Distortion with ARC Ref 150 and Maggie 3.7


I have this problem that drive me nuts for quite a while. I purchased a like new fully balanced ARC Ref 150 tubes amp through Audiogon for my single ended only CAT SL1 Ultimate preamp and connected both with a RCA to XLR interconnect. It sounded okay with most recording but has awful distortion with certain recording specifically piano and vocal. Some of this recording happens almost on entire record but some only on certain musical passage. Most of the time with higher pitch or peak of music or higher volume.

For your information I listen to vinyl only most of the time and more on Jazz music. Other component listed as follow:

Turntable: Sota Nova, Tonearm: Origin Live Illustrious, Cartridge: Dynavector XV1-S, Step up transformer: Bob's Device CineMag 1131 (Blue) feeding directly to CAT's own phonostage, Speaker: Magneplanar Magnepan 3.7. Power cords, ICs, Speaker cable, Autoformer: Paul Speltz Anti-Cable.

Trouble shooting which has been done includes: checking preamp tubes condition and checking power amp bias. Since ARC claims their Ref 150 was design for balanced preamp only so I also tested by replacing it with single ended tubes amp but the distortion remain. As for the cartridge I believe I have done the alignment pretty accurate with the Mint's Best Tractor but not very sure with the azimuth.

While tested with my other 2 pair of speakers, one which has higher spec show the same problem while the lower spec one seems get rid of distortion. So I suspected the issue probably was with the new Maggie. Called the dealer and he performed a test with his transistor amp with no distortion at all. So he assumed my Maggie is okay. Is it true that the Maggie only good with transistor amps?

By now it leaves me with total confusion! Sincerely hope fellow audiophile here could give me some advice and save me from this endless misery !

Thanks very much in advance!
pakwong
In a free society a person should be able to do his homework whenever he wants to and it's nobody's business but his own.

As others have pointed out, it's questionable why ARC makes amplifiers that cannot operate correctly with single-ended sources.
10-04-14: Onhwy61
In a free society a person should be able to do his homework whenever he wants to and it's nobody's business but his own.
Are you serious? You have issues with my suggestion?

I could care less what Pakwong does with his $$ and problems. This is an open forum and I'm contributing my .02.

As others have pointed out, it's questionable why ARC makes amplifiers that cannot operate correctly with single-ended sources.
Because it wants to?? In a free society a company should be able to produce whatever it wants. They stay in business if there are demands, otherwise bye bye.

Also in a free society a person can buy whatever they want. If they don't like ARC's approach, don't buy it. Again, if you do your homework pre-purchase, it will save some headaches.
Just read the last 5 or 6 posts. I posted a few comments a while back. Two points.

First -- Yes ... it is true. The ARC Ref 150, and presumably Ref 250, are designed to accept only a balanced (XLR) inputs. Not an SE (RCA) type. If you can rig some contraption to somehow do an end-run ... all the power to you. I own an ARC Ref 150. The last thought that would come to my mind would be to jury-rig (sp?) that type (or any type) of similar gizmo.

Second -- I've said this before and I'll repeat it once again. Maggies are power hogs.

I think Maggie 3.7s deserve a lot more juice than the Ref 150 can deliver. I'm sure the Ref 150 can drive the Maggies to an "ok" SPL, but not to the point where the 3.7s will open up and sound their best. I seem to recall that many years back, I had a similar conversation with either Len or Kal at ARC. They expressed similar views.
Bruce (Bifwynne), I wouldn't consider the use of a Jensen transformer to be a jury rig/jerry rig/kludge (whichever terminology one prefers). It's a legitimate means of converting a single-ended signal to a true balanced signal pair.

Consider also that some extremely highly regarded preamps have transformer-coupled outputs, and in some cases also utilize transformer coupling in their internal signal paths. Examples include the Coincident Statement line stage, and some ultra-expensive Audio Note models.

Of course, all transformers are not created equal. But the Jensen transformers are well regarded, and as I've indicated multiple times in this thread, a number of highly experienced members here who have very high quality systems have reported excellent results with it. And the OP was quite happy with the results he was getting with it, until an unrelated problem he experienced caused the thread to be resurrected, and various subsequent responses unrelated to that problem caused him to become concerned about theoretical issues that may or may not be subjectively significant, or even perceptible, in his system.

Regarding your other comment, I don't doubt that for some and perhaps many listeners the Ref 150's power capability may be marginal with the Maggie 3.7, and in fact that very issue is being discussed in another current thread you are participating in. Of course, the degree to which that may be a concern will depend on the particular listener's preferred volume levels, on the dynamic range of the recordings that are listened to (well recorded minimally compressed classical symphonic music perhaps being the worst case), and on listening distance and room size.

My impression, however (derived in part from your comments in other threads), is that the power supply of the Ref 150 is robustly designed, including large amounts of energy storage. Which, together with your comments about its marginality with the particular speakers, reinforces the concern I expressed in my previous post about the adequacy of the lower power rating (100 watts) of the CAT JL5.

Onhwy61, I'm surprised at your response to what I thought was a knowledgeable and entirely appropriate input from Knghifi. I would especially not have expected such a response from you in particular.

Best regards,
-- Al
Thanks Al. I take your point about using a transformer to connect an SE output to an XLR input. As I have admitted many times, I am not a EE-type, so the theory and application is way north of my pay grade. I suppose I am just biased (pun) about inserting artifacts into the signal path.

You may properly ask why, if I really feel that way, did I insert a DEQX digital time and EQ correction device in between my linestage and amp? My response: perceived sonic cost versus perceived sonic benefit. So far, I believe the latter significantly outweighs the former, ... I hope and think?????

Thanks for the electronics lesson. :)