Tube amplifier to power Sonus Faber speakers?

I used to have B&W 805D2 with Mcintosh MC275 tube power and worked beautifully. I change the speaker to Sonus Faber Olympica II and still produce an great sound. Although I think I lost a little of high frequency because of diamond tweeter. But still its a great combo.

Here's my suggestion and for a LOT less money than the ARC Ref 75....
see if you can source an ARC D70 Mk1, or better still, a Mk2. With my SF's, the D70 Mk2 makes beautiful music. If you think you may need more power ( which I would doubt), then look at a D115 or better a pair of M100's. These older W Z Johnson designs are still IMHO very competitive with some of the best tube gear around. Plus, with the older designs, one isn't stuck with having to run a balanced only preamp up-line.

Here is the simulated load graph that the Ref75 was tested with (1st link) as you can see compared to the flatness of the FR graph (2nd link)black trace, That this amp is relatively flat but is already dipping at 200hz.
But the simulated load at the 200hz is not that heavy and would be far lighter than the SF EPDR of 1.7ohms in the bass.
So even the mighty Ref75 might not fair too well in the bass with the SF speakers..

http://www.stereophile.com/content/real-life-measurements-page-2

http://www.stereophile.com/content/audio-research-reference-75-power-amplifier-measurements

Cheers George

Thanks for your clarifications Al. Let me add one too.

Most ARC amps use negative feedback and have "low'ish" output impedances, especially off the nominally denoted 4 ohm taps. Al .. as we have discussed many times before, this means that ARC amps with low'ish output impedances perform somewhat like SS amps -- i.e., like voltage Paradigm amps.

As I recall, the ARC Ref 75 has a robust power supply (520 joules) and low'ish output impedance off the 4 ohm taps (1 ohm off the 8 ohm taps; probably less than that off the 4 ohm taps). Ergo, it might not be a bad amp to consider.

That said, if the SF speakers in question (a) present very low impedance plots and highly negative capacitive phase angles in the bass spectrum, and (b) are not very sensitive, then a safer bet might be a high current SS amp with lots of watts. Or, a bigger ARC tube amp such as the Ref 150.

(P.S. J Atkinson measured the Ref 75's output impedance off the 4 ohm taps to be .75 ohms at 20 Hz and 1K Hz. See: http://www.stereophile.com/content/audio-research-reference-75-power-amplifier-measurements)

Thanks to George for finding and pointing out the HFNRR review of the speakers, including the measurements. And kudos to Bruce (Bifwynne) for suggesting the very same ARC Ref75 amplifier which the reviewer, Ken Kessler, utilized in evaluating the speaker.

A couple of corrections to some of what has been said earlier in the thread:

First, on a per watt basis the speakers are not even close to being 90 db. They are rated as 90 db/2.83 volts/1 meter, and 4 ohms. 2.83 volts into 4 ohms is 2 watts, so their rating is equivalent to 87 db/1 watt/1 meter. The distinction between 1 watt and 2.83 volts (which is equivalent to 1 watt into 8 ohms), in the case of 4 ohm speakers, is especially significant with respect to tube amps, since their power capability does not increase significantly if at all into low impedances (and may actually decrease).

And furthermore, the measurements cited in the review indicate a slightly lower than specified sensitivity, about 89 db/2.83 volts/1 meter, and indicate that the speaker is best considered to be 3 ohms. That translates to only about 85 db/1 watt/1 meter.

Second, a slight correction to something that was said about the VAC Renaissance 70/70: It is a dual mono stereo amplifier, not a monoblock. VAC did manufacture a very similar 300B-based amp configured as a monoblock, though, designated as the 140, and rated at 130 watts.

Beyond that, I'll add to what has been said, and consistent with the earlier comments by John (Jmcgrogan2) and ZD, that the VAC Renaissance amps are the only 300B-based amps I am aware of that I would expect to be able to adequately drive the OP's speakers, for most listeners with many recordings. I say that based on my own experience with a 70/70 (although used in conjunction with far more efficient speakers), on the number of 300B's they use, on the fact that the design drives the tubes very hard (such that some currently available tubes which are non-compliant with the original Western Electric specs cannot be used in these amps), on their robust and very heavy transformers and overall weight, and on the fact that they provide three rather than two output taps, with the lowest being indicated for use with 1 to 2 ohm speakers (on the 70/70), or with 2 ohm speakers (on the 30/30).

That said, finding a Renaissance amp that is in excellent condition and that does not require a major investment in retubing is another matter altogether.

Regards,
-- Al

Georgelofi gives spot on advice and the poster is strongly advised to follow it. You will need a good SS amp for these speakers. Another idea is a good hybrid amp!

Historical there have been a lot of people who like to match McIntosh with SF speakers. I am not a McIntosh guy, so cannot recommend anything specific. Personally, I would lean towards Conrad Johnson or maybe the big Cary amps with the Olympica. I have not heard anyone of them with those speakers, however.

