Anyone has heard the Bel Canto REFLink Asynchronou

The REF Link is a USB-SPDIF converter.

A smaller/less featured USB-SPDIF converter is built into the DAC2.5

The external uLink mLink and REFLink provide some form of isolation of the noisy computer signals from the DAC itself. One end plugs into the computer's USB port, the other is a SPDIF type connection to the DAC (coax/optical or AES).

Besides the isolation, the new external devices also provide
a. asynchronous USB protocol (less prone to jitter)
b. 24/192 support that matches the SPDIF input capability of your DAC2.5

If you don't intend to upgrade the DAC2.5, I think it might be more cost effective to look at the lower end devices from Bel Canto

Bel Canto has 3 new USB Link devices.

All 3 are asynchronous USB vs synchronous on yr DAC2.5 And I feel any of the 3 should work with your DAC2.5 to provide an upgrade in SQ.

FWIW, I have found big differences going from synchronous to async USB devices more so than going from 16/44 to 24/96

So CD2 lose to CD3T?

You bought the CD3T?

Have you tried it with the DAC3.5VBII?

I tested the W4S DAC2 with its own internal USB as well as the Wavelink HS. The Wavelink HS was IMHO better. Less veiled and with a better sense of imaging and soundstage.