[jacal01]

I wondered about that myself, when I saw the MkII USB specs and his rationale, since I'd previously read an article saying that the CCK would pass up to 24/96.
 
[size=medium]Here it is.[/size]

 

[xinghui0711]

Quote:

I wondered about that myself, when I saw the MkII USB specs and his rationale, since I'd previously read an article saying that the CCK would pass up to 24/96.
 
[size=medium]Here it is.[/size]

I thought that iDevices only do playback with 16/48 because of the iOS system.
Interesting thought.

 

[plakat]

It seems to be a simple compatibility problem... resolution higher than 16/48 seems to work only with some USB receiver chipsets (maybe even not consistent across iPad generations). I understand this USB chipset was chosen to ensure maximum compatibility... including driver-less operation when using the device with Windows-based machines (i.e. using system installed drivers).

 

[lee730]

Quote:

 
You're right, I was thinking of the USB receiver, which is the main weak point in the design (though he chose it to be compatible with the iPad CCK). That's a PCM2706. 

 
Ahh I was curious if you were referring to that.... Well I agree the USB does sound rather awful to my ears as well at least in comparison to the Coaxil/Toslink....

 

[uelover]

Quote:

Ahh I was curious if you were referring to that.... Well I agree the USB does sound rather awful to my ears as well at least in comparison to the Coaxil/Toslink....

 
As I mentioned earlier, I have tried to isolate the onboard USB receiver with my own external USB receiver to test out how good/bad the USB receiver on the UHA6SMKII is. Maybe there aren't many who understood what the USB receiver was back there so I shall say it again here.
 
I ran:
 
1) Mac Mini -> USB -> UHA6SMKII
2) Mac Mini -> USB -> Stello U3 (this is a pure USB to SPDIF converter that house an async high quality USB receiver) -> Viablue RCA-Male Coupler Adapter (to act as a coaxial cable while minimizing signal loss due to the use of any cable -> UHA6SMKII
 
By doing this, I managed to keep the source the same while only attempting to bypass the onboard USB receiver (**not the onboard DAC) with another high quality USB receiver.
 
The difference is audible and running the signal via my Stello U3 into the UHA6SMKII the sound is more detailed and the background is darker. Micro details and tiny nuances became easier to perceive and the definition of musical instruments became better. It is the typical kind of improvement one gets when one upgrade his/her desktop USB/SPDIF converter from a lower end to a higher end one.
 
The difference dropped when I replaced the Viablue RCA-Male Coupler Adapter with a 1.5m long Belden 1695A coaxial cable.
 
Despite that, I will be careful and not make exaggerations like what many audiophiles like to and claim that the difference is day and night. Neither does the direct USB input onto the UHA6SMKII sounded awful. It doesn't. The UHA6MKII is decent enough to be used as a standalone USB device.

 

[lee730]

Quote:

 
As I mentioned earlier, I have tried to isolate the onboard USB receiver with my own external USB receiver to test out how good/bad the USB receiver on the UHA6SMKII is. Maybe there aren't many who understood what the USB receiver was back there so I shall say it again here.
 
I ran:
 
1) Mac Mini -> USB -> UHA6SMKII
2) Mac Mini -> USB -> Stello U3 (this is a pure USB to SPDIF converter that house an async high quality USB receiver) -> Viablue RCA-Male Coupler Adapter (to act as a coaxial cable while minimizing signal loss due to the use of any cable -> UHA6SMKII
 
By doing this, I managed to keep the source the same while only attempting to bypass the onboard USB receiver (**not the onboard DAC) with another high quality USB receiver.
 
The difference is audible and running the signal via my Stello U3 into the UHA6SMKII the sound is more detailed and the background is darker. Micro details and tiny nuances became easier to perceive and the definition of musical instruments became better. It is the typical kind of improvement one gets when one upgrade his/her desktop USB/SPDIF converter from a lower end to a higher end one.
 
The difference dropped when I replaced the Viablue RCA-Male Coupler Adapter with a 1.5m long Belden 1695A coaxial cable.
 
Despite that, I will be careful and not make exaggerations like what many audiophiles like to and claim that the difference is day and night. Neither does the direct USB input onto the UHA6SMKII sounded awful. It doesn't. The UHA6MKII is decent enough to be used as a standalone USB device.

 
That's pretty interesting. So that Stello isn't a DAC itself? I was thinking it was....

 

[Currawong]

That's about on par with my experiences. I tried much the same thing with an Audio-gd DI. 
 
I've decided I'm going to sacrifice battery life and stick with AD797Bs in the amp. I might be smoking the proverbial but I feel the sound is very slightly better.

 

[thegrobe]

My 8610 unit arrived today. First impressions- pretty awesome. An absolutely silent background at the low gain setting (haven't tried high yet).It sounds strong, clean, and clear.

The size is nice and has a very high quality feel. I think I'm going to find a small rubber o-ring of the right size to place on the shaft behind the volume knob to give it a bit more drag.

I only briefly tried the DAC section, it sounds pretty good, IMO. Nothing to complain about. The only comparison is to my rockboxed 5.5 iPod and clip, however.

I've got her burning in (DAC and amp) and am going to be listening as much as possible, of course. I will post more after awhile...

So far? Two thumbs up. A massive upgrade from my previous e11 to be sure!

 

[uelover]

Quote:

That's pretty interesting. So that Stello isn't a DAC itself? I was thinking it was....

 
Stello the name for one of April Music's product range. U3 is the exact name for the device I was using. You can see how it looks like from the picture below:
 

 

[Tenormech]

I've decided I'm going to sacrifice battery life and stick with AD797Bs in the amp. I might be smoking the proverbial but I feel the sound is very slightly better.

I've heard little to nothing about the AD797B. It would be interesting to hear your impressions.

 

[DigitalFreak]

Quote:

I've heard little to nothing about the AD797B. It would be interesting to hear your impressions.

+1

 

[gnarlsagan]

Here's a data sheet on the 797: http://www.analog.com/static/imported-files/data_sheets/AD797.pdf

It says on page 12 that the 797 is recommended for source impedances from 0 < 1kohms, while the 8610 is rated for >100. A lot of this is over my head but that is a very big difference, and it seems there should be a reason for it. Otherwise the specs look impressive. Where does one buy the 797b?

 

[lee730]

Quote:

Here's a data sheet on the 797: http://www.analog.com/static/imported-files/data_sheets/AD797.pdf
It says on page 12 that the 797 is recommended for source impedances from 0 < 1kohms, while the 8610 is rated for >100. A lot of this is over my head but that is a very big difference, and it seems there should be a reason for it. Otherwise the specs look impressive. Where does one buy the 797b?

I'm not sure how much validity to put into that as the UHA6 KII is rated at less than a ohm even with OP Amp 8610 and it sounds superb with sensitive IEMs.

 

[gnarlsagan]

I'm not sure how much validity to put into that as the UHA6 KII is rated at less than a ohm even with OP Amp 8610 and it sounds superb with sensitive IEMs.

I'd like to know what source impedance refers to, the headphone, the usb input, or the output impedance of the amp itself. You think it's the output impedance of the amp? Maybe Nick can explain. What's his handle?

 

[lee730]

Well from what you had posted earlier I gathered it was in relations to the headphones having a 100 ohms impedance to be suitable with Op Amp 8610. If that is the case you couldn't be further from the truth as I feel Op Amp 8610 is the best out of all 3 sets I've tried (209 and 627AP).