Philbrick opamps P25a, P65a, P85a for preamp, etc?

Gents,

Has anyone tried these in any projects? Found a local source for these 3 models for $5ea. Looked at the Philbrick archive and the AD book on them and they seemed interesting. Just curious.

Thanks, Nathan

Forget it--these are precision opamps, way to low slew-rate and GBW for audio. Noise is high as well.

Samuel

The guts contain AF transistors and/or FET's and found these very basic schemos and thought I'd consult this forum.

> Looked at the Philbrick archive and the AD book on them and they seemed interesting.

Of course. The unwarranted popularity of "Opamps everywhere" is due to those very-very-very good papers.

The op-amps are comparable to LM741, only not as good.

Sure, we did a LOT of listening through 741s.

There was always something "off", a smeared sound.

OTOH, compared to starved 12AX7 or roll-yer-own 2-transistor preamps, a Philbrick or a 741 gives a predictable response and no more noise. In those days, a 6dB noise figure was not embarrassing.

Just do it. Except haggle down to $2 each.

For either of the mentioned prices you could at least get a few to serve as reference, as in: how much a fresher opamp can improve things.

Maybe it has a use for 'shaping' sound, like people use the Melcor 1731 etc (which could be miles better though as I understand from the words above).
And maybe it's of use for another not-critical appliction, since it will look pretty on a PCB.