LF411 Op-Amp dilemma

brad sanders radioactive at geocities.com
Fri Jan 24 06:53:24 CET 1997

>This is interesting. Not something I'm experienced in, but my ARP Quartet is
>literally chock-full of 1458's. In the overused "Vintage Synthesizers", a
>chap mentions how he cleans out all 741s in the ARP 2600 and replaces 'em
>with the LF4xx equivalent.

Believe it or not, my CD player came from the factory with an LM1458
for the headphone amp!

You MIGHT get a bit lower noise if you replace the LM1458 with a low
noise DUAL opamp (the 1458 isn't comaptible with the TL081; you'd use
a TL082, which has two TL081s in a common package).

The 1458 is pretty ubiquitous, 'tho. We're not talking about replacing
an obsolete part - cheap CD players, graphic EQs and other goodies
STILL use the 1458. It doesn't have great specs, but it's really a LOT
more "listenable" than a 748 or even an LM302.

>Also, one other point. I'm thinking of sticking a CV/gate socket on it, but
>the Quartet is fully polyphonic - I think one of those top-octave divide down
>jobbies. What sort of signal does this thing output when a chord is pressed ?

The octave divider outputs a signal all the time. The switches just
make contact with the proper signal and route it out the back. 

Can one still buy these chips? It might be fun to put together an

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