Calling all Aesthetix Callisto / Io Owners

JaFox, John,

I'm going to clarify in suggesting that the Io supply should not be used with a different pinout...it's an assumption on my part. However, I do know for certain that modifications must be done to the main unit and the power supplies in order to go from 1> to 2> supplies...logically each channel originally is accepting it's power requirements in parallel from one supply...after a 2nd supply is added each channel receives it's own supply. So some bridging must be used to make the adaptation. I have a copy of these instructions in Word format if you wish.

I just got back from Houston and I have not even taken the 2nd supply out of the box yet for a listen!...so it'll be some time before things get set up and I can make a report.

It sounds like you might be going down a different path with the Aria this will be an interesting comparison...I still have my Counterpoint SA2 all tube head amp designed by Mike Elliot and my ARC SP8 combination so I have some admiration for Elliot's designs....I guess I should get rid of all this extra stuff sometime. Is the Aria shipping?

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

Jafox, here it is: I think that thread has been deleted but I saved a copy in my computers note pad.

TUBES FOR AESTHEITX

Regarding the comments by Bud and Rayhall, the 6922 Sovtek would be my first change. For additional midrange and air, try the Siemens 6922 CCa or the Amperex US Military 7308 CEP. If either of these produce too much midrange presence, try the Mullard 6922 (gold pin). Realize, that when you upgrade to one of these higher resolution NOS 6922's you are listening with more intensity to the weaknesses of the remaining (original) tubes. You are judging the replacement, plus all that it exposes downstream. If after changing to the CCa or CEP, you find that there is too much "grit" in the sound, try swapping the 6SN-7 as described in my long post. After that, if you are feeling adventuresome, trade out the first stage 12AX7 tubes (Io only). Note, these 12AX7's are the ones I warned about, get TESTED, ultra noise tubes for this position. My first choice and the most beautiful sound is the Telefunken 12AX7. Other options are the RCA 5751, a US Military version of the 12AX7. The 5751 will alter the tonal balance somewhat, as it is not an exact replacement. There will be a slight loss in gain, with improved signal to noise and lower distortion. Overall, the sound will be a bit more on the dry side. One final suggestion would be the 12AX7 French Mazda. A good sample of this will produce significant improvements in high frequency transparency, especially compared to the Sovtek. However, the Mazda has not been without problems in my experience. The samples I received are not equally reliable or equally low noise. Some will play perfectly for many months while retaining their original "voice" while other samples will develop horrible microphonics and tube noise in as little as a week. This is a situation that could lead to disappointment with the Io, when in fact, the tubes are the culprit. Unfortunately, there must be some risk and experimentation within your own system to determine what is best.

Quick answer on tubes. If you have not swapped the EL 34 tubes in the power supplies you are in for a big surprise. Perhaps as big as the Telefunkens in the main unit.

I agree with what has been said about differences between regular and Signature models, the Signature has superior coupling caps which are a big improvement. Be sure you check the circuit board of the Io to insure the original (OEM Mills) resistors have been replaced with Roederstein. The Roederstein. are much quieter and better resolution. The defective Mills was the cause of all the uproar some years ago about "tube noise." It was defective resistors, NOT tube noise.

Jim White bought the most expensive, best quality, Military grade Mills resistors and they were bad. Caused him a lot of grief, I can only imagine what the US Government did to Mills over that deal.

As for different pin outs, I believe you have one older and one newer model power supply. The newer models have a SAFETY device. Remove the octal plug and the voltage is cut. Two places inside the Callisto and Io are 405 Volts and 610 Volts. The new plug is to protect users from being hurt.

VERY IMPORTANT !! If for any reason you wish to disconnect and re-connect the outboard power supply on Aesthetix Io or Callisto, you must wait 20 minutes before reattaching the umbilical cord.

The caps store energy and if you plug back to the main unit before the bleeder resistors bring the voltage down to safe level, you will blow the regulators. End result, no sound even though the tubes light up. Must be returned to the factory for repair unless you are very handy with a pencil solder gun and get instructions and parts from Jim White.

Very helpful post, Albert. Thank you! This has now gone into my permanent reference file on the Io.
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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.