Replace 12AU7 with 6SN7 ?

Hello Guys !
I own Ayon Triton (integrated, but use only the Power section) with 6 12AU7 an 8 KT88.
I read in some threads that the 12AU7 can be easily replaced by 6SN7 (which I have 4 of them and enjoy in my Preamp).
This to be done by a "socket converter" (available on eBay) which internally makes the required wiring for the filaments to allow the replacement.
The reported results were positive.
I asked the manufacturer the same question and the answer was "straight forward", "quote":

DO not use 6SN7 or any others as the original types are. IMPORTANT – otherwise your amp will be destroyed.

Does anybody have any experience with replacing drivers like 12AU7 to 6SN7 in Pre or Power ?

The two tubes are based on the same tooling. A 12AU7s is exactly half the plate structure of a 6SN7. They have the same gain and bias in a similar fashion.

It is also double the filament current. It is probably that fact that might stop you trying something like this. So you should check with the manufacturer of the amp to see if there is any extra filament current capacity. With 4 6SN7s you will need 1.2 amps extra.
You also have know what the filament voltage is as well as the current. The 12AU7 can run on either 12.6V or 6.3V. The 6SN7 is a 6.3V tube. If running off 12.6V in your amp the 6SN7 is not interchangeable.
If the other way around, the 12AU7 can usually be used in place of the 6SN7. We design our Purity Audio preamps to use either tube., but again., they were designed this way.
I would go by what the manufacturer says. They know best what tubes can and cannot be used in their products.