Favorite quad op-amps for synth design?

[Harry Bissell]

Comments inline....

Buck Buchanan wrote:

> Hey folks,
>
> Before I spend the next 5 hours with a floor full of catalogs,
> databooks, and selection guides...
>
> I'm wondering what the general opinion here is about use of quad op-amps
> in new designs.  Seems like there's been a certain degree of disdain for
> them in general.  I've typically stayed away from them just for sake of
> being able to swap so many types (as w/duals and singles).
>
> But it seems like by the time I've packed all the features I want into a
> design, there's enough op-amps (and shrinking board space) to justify
> using quads for *certain* duties.  Parts like the LM324, XR4136, and
> LM3900 Norton seem pretty common but are there some "standard/common"
> units that are a little more modern, have a standardized pin out, or
> better performance?

LM324:  I hate this op-amp. If I was on Apollo 13 and likely to die I'd use
it... if the pinout matched...
But seriously folks... Its single supply only. Dual supply has a crossover
notch
that makes it suck for audio. Some say a resistor to the negative rail fixes
it...
but to me thats like "Taking something that tastes bad and making it hard to
eat too..."
Has the dreaded "Phase reversal" when overdriven... Yuck !!! Also
non-symetrical output
current... bad for ramp drive, cap drive, etc...
Minus 2 stars -**

4136: wierd pinout... avoid

LM3900 Norton:  Very little experience. Used to think it sucked, but I
didn't
understand it. NOW I think its very clever. Its a Current Controlled Voltage
Source basically. Like that ARP filter that used it. Two stars **

>
>
> So I'm wondering if anybody's got some favorites that are roughly
> equivalent to the following singles and duals:
>
> LF412 - Concern being very good drift and low offset.

OK...

>
>
> OP07 - As per above when need better offset.

A (slow) favorite. Low bias current, very high input impedance, very low
input offset,
slow (did I say slow???)  .3V/uS  NO PHASE REVERSAL (avoid the inproved
OP-77 it has phase reversal...)
The OP-07 is what the 741 wanted to be when it grew up.

> xx5532 - Low noise audio. (but HIGH supply current and only "low noise" if
> the input is "low impedance"  Apps limited because of low impedance...
>
> xx1458 - cheap, low tol, for the rough stuff.  Has symmetrical clipping,
> no phase reversal, good output current limit... a TANK. I like it... Good
> for the "rough" (did I say slow???) stuff...

I like the MC34084 (motorola's 'texture' of TL084) also MC34082, 34081...
I've had better luck with it than the TL084. Sometimes the "negative side
fuzzies" on the TL084 get me (especially in voltage follower modes...) a
little load will help, or a small series resistor to decouple any load
capacitance...  Fet input, low bias current, fair offset voltage, FAST
(13V/uS) not too hungry on supply current... Can oscillate because of high
speed but usually well behaved. My all-around favorite...

AND it fits in the same socket as that piece-of-shit LM324... which should
never be used
(except on a single supply where its really not as bad as I make it sound...
I have used it...
its CHEAP...)

Nuff opinions ???

H^)    Harry (who does not exhibit phase reversal, has fairly high input
impedance, but cannot tolerate crossover distortion.....)

>
>
> Suggestions/opinions on parts as well as quads in general are greatly
> appreciated.
>
> Buck