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Asus Essence One Headphone Amp/DAC (CeBIT 2011)
Apr 10, 2012 at 12:01 PM Post #811 of 3,573
I have a simple question: 
 
I have a Asus Xonar ST right now. Would it be worth upgrading to Essence One if I would only be using headphones with it?  How much better are the DAC and headphone amplifier section on Essence One? Is the difference noticeable?
 
Apr 12, 2012 at 2:15 PM Post #812 of 3,573


Quote:
derbigpr said:
I have a simple question: 
 
I have a Asus Xonar ST right now. Would it be worth upgrading to Essence One if I would only be using headphones with it?  How much better are the DAC and headphone amplifier section on Essence One? Is the difference noticeable?
Click to expand...


I don't have ST, but I've read on other review sites, that they said E1 is warmer, and added a little bass. I have HD800 and I think it goes well with it.
Also, if you do decide to invest and upgrade, you have the options of changing the op-amps on the headphone as well, so that would change your sound.
One thing to notice that, E1 added  LME49600 --> This seems to be a brand new headphone amplifier buffer. The DIY forums seem to point out that it´s a very good one too. quote from "http://www.head-fi.org/t/542563/asus-essence-one-headphone-amp-dac-cebit-2011/645"
 
 
 
Apr 12, 2012 at 2:41 PM Post #813 of 3,573


Quote:
leeperry said:
 

yay, bad news! what about AD797B in the headamp if you could test please?
 
I think 1028 and 797 can have a resistor soldered onto one of their pins ino order to become UGS.
 
An unstable opamp is not a good thing, as it can output audible artifacts randomly. And oscillation can also shorten the MTBF. It can also make the sound brighter and shrill.
Click to expand...

I have received some AD797BR modules yesterday. Started to swap all opamps (except line out buffers) and sound really changed; became more natural, spatious, mids came out so that lows and highs seems lower in volume. Highs sound less metallic. But after some time i checked the chips and found all of them hot to touch. I knew that there must be oscillations inside.
Today I checked with oscilloscope and found it to be true.

 

One oscillation was at 43 MHz, the other at 6,1 MHz.
It is present at every module and every position in E1 with little variation in frequency.
It is strange that sound is so good despite oscillations, but I took them out.
Any suggestions from experienced people?
 
Apr 12, 2012 at 3:57 PM Post #814 of 3,573
Thanks for sharing the results of your tests!
 
Did you get the AD797BR's already soldered onto those blue Teradak adapters from Audiojade on ebay?
 
I could easily suspect that they would be oscillating, but they sound so amazing and I don't get any audio artifacts....so you know 
evil_smiley.gif

 
I agree that they're hot to the touch, but the top of the ONE was already hot w/ the stock opamps IME due to the voltage regulators and their big heatsinks. Anyway, most of the best opamps require custom designs to be stable, and they also cost too much for DAC manufacturers to use them. If the ONE came w/ 22 pieces of AD797BRZ, it would cost +$2K I guess, the only things we could possibly really care about are 1) audible artifacts 2) DC offset. I don't get any of these two 
 
I believe there are tricks to make AD797 "unity gain stable", would need to check out their datasheet.
 
Apr 12, 2012 at 4:55 PM Post #815 of 3,573


Quote:
leeperry said:
Thanks for sharing the results of your tests!
 
Did you get the AD797BR's already soldered onto those blue Teradak adapters from Audiojade on ebay?
 
I could easily suspect that they would be oscillating, but they sound so amazing and I don't get any audio artifacts....so you know 
evil_smiley.gif

 
I agree that they're hot to the touch, but the top of the ONE was already hot w/ the stock opamps IME due to the voltage regulators and their big heatsinks. Anyway, most of the best opamps require custom designs to be stable, and they also cost too much for DAC manufacturers to use them. If the ONE came w/ 22 pieces of AD797BRZ, it would cost +$2K I guess, the only things we could possibly really care about are 1) audible artifacts 2) DC offset. I don't get any of these two 
 
I believe there are tricks to make AD797 "unity gain stable", would need to check out their datasheet.
Click to expand...

Yes, i got soldered modules from Audiojade.
 
The top of the ONE becomes pretty hot, but standard opamps are pretty cool to the touch, while oscillating AD797BR`s can not be touched more than 5 seconds.
 
There are really not audible artifacts, and there is no DC offset except in I/V converter, but that is by design.
 
When I get the time to play with, I will put modules to proto-board and try some combinations to make them stable.
 
Apr 12, 2012 at 6:30 PM Post #816 of 3,573
AD797BR was also VERY hot to the touch in my old Spitfire DAC, used as PCM1793 LPF. Oscillating like hell probably, but still sounding great =)
 
I've showed your tests results to a friend of mine who's also a major opamp'holic and he said "AD797 *demands* PSU bypass caps; it is too fast to run stable and give you its best sound without them. Recommend to him to add one 50V 10uF tantalum cap per module and a 50V 100nF C0G (or NP0) ceramic per chip. This provides good bypassing while keeping the modules swappable."
 
