btbluesky OP
So I figure to get the best out of this chain is the fastest neutral amp I can get my hands on.
You’ve got that with the JC1’s in normal bias, and then in high bias mode they’ll have that Class-A warmness added. And the big + they drive those speakers of yours with breaking a sweat.
Look at the preamp for a tonal difference.
And I’ll tell you the JC1’s with a passive preamp was the second best I’ve heard the Wilson Alexia’s sound, only bettered by the Gryphon Antillion Evo with the same passive pramp.
BT just read this again from Stereophile review, and compare it to what your asking above.
The Sound of Speed, the Speed of Sound
It took but a few seconds for me to absolutely fall in love with the Halo JC 1. I first used them to drive the Kharma Midi-Grande Ceramique 1.0s, then my reference Audio Physic Avanti IIIs, which they controlled brilliantly, with the kind of relaxed ease you’d expect of a pair of powerhouse amps. If big amps are said to be slow to react, the JC 1 disproved that myth: it was lightning-fast, delivering transients and sibilants with a speed and clarity that were positively addictive.
The overall lack of smear helped create an impressively coherent, transparent, and detailed soundstage, with the kind of air and reverberant presentation I usually associate with tubes.
As almarg hinted at, I think your due for a passive preamp which is a perfect match with the JC1’s 100kohm input impedance, that will give you the most dynamic, transparent, uncolored sound you can get.
Cheers George