A little more analysing here to find the best of what to choose from, instead of just plucking from the air.
If you look at the input sensitivities of both Vincent SP-331 or McIntosh MC2200, they need very little to drive them to full output, only 1.2v at (47kohm) for the Vincent and only .75v at (50kohm) for the Mac.
The Schiit Freya will be the best, a very good match for these in all modes, (passive, tube or S/S) as it have very little gain, which is a perfect match for these amps
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The Conrad has way too much gain, and as a result the volume control will be very loud even down low in the range.
Cheers George