The Ref 150 will sound OK, but even on the 4ohm speaker tap you won’t get near the bass control/impact that the Bryston will give, as at around 100hz the Sasha has 2 ohm load plus a -45 degree phase angle, this will look like 1 ohm to the AR150.http://www.stereophile.com/images/archivesart/710Wilfig1.jpg
PS: My friend (hifi reviewer) has the Alexia, just as bad a load if not worse, no tube he tried did justice to the bass, the amp that wowed me for the money was the Parasound Halo JC1 monoblocks in high class-A mode, with passive preamp and AMR CD77.1 cdp, the only amp that just beat these was the hideously expensive Gryphone Antilion Evo.
George, thank you for your response (although not what i wanted to hear).
It seems Ill have to put further consideration into it.
I preferred the ARC Ref5SE pre-amp on a Bryston power amp.
This is a magical combo for Wilson speakers. Add Transparent REF XL cabling all around and you are set my Audiophile friend.
Whenever you can afford Transparent OPUS cabling all-around, Go For It!
I compared the Ref 150s against the Dag Momentum stereo amp in my home system which includes the Ref 40 preamp and Sasha 1 speakers. Despite the cautionary warnings of John Atkinson in the measurement section regarding the 2ohm load with a -45 degree phase angle, I could discern no difference in slam and impact between the 2 amps and no difference throughout the mid and upper bass range. The quality of the bass was different, as it always is when comparing ss to tube-- with the Dags being more taut and the ARC being thicker and "wetter". The Dag was a bit more transparent with slightly better grip all around, but the ARC pulled out ahead for me with better sustain on notes, better dimensionality as well as width and depth of field. It was a close call, but the fact that the ARC matched the Dag in the areas where the ARC had a potential weakness based upon specs was surprising and reassuring to me. The ARC has a very robust power supply and all the testing in the world cannot predict exactly how any amp will sound with any particular speaker load. But listening can. The ARC gear is extremely synergistic with Wilson and the Ref 150 is the ARC amp for the Sashas IMHO (Ref 75se not quite as good, Ref 250se barely better for twice the price)
By the way, as I tell everyone, if I decided to go solid state, I'd go Dag. A very impressive amp that is more liquid and lifelike than any ss I have ever heard.
Short answer--don't hesitate to purchase the ARC Ref 150 for the Sashas--it is my favorite amp with those speakers and I listened to many--Lamm, VTL ,Classe, Simaudio Moon, Accuphase, Spectral and others with Sashas at various dealers and Dags in my home.
Thanks for your very insightful comments based on "actual" listening in your home system. When Georgehifi raises the spector of test bench results he does make a very relevant point. Measurements and speaker load/impedance characteristics are important parameters and can be used to determine likely outcomes with certain types of power amplifiers.
Here’s the problem, what seems so clear on paper doesn’t always match what one will hear. Now if one were unable to listen for verification then the measurements and specifications would suggest caution is advised as George rightly highlights.
Now it’s possible that for instance 10 experienced listeners could split 5 to 5 regarding amplifier preference between these two worthy choices, that’s simply subjectivity. The point is you must listen to actual amplifier/speaker combinations to really know what suits you best.
Measurements predict the ARC REF 150 would be a relatively poor match with the Wilson Sasha, reality proved otherwise. All the solid state amplifiers you listed and heard driving the Sasha would be considered superior to the ARC REF THE 150 based on specification criteria. Ears trump the test bench.
From a technical standpoint I don't find it surprising that the REF 150 would do well with the Sasha. In addition to the robustness of its power supply which was referred to in Gpgr4blu's post it has a particularly low output impedance for a tube amplifier, due in part to the use of greater amounts of negative feedback (14 db) than in many other high quality tube designs. John Atkinson measured the output impedance of its 4 ohm tap as being only 0.55 ohms at middle and low frequencies (where the Sasha's impedance characteristics are most challenging), and 0.87 ohms at high frequencies. While those impedance numbers aren't quite in solid state territory, they are a lot closer to it than in the case of many other high quality tube amps.
