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


As the title says, I have a pair of Sonus Faber Olympica III's that I am more than pleased with, for which I am trying to determine the best available amplifier, preferably tube. Of course, there are always budget limitations and my budget for this amp would be $6-7,500, and I would be buying used to maximize purchasing power.

Based on a lot of research, and quite a few auditions at brick and mortar stores, various home systems, Axpona, etc. I'm honestly not sure if there are any truly exceptional tube amplifiers available within that budget that meet my needs. These speakers need 100wpc tubed, or 200 wpc solid state, into 4 ohms to really open up and perform. 

If, in the end, there are no really great tubed options, I've always heard that the Pass Labs XA-100.5's were probably the optimal choice in solid state for former tube lovers. I would also appreciate any thoughts on that option from owners. 
nightfall

Showing 14 responses by djfst

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.   If I were to go tube amp for SF, would go with the VAC 200 IQ.    Plus Kevin Hayes of VAC offers the best service around.  You are kind of limited with other tube amps (ARC, CJ, Zesto, etc) as the VAC is really user friendly.  
The new IQ continuous auto bias in the latest VAC amps are a night and day difference from their prior 160, 200, 300 phi models.  Far more smoother and transparent, tighter bass, etc and more stable power output makes it a lot easier to handle all speakers.  I owned the VAC and as well as the SF Olympicas and the Elipsa and handled them fine.  the VACs are paired with Magicos, Focals, Vandersteens, Sonus Fabers, Harbeths, and know they can drive them well, even with the stock KT88s.   But if you're in love with the PASS LABS, then you it seems like you found what the sound you're after.
This decision is not easy for sure.  There is a newer version 200 IQ on US Audiomart.  It is just a little bit more than the phi 300, but maybe talk with the seller.  The other great thing about the VAC is tube rolling.  With the auto bias, changing out the driver tubes (the 4 6SN7) can tailor your sound to your liking.  Unfortunately, whatever you have with the PASS Labs is fixed in stone.    No doubt the VAC will handle the Olympicas with ease.    I must confess, I am a tube guy and not a huge fan of solid state.  So I am biased :)  The VAC is best blend of solid state and tube sound I've come across (at least the newer models).   
that's surprising to hear, considering the 200iq is much newer than the phi 300 and has more of the flagship statement series technology and engineering built in to the 200 iq.  I talked with Kevin over the phone and he stated the 200 should drive the Sonus Faber line fine.  not sure if you spoke with him.  

the aesthetics of the iq (with the tubes in the back) represent a similar model they did before - I forget which one it was, but I know they used that design on the VAC Alpha Phi Integrated.  Personal preference, I guess.  Keep us posted on your decisions.  Not an easy decision for sure.
nightfall,

you may also want to reread this thread from a VAC dealer in florida, though it is just another man's opinion, which everyone has a different one:

http://www.audioshark.org/vac-85/vac-signature-iq200-9738.html
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.  
The 8ohm taps were clearly better, and had a hard time understanding why based on the impedance graph.   There is another audiogon forum discussing this where someone else mentions the Olympica III runs better on 8ohm taps for them too.   It was interesting, because the Primaluna taps were, 4, 8, 16.    But the VAC 200 iQ (and probably other VACs) have ranges for their ohm taps:  1-2, 2-4, 4-8.   This may explain better why the VAC runs the Sonus Fabers better, since there is a broad range where the ohms are constantly changing.  Maybe the VAC is better at handling this?   Not sure.   All I know if the 4-8 ohm taps (and the 8 on the Primaluna) were clearly better.   Judge by your ears in the final analysis.

Nightfall, the Preamp I have been saving for.  Initially was the Primaluna preamp, but would eventually love to upgrade to one of the following (again a tube guy):  Zesto Leto, EAR Yoshino 868 or 912, Herron Audio, or VAC.   I think VAC is coming out with a more affordable preamp this year.... at least that was the rumor a while ago.  
georgehifi,

I noticed the bass improvement the most when going from the primaluna to the VAC.  that would coincide with what you were saying.  The best bass on a tube amp I've heard was with the VAC.
Nightfall,

Remember that the Olympica III is moderately efficient at 90+db.  so even if it dips low with the ohms briefly, there is more at play with how well an amp can drive speakers.  The VAC dealer on the audio shark forum commented that the 100 watt specs for the 200 iQ was very conservative, and is likely much more power that is giving out.  I've noticed that in my experience with it as well.
You may be right about the Primaluna - I haven't used NOS tubes yet, so it may be all you need with whatever reference amp you end up with.  I've told by many that the the preamp selection will influence the sound a lot...  The Herron was recommended to me numerous times by a trusted dealer who I value his opinion.  He has never steered me wrong in the past.  Unfortunately, his store is a plane ride away and haven't been able to demo it yet.   I also tend to like to buy things made in the USA - to support local manufacturers and in case of a problem with the unit down the road, they are a simple phone call away.   That can't be underestimated, especially when you are talking about shipping a 100+ amp around the country vs across the world.  VAC, Zesto, Herron, VPI, etc.  are all companies I'd be happy to own and support.   Sonus Faber was the exception :)
Nightfall,

I'm also on audio asylum, but you can just feel free to PM me on audiogon.