2. amps-preamps
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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
kevinkwann
85 posts
 
"If you were me, which do you prefer?"

Good question! Both are really fine options.

I really like the idea of trying the Jensen transformer as a stop-gap. Jensen makes really good transformers and this option might work sonically. Might.

If forced to choose one option over the other, I'd go the CAT route because the JL5 would, I feel, do a better job of driving your Maggies. It's not about watts. CAT amps are designed to drive pretty much anything.
pakwong OP
38 posts
 
Martykl, if I have more than one listening room, I would have keep both! But I still think we audiophile should try to be rational as best as we can lol. The more I went deep into this hobby, the more I realized that we have to put a lot of effort to build a real good sounding system. Two or more system might be overburden to me!

Regards,
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...
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