Chord Dacs have good and bad factors which impact the performance of these otherwise excellent products. They are very sensitive to noise on signal ground due to the way they treat incoming signals, which can lead to a tiring overbright sound signature. Utilising a LPSU to power a USB card such as the JCAT can bring great improvement here, but a poor PSU will be very disappointing. The JCAT cards, being 5v powered, do not seem to perform voltage regulation on the power line out to the DAC (Marcin may correct me here but 5v in and 5v out leaves no headroom for regulators to work) - this means investing in PSU is where the big gain is when using Femto or XE with Chord dacs because they utilise the 5v USB in (for handshake at least) and any noise is going to impact the sound (this is one reason why Rob Watts prefers optical in - galvanic isolation).
On the other hand, this same design and the way Rob Watts handles clocking within the DACs mean they are largely immune to jitter. The TT2 will not care too much about the precision with which data is clocked into the DAC. So, benefit from the excellent clock in the JCAT cards may not be great. (As an aside here, I have found that cleanliness of signal and ground connections into Chord products is probably the most influential factor in getting good sound out of them. A well implemented USB cable or SPDIF cables will improve the sound more than almost anything else you can fiddle with here.)
There are measurements for the Allo Shanti on other webs sites I think - worth checking how it performs - and you also need to understand how well it deals with rf noise fed in from the mains, a lot of LPSUs are not good at filtering hf noise. More expensive PSUs may be better at this or not. Farad and Plixir have a good reputation, as does the JCAT PSU.
