[TheGoldenEars]

Does anyone know a website (preferably well known) that is known to sell only the version of the DAC without the unbalance issue? If I buy now from Amazon is there a chance I will get the one with this issue?

 

[4Real]

  Does anyone know a website (preferably well known) that is known to sell only the version of the DAC without the unbalance issue? If I buy now from Amazon is there a chance I will get the one with this issue?

You would need to get a Muses Edition, thats the only version that has a different pot on the headphone volume. 

 

[TheGoldenEars]

  You would need to get a Muses Edition, thats the only version that has a different pot on the headphone volume. 

 
Thanks! Is the Essence III clear from the issue too?

 

[Mach3]

   
Thanks! Is the Essence III clear from the issue too?

Yes it is, but good luck finding a distributor anywhere else in the world except Europe.

 

[4Real]

 

[raoultrifan]

Hi guys, 
 
I just bought myself a piece of Essence One and I'm quite happy about it.
 
Of course, I'm already thinking of modding it:
- according to csarrow and mach3: replace KT with KA caps, increase PSU's caps
- add tantalums for+/-12V and +5V
- add 3 x 2.2uF in parallel with trafo's secondary coils;
- add EMI/RFI filter (capacitors and coils);
- replace BK10 with 4-gangs equivalent logarithmic from BOURNE (Mouser has something)
- according to MaestroSfai (https://audiofilifiorentini.files.wordpress.com/2014/04/modifiche-sonore-al-dac-asus-one-che-risorgerc3a0.pdf): replace output caps with dc-servo circuit with TL072, like is already implemented in E1's headphone amp with LME49720.
Well, I still love E1's warranty right now, so...I'll probably wait a couple of years till starting these quite intrusive/obvious mods.
 
Meantime, after swapping some opams (NE5532, LM4562, OPA2604, OPA1602) in different positions I realized that best sound I could get is having OPA2604 in I/V and OPA1602 in LPF. Best soundstage indeed, but too bad I can't keep the OPA2604 in IV anymore, because of overheating: around 65C with case open and most likely 75C or even more with case closed. Will not try adding heatsinks on OPA2604 because I really think they are oscillating, so I'll try finding an oscilloscope first or I'll just try OPA1642 in IV soon.
 
Speaking of opening and closing E1's case, while keeping my AKG 550's on my head with volume pot at max. (E1's mute button = ON) I realized that I have an audible hum around 100-200Hz when case is closed or even partially-closed, but not hum at all while case is fully open. Same hum, but a little bit less disturbing, was heard with my Grado SR60i L-cush, so looks like thick aluminium case is reflecting trafo's hum/noise back inside the DAC's circuit.
Then, I realized there are tests proving the existence of this noise: http://www.homemedia.fr/tests/i/mesures/asus-essence-one-rmaa/ASUS%20Xonar%20Essence%20One%2096%20khz.htm and http://archimago.blogspot.ro/2013/02/measurement-asus-xonar-essence-one.html.
So, I found out that trafo needs to be repositioned and least hum-noise I could get is placing it vice-versa (yes, with bottom on top) and angled with about 30 degrees, like in pictures attached. This decreased the hum-noise with more than half. I've used 1 x clothes-pin and 1 x rubber-band to do this "trafo rearrangement", but I'm sure this can be done way much better looking.
 
Just to be sure noise will decrease further, I've also added a ferrite-core around the power cord and a small DIY RC filter between chassis ground and mains power ground (5K/4Watts resistor || 330nF cap), somehow similar with what Meier Corda does in his amps.
 
Is anyone else able to hear that hum I'm speaking about or just my E1 has this issue?
 
Thanks, 
Raul.
 

 
 
 

 

 

[WildStyle-R11]

Yup, My E1 has a hum too. You can clearly notice it when nothing is playing the headphones seem to block noise from outside a little, then without the hum.

