Amps for Avalon Osiris CAT JL3, Boulder 2060, Dart

I sold my Radians in order to buy a pair of Ascents Mk2 about one year ago. After that I sold my ss amps (monos) and bought a pair of Fourier OTLs (Pantheres). Quite a few members of the audio community were quite negative because Fourier has a bad reputation. My amps proved to be reliable however because the caps mounted are of Japanese origin instead of those that are from India. Pre amp is still solid state (cello). The sound is very detailed with spectacular dynamics. If a small Ongaku amp can drive these speakers a 200watt OTL has no problems at all I assume. Even digital classical records prove to be listenable now. I hear plenty of bottom end (is there any sub that will mate with an otl?). I think the Osirus could also be a good match for such an otl. I read that even newer Avalons with a more difficult load work well with Atma- Sphere. Does the Osirus also have minimum load of 5.5 ohm? Can anybody describe the difference between a Cat and an otl? Has anybody similar experiences?

Hodelrecords, it's good to hear your Fouriers are doing well. They are good sounding amps, maybe a bit on the dark side. The original power supply high voltage electrolytic caps were a brand called Binda, sourced from India, so it sounds as though the previous owner replaced them, probably a good thing.

I don't have any experience with CAT vs. OTL amps driving speakers like yours, but I am familiar with both driving Sound Lab ESLs. While I probably can't offer specific insight into which would do a better job driving big Avalons, I would generally recommend Atma-Sphere MA-2s as a minimum if you're going the OTL route; it may be only a matter of time before the Fouriers fail when driving loads that dip below 8 ohms. Avalon can give you an idea of the impedance. CAT amps should drive the speakers well; you'll have to audition them side by side with OTLs to see if you give up some transparency for the sake of control.

Brian

I too grew up in New York and spent many years living in Northern new Jersey. I have lived in Ca. since 1980. I also have Ascent Mk 2 speakers and they are driven by a Pass 350.5 and there is an REL Stadium II in the right hand corner. I do employ an Audio Research Ref 2 as a preamp and there are a pair of Amperex A Frames as the first amplification stage. I have owned many cominations through my 40+ years and an audio nerd and this is the first time I am not considering an upgrade.
Jeff

Essentialaudio, thank you for your insigts about the difference in sound between the Cat and an otl like Fourier. I have considered Sound Labs but they proved to be too big for my 4x8 meter European room. Until now I am not worried about the Fouriers, they are over 10 years old now and have always driven unkind loads including Avalon Eidolon's. The Atma-Sphere's I know well are extremely detailed amps but lacked power in the lower regions although this might have ben caused by the speaker used (Voce divine's if I remember them well). The main complaint I have aout the Fouriers is the noise level of the fans. The biggest mistake I have ever made has been the purchase of a pair of Mark Levinson 20.5. These together with ML 25+26 lacked dynamics. The big Cello's I had were in a totally different league but the otl's had a more life like midrange representation. You can't have it all. If my Fouriers fail I will try Atma-Sphere.

Hodelrecords, since you may consider Atma-Sphere amps, I thought I'd chime in. The Atma-Sphere MA-2s have no trouble here driving the bottom end of my Avalon Eidolons. They have proven to be a great combination with excellent control, speed and agility. Of course, I can't comment on how they might work with the Osiris, but the Eidolon's 4 ohm nominal (3.5 ohm minimum) impedance is simply not a problem for the MA-2, a superb combination all around.
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