[evonimos]

Hi!

Was thinking of a way to audition and compare dual opamps.
Tools for the task:

- Modified AD24QS: good quality ADC to feed the digital signal to a computer
- Modified VSPS: simple, opamp-based stage that would serve as the platform for rolling different opamps

- A Jico J44A-7 on an SL-1200MKII turntable: good source that could provide a quality signal

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I've been mulling over the choice of the record track to use for the task.
Any feedback on that, would be welcome.

At the moment, I'm using track B1 from this album: Ray Charles - The Great Ray Charles
In my opinion, it's a good quality re-issue of a great early Stereo recording.

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Regarding auditioning, I recommend using the free foobar2000 player.
Provides you with a free ABX Comparator plugin.
Makes it possible to do blind tests and also gives the ability to switch on-the-fly between tracks, while keeping playback position.

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So, i recorded the first couple of opamps which most of us familiar with.
It's the ubiquitous 5532 in two of its current popular versions.
NE5532 by Texas Instruments and NJM5532 by Japan Radio Co.
As a point of reference, i've also recorded the same track through a fully-discrete, dual-mono, RIAA preamplifier that i've built and use regularly.

Ray Charles - Doodlin' - NE5532
Ray Charles - Doodlin' - NJM5532
Ray Charles - Doodlin' - Discrete

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Disclaimer:

All that stuff is probably a bit too nerdy but, there might be folks generally interested in that kind of stuff.

Personally, when i engage in that process, it's mostly out of curiosity.
It's an exercise in trying to identify audible differences between various opamp renditions.

However, I wouldn't advice to try and establish conclusions or any sort of definite ranking based on it.
Also, don't forget that auditioning is a personal and ultimately subjective experience.

 

[evonimos]

Two more commonly used opamps, are the LM4562 by National Semiconductor and the OPA2134 by Burr Brown.
The LM4562 in particular is one of my favorites, but It needs proper decoupling to perform as intended.

Ray Charles - Doodlin' - OPA2134
Ray Charles - Doodlin' - LM4562

 

[evonimos]

Another couple of well-regarded opamps, are the MUSES8820 by Japan Radio Co and the AD823 by Analog Devices.
The latter is a very nice sounding opamp, performing well in a variety of applications.
In my opinion, the AD823 gets top ranking together with LM4562 and LME49720HA.

Ray Charles - Doodlin' - MUSES8820
Ray Charles - Doodlin' - AD823

 

[evonimos]

Next ones coming:

- OPA627 by Burr Brown - Legendary status, no need to elaborate on them.
- NE5534 by Texas Instruments (and others) - The single-channel version of the NE5532, although they are 'faster' and sound somewhat different.

So these are single channel and i use them with a single to dual socket adapter.
They are the same package (DIP8), single-channel only and have different pin out.

I'll say upfront: I prefer them to their double counterparts. To my ears they sound better.

By the way, I am pretty sure that it is hard for most folks to pick up any differences between the recordings.
This is a testament to the quality and consistency of opamp sound performance.,
Also, it can prove that there's a lot of mythology and hear-say, without much to back it all up in audiophile circles.

Yet, there are small identifiable differences if one is willing to really pay attention.
These differences will obviously be easier to pick up with proper playback equipment, but that's another subject altogether.

OK, will update the thread soon, with the audio files and maybe some pics.

 

[snellemin]

I've messed around with Opamps, capacitors and buffers and the effects it has on sound. Operating temps on the buffers also has a sound effect, but that is on bigger stuff. Hence why I have a variety of amplifiers with different combo's of opamps and buffers, so I don't get "bored" with a sound signature.

 

[evonimos]

Finally found time to record and upload the single channel ones:

Ray Charles - Doodlin' - NE5534
Ray Charles - Doodlin' - OPA627

As expected, the OPA627 sounds great and it almost matches the reference performance of the fully discrete transistor RIAA.
It's very close to it, but the discrete still has the edge in terms of transient dynamics and speed (better rhythm/pace) and staging.

Regarding the NE5534 (plastic DIP8 package) by Texas Instruments, in my opinion is the second best. Not far behind the OPA627.
And given its price/availability, it's still probably one of the best value single channel opamp out there.
Overtakes the dual LM4562 (a very solid dual opamp) and the rest, having better staging, more air around instruments and a fuller body without loss of detail.

An honorary mention goes to the MUSES8820, especially for vinyl (RIAA) applications.
It's a great value, easy to implement dual opamp that offers very good sound with a distinctive analogue flair to it.
Also, AD823 is very good, with cohesion and detail without being tiring.
And of course there is the ubiquitous Texas Instruments NE5532 which remains an amazing value for what it offers as a dual opamp.

So to sum it all up, i believe that if you know how to properly implement them, standard opamps can sound fantastic and certainly above their price.
For headphone applications, they are perfect in gain stages in amplifiers and with their low-power consumption are pretty much essential in portable designs.

You really need a 'trained ear' to be able to distinguish between the minute differences in performance among them.
Even in comparison to more elaborate designs like tubes or fully discrete designs, you would find it hard to tell the difference.

I'm also intrigued by the offerings of several avant-garde opamp specialists (like Burson et al), but have not had the chance to get my hands on one of those yet.

Best regards and enjoy!

 

[Ghoostknight]

The OPA627 was the closest IC opamp i heared to the Burson V6 Vivid, definitely a special sound under IC opamps

Also the OP1656 is a (modern) gem imo, tho OP1612 is not far off

for me the LM4562 sounds too bright and "brittle", the OP2134 sounds really boring/0815 compared to others

IMO if you are used to these minor changes opamp rolling can still make "a lot" of difference, tho the "a lot" is definitely debetable

for me the changes of opamp sounds a bit like you messed with the EQ in +/-1db on different bands, atleast thats how i would describe it