there. It's unlikely anyone here's tried all of em

. And even if they have their musical tastes could differ to yours.

 

[tomb]

The OPA551 is a familiar Opamp replacement for BUF634 in certain situations. The Millett Hybrid comes to mind. So, I suppose it has a decent current capability in a unity gain mode. From what I've read, it cannot be operated as a drop-in replacement for BUF634 (even if the two pins are jumpered as in the MH), because it is not compatible with the loop topology in some circuits such as the PIMETA.

Amb seems to be the biggest proponent of the OPA551 chip, and sells them on his site. I think he is the one that initiated its use as a BUF634 replacement in the Millett Hybrid. I believe he is even contemplating using one in the ground channel on his and Morsel's Mini3 design. You might contact him for other potential applications using this chip. Even considering all of that, I haven't seen it used as the primary opamp in an amplifier.

 

[jcx]

the only reason to consider them is for the +/- 30 V supply - and that's only relevant to high Z cans (or the stupidly inefficient akg k1000's mid Z cans)

the 551's 3 MHz unity gbw is marginal, the 552's 12 MHz @gain av5 min is still low speed for a ouput in a multiloop - you need to know how to compensate a multiloop when the output amp is slower than most of the commonly used input/sero amplifiers

 

[amb]

See the following headwize threads about the OPA551:
http://headwize.com/ubb/showpage.php?fnum=3&tid=5811
http://headwize.com/ubb/showpage.php?fnum=3&tid=6143