cryod tube vs non-cryod tube

I just recently tried some el34 SED ( not Svetlana ) cryo quads and the difference is deffinetly there. At least for my system . If I was to put a percentage maybe 10% better. The difference I found was refinement all notes were crisper and had better definition ( not brighter ) in the highs, with the mids bieng a touch more organic ( a touch more meat on the bone ). And the lows didn't seem any difference whatsoever ( that I noticed ).
I will however by more of the same ,so its enough for me to re-buy and sheck out the extra cost.. This is only one situation and one tube type! I can't vouch for any others However, I just placed an order for 2 other pairs.1 Pair 12bh7a GE cryo'd and 1 pair of EI 12ax7 cryo tubes.I hope they work as well as the others...Not sure if that helps or not....

There seems to be pretty good evidence that cryo treating tubes change their sound. I've heard tubes that were improved and some that were absolutely made worse.

Cryo treating new production tubes is not much risk money wise, but I would be hesitant to treat rare, expensive NOS tubes such as Telefunken or Siemens 9 pin design.

Good that Thorman got positive results.

If anyone has cryo treated NOS Euro tubes (like Tele's), I would love to know the results. If possible, discuss the equipment that benefited and test conditions. In my opinion, the best possible world would begin with a matched quad, thoroughly listening to each pair before and after cryo treatment.

I guess from what i am seeing a lot is some sellars are cryo-ing " new production tubes" where there isn't that much risk ( as Albert mentioned ) to either party involved. For me buying a cryo quad of el34 SED at $150 -$175 a quad is better than 300-500 quad of nos el34 tubes. Being the Cryo quad to me is/was better it was worth the risk. I also think ( as mentioned ) not all tubes sound better cryo'd ,and thats why you see sellers carrying only certain brands and types to be cryo'd and logocilly ( i hope ) the ones being cryo'd should be the tubes that work well with the process...

one would be a lot colder than the other....