Calling all Aesthetix Callisto / Io Owners

Wow, cool to see this thread still has a heartbeat. I started this thread for some assistance to get the Callisto "up and running". After reading much of Albert's tube advice, I started this thread to share my own tube experiences for the Callisto. So much had been discussed on the Io but not so much on the Callisto. Another thread to check out is here.

Last year I put a lot of time into investigating and trying out EL34 and 12ax7 tubes. This year I finally got around to trying many 6DJ8/6922 variations. The Tele 6DJ8 tube BY FAR is the most impressive of them all and it equally performs magic in the Io and Callisto whereas the Tele 12ax7 is wonderful in the Io but absolutely flat in the Callisto. For the Callisto I can't make up my mind if I prefer the Brimar or the Mullard gold pin 12ax7.

My Callisto is the Sig version but the Io is/was not. I took the Io over to Steve Huntley (GNSC) and he went through one pass on this, upgraded nearly half of the caps to Dynamicaps (the primary update for a Signature version), tweaked a few other things and added a bunch of dampening to the chassis. When we listened to this in his system a week or so later, frequency extremes opened up dramatically. Tonal coherency was far far better and thankfully that incredible bloom was there as before. Steve said he had some ideas to replace some parts in the PS and some more changes in the audio chassis. I would love to go for this but the sound is just so good right now that I am not ready to part with this for a couple weeks. But I will look to do this at the start of the year and report back. I feel very fortunate to be 15 minutes away from GNSC.

Jafox,

Why did you install NOS tubes and have your Io modified? Did you try to address a specific problem?

Rmaurin,

>>Why did you install NOS tubes?
After owning the ARC SP-10 and LS5/PH2 for a combined 15 years, I was familiar with the sonic differences between some brands of 6DJ8/6922 tubes. The Amperex were much more to my liking over the stock russian based tubes in the ARC models. However, I had little experience with the premium tubes from Mullard and Telefunken from decades ago. When I decided to try the Io (the non-signature model), I had read a lot of information on A'gon about how some tube changes could transform the Aesthetix models. The stock Io sounded pretty darn good but I wanted to hear what all the hoopla was about so I bought a dozen or so Mullard, RCA, Siemens and Tele tubes and tried them in the Io. All that I had read was instantly confirmed: $500-600 as a starting point to change out some of the Sovtek tubes brought on a huge refinement - the sharp edge of the Sovteks was gone and a more lush presentation was there. Since that time, I have pretty much finalized a tube set to my liking for the 2-chassis Io at just a shade over $1000 that takes this unit far far beyond what I ever could have imagined possible. Once you hear this, there is no going back to the Sovteks. And when I did a similar change to a CAT Ultimate II earlier this year, only then was that unit even listenable; the Sovteks there makes this preamp way too fatiguing to my taste.

>>Why did have your Io modified?
If you realize that the Io and Callisto are designs that are now 10+ years old, just all the improvements in passive parts alone has to imply a major benefit to upgrading the internal components. I investigated what the component changes were between the standard and signature Io. Considering the cost would be $2500 to "upgrade" to the signature version, and all the hassle, cost and risk of shipping these to/from the Aesthetix factory, I contacted Steve Huntley at GNSC to see if he would be willing to pop off the tops here and give me some insights and estimates as to what could be done. And I had a good idea as to the premium parts used in the signature since I have a Callisto Signature.

I heard my unmodified Io in Steve's system and compared to his phono setup, the Io had greater bloom and midrange definition, but clearly lacked refinement at the frequency extremes and also had mediocre resolution. Based on what Steve could hear that day, he was confident that a dozen or so select component changes would be a good starting point to tackle some of these weaknesses. And a week or so later, all it took was a quick listen to realize Steve's efforts had paid off. I could have left it there for yet another level of updates but it sounded so mighty good that I needed to get it home to enjoy the improvements. And because Steve is also here in the twin cities metro area, I could meet with him personally, talk about the pros and cons of each update and the respective cost and do a little at a time as there is no shipping back and forth. I am very fortunate in this regard to have this service locally.

As time goes on, I am more and more a fan of modifications once I find a product that really captures the essence that I seek. The Aesthetix models do this and becuase they have so much room in their chassis to take on the premium parts that are now readily available, it makes a lot of sense to do so. And when going down this route, the improvements you gain are at a cost that is impossible to achieve through buying a new model or a factory upgrade. Michael Elliot, the chief engineer of Counterpoint and Aria components, explains it best here.

For example, look at all the ARC line stages that have been their best model (LS5 I, II, Ref 1, Ref 2 I and II, and now Ref3) since the life of the Callisto. And imagine the cost it would have been to constantly upgrade from each to the next. The fact that the stock Callisto still competes after all this time indicates it was done right from the start. And if I can transform this design with $500-1000 in parts improvements to take it to the top of its class, then why would I want to "upgrade" to another model and take a multi-thousand $$ hit?

Assuming one were only listening to vinyl, in what sense is the Aesthetix Io with volume controls (or the Manley Steelhead with volume controls) *not* a full-function preamp?

Wouldn't adding a separate linestage just add more circuitry and another pair of interconnects to the signal path unnecessarily?

I don't doubt that both of these 'phonostages' actually sound better when used with a separate linestage, I'm just not sure why that is the case.

Exlibris says,

I don't doubt that both of these 'phonostages' actually sound better when used with a separate linestage, I'm just not sure why that is the case.

That sums it up, it just happens that the additional gain, impedance matching and circuity helps the sound.

Don't you think we Callisto owners would be eager to pocket the thousands of dollars from selling, plus freeing up shelf space if it did not matter a great deal?

The Io is great but it does not perform nearly as well by itself as through the Callisto (or an ARC Ref).

There are lots of things in high end audio that don't make sense, perhaps this is one of them.