Best Tube Amp For Sonus Faber? Or Pass XA-100.5? $6-7,500 Budget, Purchasing Used.

djfst,

Quite a bit earlier in this discussion you said "  Would not go with the VAC Phi 300.1.   Definitely go with the updated VAC Signature 200 IQ with continuous auto bias.  100+ watts and has all the bass and tightness of solid state and the midrange is fantastic.    Retails for $14k but there is a like new one listed on US Audiomart.  With the auto bias of the 200 IQ, you can plug in any KT88, KT120 or KT150 and change out the 6sn7 driver tubes if you want to tailor the sound.  It is so user friendly and the stock tubes are wonderful though.  Have owned both the Sonus Faber Olympica III and the Elipsa SE.  The VAC controls the bass of the olympica which can often sound a little bloated if not having a high quality amp."

Which VAC amp were you referencing as handling the Olympica III and Elipsa so well? I originally thought you were referring to a previous amplifier, not the Signature 200IQ. If it was the Signature 200IQ stereo version, that would carry a lot of weight towards my decision. 

Sorry for the confusion - It is the stereo Signature 200 iQ that I used with the Sonus Fabers and I felt it handled them with ease.  I moved from a Primaluna HP amp and the 200iq was a significant jump.  Everything came into focus and the bass improved significantly.  

That now makes sense about the current version 300.1a  beating the lower priced 200iq.  I thought you were referring to the older 300 model that is listed on audiogon.   It would seem strange that Kevin and Brent would give different information, but Kevin told me the power output of the 200iq would hand the Olympicas fine.   It may also have to do with the quality of the wattage.  The VACs put out a lot of power, but it is quality continuos power - Kevin gets a lot out of his amps.  Happy to help and keep me posted.  I understand being burned before on your prior purchase - I feel for you.   Kevin is one of the most honest and nicest guys in the business and can't believe he will steer you wrong.

Also - I always use the 8 ohm taps for the Sonus Fabers (both the Olympicas and Elipsa), though they are rated at 4ohms.  Definitely performed best on the 8 ohm taps for both the Primaluna and VAC amp.

Did you ever look at the impedance curve for the Olympica III?  Here is the link:  http://www.soundstagenetwork.com/index.php?option=com_content&view=article&id=1285:nrc-measu...

They only dip into the 2ohm territory very briefly and stay at or above 4 ohms most of the time.   At 91db,  I didn't think they were extremely challenging to drive well, compared to some other SF models like the Amati Futura and other homage models as well as other manufacturers speakers.  

Thanks for the tip on the 8 ohm taps. I would not have expected that. Another reason why it's good to experiment on what might work best. By the way, what preamp were you using with the Olympica III's and the 200IQ?

Very eager to call VAC tomorrow to get clarification, and answers to some key questions. After that, I think I will know where I stand, and what to do. 

They only dip into the 2ohm territory very briefly 

Yeah but it spans between 70hz and 150hz right in the power region for bass, and you'll get a big dip in power there if the amp can't give the current into it. especially from an 8ohm tap.
This is a more telling graph.
https://ibb.co/hoYNyF

Cheers George