Using different tube types in Ampeg V-4

Hello there...

I have an early seventies Ampeg V-4 head. It used to use 7027 power tubes, but upon retubing, I had a local tech install KT-88's instead. My question is...can I now put in 6550/6L6 tubes, as I've heard that they are essentially the same tube as the KT-88, with tonal and construction variations, of course. I'm looking at tubes on Ebay and online stores, and I'm hoping to have the option of purchasing different types of tubes. Also, how important is it to use a matched set of tubes? Can I just plunk the new tubes in and go, or do I have to perform some kind of a check on the amp?

Thanks for your time, -Cole

I've heard of folk changing out tubes after a few years because the amp has lost some brightness....and even swapping the tubes for different varieties, although I've never done it myself. My guess is that it would not be a dramatic difference unless the tube had completely different input/output properties, but YMMV. I would ask a pro-tech.

__________________
THIS SPACE FOR RENT

The KT-88 and 6550 are pretty much the same tube, but the KT-88 is suppose to be voiced better than the 6550 which was more of an industrial tube. I just picker up a 1980 Marshall JMP 50 2204 which has 6L6's in it and is also why i'm here looking for options on other tubes. To put it nicely the 6L6's in an amp made for 6550/KT-88 sounds like pooh. I'm looking for a NOS 6550a set to put in and get it back to origional. Power tube should always be matched so the tubes can be biased correctly. Hope this helps.

KT88 is same as 6l6, the quality is high. but it is expensive. sometime it used in Hi-Fi.