The Best Sounding DUAL opamps

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#241
You must test by measurement when swapping opamps. Stability is one such test, and how the opamp stage handles a fast squarewave another. Its quite possible to have an amplifier (opamp, discrete, power amp etc) that handles a sine wave seemingly perfectly and yet has major issues with squarewave testing.

http://www.diyaudio.com/forums/anal...u-have-checked-see-its-stable-havent-you.html

and as an idea what squarewave testing shows,
http://www.diyaudio.com/forums/analog-line-level/196461-different-opamp-compensation-technique.html
 
#242
Mooly said:
You must test by measurement when swapping opamps. Stability is one such test, and how the opamp stage handles a fast squarewave another. Its quite possible to have an amplifier (opamp, discrete, power amp etc) that handles a sine wave seemingly perfectly and yet has major issues with squarewave testing.

http://www.diyaudio.com/forums/anal...u-have-checked-see-its-stable-havent-you.html

and as an idea what squarewave testing shows,
http://www.diyaudio.com/forums/analog-line-level/196461-different-opamp-compensation-technique.html
Click to expand...


Thank you for the links and valid information, but I think most of the internet inserts op-amp's blindly into their equipment and typically arrive at the same conclusions in sound quality and tonal colour.

At times, they'll say "the IC was really hot!", so they'll pull it out.

Not everyone has measuring equipment, I still tell 'the internet' to blindly insert the best op-amp's.

If they didn't, how will they ever experience the amazingly better sound?
 
#245
Mooly said:
You must test by measurement when swapping opamps. Stability is one such test, and how the opamp stage handles a fast squarewave another. Its quite possible to have an amplifier (opamp, discrete, power amp etc) that handles a sine wave seemingly perfectly and yet has major issues with squarewave testing.

http://www.diyaudio.com/forums/anal...u-have-checked-see-its-stable-havent-you.html

and as an idea what squarewave testing shows,
http://www.diyaudio.com/forums/analog-line-level/196461-different-opamp-compensation-technique.html
Click to expand...

I joined the forum after the second link you've provided ended... glad you pointed to it... very useful. It also "proves" that better measurements do not equal better SQ..
 
#246
Just wanted to report that i did finally measure all opamps in my Buffalo IIIse+Legato line stage DAC on very good friend's equipment and none of those i tried showed any sign of oscillation or any wrong behavior otherwise.
With Buffalo IIIse dac + Legato line stage i measured paired OPA627, OPA827 in adapters as well as LME49860. (The default opamp was LM4562NA). Rest of duals excluded because they can't compete with these mentioned above.

As for final impressions on the sound - the most interesting thing was to test paired single opamps against dual opamps.
So compared to LME49860 which i selected as the best dual in my configuration - the OPA627 perform a little bit faster and cleaner, however it's sound is a bit forward and mid-centric, there's less bass vs mid. Otherwise it sounds as good as expected, i just wish it had a bit more bass (or less mid?)...
On the contrary - OPA827 is more bass-centric and has deep and dark, warm, laid-back sound with impressive soundstage. It even feels somewhat "too dark" sometimes and bass is a bit too much, but it's quite pleasant to listen to. I'm yet to decide on this one...
LME49860 is a very good all arounder. While not better at any specific area than single opamps mentioned - overall sound is very good. It has powerfull bass, good soundstage, detailed highs. It's only drawback is a slight "synthetic" highs of all LM opamps...
 
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#248
That OPA172 looks dismal for audio due to its incredibly low PSRR (fig10) from the -ve rail (23dB @ 20kHz). However it may be that TI has found another way to measure PSRR as the CMRR plot looks highly respectable and normally CMRR tracks PSRR quite closely. I didn't see any test circuits for how they measured the parameter.
 
#250
Kind of ironic that they headline the low input offset voltage spec (200uV) and then promptly trash that with the application circuit they show (LSK489 has 20mV max offset). LSK489 isn't that low noise (1.8nV, so perhaps 10dB better than the opamp) so hardly seems worth it.
 
#252
He,he,he,he......Thanks for the input guys !!
Some specs looked good but the rest didn't look so good to me either.

I was hoping that if it does sound good than maybe it could be used in a composite design with a chipamp, else maybe I will just use it for a dc servo or something else non-audio. 😉

jer 🙂
 
#258

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