Such low values will minimize the tonal effects that would otherwise result from amplifier/speaker impedance interactions, and will result in better bass control than in the case of most other tube amps, and in conjunction with the robust power supply will enable it to supply more current into low impedances than in the case of most other tube amps.
So from a technical standpoint I don't find Gpgr4blu's experience with the combo to be surprising. And I'll add that I always consider his posts to be among the most credible to be found here at Audiogon.
The black line is what the Ref150 looks like into an "average simulated speaker load", as you can see it’s not flat and becoming a bit of a tone control.
I would expect this tone control effect to get worse not better with the loads that the Sasha represents, compared to the tested "average simulated speaker loading"http://www.stereophile.com/images/712ARCfig01.jpg
By contrast here is what the Parasound Halo JC1 looks like into that same "simulated speaker load" stays flat and doesn’t become a tone control. http://www.stereophile.com/images/archivesart/JC1FIG1.jpg
And in favour to the AR, the Parasound shot is .5db graduations unlike the Ref150 1db graduations.
Well i really appreciate the information from you all. The time taken and detail is very helpful. Thank you.
George i see from the data it is clear the JC1 would be a better match.
There is a Pass X350.5 available near me too. (I am in Australia). I assume the Pass, Bryston14 and JC1 would have similar characteristics with the sashas. Although i havent had the possibility to compare, would love to try the Pass.
The ARC ref150 appeals to me more (if it performs correctly with Sasha).
gpgr4blu, Al & Charles your comments are very encouraging, although i am aware what you want to hear is easier to listen to.
I emailed ARC and they reply any of the REF amps 75w and up will drive sasha without difficulty and recommend running off the 8ohm tap.
Jafant, I have heard the Transparant Audio Cables are great with Sasha.
I am very curious to compare them with what i currently have. Clear Day Double shot guns (also have
XLO Electrics Signature cables). I do like my LS26 but will keep an eye out for Ref5se !
At this stage i feel i will purchase the ref150
(the one in question is not SE btw)
and give it a try! It is not all that easy to find one here. If it doesnt perform well I will resell (or start a second system around it) and look out for JC1 or perhaps Pass for the sashas.
Thank you all again
Peter McGrath of Wilson urged me to try the 8 ohm taps for driving the Sashas and he was right.
My Ref 150 had stock KT120s when I conducted my in house test. I have since placed KT150s in the amp and found a marginal but noticeable upside in all aspects.
Good luck and let us know how you make out.
gpgr4blu, i will be sure to let you know how i go. It may be a week or two before i reply. The ref150 im looking at has the stock KT120 (just re-tubed). Interesting to hear you found the KT150s marginal/noticeably better. Ive read some comments on this topic.
rob67 OP14 posts04-15-2017 12:06pmGeorge i see from the data it is clear the JC1 would be a better match.
There is a Pass X350.5 available near me too. (I am in Australia).
I don’t see any problems with the Pass amps with the Sasha’s, as their output impedance should be fine (low enough), even though they’d be a lower negative feedback design than the JC1’s, they should stay relatively flat still with the Sasha’s load, without becoming a tone control.
PS: that is a good price for the Pass, they usually fetch closer to $10K used here in Australiahttp://www.stereo.net.au/forums/topic/121446-fs-pass-labs-x3505-amp-price-drop/
I find it interesting that the ARC amp's 8 ohm tap is preferred given the Sasha's 4 ohm nominal impedance and its characteristics. Listening obviously sorts these things out. I look forward to reading your listening experiences.
I find it interesting that the ARC amp’s 8 ohm tap is preferred given the Sasha’s 4 ohm nominal impedance and its characteristics.
Yes, that is somewhat surprising, Charles. And even more so because JA’s measurements
of the amp indicate that THD performance and maximum power capability are both significantly compromised when speaker impedance is less than the nominal rating of the tap that is being used.
