Calling all Aesthetix Callisto / Io Owners

Thank you all for your comments:

Nkj: It's unfortunate that the PS's are pinned differently for the Io vs. Callisto. Must be a subtle difference needed between the two products. But that ends my chances of hearing either one at the moment with 2 PS's. But thank you for confirming that this could not be done. I am eager to learn what comes of your 1 vs. 2 PS for the Io signature listening session.

Rushton: Good descriptions as to what should be expected. When I changed all the Sovteks to Telefunkens in the Io, interesting that I did not gain any of the benefits that you listed with the Aesthetix upgrades. But what I did get was a much more full sound in the mids with incredible decay of notes and presence. The last ounce of sterility was gone. And this change alone caught my attention as it was so incredible. Otherwise the Io's sonics were pretty much the same with the stock tubes.

I feel I could use a more coherent tonal balance provided by a little more extension at the frequency extremes rather than an increase in dynamics and reduction in noise provided by the 2nd PS. So it looks like a change to the Sig would be the ticket for me with the Io if I decide to keep it vs. the soon to arrive Aria preamp.

Tabl10s: Right on! I guess I should have thought of this as I have read many times that other people have had to do this. But this was the first time I had a volume pot that did this. And sure enough, I rapidly moved the control back & forth for a good 10 seconds or so, with the unit powered off of course, and now the problem is gone. Super!

I am so spoiled with the silky smooth control on the BAT 31SE and it's awesome remote that handling these huge clunky controls on the Callisto will be a very big change to get used to. But already the Callisto has a much more authoritative presentation and more energy on the top vs. the BAT. It is most impressive with the CAT amps. But what surprises me here is how well the BAT competes with the Callisto Sig at double the price. There are clearly many very talented audio engineers out there.

Thanks again.

John

Fmtien: Advice from Tab110s was just what the Dr. ordered. The noise when I move the right volume pot is now gone. Very happy camper here. Concerning the number of steps vs. the BAT, the Callisto is more than adequate for me but the BAT does indeed allow for much more refinement of level adjustment. I really like this aspect of the BAT very much.

And yes, I have paid a lot of attention to Albert's writings. But the focus has mostly been the Io which is why I was asking about the Callisto. I will have to go back and read more carefully his attention to the Callisto and the most important tube positions he suggests to change first. When I first got the Io, he wrote to me with great advice and the performance of my Io skyrocketed.

NkJ: Yes, I would much appreciate the instructions on multiple PS's. I am eager to hear of your listening results. And keep the SA2/SP-8. When I heard the SP-8 in 1982 (I remember that event so well) I heard music from a home system like I never did before. And no, the Aria is not out yet but I am eagerly waiting. I'll let you know.

Thanks much.

John

A most valuable post indeed. Very much appreciated, Albert. I will try some of the recommended tubes to learn if they make as huge a difference in the Callisto as did so many tube changes in the Io. Fun Fun.

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.

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?