[ROBSCIX]

The LME49720NA and the LM4562NA are identical opamps acoridng to the specs and Nationals info. Usually using three of the same opamp will yeild poor results as what you find good or bad about the opamps will compound. This is usually dependant on the opamp as you may like the signature.

There are a couple STX owners here that use the Dual LME49710HA on an adapter. These units were built by me for their cards.

 

[Salvador]

2x LME49720NA (I/V) 1x dual LME49710HA (buffer) Impressions:

I tried out this combo last night and I think I prefer the 720NA's over the 720HA's in the I/V section when pairing it up with the dual 710HA's.

There's a bit more bass with the 720NA's which I prefer. The 720HA's has a bit of an edge with the highs but at the expense of bass.

One of the biggest differences that I found though is that the vocal projection in the soundstage is more focused towards the middle rather than dispersed. With the 720HA's, I felt the singer's voice was coming from all sides as opposed to coming from the center.

 

[ROBSCIX]

So your keeping the 720NA and the Dual 710HA for buffer combo?

There are a few that prefer the 720NA over the HA's. The Ha's seem to have less bass with certain setups.

What do you hear when comparing the single 720HA over the dual 710HA module?

 

[Salvador]

Quote:

Originally Posted by ROBSCIX /img/forum/go_quote.gif So your keeping the 720NA and the Dual 710HA for buffer combo? There are a few that prefer the 720NA over the HA's. The Ha's seem to have less bass with certain setups. What do you hear when comparing the single 720HA over the dual 710HA module?

Yes i prefer the 720NA's over the 720HA's for I/V. Kudos btw to shahrose for suggesting this. On my paradigm studio 100's, the bass response is better on the 720NA's. The vocal placement and localization of instruments is also better on the 720NA's.

I haven't switched around the dual 710HA's at buffer yet . I'll switch the buffer to 720NA's then 720HA's to test later on. For now I'm still in the process of evaluating 720NA's for I/V and 710HA's for buffer.

I'll post my impressions once I test

 

[ROBSCIX]

Sure. Do you enjoy the sound of the 710HA for buffer?

 

[Salvador]

Quote:

Originally Posted by ROBSCIX /img/forum/go_quote.gif Sure. Do you enjoy the sound of the 710HA for buffer?

Oh yeah for sure.

But at this point I'll switch around the opamps for the buffer while keeping the I/V's the same. After that i'll be able to better decipher the differences between the 710HA, 720NA/HA in the buffer position.

 

[ROBSCIX]

Sounds great, post your impressions. I am interested to hear what others think of the Dual LME49710HA module.

 

[penguindude]

Anyone knows how the 1792A (STX dac chip) compares to the AK4396 miracle DAC chip?

 

[ROBSCIX]

If we compres specifications of just the chips the 1792A surpasses the AK4396

PCM 1792A
SNR:127dB
DYN:127dB
THD+N:-110dB

Spec sheet-> Link

AK4396
SNR:120dB
DYN:120dB
THD+N:-100dB

Spec sheet->Link

These numbers are spec values so usually for real world values providing a decent circuit the actual measurments would be about -3dB difference from the spec values.
-Usually, devices using the AK4396 DAC will hit about 116-117dB for SNR and the STX and ST which use the 1796A are about 124dB SNR.
It is hard to judge an audio design just based on the spec values fo the DAC. Although they are a good indicator there is more to the sound quality then just the DAC. The overall sound quality is based on the filtering and output sections along with power, design and component choices.
The PCM1796A is fairly new in soundcards designs but there are many popular soundcards and many external DAC's built upon the AK4396 DAC chip.

Hope that Helps.

 

[Shahrose]

Quote:

Originally Posted by Salvador /img/forum/go_quote.gif Yes i prefer the 720NA's over the 720HA's for I/V. Kudos btw to shahrose for suggesting this. On my paradigm studio 100's, the bass response is better on the 720NA's. The vocal placement and localization of instruments is also better on the 720NA's. I haven't switched around the dual 710HA's at buffer yet . I'll switch the buffer to 720NA's then 720HA's to test later on. For now I'm still in the process of evaluating 720NA's for I/V and 710HA's for buffer. I'll post my impressions once I test

I found the 20HA to be a bit hot up top. It added sibilance to tracks I know did not contain any since I've heard them on other fairly solid equipment, including my own speaker setup. The NA I found had a wider soundstage, slightly better imaging, definitely more bass and a smoother/more natural treble that wasn't any less extended than the 20HA.

 

[Ra97oR]

Does changing the buffer changes the sound on headphone out? I thought it on changes the line out right?

 

[ROBSCIX]

No, the buffer is only for the line out.

The I/V affect both line out and can output.

 

[gurubhai]

... & all three opamps affecting lineout also affect headphones if using an external amp connected to lineout.

 

[chinesekiwi]

Ok decision time!

Since Sharrose also has a STX + Rockhopper M3 combo like me I read his opinions with extra attention for synergy reasons and it looks like the LME49720NA in I/V looks like a very safe bet and I'll probably no doubt order them since they're relatively quite cheap compared to the other combos here. I'd rather not use adapters.

I know that there have been 3 x LME49720NA (2 in I/V, 1 in buffer) comparisons but this is a long thread so could anyone restate their impressions of them?
Any good DIP8 opamp options for the buffer for the LME49720NA's?

EDIT: So I've read that 3x of something = not so good.
mmmm.....my current LT1057's in the buffer could be an option....it's a bassyish opamp.
Any other suggestions = much appreciated.

 

[RicHSAD]

Trying OPA2228P+2xOPA2107AP atm and I'm liking it. Getting really hard to tell what's better. The only setup I didn't like so far was the LT1057s in I/V.