Preamp Quandary - sonics vs. ergonomics??


I have been auditioning (buying and selling) preamps for over a year now. My only absolute criteria is that the preamp must be a fully balanced design that has low enough output impedance to effectively drive my McCormack DNA 500 amp (10K input impedance). However, since my system is in the living room, there are some ergonomic considerations including the potential for other users. After trying several, I currently have two pretty good but different preamps, an Atma-Sphere MP3 that is maxed out with teflon caps, regulated power upgrade, caddock resistor package, and user-applied 3M constrained layer damping sheets. It also has Jensen transformers for phono that I do not use. My other preamp is an Ayre K-5xe which is an outstanding ergonomic match with my CX-7e source. The comparisons are;

Ayre K-5xe - very user friendly, stays on all the time, uses the same remote as my CX-7e source, no heat issues, dead quiet, smooth sounding with tight punchy bass and adequate decay for a SS unit, no turn-on/off issues, heat, DC worries or other tube related concerns. In other words a competant performer which is the perfect operational match for my situation.

Atma-Sphere MP3; deep bass, dynamics that you can feel in your chest, well-extended for a tube unit and has that "rightness" only tubes seem to be able to provide, outstanding 3-dimensionality, and an outstanding midrange that puts the performers in the room with you. In short, this is the best sounding preamp I have heard in my system, but not the easiest to use.

Have any of you made a similar choice, and did you have any regrets?
mitch2

Showing 3 responses by mitch2

Thanks guys for your comments.
Tvad - you are right, I do like the McCormack and think it is an outstanding amp. I never have to worry about SS haze or grain with that amp, and I never have to worry about lack of power for the Aerials. I am curious whether your comment about boxing myself into a corner is related to using only balanced connectors, the lowish 10K input impedance, or both. If the impedance, I agree with you and have sometimes thought about other amps that might match it sonically and power-wise, with higher impedance. The most likely candidate is the JC-1's, although others I have considered are Mac 402's and Pass 350.5 (only 20K). If my pre to amp run wasn't 3M long, I would more likely try the single ended CJ Premire 350. BTW - I also agree fully with the last sentence of your second post which is well-stated.
To Jmcgrogan2; as weird as it sounds, the lack of a remote is the least of it, especially since almost all digital sources have remotes that can stop play or advance tracks. I almost like not having one for the preamp because I tend to set the level and enjoy the music, instead of messing with it all the time. The issue is more related to general tube things like heat, remembering to turn off the amp before the pre (A-S doesn't use a mute switch), differences in tubes, tubes wearing out, and that little bit of extra noise (although not much with the A-S). CMO has a good point, and I have considered a Calypso and ARC Ref 3, but probably not the BAT because I cannot afford the 51SE and I am concerned about the 6H30 "supertube." The models without the 6H30 (the 31 and 51) are said to lack resolution and high end extension, so I thought those would be a backward step from the A-S. I have tried the VTL 5.5 (nice and musical but poor soundstaging compared to the A-S), and the SF Line 3 SE (comparatively marginal bass definition and lack of "thereness"). I would like to hear the Ayre K-1xe in my system, but it is quite pricy. If I were to change everything, other combos in my price range I have thought about but not heard are Mac 402/C46, Calypso/JC-1's and CJ 350/P17LS2,P18, or P16LS.
The A-S really is a nice unit, but probably best suited to a dedicated room or single-operator system. I am listening to the K-5xe now, and it is very nice in every way, with no flaws or shortcomings, but just not quite the last degree of richness, clarity and dynamics that the A-S provides. If I had never heard the A-S, I would probably be perfectly happy with the K-5xe.
More good responses, and a good discussion, thanks guys. Jmcgrogan2 - I must have been thinking of the Ref 2, you are right the Ref 3 is more expensive. Bob_Reynolds makes a good point, and that is exactly where I am at now, trying to decide if I am able to simply forget about it and enjoy the music. With either of the two preamps I have now, my system is perfectly matched impedance-wise, and sonically, but they just don't sound the same. I can't really lose, both sound great, I just like the sound of the A-S better. Actually Kurt's suggestion is my "plan B." If a K-1xe or K-1x had been available at a lower price, I would have tried one of those first instead of the K-5xe, but after reading all the rave reviews I thought that maybe the 5xe would have been close enough, and it may still be, but I will probably eventually try and hear the K-1xe or maybe the 1x to start then go for the upgrade. So, whichever of the two I now have that I decide to sell, I will probably stay on the lookout for a decent priced K-1x to try. These may start to become more available if Ayre releases a Ref series preamp as they say they plan to. In the meantime, I will have a hard time giving up the Atma-Sphere. The other thing I always consider is the company itself, and in my opinion SMc-McCormack, Ayre, and Ralph and crew at Atma-Sphere are all at the very top of service-oriented audio, you just cannot go wrong with any of those. Finally, Jaybo which McCormack pre do you suggest? The only one I would consider trying is the RLD-1 with full SMc upgrades, but it is not balanced. Steve has been promising a new preamp for about a year now, and I will be real curious to see what he comes up with.
Can't do that with the DNA 500, per Steve McCormack -
"I usually design my amps with a 100K input impedance for maximum compatibility, but using the Jensen (or Lundahl) input transformers forces a shift to 10K (at least for the 1:1 types I prefer). It would be nice if I could offer all of the advantages of the transformer input topology along with high input impedance, but I feel strongly that the strength of this approach more than outweighs this small disadvantage. Using these transformers allows me to simplify my input stage somewhat, and provides a “brickwall” filter against DC and RFI – without the need for blocking capacitors or additional filters. Like many audiophiles, I used to look askance at the use of transformers, but I must say that I have become very fond of them. Used properly, I feel they offer a lot of advantages, and their main drawback is high cost."

the whole thread is at;
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1140406847&read&keyw&zzjensen+transformers