The WINPOON (WIN(G)POON?) counts as an upgrade :-).
I had been using a KanaaN Digital to Analogue Audio Converter 2nd Generation - SPDIF/ Toslink to R/L Audio Converter - Digital (Toslink/Coaxial) to Analogue (Cinch) and 3.5 mm Jack Converter - Audio Converter DAC
but, for me, the sound was just a bit too "soft" so I decided to try the WINGPOON instead.
I struck lucky. The sound (connected via RCA interconnects) is definitely more controlled and firmer than the KanaaN. Trebles are clearer without being overly bright and the bottom end is less flabby plus it has decent presence. However, through the 3.5mm jack, the bass is definitely lacking so if you're buying this for headphone use, this may be a factor to bear in mind - bottom end is fine via RCA connectivity to an amp+speakers or an amp with its own headphone socket. So far, I haven't experienced any background noise or interference.
It may or may not be of interest that the KanaaN and now the WINGPOON have seen off two "proper" DACs - a Beresford Bushmaster Mk II ("almost but not quite") and the thoroughly disappointing Musical Fidelity V90 DAC. I have two optical sources: a Cocktail Audio X10 with 1 TB HDD
and a TV. Both the Bushmaster and the V90 have two optical inputs and, as advertised, the WINGPOON only has one. However, the combined cost of two WINGPOONs is only one fifth of the cost of, for example, one V90. Currently, the X10 is connected to the WINGPOON and the TV is connected to a KanaaN. Each DAC is connected by the RCA outputs to its own line-in on an old Arcam amp.
For optical cables, I am using AmazonBasics Digital Optical Audio Toslink Cable 6 Feet / 1.8 m
- these seem to work perfectly well. I already had a selection of RCA interconnect/phono cables from an earlier hi-fi set up but if a pointer is helpful, you could do far worse than the Profigold BA-PGA4201 - Audio Lead 2RCA To 2RCA - 1.0m
Included with the WINGPOON package is the DAC itself (the white box pictured) + a mains power supply unit and a small booklet that is, frankly, somewhat rudimentary. The WINGPOON can definitely be powered by USB instead of mains power if that's for you. The mains plug supplied to me was UK 3-pin.
Why 4 stars and not 5? The quality of sound via the 3.5mm (headphone) jack really isn't that great and, to some, that will be a deal breaker. For info, it's possible to have simultaneous output from the RCA connectors AND the 3.5mm jack.
Hopefully, the above is helpful - happy listening.
NB: Purchased from 3C4U (fulfilled by Amazon) - prompt delivery.
UPDATE (May 2015): I finally found a DAC that has seen the Win(g)poon consigned to storage. The Win(g)poon did a perfectly good job as a stop gap until I found a long term alternative I was happy with. For those to whom it may be of interest, I purchased a Cambridge CXA60 integrated amp which has an onboard WM8740 DAC chip from Wolfson. Unsurprisingly, it is a significant improvement on the Win(g)poon. However, if money is tight and you need a very cheap starter/stop-gap DAC, I still think the Win(g)poon is a decent option.