Schematics I’ve seen for other ARC balanced amps, such as can be seen near the bottom of the page here
for the older VT100 model, show what I believe to be a somewhat unusual circuit configuration on the output transformer’s secondary (output) winding. With the 4 ohm terminal being connected to circuit ground, and presumably corresponding to a center tap of the winding. And with feedback into one half of the balanced signal path being taken from the "Common" terminal, that is connected to one end of the winding, and feedback into the other half of the balanced signal path being taken from the other end of the winding (that being connected to the 16 ohm terminal on some models, although the VT100 omits the 16 ohm terminal). So assuming the REF 150 is configured similarly in that respect the explanation might relate to the fact that the 8 ohm terminal is electrically "closer" than the 4 ohm terminal to the point on the winding from which feedback is taken into one half of the balanced signal path, resulting in a closer match with the characteristics of the other half of the balanced signal path that takes its feedback from the Com terminal. That benefit perhaps outweighing the adverse effects on THD and power capability which JA found to result from connecting a 4 ohm load to the 8 ohm tap.
In any event, as you said listening sorts out the net result of all of the factors that may be involved.
Hmm! Been using REF250 4 ohm tab to drive my TAD E1s. Going to try 8 ohm tab and see if I hear any differences.
Agree Charles and Al. It seems counterintuitive that the 8 ohm taps would work well. I never even considered it until Peter told me that he always sets up the Ref 150 from the 8 ohm taps. After giving it a try, I have to agree. I assume the same holds true for the Ref 250.
Check out Roy Gregory"s comments on the 8 ohm taps with Sashas but not necessarily with other speakers. http://www.theaudiobeat.com/blog/audio_research_reference_150_se.htm
I tried running off 8 ohm tab and doesn't sound as good as the 4 ohm tab. It's more open, airy, bigger sound stage but lacks weight, impact, texture and color.
Bought amp new and only used 4 ohm tab so more time on 8 ohm tab will help with texture and maybe weight but sound stage is bigger than life.
@gpgr4blu how does the sound differs between 4 and 8 ohm tabs with Sashas?
The comparison was made for a weekend about 5 years ago. My recollection is that there was more width, depth and musicality to the 8 ohm taps. The music felt more liberated from the speakers. Unfortunately, it is hard for me to reach the taps in my current set up to switch them and make that comparison today and provide more specifics. I see that you have TADs. My understanding is that the 4 ohm taps should be used for 4 ohm speakers generally as yours are. It is just in the context of Sashas (and possibly other Wilsons?) that ARC and Wilson recommend the 8 ohm taps from the ARC Ref 150
keep me posted & Happy Listening!
Just out of curiosity, are there any concerns in general for stress to the amplifier for running a 4 ohm speaker using an 8 ohm tap?
Kalali, my understanding is that in general it is extremely unlikely that a 2:1 mismatch between nominal speaker impedance and output tap rating, in either direction, would cause any harm. And I’ve never seen any reports of experiences to the contrary. Also, in this specific case a lot of additional confidence is of course provided by the fact that Peter McGrath specifically suggested doing that, as well as by the comments in the Audio Beat article Gpgr4blu linked to.
I believe that in general a greater possibility of damage would arise if a speaker having a particularly high impedance, such as 16 ohms, were connected to a 4 ohm tap. That may result in "back-emf" from the speaker being applied to the tubes and circuitry on the primary side of the output transformer at voltage levels higher than the designer may have anticipated, since the transformer’s turns ratio for a 4 ohm tap is greater than for an 8 or 16 ohm tap.
I picked up the Ref150. (Not any easy task in itself). Will be connecting to Sashas this weekend.
I look forward to your review this weekend even though the amp will gradually improve over many hours (ARC says 600--not sure it's quite that long).
New Ref150? Didn't know you could still buy them new from ARC. Or is it SE?
I purchased the Ref150 used.
It has been serviced and re-tubed with new KT120s.
I have since picked up and listened to the Ref150 !!
I must say its a great sounding amp.
With the Wilson Sasha 1s, 8 ohm tap (4 ohm sounded wrong).
