Thanks for your input Bob. I may try some different op amps. The 797s are low noise but bipolar. I haven’t made any measurements with JFET op amps. Mine are all socketed though so swapping is easy enough.
Even a TI OPA604 or OPA134 would probably do the job fine. JFET op amps have come a long way in the last 40 years. When their noise is adequately low, like 3-5 nV/rt Hz, they are a very convenient choice, and some people prefer their sound. Their absence of input bias current often makes biasing issues go away and avoids shot noise contributions from input bias current.
Cheers,
Bob
Cheers,
Bob
