P88 Preamp Issue

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You see R2L, 1k, in your diagram,.
This resistor should be as close as possible to PIN 3.
Now, also PIN 2 can need a Gate Stopper resistor, ~ 1 kOhm.

So my advice:
Put one 1K resistor, as close as possible to PIN2.
That is from junction R3L/R4L to Pin2 of the OPA2134.

High input impedance Op-Amps, often needs these Gate Stoppers,
as they have JFET transistors as input devices.
By the way, Same goes for PowerAmplifier MOSFET, HEXFET in output stages.
These resistors should also be as close as possible to GATE.


Lineup 🙂 regars

Any ideas?

Thanks again everyone 🙂

I can only repeat my First advice.
Put 1 kOhm gate stopper resistor at every Op-Amp input pin.

Input pins to 8-pin dual opamp are:
Pin #
2, 3, 5, 6


Op-Amps input JFET transistors, do NOT like to have 'long wires' attached.
And what is a long wire, may be 'only 10-20 cm' ( 4-8 inches )
in some unhappy cases.


Bengali 🙁
I am sorry.
I won't post any more here.
As you do not read & listen to my good advice.
Sorry. Really sorry.
To bother you with 1 post .. again. The same post.

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