Audiophile USB to PCM


I have an excellent upsampler and dac (dCS Purcell/Delius) and am looking for the very best USB to PCM conversion. So far, I've tried SlimDevices Squeezebox, and Xitel Pro Hi-Fi link.

Both are very good, but I was wondering if there are any other options I should be considering. Both the Sutherland USB Preamp and the Wavelength USB Dac convert to analog. I'd like something of similar quality that stops short of the digital to analog conversion so that I can let the dCS gear do that.

Any suggestions would be appreciated.

harry
hbrandt
Others:

HagUSB, LessLoss, m-audio audiophile USB

Waveterminal is not current, not manuf. anymore.

Steve N.
I currently use FLAC+Foobar with M-Audio 192 Audiophile (PCI card and ASIO) feeding my Marantz AV Receiver thru SPDIF, but I want to go a step further and feed an external DAC thru the USB port and finally into my Aragon 18K pre-amp , Aragon 4004 MkII Dual-Mono power-amp and Mirage m-5si speakers.
So we have two problems, USB->SPDIF and choice of DAC.
I'll takle the USB->SPDIF now as DACs are a whole other matter, we (end users) have not many (credible!) options availabe and the price factor compplicates things.
LessLoss and HagUSB both cost about the same, but dont know much about LessLoss's product then we have a 30USD option from http://www.diykits.com.hk/dac.html (is it an option?!?) and finally the Emprirical Audio's products, of which I do not question the quality just the price, not that they are over-priced, just to me unfortunalty especially since I still have to buy a DAC (any comments on CIAudio's VDA2 http://www.ciaudio.com/vda2.html)
This leaves a huge price gap with only one contender the USB Freeway2, is it so clearly inferior to the other models?! what can I expect from it?
Go on Ebay and do a search for "USB to SPDIF Converter". There is one on there now for $35. Then go find an EAD DSP-7000 MKII DAC on the cheap and I think you will experience a life changing event for around $300.
The Sonos ZP80 has Optical and coax digital output for superior audio quality. I use it with Mark Levinson DAC, N32 Pre Amp and Wilson speakers. Not as good as vinyl but easy to play and quite good.
Could someone please explain what the benefits are of going USB into a device that will output SPDIF, as compared to going ethernet (network) into a device that will output SPDIF?
What determines the quality here is the device that creates SPDIF signal, not the type of async transport to it?
So the question is, why not using SB3? Why insist on USB as transport?