Opamp qualities and selection

[vansinn]

In the past, I've mostly used LF 347 for multipole filters and stuff requiring several stages.
Old Depot discussions are gone, where we covered qualities of the various single, dual and quad opamps, like LF347, TL084, the Burr Brown's and the Analog Devices.

Now, I'm not really thinking about which is the best, but more about which are good candidates for which applications.

So, things like types of filters with how many +- dB, low-gain and unity gain buffers, hi-gain applications like with compressors and distortion stomps, needed open loop gain, stability and compensation needs, noise figures, ability to gracefully handle overload, how tone might be affected in good or less good ways, like JFET inputs, MOS types, bipolar designs..


I'll hit a few opamps and applications as I see it:

Signetics NE 5532/34's: Good for keeping clarity, when higher gains are needed without changing tone. Less of a 'guitar' tone, as those are quite transparent.
CA 30xx CMOS: Can add a touch of soft tone, useful for unity/low gain. Handles some overload gracefully. Not good for higher gain applications.
Various AD and Burr's featuring JFET inputs: Handles overload gracefully. Good for higher gain applications.
LF 347: An overall good workhorse. But is it good for demanding higher gains in complicated filters?
TL 084: Same as LF 347; tone seems a little different, but how to explain?
Old-school TL 54xx types: Not generally too interesting, but can have an interesting way of distorting when overloaded.

[rabidgerry]

I'm curious at this now,  are there good mods that can be utilized for different qualities with the MP1?

I came across this from some guy online

http://www.kylheku.com/lurker/message/20121021.052448.3659b97d.en.html


https://www.youtube.com/watch?v=6xRAAWZeC9Q

[rnolan]

Hey RG, I don't know if it's the same guy who posted similar on here quite a while ago.  If you search around you'll find his post.  He was going to write it up as a "how to" for us but that never happened  :facepalm: .  Anyway, he changed out all his opp amps with similarly good results.  It would be good if MJMP could put together a kit of all the needed parts and instructions "The Sonic Moderniser Mod" or some such.

With regard to ADA just saving money with cheaper opp amps,  :dunno: , you'd have to compare what was available back then and how much they cost at the time, the internet has provided a much bigger market than existed then and made the economics of it very different, not to mention developments in opp amps and other components.

No doubt you can mod a MP1 in many ways for different qualities and characteristics, IIRC there was quite a focus on that sort of thing on the original forum, these days we seem to be mostly keeping them alive and kicking.

[peoriashows]

I literally jut posted a link from a guy that also suggested using the MC33079 for a better noise mod.

[MarshallJMP]

He's using that for the replacement of the tone section op amp. Not for noise reduction.