Fet Input Op Amps: At what point are they necessary?

[Bamalama]

C'mon leadbelly, there's plenty of room to just answer the question the guy is asking, which seems to boil down to "is there a higher performance option than my 2134 for this application".

Doesn't even need to be higher performance. Just needs to be FET, a bit cleaner and stronger than a TLO72, and not quite as hard-sounding as a 2134.
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[PRR]

> TL07x ....oscillate on 6' cables ...despite 50 Ohm isolating series R

The series R should be "not small" compared to opamp open-loop output impedance. The '07x amps have a whopping ~~200 Ohms here, so you need at least 300r between the pin and the outside world (even a small 6-foot world). '5532 is under 100r (maybe near 30r) so 100r in series leaves plenty of output for the NFB to do its thing.

 

[jcx]

even 1k output R is probably good enough for guitar, but I had a DC accuracy, settling time specs to meet with the DAQ input's pull down R, cable C so I couldn't go higher

instead, faster, more modern op amp with lower and more constant output Z