2. amps-preamps
  3. 1407646817

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
pakwong OP
38 posts
 
Yes kevin, I try to keep rational thinking and focus on the Jensen transformer first.

A friend of mine also recommended JL 5. Although only rated 100 watts and have 8 KT120 power tubes just like the Ref 150, people who have been with CAT still think the JL 5 would be an all round winner. Only when think of the 100 watts JL 5 driving the Maggies which has been known to be extremely power hungry, it's normal for a audiophile to try to think "rational" lol
bifwynne
2,206 posts
 
Pakwong ... I still think the Ref 150 is a marginally powered amp for your Maggies. But the most recent posts which speak to the Ref 150 using balanced inputs is extremely important. I cannot overstate how critical it is that you use a linestage/pre with balanced outputs.

Don't know what your budget is. But let me suggest that from time to time, I have seen ARC Ref 3s going for the low $5000s. Even an LS 27 linestage/pre would be a great match.

Last comment. I own a Ref 5 SE/Ref 150 combo. I love my ARC gear. The sound is great. It's built like a tank. ARC provides great customer support. I hope you can figure out a way to keep your Ref 150. IMO, it's a classic piece of kit that will keep its value for a long tim.
syntax's avatar
syntax
2,193 posts
 
Although only rated 100 watts and have 8 KT120 power tubes just like the Ref 150, people who have been with CAT still think the JL 5 would be an all round winner. Only when think of the 100 watts JL 5 driving the Maggies which has been known to be extremely power hungry, it's normal for a audiophile to try to think "rational" lol

I listened multiple times to JL5 and I think it is a great amp. Are you ready to buy them unheard? Try to ask a dealer for loan, they won't do it for free but even when you pay the shipping both ways and an extra for the dealer .... this can be cheap when it will support your decision...but I would still do a comparison with a high powered transistor amp to check what is going on with the higher frequencies...
pakwong OP
38 posts
 
Many thanks to Bifwynne and Syntax for your kind advice on amp selection.

I do have an offer for a Ref 5. Whether buying it or not I think I would still keep the Ref 150. For the JL 5 it kinda impossible to arrange for home audition down here but a single ended amp whether tubes or transistor would be a more "rational" option to me as my CAT already have build in phono stage. If I choose the ARC path I would have to digs for extra money to invest on a good phono preamp.

I do wish that the transformer option would eventually work out as I felt that the CAT-ARC-Maggie's combination sounded quite alright to my ear. It produced romantic and airiness sound stage with good ambient which suited my musical taste. I can't be more happy if it turns out that the Ref 150 does sounds much better when the amp finally able to unleashed their full potential with balanced input signal!

Regards,
mrderrick
292 posts
 
My recommendation may have been overlooked as to its relevance, ARC made several active balanced line converters specifically to address the same issue you are having. The BL-1 and BL-2 balanced line converters. While these are out of production, I do see them come up for sale both here and on Ebay several times a year. You could post a "Wanted to buy" ad. You could then keep your current pre.
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