[imran27]

I just thought of doing some study on why OPA1641/2 hasl/reported to have such a great soundstage, I probably found something relevant from the datasheet. The gain and phase vs frequency plot shows that the phase is almost flat for up to 1 MHz compared to OPA1612 which is inversely proportional to frequency up to 1 kHz and then constant up to 1 MHz.

This is making OPA164x more and more favorable.

 

[imran27]

I reviewed the datasheets of AD opamps and they also have this flat phase response.
 
I want some user opinions on LM4562 vs OPA1642 especially in terms of details and soundstage.

 

[Mad Max]

1642 can be pretty holographic-sounding as far as soundstage and quite detailed, I have found.  4562 can dig up a bit more detail, but soundstaging isn't anything special.

 

[imran27]

  The headphone OUT is actually a single low voltage supply Cmoy with a 1000uF cap coupling capacitor on the output.
 
Any comments on the OPA2365?

I accidently destroyed the Vss pin of AD8397 so I had to replace it with the OPA2365.
 
First impressions are: Much more detailed sound, more clarity and balance. Bass is more forward, treble feels a little fatiguing at times, but these are first impressions. Soundstage as expected is more intimate compared to the AD8397. Bit I am liking the details it can extract and the clarity, it is a very good sounding opamp compared to AD8397.

 

[pelopidas]

Have you measured the offset from the output of the opamp to ground? The reason I ask is that if the offset is under 20mv, you should consider removing the output capacitors. That will have a positive effect on soundstage and detail resolution. (Even more than input capacitors which are usually film and not electrolytic) Remember, audio is AC meaning the voltage swings in both directions. Electrolytics allow in one direction and block in the other.

 

[imran27]

1.215V, too bad. Anyways, I have 2000uF for the output, I think that's a pretty high value.
 
 

 

[pelopidas]

Wow. There is something wrong with the circuit design. Can you upload some clear pictures (front and back) so we can see the resistor values etc?

 

[Tambourine Guy]

How about those discrete type opamps? How do they generally stack again the ones from TI or AD opamps? 

 

[Mad Max]

The ones that audio-gd used to make are alright, they kill older opamps in sound and OPA209 after you replace their crappy MKT decoupling PSU caps with anything better, but aren't as high-fidelity as chips like ADA4627, TL5580, ADA4610, OPA1652, or OPA827 and more.
I still have the Sun opamp, very fun-sounding little thing.
Edit:

 

[leeperry]

and they need a lot of juice anyway, ±18V to sound their best IIRC. OPA827 needs ±4V.

 

[imran27]

The ones that audio-gd used to make are alright, they kill older opamps in sound and OPA209 after you replace their crappy MKT decoupling PSU caps with anything better, but aren't as high-fidelity as chips like ADA4627, TL5580, ADA4610, OPA1652, or OPA827 and more.
I still have the Sun opamp, very fun-sounding little thing.
Edit:

Did you just mention OPA1652? How are they? They are fairly new btw

 

[Tambourine Guy]

  The ones that audio-gd used to make are alright, they kill older opamps in sound and OPA209 after you replace their crappy MKT decoupling PSU caps with anything better, but aren't as high-fidelity as chips like ADA4627, TL5580, ADA4610, OPA1652, or OPA827 and more.
I still have the Sun opamp, very fun-sounding little thing.
Edit:

Do these discrete type opamps share any common sound characteristics? Is it like tube vs solid-state where they have a sound that is instantly identifiable as being a discrete type... if that makes sense. 

 

[Mad Max]

Did you just mention OPA1652? How are they? They are fairly new btw

 
It's an awesome chip to use if you don't need strong output current drive.  Very "blind-roll" friendly, every opamp roller should try it at some point.
Or if you are looking to replace a bipolar opamp in a circuit, OPA1662 is just as good, though I still like 4898 better.
 
The one I'm really taken with lately is ADA4610-2B.  It is not finicky, has very low output impedance, and output current drive is better than 4556 and most of the opamps discussed in this thread.  It is uber-hi-fi like OPA827, ADA4627, LME49860, and LME49990.  Comes in MSOP as well, so it rocks as a big upgrade from 4580, 5534, and 4556 in a lot of situations, even mic preamps.
 
 
 

 
Do these discrete type opamps share any common sound characteristics? Is it like tube vs solid-state where they have a sound that is instantly identifiable as being a discrete type... if that makes sense. 

 
Not really if I recall correctly, but once you get a couple and get used to their particular sound, then you'll learn to identify them.  The Sun and Moon opamps are instantly identifiable, however, as they each do boast a unique sound.

 

[SpudHarris]

I have ADA4610-2B's here so curious... Although I haven't been tempted by anything since using Signetics 5534's (OBCA).

 

[Mad Max]

Digikey tells me LME49990 is being discontinued.
 
Edit: The new OPA1688 looks interesting.  So it achieves lower distortion with higher-impedance headphones + louder volume?