The best sounding audio integrated opamps

[leeperry]

Originally Posted by Andrea:

No please...avoid using the extension with the regular chip opamps. The Audio-GD seem to work even-with-those-extensions just because they're slow and appear to be compensated to be very stable. I don't dare to imagine what would happen if you try them with the LT1028 or the AD797...

oh ok, thanks for the tip!

I'll try to use additional sockets as risers then...anyway, yes the 1364 is colored! but I love how it sounds w/ the Earth, it has a very lively sound w/ a stunning 3Dish SS...it feels like the audio is almost 360 degrees, maybe more like 270

as Slash47 confirmed, sometimes you feel like you're in the studio cabin with the singer just in front of you...feels rather stange when you listen to deceased singers

[Andrea:]

Originally Posted by Mooly

Andrea, can I ask, are you doing any measurements (at a basic level) such as how well each opamp performs with say a 10khz squarewave applied and looking very closely at the rising and falling edges of the waveform ?

IMO you MUST optimise the circuit for a given device

Just an observation, that's all.

My only instrument is my ears. IF your point of view is true, then why do I consistently get essentially the same results with the same opamps in my two DACs (where the opamps are made to work quite a bit differently - starting from type and amount of supply voltage) and even my 24V-powered "cmoy" (tweaked to accept fast bipolar opamps) ?

As far as my experience goes, your statement is only relatively applicable to the very fast opamps not designed for audio; these indeed can misbehave if placed in circuits designed for the typical OPA2134, NE5532/5534...


Also consider that this DAC I've been playing with came with an LT1364 (70 MHz, 1000 V/us, single-stage opamp) as the stock opamp. Yet the LT1028 (88 MHz, 15 V/us, three-stage opamp designed for audio, not said to be gain of +1 stable) sounds miles better than the LT1364 or two LT1363...

While my other DAC came with two NE5534 on sockets. Yet the LT1028 was great there too, and extremely similar sounding to wht I'm hearing now, though I decided to keep the LME49710NA in there.


I would say that it's much more relevant the sonic synergy between DAC chip & opamp(s)...




Ah, I would also observe that checking for square wave perfection is doing a pure abstraction..

[Andrea:]

In summary, the fine tuning of a given opamp doesn't really seem to make the magnitude of difference the different opamps themselves make on sound. Surely, when you've elected your opamp of choice, fine tuning the circuit around it would be the ideal thing...

But us poor non technical beings prefer to simply test a variety of opamps and then let Fortune speak

[Andrea:]

I'm in love with how-the-dac-sounds-with-the-lt1028!

[danielwritesbac]

Originally Posted by Andrea:

I'm in love with how-the-dac-sounds-with-the-lt1028!

There's a couple of possibilities.

One is how the opamp works in-circuit, like this: HDOA - High Dynamics Op Amp Its an example of a circuit specifically designed to support a given opamp.

The other is how the opamp drives the next stage (your preamp or amplifier), like this: BUF634P BUF634U replace OPA627 AD8610 AD797 DAC Buffer - eBay (item 330354626320 end time Nov-21-09 22:17:53 PST)
The high current opamp usually has the effect of causing even a small amplifier to try to turn over the house.

[nelsonvandal]

What you should know before taking any advice from Andrea is that he changes oppinion more often than any of you change your underwear. He seems to truly believe in numerology and he doesn't believe in a scientific approach.

Andrea, optimization of a curcuit for a specific opamp matters. Many opamps are "undercompensated" when used at lower gain. This may result in a nasty peak of the square wave. I've found that peaking amps can sound harsh. An overcompensated amp might sound lame. No matter if the amp is fast or slow it can still be over- and undercompensated.

[danielwritesbac]

Originally Posted by nelsonvandal

. . . optimization of a curcuit for a specific opamp matters. Many opamps are "undercompensated" when used at lower gain. This may result in a nasty peak of the square wave. I've found that peaking amps can sound harsh. An overcompensated amp might sound lame. No matter if the amp is fast or slow it can still be over- and undercompensated.

For doing it by ear, that's a two step process.
This thread illustrates the first step.

1). Its not impossible to compare the differences in opamps from within a general circuit. From a large selection keep the 5 or 6 best results. A bit of engineering savvy can help reduce the amount of selections to purchase.
How to find? Its a game of "Spot the Plonker," whereby you remove the least likely of the available selections until you narrow the contenders list down to 5 or 6 models.

2). Re-evaluate the 5 or 6 best results to see what they have in common and then re-observe them after they are each installed into an optimized circuit--try to make them all better and see what happens with that.

Although the simple 2-step approach is flawed, its also financially inadvisable to do it correctly, which would be something like comparing 270 different models of opamps, each used optimally. Perhaps it could be done at a large university with both audiologists and engineers.

[Andrea:]

Originally Posted by nelsonvandal

What you should know before taking any advice from Andrea is that he changes oppinion more often than any of you change your underwear. He seems to truly believe in numerology and he doesn't believe in a scientific approach.

Andrea, optimization of a curcuit for a specific opamp matters. Many opamps are "undercompensated" when used at lower gain. This may result in a nasty peak of the square wave. I've found that peaking amps can sound harsh. An overcompensated amp might sound lame. No matter if the amp is fast or slow it can still be over- and undercompensated.

Ah, my old friend.

Dude, when the thing has a nasty behaviour at the instruments, then all the more so it has nasty acoustic imperfections.

If it is undercompensated, you can hear that. If it's overcompensated, you can hear that, too...

Do I not believe in any scientific approach? You're ridiculous.

I think that the scientific approach must follow the 'human' approach (senses, understanding, discernment, reasonableness). Not abstractly guide it. I believe in the natural hierarchy of earthly things (if anything).

[Andrea:]

And the LT1028CS8 sounds amazing in my DAC(s).


Also the AD845KN sounds amazing in my "cmoy".



That is all that I've been saying from the start.

[Andrea:]

Plus, as I said, my other favorite opamps for my familiar applications (which I mentioned from the start) are LME49723 (possibly LME49725 too), OPA132UA for a FET opamp, and LME49720HA among the metal tins...