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Amp/Preamp Asylum: REVIEW: Aesthetix Io/Callisto Preamplifier (Tube) by jrus

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REVIEW: Aesthetix Io/Callisto Preamplifier (Tube)

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Model: Io/Callisto
Category: Preamplifier (Tube)
Suggested Retail Price: $6500./$9000.
Description: Pure Tube Phono/Line Preamps
Manufacturer URL: Aesthetix
Model Picture: View

Review by jrus ( A ) on February 21, 2003 at 19:22:40
IP Address: 68.6.87.18
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This is a review of the Aesthetix Io Phono Stage and Callisto Line Stage Preamplifier. I’m an old timer in the sense that I still think of a "preamplifier" as one component which performs both line stage and phono stage functions - like in the good old days before CDs. So I usually think of this pair as "my preamplifier". It occurred to me when I wrote this that most of these reviews are very positive. I’ve written two others and they were very positive, and it made me think about the value of reviews that you pretty much know are going to be glowing before you even read them. In my case, I spent a very large amount of time picking my stuff. In the case of this preamp, its taken more than ten years. I did my last system upgrade in 90-91 and after lots of searching and listening, couldn’t find a preamp I wanted to buy. So I ended up with a pretty damn good system except for a not so good, un-upgraded preamp and things remained that way until about a little over a year ago when I ordered the Io. I spent all that time looking for my "preamp upgrade" and then I found the Aesthetix components. So, there are a TON of poor reviews I never wrote because I didn’t buy those components. They always added some sonic character that I found undesirable. And sort of by definition, the review below is the result of finding something I find spectacular enough to have bought after all that time. So it's not an objective review in that it represents an essentially randomly selected component which may be good or bad, but it is objective in that it's a review of the component that prevailed over many many un-reviewed and rejected components. The only thing missing is a list of those rejected components and I’d prefer not to provide that for my own reasons.

I’m a died in the wool analog/tube/planer-speaker guy. To my ear, digital sounds good at best (never great), solid state always sounds "incorrect" at least to some extent, and box speakers make music sound like its, well, coming out of boxes, no matter how expensive they are. I’ve been trying to get as close as I can to bringing the sound of live music into my home for over 25 years. Half of doing that is finding good source material. The other half is obtaining a good stereo. I am a musician (classical pianist) by avocation and physicist by vocation. My system consists of the incomparable Walker Turntable with Koetsu Platnum Onyx cartridge, Aesthetix pre(’s), the magnificent VTL Reference 750s, the incredible Magneplaner 20.1s and the amazing Supernal and Hovland interconnects (obviously, I love my stuff). I like all kinds of music except most country/western. Rap is not music, and I don’t like it. I bought everything I have from a cost-no-object point of view. If I had a zillion dollars, I would not replace anything in my system with anything else that I know of at this time. (I tried to word all of that to specifically expose as much as possible my personal prejudices for your use in calibrating my comments. I don’t pretend for a second that any of that is anything more than just my subjective view point - and that, only of things at this particular time.)

Ok. There’s something about the sound of music reproduced using very fine tube electronics that is more natural and real than with solid state. I could try to describe it but I’m sure you already know what I’m talking about. I’ve heard people talk about a "tube sound" but to my ears, good "tube sound" is merely the absence of bad solid state sound. Not something in and of itself. I’ve listened to a ton of the best solid state stuff. Its advocates always claim that it sounds "as good as tubes" without that "solid state sound" but it never does. Ever. My experience has been that if there is a solid state device in the signal path, you inevitably hear its undesirable effects in the music. At best, you don’t hear it at first, but over time, it starts to wear on you as your mind averages its "sound" from lots of different source material. Poorly designed tube stuff sounds worse than great or even good solid state. Tube stuff has to be good tube stuff. My personal idea of a great sounding system is one that reproduces what’s in the source material as faithfully as possible. If it happened to be recorded from the center of the 15th row (or whatever it is), then you’re looking for HPs fabled "Absolute Sound". However, if it was recorded from over the stage (as orchestral music usually is for example), then you very much DON’T want it to sound like it came from a sitting position in the 15th row. Your sound system can’t be held responsible for the contents of the source material.

Something that sounds good, sounds good right away and that’s that. It takes both good source and good reproduction for that to happen. But since you’re unlikely to know enough about your recordings to know if any particular one sounds "as recorded" on your system, how do you tell if a component is coloring its sound? Actually, I don’t think you can except in extreme cases. But, if you listen to lots of stuff over a long period of time, idiosyncrasies in your sound system began to stand out. After awhile (maybe a real SHORT while), you hear them instantly. In almost everyone’s case, the room you’re listening in is an example of this. If everything is perfect, you would hear the sound the microphones heard that created the source material, in your listening room. There are a lot of reasons why that could never really happen. To start with, no matter how well the source material and your equipment reproduce that sound, you’re listening to it in your unique listening room and that uniqueness becomes part of the sound you hear. Nonetheless, it is the case that an essential element of "liveness" is lost in all the systems I’ve heard that is not lost by the Aesthetix Io / Callisto. Let me try to describe it this way. Have you ever gone to a concert before the music starts and as you walk into the auditorium itself, notice the sound of the hall itself that’s so "alive" that it kind of hits you in the face with its presence even though its just made of the arbitrary sounds in the hall (instruments tuning up, people talking, etc)? Its all around you and has a specific feeling of "realness" (best word I could think of…) to it. When the music starts, that characteristic becomes the context you hear the music in. It's the environment the music is in. I’ve never felt that in reproduced music before and its part of why it never sounds "real". As it turns out to my surprise, it sometimes IS captured in source material (for example, Falla, "The Three Corner Hat", Ansermet/LDLSR/Decca SXL 2296) and the Io/Callisto allow you to hear it. Somehow. This is a lot of what makes them sound unlike anything else on the market. Dynamics, both macro and micro, are also responsible for this "realness" that reproduced music only hints at. The Io and Callisto are better than anything else on the market in this regard, giving them that "real" quality that is so illusive.

