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Walt:

You obviously missed the whole point of this device. If you read the whole data sheet you would see it is nothing like a common differential Op Amp. It is specifically designed to get the maximum benefit when converting from a balanced to unbalanced line where even a precision differential Op Amp cannot compete when doing the conversion because of even extremely small differences in input impedance. Here are a few extracts that should help explain if you do not want to delve into the whole data sheet. When doing a conversion from balanced to unbalanced, the goal is not to create a "toaster" with high dissipation, but rather to retain the CMRR of the balanced line when doing the conversion while not stressing the output stage of the output balanced line.

Thanks for finding them, but the THAT1200 is incompatible with the existing design, so cannot be tested directly from what I see in the datasheet.

The IC's I am testing are the TI OPA132, OPA134 and LME49710's. The discrete units are Sparkos Labs 3601, Staccato OSH-S so far. The SX52B is a dual discrete that looks interesting, but not compatible with the single units.

The SX52B's would work with either the Douk A5 or FOSI V3 Mono amps.

[quote="tomp"]Walt:

You obviously missed the whole point of this device. If you read the whole data sheet you would see it is nothing like a common differential Op Amp. It is specifically designed to get the maximum benefit when converting from a balanced to unbalanced line where even a precision differential Op Amp cannot compete when doing the conversion because of even extremely small differences in input impedance. Here are a few extracts that should help explain if you do not want to delve into the whole data sheet. When doing a conversion from balanced to unbalanced, the goal is not to create a "toaster" with high dissipation, but rather to retain the CMRR of the balanced line when doing the conversion while not stressing the output stage of the output balanced line.

I didn't miss the point. My point was that the more crap you put in the critical signal path playback quality deteriorates accordingly. Personal experience -- not theory.

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Walt