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Asynch USB or super clock thru S/PDIF for $3.5k?

I posted this over at computeraudiophile, but got very little feedback, so I'm trying here. Looking for input from experienced users regarding sound quality of these two approaches. Right now I only have a SB Touch, but I'm considering a computer with external hard drive and a DAC:

Approach 1: Asynch USB. Wavelength Cosecant or Ayre QB9. About $3.5k. Just one input. Until I get a dedicated computer I would need to mod the Touch to output thru USB.

Approach 2: Super clock thru S/PDIF. PC to Offramp 4 w/Turboclock to Bryston BDA-1. About $3.5k too. More pieces in the chain, and more power cords and IC. Steve Nugent is a big supporter of this approach and says the DAC matters less IF you have a VERY good clock upstream. Initially I would use the Touch with the BDA1, then get the PC + Offramp.

All these DACs have discrete analog sections and all are very well thought of. My preferences are for soundstaging, 3D imaging, naturalness of the presentation and articulate, deep bass. FWIW, preamp is Lamm LL2 so I can only connect through RCAs. Amp is McIntosh MC275 (tubed).

Thank you!
lewinskih01
marcober
16 posts
 
I want to OUTPUT from spdif to INPUT to USB Ayre QB 9 (USB only).
Any suggestions w/o fooling with the software?
Thanks
sandstone
358 posts
 
Marcober, I'm quite certain that you can't do it yet.
I'm assuming that you're still trying to connect Ayre with your Squeezebox, because that's likely the only reason on the planet for trying this.

If you've been keeping up with John Swenson, et.al. over at the Squeezebox Touch forum, then you already know this has been a quest of several years for them. More recently, it seems the impedance matching issues with S/PDIF interfaces (which according to the forum are often non-standard) have risen their head yet again.
Regarding connecting the QB-9, even with planned SBT software mods to support USB out in general, it's my understanding that Asynchronous mode isn't supported.
marcober
16 posts
 
Thank you but I'm still looking for a solution.
MB
sandstone
358 posts
 
Good luck, and please let us know if you find one.
sandstone
358 posts
 
Steve,
"Async USB requires USB 2.0 compliant ports on the computer"

Shouldn't the rest of this sentence read as follows? "....if resolutions in excess of 24/96 are to be supported"

For instance my Ayre has a dip switch option (Rsrv A) for USB Class 1 where it still runs in Asynchronous mode, but is limited to 24/96. 24/196 requires Rsrv B setting for USB 2.

There's also this:
http://thewelltemperedcomputer.com/HW/USB_DAC_AsyncSlow.htm

Best,
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