Dear Apcdan:
My apologies -- I completely forgot to address your query about feedback.
All VAC amps have excellent power supplies and should have absolutely no trouble driving your Thiels with zero feedback (although the bigger Thiels, for their part, allegedly have complex crossovers that suck amps dry).
You should experiment, obviously, but feedback is generally a pernicious thing that should be avoided if possible. Feedback will help control woofers if there is a real mismatch between your amps and speakers (i.e., where the amps just can't control the woofers), but generally speaking, adding feedback flattens out the sound and can quickly make a tube amp sound like a bad, two-dimensional solid-state amp. In addition, and very importantly, an amp using feedback sounds worse the more you turn up the volume, as the sound hardens.
Make sure the amps have been warmed up for a good hour before you play music (15 minutes definitely is NOT enough).
I would set the amps for zero feedback, and very thoroughly run them through their paces with all kinds of music over a number of hours. They should sound better at all volume levels this way. You have a great preamp, amps and speakers, so the sound should be absolutely top-notch.
I'm confident that your only problem will be too much preamp gain (which really isn't a problem inasmuch as it is easily remedied).
Good luck.
My apologies -- I completely forgot to address your query about feedback.
All VAC amps have excellent power supplies and should have absolutely no trouble driving your Thiels with zero feedback (although the bigger Thiels, for their part, allegedly have complex crossovers that suck amps dry).
You should experiment, obviously, but feedback is generally a pernicious thing that should be avoided if possible. Feedback will help control woofers if there is a real mismatch between your amps and speakers (i.e., where the amps just can't control the woofers), but generally speaking, adding feedback flattens out the sound and can quickly make a tube amp sound like a bad, two-dimensional solid-state amp. In addition, and very importantly, an amp using feedback sounds worse the more you turn up the volume, as the sound hardens.
Make sure the amps have been warmed up for a good hour before you play music (15 minutes definitely is NOT enough).
I would set the amps for zero feedback, and very thoroughly run them through their paces with all kinds of music over a number of hours. They should sound better at all volume levels this way. You have a great preamp, amps and speakers, so the sound should be absolutely top-notch.
I'm confident that your only problem will be too much preamp gain (which really isn't a problem inasmuch as it is easily remedied).
Good luck.