The Orthos are advanced for tube amps in that they run power on self checks. They will shut down if they fail that.Is this the room the X-stremes are going into ? What size is it ? He is doing REL subs instead of MBL sub stacks, why ? Limited space ? Cost ? I am looking forward to this install ! Did the tubes in the Ayon's blow when they started using them on the MBL's ? I have heard of that happening with even the most powerful tube amps, when trying to drive 101E's.
They also run seriously cool for such huge amps, with 10 KT150 per channel. The KT150s barely get warm.
The trouble is, if you tax them with bass transients, they shut themselves down. In my opinion this happens below the supposed power outputs in triode mode. I spoke to an Ayon technician at Munich about this and he wouldn't say anything about it. That smelt a bit to me.
I think they probably will stay up in 4 Ohm pentode mode if used as I described in my earlier post. In that mode they are 88DB 4 Ohm speakers. Duettas are 86 DB 4 Ohm. Loud in triode mode they might not. Only one way to find out.
They do sound very pleasant but they are not the most dynamic and lively of amps.