Is your preamp-to-amp connection balanced or unbalanced? And how long is the cable?
Assuming that your version of the Calypso is the same as or similar to the one measured by Stereophile here, the unbalanced output has an unusually high output impedance at mid and high frequencies of 2400 ohms. That will result in a slight but very conceivably significant rolloff of the upper treble, if cable capacitance per unit length is high and/or if the cable is particularly long.
If that is the case, the logical solution would be to connect via the balanced interfaces which are present on both components, since the mid and high frequency impedance of the Calypso's balanced outputs is far lower, at only 112 ohms.
Regards,
-- Al
Assuming that your version of the Calypso is the same as or similar to the one measured by Stereophile here, the unbalanced output has an unusually high output impedance at mid and high frequencies of 2400 ohms. That will result in a slight but very conceivably significant rolloff of the upper treble, if cable capacitance per unit length is high and/or if the cable is particularly long.
If that is the case, the logical solution would be to connect via the balanced interfaces which are present on both components, since the mid and high frequency impedance of the Calypso's balanced outputs is far lower, at only 112 ohms.
Regards,
-- Al