[sdiy] best opamps for line level to synth level preamps

[Magnus Danielson]

From: Ingo Debus <debus at cityweb.de>
Subject: Re: [sdiy] best opamps for line level to synth level preamps
Date: Sun, 24 Jul 2005 15:03:10 +0200
Message-ID: <4913ED36-FC43-11D9-9732-000A9571C136 at cityweb.de>

Hi Ingo,

> Am Samstag, 23.07.05 um 01:11 Uhr schrieb megaohm:
> 
> > I've swapped the following opamps for the TL071/TL072:
> >
> > MAX437 - I couldn't detect a difference.
> >
> > OP27 - same.
> >
> > OP275 - same. This distorted earlier as I raised the input level.
> >
> > OPA2134 - same
> >
> > I repatched and changed channels so many times I became confused as to
> > which opamp or preamp channel I was hearing. I thought this would make
> > me more objective. It must have because I couldn't tell one opamp from
> > the other.
> >
> > The circuit itself may have to be tweaked for each opamp to bring out
> > their best performance. Also, different qualities and size of caps
> > could play a significant role.
> > My studio setup may be to blame for the nondifferences between opamps.
> > I consider it far from ideal.
> 
> I rather suspect you just destroyed another audiophile myth. ;-)
> I bet many of those who claim "this opamp sounds better" never did a 
> direct A/B comparison like you describe.
> 
> At which gain were the opamps running?

Actually, I think that maybe the audiophile myth you are thinking off was not
destroyed as such, rather the rule "this is the best op-amp for all tasks".
Then again, this was a non-ideal test-situation.

There is no such thing as a golden op-amp which will "sound best" at all
possible applications. For this application it may very well be that the
differences where effectively neglible and then a TL071/072 solution is best in
price/performance (lowest price for the same performance).

There is no black and white on these things, just a palette of colours where
there is no plain black, white, red, green or blue. We just have to choose the
colour which makes best match for each application, where selection of op-amp
and surrounding circuit is part of the recepie to get the colour. Great
engineering is not done by finding the perfect solution, but finding the best
and most economical approximation in a situation where the perfect solution is
not attainable.

Anyway, it would be good to have a little better understanding of the cirsuit
(give us the schematics!) so that we can investigate it further.

Cheers,
Magnus