I owned the Aesthetix Callisto Signature and Io non signature for 5+ years. The Signature update is not that big of a deal when it comes to parts updates. Caps updated to DynamicapsÂ….big deal! They were fine a decade ago but nothing special now. For a "Signature" product to use these as the top capacitor is questionable. And a handful of resistors in "ideal" locationsÂ….again, big deal. And the price markup for the parts "updates" is crazy.
The major improvement is to 86 all the Sovteks in these units and play a combination of Tele, Mullard and RCA. A non-sig unit with rolled tubes will easily destroy a signature unit with stock tubes. I suspect the same is for the Aesthetix digital gear.
It is very easy for Grannyring to spend a fraction of the Signature update and put in the same parts and achieve the same. I did this with the Io. In in fact, for the same cost, it is very easy to DIY to take the non-sig product beyond the Signature.
Having to "hear" an authentic Signature model to get the true Aesthetix magic is ridiculous.