[g0ldl10n]

I’m using two, just like I do with the 6J5’s.

Do you have another amp you can run them in without adapters? I also purchased a quad from that seller 3 or 4 months back and all 4 tubes tested as advertised, and ive ran them with no problems in my amps. If you have another circuit you can try them in without adapters and they still seem to cause issues, id contact seller for replacements, otherwise, we know the issue is isolated to either the adapter or amp, but likely adapter if the amp runs without issue using other tubes.

 

[mordy]

I’m using two, just like I do with the 6J5’s.

I use socket savers in all sockets and they lower the temperature of the chassis. In addition, I use two inexpensive 4”USB powered fans - one blowing on the transformer and one blowing on the tubes.
Usually I measure the temperature on the transformer housing which tends to get the hottest. The socket savers and fans lower the chassis temperature at least 10-15C and the transformer housing usually does not exceed 45C, even on a hot summer day.
Anything over 80C is dangerous for the electronics.

 

[bigjako]

My concern is just that the 6S2S run much hotter than the 6J5s or 6C5Gs do, all else being equal. @g0ldl10n I don't have another amount that I can run them directly in, but I can try the quad in my HA-300, though based on my initial experience with them I'm somewhat hesitant to do so. I may try the other pair in the quad and see if get similar levels of heat with that pair, first.

 

[g0ldl10n]

My concern is just that the 6S2S run much hotter than the 6J5s or 6C5Gs do, all else being equal. @g0ldl10n I don't have another amount that I can run them directly in, but I can try the quad in my HA-300, though based on my initial experience with them I'm somewhat hesitant to do so. I may try the other pair in the quad and see if get similar levels of heat with that pair, first.

Well, if as you said all things being equal other 6J5 types run considerably cooler, and 6S2S run hot enough to cause concern where normally there is none, does seem quite odd - I have quite the stash of these 6S2S tubes (some of my favorites tbh) and have never experienced such behavior from them.

I do wonder if you were to take infrared thermal readings how much higher they would be from the other 6J5 types - that would give us more of an idea if for some reason they just run a bit hotter, but not to a level of concern, but just guessing here. Dont do anything that you feel might damage your other amp though.