Using different power tubes in the Mark V

[spawnofthesith]

Hey, I was wondering if it was possible to run powertubes besides 6l6s and el34s in the mark v. I guess the two most important questions would be, 1) would KT tubes even fit with the spacing in there, and 2) I would assume that KT77s would be safe to run with the bias set to el34, but how about others like KT88s? To operate safely I would assume you would need to swap some resistors right? So I guess bottom line, anyone tried experimenting with different power tubes at all, if its even possible?

 

[blazer986]

I emailed eurotubes a few weeks back about running a quad of 6v6's and got the following response:

"Unfortunately the bias is simply too hot to run a straight quad of 6V6’s in any of the modes. It’s really the inside two sockets that are the culprit. They run much hotter because of the simulclass layout.

We have had success running an integrated setup with a pair of the JJ 6V6’s in the inside two sockets along with a pair of the JJ KT77’s in the outer sockets. This setup can be run in the EL34 mode and it sounds really good."

Given that response I would assume that running KT77s would be fine in el34 mode. You may want to send them a message, they are pretty big into KT66s and KT88s. I bet they could give you a little more insight.