I thought all those WIMA caps close to the DIP8 sockets were here to avoid oscillation?
If you could find a way to get AD797 stable in the ONE, we would all be very grateful 
beerchug.gif

 
Apr 12, 2012 at 9:01 PM Post #817 of 3,573
Hello,
 
I was thinking of getting a essence one soon and I wanted too know what would be good op amps that would give hd800s a good amount of bass but not over done?
 
                                                                     Thanks in advanced,
                                                                                      SONIC BOOM
 
Apr 13, 2012 at 2:55 AM Post #818 of 3,573


Quote:
leeperry said:
AD797BR was also VERY hot to the touch in my old Spitfire DAC, used as PCM1793 LPF. Oscillating like hell probably, but still sounding great =)
 
I've showed your tests results to a friend of mine who's also a major opamp'holic and he said "AD797 *demands* PSU bypass caps; it is too fast to run stable and give you its best sound without them. Recommend to him to add one 50V 10uF tantalum cap per module and a 50V 100nF C0G (or NP0) ceramic per chip. This provides good bypassing while keeping the modules swappable."
 
I thought all those WIMA caps close to the DIP8 sockets were here to avoid oscillation?
If you could find a way to get AD797 stable in the ONE, we would all be very grateful 
beerchug.gif
Click to expand...

It is emhasized in datasheet that needs PSU bypass. Those Wima caps are for that purpose, but maybe too low value or too far from chip on module. At these high MHz frequencies every milimeter matters. There will be no problem to solder bypass caps, but problem will be to make propper ground connection - the ONE could look like Power Plant
beyersmile.png
.
 
 
 
Apr 13, 2012 at 3:51 AM Post #819 of 3,573


Quote:
sonic boom said:
Hello,
 
I was thinking of getting a essence one soon and I wanted too know what would be good op amps that would give hd800s a good amount of bass but not over done?
 
                                                                     Thanks in advanced,
                                                                                      SONIC BOOM
Click to expand...


 
The stock op-amp already gave hd800 pretty good bass, but I used LME49990MA in I/V section and plan to use LME49710HA for my headphone buffer which will give further bass (according to someone online and in this thread) and maybe AD8620BR or OPA627AU in the LPF section
 
 
 
Apr 13, 2012 at 10:04 AM Post #820 of 3,573
 
Quote:
dmarasovic said:
It is emhasized in datasheet that needs PSU bypass. Those Wima caps are for that purpose, but maybe too low value or too far from chip on module. At these high MHz frequencies every milimeter matters. There will be no problem to solder bypass caps, but problem will be to make propper ground connection - the ONE could look like Power Plant
beyersmile.png
.
Click to expand...


It'd be awesomtastic if you could find a way to make them stable in the ONE 
happy_face1.gif

 
Apr 14, 2012 at 11:30 AM Post #822 of 3,573
I'm probably getting this DAC very soon, but I wonder one thing. Would using S/PDIF out of a soundcard be a better solution than using USB out of the PC?  I was thinking of getting some cheap card, like Asus Xonar DX,  it can output 24 bit /192khz trough S/PDIF. Would the drop in performance when used trough USB be noticeable, or in other words, is it worth buying another card just to use it as an output. Also, if I had the card as output, I could use all the settings from the drivers, such as dolby, equalizer, etc.?
 
Apr 14, 2012 at 11:33 AM Post #823 of 3,573
Quote:
derbigpr said:
I'm probably getting this DAC very soon, but I wonder one thing. Would using S/PDIF out of a soundcard be a better solution than using USB out of the PC?  I was thinking of getting some cheap card, like Asus Xonar DX,  it can output 24 bit /192khz trough S/PDIF. Would the drop in performance when used trough USB be noticeable, or in other words, is it worth buying another card just to use it as an output. Also, if I had the card as output, I could use all the settings from the drivers, such as dolby, equalizer, etc.?
Click to expand...


USB should not sound any worse than S/PDIF. The Xonar DX does not have Dolby Headphone on the digital output, as far as I know.
 
 
Apr 14, 2012 at 11:40 AM Post #824 of 3,573

derbigpr said:
Would using S/PDIF out of a soundcard be a better solution than using USB out of the PC?
Click to expand...


No, USB is better.
An S/PDIF receiver must reconstruct the sample clock from the signal, and the signal gets distorted due to the cable's impedance, thus introducing jitter.
When using asynchronous USB, the receiving device uses its own sample clock.
 
Apr 14, 2012 at 11:40 AM Post #825 of 3,573


Quote:
stv014 said:
USB should not sound any worse than S/PDIF. The Xonar DX does not have Dolby Headphone on the digital output, as far as I know.
 
Click to expand...



What about using ordinary RCA outputs on the DX? Would that be any better than using USB?
 
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