How to accurately gauge speaker sensitivity to match with tube amp?


I'm in the process of matching speakers to my amplifier and need a bit of advice. Most recently, I'm trying Focal 936 towers with my Quicksilver Mono 60w amp. They were sounding pretty decent until I experimented by hooking up my old Adcom 535L amp. All of a sudden, there was a giant jump in control, tautness in the bass, quickness in transients. The QS stuff was doing quite decently, but the Adcom really snapped these towers to attention. The mids and high ends, not to mention the soundstage, were worse with the Adcom — no question. But there was quite a difference with the other qualities just mentioned.

My question becomes one of sensitivity. The Focals self-rated as 92 db. Stereophile rated them as 89.5db. I realize that these are average measurements and a much bigger picture is told by the impedance graph (and other factors).

As I continue to search for the right match of speaker (I have a couple contenders), I'm sure one piece of advice is to look for speakers with higher sensitivity averages. But what else should I look for to help make a guesstimate about whether the amp will drive the speakers with the kind of control they are capable of? [Specs for this amp are here: http://quicksilveraudio.com/products/sixty-watt-mono-amp/ ]

I realize I need to hear speakers, in my house, with my gear, etc. to get a sense of them. I’m working in exactly this way. Your advice can help me eliminate candidate speakers that would pose similar challenges to my amp as these Focals have.

And I just bought the amp, so I don't want to change it.

Thank you for any thoughts. 

P.S. Anyone who has has had great success with this amp or similar, please shout it out.


128x128hilde45
I have the Quickie mid monos that are currently tucked away in a cabinet for back up duty.I always liked the bass that to me sounded full and natural as opposed to tight and punchy.Adding a couple of subs gave me the best of both worlds.They did well with my Tekton monitors.If I were to go for Tektons again I would audition the Perfect SET with the two 10" woofers(which are designed to work with medium powered tube amps).I took them to my brother's place and ran them with his Klipsch Cornwalls which was an excellent match.The highs and mids sounded about the same as with his Parasound amp,but the bass became really outstanding.Full,natural,and punchy.We also tried them with a vintage pair of Heresys.The highs were not great(scratchy)but mids and bass were excellent.
My two cents:-)
I might have a chance to try tektons, thanks. 

I am returning the Focals and will try something else. I'm not changing amps. 

For a change of pace, try ProAc DT8.

Full tested specs here. https://planethifi.com/proac-response-dt8/#Impedance_and_electric_phase

Not as accommodating as the Fritz, but still recommended for use with tubes from 25W up.

For years I drove the ProAc Response 2.5s with a 12W 300B SET amp.  The modern "D" series needs more juice, though, but not the DTs.

driver tubes ... have more influence on the sound than power tubes 
Nonsense. Tubes are like fine wine. They vary bottle to bottle and with temperature, age and side dishes [system and programme].

@hilde45 - IMO, there are better options than a sh.tload of tweeters, unless you happen to love phasy sound fields. Tekton's patent is one of the funniest I ever read, right up there with Michael Jackson's moonwalk shoes.
Well, it seems that audiokinesis put me in my place.  Hey guys, it's just been my experience that woofers are quicker and tighter with a higher damping factor amp.  I saw the specs on the QS amps and made the comments that I did.  However, I have little experience with tube amps and my reference is primarily with SS amps that have at least 150 watts per side, a lot of output current, and high damping factor.  And NO, I am not referring to Class D amplifiers.  This is especially true when operating with speakers that have 10" or 12" woofers.

I hope that you land on a wonderful sounding set of speakers that work exceptionally well with your QS amps.  Enjoy the journey and, most certainly, the music.