[adrianbrac]

Hello Everyone,

Firstly, thank you all for the great information posted on this site. I always read, but never post. I am definitely a new member here, and will be reading more avidly.

I've been into sound systems for a while. I am migrating from Car Audio, since I will be moving overseas and be without a vehicle for some time. I would definitely like to expand my knowledge in the Home and Computer Audio arenas, and I think this is a great place for that.

One of the things I have been reviewing for the past few weeks now is the Asus Xonar HDAV 1.3 Deluxe sound card.

My current project (which I am using right now) is an HTPC Music Server that has onboard sound (sad, I know...), but will be receiving the HDAV 1.3 Deluxe on Monday (yay!!!).

I've researched the OP AMPS that this soundcard has:
-JRC/NJM2114D for all 8 analgoue channels (8 total)
-LM4562's as buffers to the 8 analogue channels (4 total)


My biggest question is about which OP AMP's to be using with this system. I am planning on buying quite a few, I just need some help with the ones I am looking at.

Here is the list:
Single Channel-
Burr-Brown OPA627
Dual Channel-
Burr-Brown OPA2227PA
Burr-Brown OPA2277PA
Analog Devices AD8620
National Semic. LM4562
Special Order Dual Channel-
Audiophile OPA2627 "Superchip"

Here is what I know about the card from reading about it. Each analog channel has a dual op amp (regardless of channel singularity) with the NJM2114D OP Amp. Furthermore, four LM4562's are used as buffers to each channel. I am guessing that the dual op amp for each channel is for ease of use. The LM4562's are used to combine two single channels into one for analog connectivity.

Question is... since these channels are seperated to one channel (eight total), can I use a single-channel op amp, like the OPA627 in place of the NJM2114D's? Or does it need to be strictly a dual OP Amp?

If it needs to be a dual OP Amp, would the Audiophile Products OPA2627 "Superchip" suffice for that type of connectivity?


I am planning on loading up on these op amps, so I will be buying 12 of each to ensure I have enough for each channel.

Any recommendations for this project would be outstanding. I leave the country in two and a half weeks time, so the sooner, the better. Thanks again for all the info you guys have posted. I'll be giving my reviews on the op amps after a while.

Currently own a set of AKG K271 @ 55 Ohms.

Regards, Adrian

 

[ROBSCIX]

The JRC2114D for a differential input current to voltage converter section.
You have 1 JRC2114D for each channel. For the left and right channels you have two JRC 2114D's each one if further buffered by one side of the LM4562NA. That forms a integrator/buffer.

Left channel differential input-> JRC2114D\
____________________________________LM4562NA->stereo output(L&R)
Right channel differential input->JRC2114D/

You have the above opamps circuit for each stereo pair, Fronts,rears,sides and center and subwoofer.
You need dual channel chips for each opamp position. Although you can get a bit creative with the center and subwoofer because each channel is different.
It is always advisable to change the JRC2114Ds in pairs as they are matched channels.
With the center and sub you can use a different opamp, such as 1 LM49720HA for the center and a OPA2227 for the Subwoofer....etc.

Hope that gets you started.

 

[adrianbrac]

Thanks for the recommendations. I was thinking about trying out the OPA627's in place of the JRC2114D's, since they are single channel. If it is important to keep the dual op amp setup, vice the single op amp OPA627's, could I use the Audiophile OPA2627 "Superchip" in place of the JRC2114D's?

I heard the LM49720HA is an identical to the LM4562. Is that true?

 

[adrianbrac]

Any recommendations?

I've been reading alot of the Datasheets for the following opamps.

OPA627AU
OPA2227PA/UA
OPA2277PA/UA
LM4562NA
LM49720NA
AD8620ARZ

and the original NJM2114D.

The absolute max ratings for the NJM2114D is +-22v. Now keeping this in mind, all Op Amps handle above this, with the exception of the OPA2227 (+-18v).

Should I stay away from the OPA2227 for this reason? I don't want to buy an Op Amp, then later burn it out due to voltage parameters.

Also, I've been reading on the Brown Dog Dual 8-SOIC to 8-DIP adapter. Can I use this to integrate two OPA627AU's to make a Dual Channel OPA627?? Essentially an "OPA2627".

Please let me know. I am in the process of ordering these IC's. Help from the great people here would be excellent. Thanks again.

 

[adrianbrac]

Any help would be great. Bump.

 

[ROBSCIX]

Quote:

Originally Posted by adrianbrac /img/forum/go_quote.gif Thanks for the recommendations. I was thinking about trying out the OPA627's in place of the JRC2114D's, since they are single channel. If it is important to keep the dual op amp setup, vice the single op amp OPA627's, could I use the Audiophile OPA2627 "Superchip" in place of the JRC2114D's? I heard the LM49720HA is an identical to the LM4562. Is that true?