The reason I made such a big point of all of that is to help explain my experience that the Aesthetix’s pre’s are the most "real sounding" electronics I’ve ever heard. I’ve had them for over a year and listened to them A LOT. That’s my review. I’ll try to expand on it a little, but essentially, that’s what I have to say.

The first thing I noticed with the Io phono stage is that there was a TON more stuff going on in my recordings than I ever had any idea was there. Not the same stuff in every recording but nearly always more stuff. The sound stage would sound much much wider on one recording, I’d discover that there was deep, tight bass on another that I didn’t realize was there before. I heard the bird actually flying over head (I’m not kidding!! OVER-MY-FRICKING-HEAD!!) on Pink Floyd’s Ummagumma Studio Album (side 3; Roger Waters’tracks - how the HELL did they DO that ?!?!?!). I could hear stage depth in some recordings I didn’t realize was there and violins on some recordings sounded like they were being played right in front of me. The sweetness and complexity of its distinct tone, clear like it is in a violin heard live. In lots of cases, I heard instrument parts I didn’t know were there. Or there was a subtlety of balance between instruments I didn’t hear before. It isn’t all good though. Some recordings have lots of edits I hadn’t noticed and they practically slap me in the face now when I listen to them. Sometimes I can hear a slight change in environment/ ambiance that was too subtle to show up before - something different in the recording space (maybe even location) between the spliced takes. I know what a piano sounds like and no recording I’ve ever heard comes close. Listening with the Io phono stage, they all still sound wrong and I can hear exactly WHAT is wrong more clearly. This would actually be bad except that what I was hearing before was the reproduction of some of the incorrect piano source sound AND a lessor component adding its own "thing", which makes things even worse. When will SOMEONE work out how to record piano. If we can hear it, it should be recordable.

The thing with the Callisto is exactly the same. The comments above refer to the Io played through the Callisto. If there were a lessor line stage component (as there has been at several points during my upgrade process), it contributed too much of its "self" to the sound to hear the source properly through the Io though the elimination of the phono problems alone (with the Io) provides a huge improvement by itself. Another way I experienced this was by listening to CDs. They sound a lot better than I’d realized in some cases but for a variety of reasons that depend on the source itself. Mostly, the same "more stuff" thing as the Io. I can’t identify a "Callisto sound" (or an "Io sound" for that matter), I just hear more of whatever is on the CD.

Reviews in The Absolute Sound describe the Io and Callisto as having a slightly "dark" sound. This is "Absolute" nonsense.

I started with the standard Io and Callisto and ended up with the Signature versions of both and with two power supplies each (each component comes with a single "stereo" PS in its standard configuration). Each upgrade increased this ability to hear what is on the source even more. It doesn’t change anything, it just does what it already did, more. Aesthetix’ iron clad rule in developing improvements is just that. My advice is to upgrade as high as you can afford. The basic Io and Callisto sound better than anything else I know of and the Signature and/or dual power supply versions continue from there. I suppose its the case that since the standard Io and Callisto can be improved upon, they must have some personality of their own. And by extension, so must the Signature and/or dual power supply versions. But I’m not surprised at that. Except for certain things here and there, no reproduced music ever sounds like live music, even with such great components as the Io and Callisto. There may be yet more "source" on some source material, that could be extracted (or maybe: "not subtracted") by further improvements, I don’t know. By the way, I couldn’t say whether the upgrade to Signature or the addition of a second power supply ($2500. each) gives a greater improvement. You just have to listen and decide for your self. Jim recommends the signature first, primarily because it doesn’t require more shelf space, power consumption, etc.

Now, another important thing about buying stuff at this (or any) price level is the quality of service and support. My experience has been that this is usually pretty poor in the hi-fi-biz. And there is absolutely nothing in the world I hate more than being bullshitted. Unfortunately, hi-end audio is like one giant bullshit hurricane. I think it makes the used car business look honorable by comparison. Just read a review in Stereophile and then go listen to the actual component. I’ll bet those guys don’t even listen to the stuff they’re reviewing sometimes. I’ve had some pretty bad experiences but I won’t bore you with my war stories. Let me just say that the guy who created the Aesthetix components and owns the company, Jim White, is a totally honest, real guy ("real" is my very highest accolade for a person in this context - I haven’t got a higher complement to give). It's safe to buy from him. And the people who work with him (for example, Michele) are exactly the same. But a word of caution - if you have a problem of any kind, be sure to speak directly with him about it. Don’t work through your dealer or the distributor, and don’t interact via email. Explain things directly to Jim and he’ll take extraordinary care of you. He loves producing this amazing stuff, is justifiably very proud of it, and wants each component to speak for itself in terms of his achievement in your system (my translation of his words). If you have a problem, he’ll work with you until everything is perfect. He’s the precise opposite of a "lets see how we can get more money out of this customer" guy and all that that implies.

