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**Arny Krueger** · October 17th 08, 07:56 PM posted to uk.rec.audio,rec.audio.tech

"GregS" wrote in message

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Chronic Philharmonic wrote:

"Arny Krueger" wrote
"Marky P" wrote

LM741 (pretty sure this is an op amp)

Yup and a real oldie. Slow and noisy, not to mention
power hungry and a weak output for what it does.

This was arguably the "breakthrough" IC op-amp. It was
one of the first popular devices that was actually a
monolithic design, and not a hybrid like some of the
original Burr Brown modules. It was compensated for
unity gain, which made it much too slow for anything
but a buffer for audio work. It had a slew rate of 0.5
volts/microsecond. With a +/- 12 volt power supply, 6
kHz rail-to-rail was about it for non-slew rate
limited signals. You could get 20KHz through it if
you were content with about 4 volts peak.

I think it had more applications in analog computing,
integrators, low frequency function generators, servo
controls, etc.

True but it DID get used in audio. Its companion, the
748 was uncompensated internally (like the 5534 vs the
5532) and always seemed less noisy to me, so I used
quite a few of those.

The on-chip compensation cap for the 741 was a
well-known source of noise.

LM301s were another alternative once the market matured
some more.

I believe that the integrated preamp/crossover for the
original Infinity Servo-Static system used 741s.

As others have pointed out, their slew-rate limitations
were not that bad if you were running them at usual
consumer levels like 1.5 volts RMS.

The more recent NHT pro monitors used RC4136's in the
active stages.

I was talking about the Ken Kantor pro speakers.

I have the schemtics for the A10 and A20 amplifier-equalizers here before
me. They are loaded with 4558s, no 4136s in sight. I looked inside my A10
and found that they were indeed 4558s.