No!! You have to replace the JRC2114D with another dual channel opamp. That is what the circuit requires.
The HA version is a metal can opamp and higher quality then then normal chip versions. If your comparing chip to chip then some say they are the same and some say they hear differences. The metal can versions sound betetr then chip versions IMO.

 

[adrianbrac]

So, I cannot use a PCB that mounts two single channel opamps to an 8DIP?

I am ready to purchase quite a few op amps, and the majority is Single Channel SOIC. I am planning to mount two SOIC's to one 8DIP connector (Brown Dog Single-to-dual Op-Amp Adapter (p/n 020302)).

 

[ROBSCIX]

Yes, you can us adapters for making two single channel modules into a dual channel module. This is done all the time as many units that you woudl want to try for audio are single achannel and/or SOIC. They require adapters to be used on a soundcard or in a external DAC/Amp ..etc

Do you have any experience with soldering?

 

[adrianbrac]

Yes. I have alot of experience with electronic equipment. I opted out today, and ordered:

-Four OPA2227PA's
-Four OPA2277P's
-Eight LME49720's

I plan on getting more later on, like the OPA627's, AD797's, and AD8620's

I would like to try them all, but it is hard to find a vendor that actually sells all of them. I know the 627's are very expensive, so I will only try and do the L/R channels to test them out before completely replacing all the OP Amps to that specific model.

 

[ROBSCIX]

To note, the 637 are not stable in the I/V position in this circuit layout. The 627's work fine as I have tested them for I/V and buffer. Both work for buffer, not I/V though.

You might consider testing all the way you mentioned. Just buy a set to test out in the fronts. If you like them then buy more. Will save you from buying a bunch of opamps your not going to use.
Hope this helps.

 

[leeperry]

Quote:

Originally Posted by adrianbrac /img/forum/go_quote.gif I plan on getting more later on, like the OPA627's, AD797's, and AD8620's

AD797B is amazing, many ppl said that to me...and it ends up they were totally right

 

[adrianbrac]

I've read a few places that the 797 outperforms the 627 in some systems. I'd like to see if that is true.

Tomorrow when I receive the Sound Card, I will post some pictures here to show everyone the OP Amps. I have had a difficult time trying to find accurate pictures of the main board.

I will also submit a review of the stock product with the original Op Amps. Once I receive the other OP Amps, I will do install the configuration that ROBSCIX mentioned, and let you know after a few days of running. I am sure they take some time to break in properly (as with any electronic equipment).

Hopefully, this setup will make the sound come alive.

If I am lucky, I can find a few places in Japan that sells these chips for a valuable price (moving in a few weeks).

 

[ROBSCIX]

AD797's are decent enough have a few of those in my collection. They sound decent but I like other units much better. Application and the circuit plays a big part also in the end signature.
It is all about what you like, I can make suggestion of configuration that you may like but the end decisions is yours. I must have went through about 40-50 configuration on that card just trying various signatures.

Happy testing.

 

[adrianbrac]

Thanks Rob. I just installed the card, updated the drivers. Sounds great on FLAC. Extremely clear. Can't wait to see how the other OP AMPs perform. I think it will be a fun experience.

I am only having trouble with the front panel connection. I need to revisit the case and see what my findings are. Pictures will be posted shortly. I need to build a site to load them.

 

[adrianbrac]

A few things users of the Xonar HDAV should know are the front panel only engages when the user switches the output device to Front Panel from the Xonar HDAV Center control panel. There are many features this card offers, and sounds exceptionally clear for everything.

Blu-ray playback is superb on the HD playback. Using the Splendid HD setup has not shown a huge difference in performance. The Nvidia GTX 260 has plenty of hardware juice to spare, it runs hot though.

Update: I just received my OP Amps today. I was thinking about throwing the Specific setup Rob mentioned at the beginning of the Post, as I have both Op Amps on standby. I am also tempted to OPA2277P's perform. Hopefully they will be pleasent on the Front Channels, but requires a Soundcard pull and dismantling.

I took pics of the soundcard that way other people that search for the board can see exactly what the main board looks like without the cover on it. I noticed J11 (left of the green front panel jumper) and thought it may be used as an internal SPDIF. I wonder if it actually utilizes this function. If so, that will save plenty of time of running a digital sound signal to the video card without all the HDMI jargon (Video HDMI-->Sound HDMI-->Monitor/TV).

I think they did not advertise the internal spdif for the reason of using the Splendid HD processor. Marketing gimmick? I'd say so.

Pics posted shortly.