I purchased this modified DAC in November 2007 directly from Underwood Wally. The Cullen Stage III DAC was the highest modification then offered. It sounds as good as any CD source that I have heard. The Stage III DAC has inputs for USB, coax, and Toslink. If offers both balanced and RCA outputs. Upsampling can be set to either 24/96 or 24/192. USB accepts 16/44 , Toslingk 24/96, and Coax 24/192 sampling rates.
Here is some information from the original 2007 Audiogon ad:
"The modification is done by Rick Cullen at Cullen Circuits. Cullen is the California OEM company that made the DAC's until recently. They are now made in China to keep the costs down. Rick knows more about these DACs than anyone. The Level-3 Cullen Mod is the most comprehensive out there and clearly the best that we have heard.
The modifications consist of the following:
Replace 28 resistors in the audio signal path with Dale Rn55d copper leaded parts
Replace 11 electrolytic capacitors with audio grade Muse caps
Replace 8 FETs in the DAC's output stage with hand matched low noise parts
Install ERS EMI/RFI Suppression cloth
Install WBT NexGen 210cu RCA jacks
Install clock Modification board that replaces the 2 stock clocks with new Cullen designed clocks with ultra low jitter. This is done to both the clock and CODEC."
As you probably know, Cullen Circuits is now Wyred4Sound.
I am selling this unit because it hasn't been used in over two years. I have run it with CD players, DVD players and even a Laser Disc player as transports and it sounds great with all of them.
Email me with any questions. Please add 3% for Paypal. This item will ship FedEx Ground and be double-boxed. Thanks for checking out my ad.