 

[4Real]

Zero hum for me with the muses edition, first thing I did with mine was test for any noise at full volume, and I can honestly say its dead silent, and that was in high gain with sensitive IEM's,

 

[raoultrifan]

Thanks guys,
 
 
4Real, my E1 has Muses Edition PCB inside, the one with gain jumpers but with B10k pot, so this is not related to PCB at all, but to transformer inside PSU. If you have zero hum-noise with sensitive headphones, than I'd say you're lucky.
 
Regards, 
Raul.

 

[DMarasovic]

  Is anyone else able to hear that hum I'm speaking about or just my E1 has this issue?
 
Thanks, 
Raul.

My E1 is also dead silent. I have swapped lots of IC's and it was never able to hear or measure hum. Hum can be produced by oscillating amp, so check to use recommended one and assure that IC sits in position with good pin contact to socket. When IC is oscillating, it produces high (even radio) frequencies and everything around it acts as an aerial. That could include power transformer.
 
Regards.
Damir

 

[raoultrifan]

Hi Damir,
 
With default opamps I got the same hum. Like I said before, rearranging power transformer resolves the issue. I have reasons to believe that all E1s are like that because they all share the same trafo part no., so all you need is AKG K550 and a dead silent room (at 2AM in the morning) to do the testing. You will not hear hum with any kind of headphone, even not with all IEMs, so try it out with K550 please.
 
Feel free to check the screenshots here: http://www.homemedia.fr/tests/i/mesures/asus-essence-one-rmaa/ASUS%20Xonar%20Essence%20One%2096%20khz.htm and http://archimago.blogspot.ro/2013/02/measurement-asus-xonar-essence-one.html.You can see the hum I'm speaking about, especially 2'nd and 3'rd harmonic (around 200 Hz and 300 Hz). DACs having external PSU doesn't have this hum at all...just pure white noise maybe, but not hum.
 
Cheers, 
Raul.

 

[4Real]

  Hi Damir,
 
With default opamps I got the same hum. Like I said before, rearranging power transformer resolves the issue. I have reasons to believe that all E1s are like that because they all share the same trafo part no., so all you need is AKG K550 and a dead silent room (at 2AM in the morning) to do the testing. You will not hear hum with any kind of headphone, even not with all IEMs, so try it out with K550 please.
 
Feel free to check the screenshots here: http://www.homemedia.fr/tests/i/mesures/asus-essence-one-rmaa/ASUS%20Xonar%20Essence%20One%2096%20khz.htm and http://archimago.blogspot.ro/2013/02/measurement-asus-xonar-essence-one.html.You can see the hum I'm speaking about, especially 2'nd and 3'rd harmonic (around 200 Hz and 300 Hz). DACs having external PSU doesn't have this hum at all...just pure white noise maybe, but not hum.
 
Cheers, 
Raul.

Damir said he doesn't have hum.
 
Why would you only here it with the AKG
 
I've used a number of full size cans with low impedance that are sensitive, like the X2 for example.
 
I've also used a number of IEM's with great isolation, ranging from 16ohms - 32ohms, I have zero noise with any of them.
 
I have amps that have an audible hum, hiss or both, but my muses edition isn't one of them, which was a surprise as I expected the opposite to be true.

 

[raoultrifan]

Thanks 4Real, 
 
I'm sure you are right. So, maybe ASUS is installing 2 different type of PSU transformers after all.
 
Anyway, E1's trafo is way too close of headamp and it's totally unshielded, so...for those who have the "hum issue", looks like repositioning trafo's helps a lot.
 
Thanks,
Raul.

 

[4Real]

  Thanks 4Real, 
 
I'm sure you are right. So, maybe ASUS is installing 2 different type of PSU transformers after all.
 
Anyway, E1's trafo is way too close of headamp and it's totally unshielded, so...for those who have the "hum issue", looks like repositioning trafo's helps a lot.
 
Thanks,
Raul.

I'm sure there are many factors that come into play. 
 
Others may have a different experience, I'm just saying that mine is different from yours. 

 

[raoultrifan]

Also, quality control for Muses Edition should probably be different, mostly because it's cost is 75% higher than E1.