Interesting article on op-amps and the myths associated.

[nosebleedaudio]

One on my main tests for an Amp stage is testing at high gain, over 40dB..
Low distortion at 10dB and esp @1KHz Only is not a big deal.
For example: the Amek Media 51 Mic pre specs are .001% at min gain, .05% max gain (@1KHz)..This is a BIG difference IMHO...

[Matt Syson]

Hi
To an extent a 'shootout' simply proves they are different, which is what we knew to begin with.
The 'sound' of any circuit is dependant on what we are doing to it and it's complete surroundings so when comparing a TL072 (or whatever) with anything else you have to re evaluate the whole circuit, not just bang a different chip in the hole. OK in some instances it may make it 'better' but better at what?
A 'plug in' replacement generally means it will work and probably won't smoke.
The designer decides what (s)he wants to achieve then goes about achieving it using the parts available and with regard to constraints such as cost, availability, second sourcing and a whole raft of other considerations.
Matt S

[dcollins]

Originally Posted by JohnRoberts

You should be able to measure subtle differences with a high resolution test bench.

And how. Some are better than others.

http://www.sg-acoustics.ch/analogue_...distortion.pdf


DC

[JohnRoberts]

Originally Posted by dcollins

And how. Some are better than others.

http://www.sg-acoustics.ch/analogue_...distortion.pdf


DC

Yup, Sam has done some good work.

I have an issue with how some uber-opamps have to trick up linearity measurements because they are too clean to measure normally, but it's like chasing the echos of the footsteps of the angels dancing on the pin head.

JR

[brianroth]

Originally Posted by Matt Syson

Hi Brian
This is only really relevant if they were doing equivalent jobs.
Chips at 'interface' points suffer far more than in the 'middle' of a piece of (reasonably designed) circuitry. Static discharges and external short circuits can cause havoc with any chips.
The die temperature in a 5532 is supposedly pretty high and of course will be significantly higher than a 'half the quiescent power' 5534.
Matt S

Hiya, Matt. In the recent case I mentioned (MCI 636 desk), the "blown" 5532's were indeed "buried" inside the signal path vs. being at I/O points to/from the desk. Chips had early 1980's date codes, FWIW.

Perhaps newer 5532's have better life spans....

Bri

[dualflip]

Anyone else wants "Ne5534 FTW" t-shirts? would love to have one!

[brianroth]

Originally Posted by dysenterygary

Has anyone ever done a sound test of a TL072 vs its super expensive counterpart in a shootout in proper circuits? I've searched a bit but didn't come up w/much.

Back in the mid/late 1970's, my THEN YOUNG brain <g> concocted an odd sort of shoot-out, using speakers/ears.

I tried a few different topologies (mostly gain variance), but with six (or more?? I forget) identical "stages" cascaded (with appropriate level matching between stages). That string of "series" stages was compared to a wire via an A/B switch. No, NOT double blind, etc.

Reason? I was attempting to sort through what happens inside of a recording desk with the ALWAYS present cascaded stages.

IIRC, the cascaded 5534's hardly screwed up the sonics vs. the wire. But, speakers and power amps weren't as good as they are now.

The 741 opamps DID sound pretty bad compared to the wire in the same testing setup.

Yes, yes....far from scientific, even though I did have access to (then) state of the art Sound Technology, etc. testing gear.

But, it convinced me to proceed using 5534's at the time.

Bri

[Ike Zimbel]

Originally Posted by JohnRoberts

...but it's like chasing the echos of the footsteps of the angels dancing on the pin head.

JR

Yes, but how many?

[JohnRoberts]

Originally Posted by Ike Zimbel

Yes, but how many?

Two each...

JR