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
I have a headroom total bithead right now, which goes out of the USB of any computer (instantly recognized as a destination for sound out in your preferences) and to some ultimate ears or powered monitors. it's more than okay and a huge improvement over the minijack out for the cans. however, I am looking into the apogee mini-dac versus the wavelength brick, for a more permanent setup with a computer that I might leave in my main system. another thing I tried is the new outlaw rr2150 receiver, which is a strong integrated amp that has a USB input. sounds pretty great for the money. any comparisons already made between brick and mini-dac?
Can anyone list all or most of the current devices out there that convert USB to S/PDIF for connecting a computer to a DAC?

I am aware of the products by:

Red Wine Audio
Empirical Audio
U24 Waveterminal
M-Audio Transit (modded and unmodded)
Airport Express (modded and unmodded)

Others?
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.