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BEST AMPS FOR WILSON SASHA

hi, i have in this moment a ayon cd5s cdplayer with built in preamplifier , pass x250 amps and wilson sasha speaker ( i love sasha), i want a new and better amplifier, the options are two, pass xa100.8 monoblocks or cary 211fe monoblock, what is the better option for the sasha?, your opinion please
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georgehifi's avatar
georgehifi
10,312 posts
 

A big +1 for the Pass amps, as they will stay uniform over the audio band range in frequency response driving the Sasha varying loads.

The 211’s will act like a tone control and not stay flat in it’s power delivery, especially around 60- 100hz where the Sasha is 2ohm and -45 degree phase angle and where the power is really needed, the 211’s will sound thin/bright and with very low bass drive and control.

(That 2ohms and -45degree can equate to an even lower than 1ohm perceived load to an amp!!!)

http://cdn.stereophile.com/images/archivesart/710Wilfig1.jpg

Quote from Stereophile measurements:

Sasha’s plot of impedance magnitude and electrical phase (fig.1) reveals the speaker to be a demanding load for the partnering amplifier to drive. Not only does the impedance drop below 4 ohms for most of the lower midrange and upper bass, with a minimum value of 2 ohms at 86Hz, but there is also an amplifier-unfriendly combination of 3 ohms and –43° phase angle at 61Hz.

Cheers George

almarg's avatar
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almarg
9,670 posts
 
I agree with George. The Sasha’s impedance curve suggests that it probably would not be an optimal or even a good sonic match for a triode-based amplifier that is described as using no global feedback.

It would be possible to say with greater certainty if the output impedance or damping factor of the 211FE were specified, or indicated in published measurements, but I couldn’t find any such numbers.

The ARC tube amp Mark indicated a friend uses successfully with the Sasha 2 is a different animal altogether. Like many ARC amps it uses a significant amount of feedback (14 db), and has a higher damping factor (12), and therefore a lower output impedance, than most other high quality tube amps. And of course it is significantly more powerful than the 211FE.  So I would not extrapolate any expectations about a 211FE/Sasha pairing from reports about ARC tube amp/Sasha pairings.

Good luck. Regards,
-- Al

georgehifi's avatar
georgehifi
10,312 posts
 

And to boot Al,, not just zero global feedback to bring output impedance down, but in conjunction with a minimum transformer tap of 4ohm, is another indication of a "not very good match", with these types of impedance loads that Sasha's and many other have.


Cheers George  

charles1dad's avatar
charles1dad
10,250 posts
 
This is a case where an audition of the Cary 211 parallel SET with the Sasha is a must before purchasing. In the Stereophile review cited by George , Art Dudley said his Shindo 25 watt tube amplifier was really quite special driving these speakers and this combo made beautifull music. However the Shindo amplifier is push pull and may also utilize NFB.

On paper I’d have to agree strongly with George and Al, the Pass Labs seems the more appropriate amplifier given the Sasha’s impedance characteristics. Zero NFB SETs can be marvelous but they must be mated to a compatible speaker. If you’re unable to audition the Cary with your Sasha, IMO the Pass Labs is by far the safer and wiser choice
Charles, .
alfa100's avatar
alfa100
221 posts
 
i am running Sasha wit Xa 100.8  and beginning to think I need more power .  Bass needs more impact and midrange more projection.  i am looking at the Burmeister 911 mk3 or Xa 160.8
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