Tube rolling for Aesthetix Io power supply

I see from previous posts that  NOS KT 66s are recommended for replacing the stock EL34s in the Aesthetix Io power supply. Are not the KT 77s a better fit for EL 34s ? Are they interchangeable ?
thnx in advance.

It's possible to use EL34, KT77 and KT66.   If I remember correctly a hole must be punched in the chassis top to clear the KT66.

Best (most accurate) sound is probably with the EL34, best of those in my experience is old, genuine Mullard. 

The KT77 Genelex is excellent and what I ran in my Aesthetix but there‘s a  Lot of difference in price.  For most folks the Mullaerd EL34 is by far the best value and a great overall match for Aesthetix sound.

The Genelex (MO Valve) KT66 is a more weighty and warmer sound so depending on your system, room acoustics and other tubes in the Aesthetix there are lots of variables.

By the way, the chassis punch to open the Aesthetix lid is expensive for a one time use.  I might be able to find specs on the one I used.  Other option is leave lid off but lethal voltages reside in the Aesthetix power supply, as most high end tube electronics :-).
Thanks Albert, as always your advice is very much appreciated. Leaving the cover off is not feasible for the reason given and besides I already have a stock of NOS Mullards (xf1s & 2s, with single & double o getters) so I´ll stick with these.

Hi ,

I have an Io with volume controls and two supplies. I use original Mullards in the Io. Tighter than with the original Electro Harmonix.

They test like new compared to another NOS Mullard for reference after being in for about 4 years.

I pull all the tubes in the Io and power supplies at least 2x  per year to  clean the pins and "very very lightly" condition them with deoxit. WOW.. you should try it along with the IEC connector  and fuses caps.

The 12AX7s in mine are NOS RCAs of which I bought several sleeves from ebay years ago. I routinely test and replace those as necessary but the NOS last for years as well.

I would not punch holes in the case unless I got a spare one.. not worth it IMO to devalue the piece. You can try the KT66s - I found them "rounder" sounding than the EL34s- I tried original GEC KT66s YMMV and all that.

Good Luck