[Alf]

A47-based headamps use 2 opamps per channel to get more juice out of weak chips. I wonder whether this approach would have any benefits over a simple CMOY approach with 1 opamp per channel if used with AD8397. Any thoughts?

 

[ericj]

A single ad8397 can deliver more current than two of just about any dual opamp out there.

Relieving the gain stage of the work of driving current load can make an opamp slew faster, but the ad8397 is extremely fast as it is.

The downside is that the ad8397 is a cranky bipolar part that can be tricky to stabalize. It oscillates easily and you cannot use arbitrary resistor values in the feedback loop or else you'll get a very high DC offset. R3 and R4 must equal R2 when paralleled.

The ad8397 is thus not well suited to beginners.

 

[tangent]

In addition to what Eric said, the AD8397 doesn't like to be run in gains of 1, which the A47 design uses. It can be made to work, but it is not trivial.

 

[The Monkey]

OT: I like your new sig, Tangent.