In brief, compared with the Bryston 14BSST2, the Bryston is fast and commanding, especially in the lower frequencies, but in my opinion the Ref150 does everything else better.
I switched amps quite a number of times to A/B them.
Very different amps of course (tube vs SS).
I found the Ref150 wider, deeper, more realistic, detailed, had longer reverb tails, more relaxed, open, organic, musical....
The Bryston is also a great amp and i enjoy its energy and speed, it can be more exciting (music dependent) less flattering, a bit more clinical. Sounds in the mid/high & high frequencies seem to compete a bit in comparison to the Ref150.
I thought "oh no ill have to keep both amps" Bryston for more aggressive music, as it is more impressive down low and with fast attack, (where the Ref150 seems to be lacking).
But after a while i started feeling rather than the Ref150 lacking, perhaps the Bryston was exaggerated. Perhaps the Bryston is what i am used to and different can sometimes seem "wrong" initially. Bryston is known to be quite flat though.... Regardless that Bryston punch is fun at times.
I will spend a little more time with both, playing differing musical styles. The Ref150 with the Wilson Sashas may be a bit slow & light on Low frequencies but ill give it more time. I am also considering trying it with the KT150 tubes, this may give me just that bit more energy im missing after the Bryston. I emailed ARC and they gave the tube swap the ok.
Linn LP12, ARC PH3, ARC LS26, the amps... Wilson Sasha1
Bryston for more aggressive music, as it is more impressive down low and with fast attack, (where the Ref150 seems to be lacking).
But after a while i started feeling rather than the Ref150 lacking, perhaps the Bryston was exaggerated.
"exaggerated" ?? no.
Electronic/mathematical certainty that the Bryston has the better control and drive "down low" with the Sasha's scary impedance down there.
Yes, you are probably right, unfortunately.....
That low extension is very nice too !
Bi Amp would be interesting but im not sure you can with sasha1
It seems there are often trade offs to accept when comparing components. The Bryston does a couple of things better and the ARC does many things better per your description. It will be interesting to see what is gained from the use of the KT 150 tube in place of the KT 120.
when describing the ARC you used terms such as "more realistic, relaxed, open, organic and musical". That's saying quite a lot and especially in important areas.
Bi Amp would be interesting but im not sure you can with sasha1
I’m doubtful that biamping these two amps would be worth pursuing.
For one thing, in a passive biamp arrangement (i.e., biamping without inserting an electronic crossover between the preamp and power amps), you would in effect be converting the Bryston amp that is capable of providing 900 watts into 4 ohms into not much more than a 150 watt amp.
That is because while a passive biamp arrangement relieves each amp of the need to provide current and power in part of the frequency spectrum, assuming the amps are properly gain matched in some manner both amps would still have to output essentially identical voltages corresponding to the full range signal. So turning the volume control up high enough to utilize much of the Bryston’s power capability would drive the ARC amp into clipping, and make those settings of the volume control unusable.
And using an electronic crossover ahead of the amps, in addition to the speaker’s internal crossover, would result in having two crossovers in the signal path which may very conceivably do more harm than good.
Finally, of course, having the speaker powered by two very different amps would raise concern about possible loss of coherence in the overall presentation.
You are correct, biamping would present all sort of problems, not to mention the sasha wont accommodate it. Thank you for a more technical insight.
"more realistic, relaxed, open, organic and musical". That's saying quite a lot and especially in important areas".
Very true, it is saying a lot and I couldn't agree more with your comment:
"It seems there are often trade offs to accept when comparing components" a lesson to be learnt there for me.
I appreciate your comments.
I will attempt practicing contentment, but still i wonder if there is an amp which can cover all aspects.... I wonder if the KT150 will give that bit extra.
I will report back in time regards the KT150
Good luck with your continued testing. The KT 150s will aid the low end a bit, but probably will not match the speed of the Bryston. Listen to a lot of music in the low end and you should hear that on certain sounds, there will be very little difference. On others, there should be a distinct difference. Re impact, often there should be close the same feeling in the gut but a different presentation creating that feeling. It seems to me the differences you are describing are the classic differences between tubes and solid state. Think of what will satisfy you in the long term based upon the type of music you listen to most of the time. Based upon that, you will make the choice that suits you best.
