LME49720 & 49720 improvement

[Emmathom]

Hi Gentlemen

I need your knowledge & advice please

I recently opened my DAC (ES9018 + Xmos) and noticed LM49710 & 49720 at output. I must say that I don't have the DAC schematic.
My questions are :

- are they "good OPAs" ? where would you classify them in a "good sounding" scale ?

- if they can (must ?) be replaced which ref. do you advise to possibly improve the sound ?

Thanks for your answers !
Best Regards

 

[ccaudle]

are they "good OPAs" ?

Some of the lowest distortion op-amps ever made. There is no technical improvement to be made by replacing them unless there is some other design fault which uses them in a non-optimal manner.

 

[Emmathom]

Thank you @ccaudle !
Happy to notice that some chineese manufacturers work for quality.
I use this DAC since 2010 (my first and only) and the sound is really good. Even the board is well built...

 

[elskardio]

Thank you @ccaudle !
Happy to notice that some chineese manufacturers work for quality.
I use this DAC since 2010 (my first and only) and the sound is really good. Even the board is well built...

I wouldn't change a thing! Those are all high quality components. You even have Nichicon Muse Capacitors.

 

[Emmathom]

I wouldn't change a thing! Those are all high quality components. You even have Nichicon Muse Capacitors.

Yeah and Wima FKP2 too ! Great

 

[ruffrecords]

The only downside I can see is some of the soldering looks like it has been done by a 5 year old

Cheers

Ian

 

[Emmathom]

The only downside I can see is some of the soldering looks like it has been done by a 5 year old

Cheers

Ian

Yes I must refresh/resold that with silver solder one of these days...

 

[living sounds]

Thank you @ccaudle !
Happy to notice that some chineese manufacturers work for quality.
I use this DAC since 2010 (my first and only) and the sound is really good. Even the board is well built...

Nichicon Muse (the green ones) are my favourite electrolytics in the signal path. The violet ones at the bottom look like Os-Cons - good choice for digital decoupling. It looks a little bit like they are using 0.1uf film caps and low ESR caps for audio PSU line decoupling, that I am not a fan of. The big square WIMAs could be for S/H duties, where polypropylene is a good choice.

If they made LME497XX work as they should I wouldn't change a thing.

 

[Emmathom]

Nichicon Muse (the green ones) are my favourite electrolytics in the signal path. The violet ones at the bottom look like Os-Cons - good choice for digital decoupling. It looks a little bit like they are using 0.1uf film caps and low ESR caps for audio PSU line decoupling, that I am not a fan of. The big square WIMAs could be for S/H duties, where polypropylene is a good choice.

If they made LME497XX work as they should I wouldn't change a thing.

The 10nF (red cubes) must be FKP2 which are my best cap espescially close to OPA for last PSU filtering.
What means S/H duties ?