I was checking in the owners manual and there is actually no statement to the minimum impedance that can be used with this preamp. Bhouser brings up a good point with this. I think, however, that the 50k is refering to a balanced impedance into the amp since the Aesthetix pre is designed to be used for balanced ins and outs. It actually converts a single ended input to a true balanced circuit in the preamp. This would place a single ended impedance at 25k for the amp. (The single ended outs are converted from balanced also) I use the Ayre in balanced configuration which shows a 200k input impedance to the Calypso(100k on each leg.)
I would give Aesthetix a call and ask them.
I used an Audible Illusions L-2 that was rated for no less than a 20k input but Art ferris told me 10k was ok and it did not use a buffer circuit like the Calypso which should make it immune somewhat to impedance mismatches.
I would give Aesthetix a call and ask them.
I used an Audible Illusions L-2 that was rated for no less than a 20k input but Art ferris told me 10k was ok and it did not use a buffer circuit like the Calypso which should make it immune somewhat to impedance mismatches.