One last thing. Jim uses Sovetk tubes in these units. There are a LOT of tubes in them (I haven’t replaced any yet due to failure). The performance of the components depends a great deal on the brand of input tubes. Amazingly so. "Wrong" tubes can actually make them sound bad. My experience is that the Sovetk tubes in the "input" positions of both the Io and Callisto sound very good but are noisier than they need to be, especially in the Io. I’ve experimented with lots of them and found brands that sound as good or better than the Sovteks and are much, much quieter. You’ll want to do your own experimenting. I mentioned this to Jim recently and he told me that he’s gone to a screening process now that results in only the best tubes (which works out to be about 25% of those tested) in the sensitive input positions. I haven’t heard the results of this, but based on my experience with him, it is no doubt true.

That’s it. If you’re looking for a high-end preamp, listen to these components before you buy anything else. As a result of Jim being such an accessible person, I’ve learned a lot about the components that I didn’t know before I bought them. I’ll pass some of that along here:

Io is an all vacuum tube design with three gain stages and an output stage. There are 16 tubes in the main unit (8 per channel) and 8 tubes in the power supply. Although the total tube count is 24, only 4 of them are critical for noise performance in the unit. It was designed to provide enough gain to accept the lowest output moving coil cartridges. It can accept both XLR and RCA inputs, and provides both balanced and unbalanced outputs. For the unbalanced outputs, both plus and minus phases are provided. While most phono stages designed for low output moving coils have a maximum gain of approximately 60dB, the Io has 80dB and can be adjusted to 74, 68, 62, 56 and a special provision is possible for 50dB gain by removing the final gain stage. Loading provisions allow for 47K, 10K, 4.75K, 1K, 475, 243, 121, 75, 40.2, 20, 10 and numerous intermediate values. The combinations of gain and loading allow the Io to be precisely tailored to your cartridge. Each gain stage in the Io is fully isolated from all other gain stages by a massive power supply filtration network directly associated with that gain stage. All stages use the highest quality components, including Roederstein resistors, Reliable Capacitors (both Teflon and polypropylene), Dynamicap capacitors from Infinicap, Nichicon electrolytic capacitors, silver ceramic vacuum tube sockets, Cardas RCA jacks, Neutrik XLR jacks, Cardas internal wiring, Cardas quad eutectic solder, Mercury magnetics power transformers and chokes.

The power supply consists of 14 DC regulated heater supplies and two high voltage supplies. The heater and high voltage sections are completely isolated through the use of separate power transformers for each function. The heater transformer has 14 secondary windings. The high voltage supplies each have a bifilar 10 Henry common mode choke feeding an EL34 pass element. Each EL34 is controlled by an active regulator composed of three 12AX7s in a differential amplifier configuration. One high voltage supply delivers 600v at 100ma and the other delivers 400v at 100ma. The power supply is identical for the Io and Callisto.

The Callisto is a pure vacuum tube linestage consisting of a differential amplifier gain stage and an output / buffer stage. It uses four tubes per channel: (1) 12AX7WB, (2) 6922, (1) 6SN7 for a total of 8 tubes in the main unit (and again, 8 in its power supply). It has a maximum gain of 23dB (SE in - SE out) or 29dB (balanced in - balanced out). The volume control is a 46 position balanced stepped attenuator which switches in only one series resistor and one parallel resistor at each volume position. It has a constant input impedance of 100K and each step is 1 dB through the critical ranges (as an option, a pair of attenuators of identical design can be included on the Io, which makes it possible to set up a pure phono system (no line-stage) should that be desired. An Io so configured also has a high-level aux input, ideal for a CD player or tuner). Channel to channel tracking is within .2dB throughout the entire volume range.



Product Weakness: Uh, I'm thinking ...
Product Strengths: Incredibly undamaged sound reproduction


Associated Equipment for this Review:
Amplifier: VTL Ref 750s
Preamplifier (or None if Integrated): Aesthetix Io and Callisto
Sources (CDP/Turntable): Walker Proscenium Gold Signature
Speakers: Magneplaner MG20.1
Cables/Interconnects: Supernal/Hovland
Music Used (Genre/Selections): Classical/Jazz/Rock/etc
Room Size (LxWxH): 18 x 14 x 8
Room Comments/Treatments: Echo Busters
Time Period/Length of Audition: 1+year
Type of Audition/Review: Product Owner




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Topic - REVIEW: Aesthetix Io/Callisto Preamplifier (Tube) - jrus 19:22:40 02/21/03 ( 8)