I have original Cremona and I drive them with a relatively neutral SS amp (Levinson 432) and a tube pre-amp (Cary SLP-05). You should consider that option also.

Hi Frontier1, your speakers though advertised at nominal 4ohms, is not showing the whole picture. As the lab test results show in the link, they have an amp hungry impedance with -phase angle load of 1.7ohms in the bass. They maybe efficient but they are a hard load.

This to me says if you want to get the very best out of them, especially in the bass, you need an amp that gives good current, the ability to almost double it's watts down to 2ohms.
EG:
50w into 8ohms
100w into 4ohms
200w into 2ohms
These amps are good solid state with BJT (bipolar) output stages (not mosfet)This is also why even good P/P tube amps will wimp out a little down low, even with 4ohm taps.

http://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0CC8QFjAC&url=http%3A%2F%2Fwww.perfect-sense.se%2Fwp-content%2Fuploads%2F2014%2F11%2FSF_Olympica-II_Hifi_News_2014.pdf&ei=JN58VIbNE4bc8AXerICgCA&usg=AFQjCNH3FtXaUGr8-3B3--LdKjP2VA7QYA&bvm=bv.80642063,d.dGc

Cheers George

Perhaps consider a hybrid amp (tbe/MOSFET) such as the Butler TDB2250 or the Monad. The 2250 has 250 watts/ch. and the Monad is 100 watts/ch. pure class A...

I would like to suggest ARC as a tube amp to consider. FWIW, I believe ARC is currently using SF as its reference speakers when checking the performance of its gear.

That should be no surprise since SF and ARC are member companies of the Fine Sounds Group. This may be a leap of faith on my part, but that might permit an inference that ARC and SF make for a good match.

The specific ARC amp you might want to consider is the Ref 75. This pup has garnered quite a bit of favorable comments. I own its big brother, the Ref 150. The two amps share similar circuitry and probably share a similar house sound.

Not sure how much you want to spend, but the ARC Ref 75 is a keeper.

"Since the minimum recommended amplifier requirements for your speakers, according to Sonus Faber, is 50 wpc, I think you can forget about 300B tubes or something of that ilk. Unless you can swing a pair of VAC Renaissance 70/70 monoblocks. That's 65 wpc of push-pull 300B's, total of (8) 300B tubes could be costly."

I have a VAC 30/30 myself. It can easily drive the OP's speakers. I had mine on a pair of Martin Logan SL-3's for a few years and never lacked for power.

or you may try also KR Audio amplifiers....sort of half way between the tube and power of SS.

I certainly relate to the preference for Tube amplifiers but you must have the proper speaker for a good match. Some speakers simply require SS based on their design load characteristics . The 300b is a wonderful tube but not with all speakers.

Why obsess with tube amp if Sonus Faber won't sound best?

Frontier-

look into ARC, Conrad Johnson and Rogue Audio for your tube needs. Keep me posted and Happy Listening!

The Sonus Faber dealer here in SW FL uses fairly large Audio Research tube mono blocks (sorry, I can't remember the models) to power his Olympicas. The sound is top notch.

I'm using wyetech lab ruby 211 with RCA tubes on sonus faber guarneri homage ,a friend is using the same amp but wyetechs 300b version, on his amati futuras ,you should get wyetech labs onyx for the olympica

BTW, i do not have good experience with the 845 amps...but edgy is not a word i would normally have associated with them...unless they are bring driven beyond the range where they are comfortable/linear.

That might be what is happening in that instance? Particularly if you felt it also lacked dynamics/power?

Interesting...i have always liked SF Homage series with mid-powered tubes and Class A SS. But on the other series, i have found the mid-powered tubes did not seem to be able to bring them to life as well as higher current SS amps. A personal choice.

...if you wish to stick with tubes, i think something quite high current would be the order of the day.

Perhaps try CJ if you wish to keep mellifluous qualities of some tubed equipment, while also having sufficient control/power/current to bring them to life. ARTsa for example?

. .... Sonus Faber Olympica 3 speakers. They are 90DB and a 4 ohm load. I've always preferred tube amplification and am finding it a challenge to identify ..... rather 300B or something of that ilk. I tried an 845 based amp but found it edgy and limited in power and....

Ready for Challenge .... great .... That is the right spirit to invest endless time to try to match a mismatch... 300B with 90 dB amps... What a great idea. ... Ever saw a Duck with teeth? No? Don't worry, you will find that one sooner ...
Good luck -:)

I use the Audio Research VSi60 (50wpc) tube amp with my Olympica II speakers and find it to be an excellent match. I typically listen with the volume between 30-40% of full on and it can play quite loudly if I turn it up higher. The Olympica III is more sensitive than the II so unless you'll be using them in a very large space or typically listen with the volume really high, the VSi60 might be a great option to consider depending on your budget.