Good advice gpgr4blu, always choose based on what will please you for the long term . This philosophy has saved me from much remorse and regret. I’ ve found that the equipment that pulls you into the music and connects on an emotional level will satisfy for many years.
Bi Amp would be interesting but im not sure you can with sasha1 I’m doubtful that biamping these two amps would be worth pursuing.
If they are like the 6 7 8’s they are hard to bi-amp, let alone go active, as the mid/tweeter head unit has the x-over in it also for the bass unit and there is a pig tail that connects the twohttp://www.haishan-audio.com.tw/uploads/2/1/1/4/21148348/7651487_orig.jpg
Try a 10g Furutech FP-S55N Power cable with NCF connectors, it will dramatically improve the bass. I use them on my ARC Ref250 and from wall to power distributors. PM me if interested and I can recommend a dealer for possible home demo.
Another option is get a pair of Ref250 with KT150. The bass is comparable to my Hegel H30 summer amp.
I hope you are correct in saying what i am describing is the difference between SS and Tube (not a lack but a different presentation).
If i could pick a word...SS has fast ATTACK!
I particularly like your comment "
Think of what will satisfy you in the long term based upon the type of music you listen to most of the time".
This resonates with me. Although ill add "also what music you will end up listening to, now that Ref150 is here".
The 150 has found me questioning, what are you going to enjoy in the future? I find it interesting that the amp has made me question this. Almost like it is leading me in a direction, sooner rather than later, a direction that i would have gone down eventually.
I will look out for the AC power cables you mention, although I am in Australia so the model number may be different. If you know the AU equivalent please let me know. I would love to have the Ref250's with KT150 but that is rare here. ( I will keep an eye out !!).
There is a shunyata zitron cobra AC cable available here, do you think that may be ok?
I must say i know nothing of cables... interconnect, speaker, AC or otherwise...
In the mean time i am upgrading my Linn LP12 , Cirkus, Trampolin, Dynavector XX2 MK2..
(whilst simultaneously looking at other options in turntables, VPI, SOTA, etc). Not totally convinced with the LP12 as yet.
Ordered a Clear Audio Smart Matrix RCM & also looking at upgrading phono stage from ARC PH3 to Herron or K&K etc...
Lots going on...
Next weekend i am driving 10 hours (melbourne to sydney) to buy a used ARC Ref5se (currently i have a LS26) I will keep you posted.
All the best and thank you for your support.
rob67, Definitely checkout the Furutech. I was planning to buy 2 Rel G1 MKII subs until adding 2 FP-S55N from wall the power distributors.
I had Shunyata Alpha HC and Sigma HC on the Ref250 and they're very good PCs. You can't go wrong with either brand.
FWIW, ARC voices their components with Sain Cables and Shunyata.
No cable, power, speaker or interconnect, will fix the problem of of a tubes drive-ability around the Sasha’s 100hz nasty load impedance, they "may" hide it in some way, but at a cost of the music itself also. That Sasha’s load needs current drive, not band-aid fixing.
It’s obvious that the Bryston can do the right thing down there in the bass, but it seems the rest is not right tonally to you.
So maybe you should look at an amp that has the current the Bryston has but with a different signature in the mids and tops. maybe one of Pass Labs with high Class-A bias could suit, or as I mentioned before the Halo JC1’s in high Class-A bias mode.
I have purchased a few things.
The setup is now:
I am currently getting a LOMC DVXX2mkii fitted to the Linn.
Looking forward to it.
I am also buying a PS Audio P5 (used)
I have no idea what to expect but I am curious.
I assume i will run everything from it with the exception of the ARC Ref150.
Any tips would be much appreciated.
Very nice! rob67
Thanks! for the update. I wanted to add this advice;
if you are into electric guitar/electric bass-driven music, a solid state power amp is key. Otherwise, enjoy your ARC Ref 150.