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View Full Version : KT-66 in place of 6L6's

hackenfort
03-03-2008, 11:08 AM
I have a couple of sets of Tung Sol KT-66's I got from a friend. He tells me they can be used in 6L6 applications

I thinking of changing out a quad of 6V6's in a Fuch's 30 for a pair of 6L6's, can I use the KT-66 safely in the amp.
mcdes
03-04-2008, 03:28 AM
im not 100%, but if you go to www.kcanostubes.com (http://www.kcanostubes.com) it has a list of tubes and the kt66's are bunched in the same catagory as the 6l6's so it would indicate yes, but ask an expert first to make sure,they are only an email away.
BLC
03-04-2008, 08:20 AM
Yes, the KT66 is a kinkless version of the 6L6.
redtoploader
03-04-2008, 09:09 AM
They do draw more heater current though.
Kiwi
03-04-2008, 09:17 AM
My limited knowledge of the topic is this: First check with the technically skilled folks to determine if your transformer can safely supply the extra heater current that KT66s draw.

If so, then yes, it's a replacement for 6L6s. Not sure what else you'll need to do to replace 6V6s, though - again, check with an expert.

=K
VanR
03-04-2008, 09:43 AM
They do draw more heater current though.

Yeah something like .5 mA more per tube.
6L6=.9
KT66=1.4 I believe

EDIT actually Duncan says 1.27mA
ScottR
03-04-2008, 09:51 AM
why not PM/email Andy Fuchs and ask him? He's on here alot
Blue Strat
03-04-2008, 10:07 AM
why not PM/email Andy Fuchs and ask him? He's on here alot

Excellent idea! The amp designer is the only person who can tell you whether or not the amp and transformers can handle he extra heater requirements for the tubes.
hackenfort
03-05-2008, 05:32 AM
Thanks for the info, I did write Fuch's Audo, they responded quick stated that they would work fine
billyguitar
03-05-2008, 01:45 PM
Back when Groove Tube released their KT66 about 10 years ago, I was using a '57 Bassman that I was running cathode bias. I ordered the KT66s and put them in the amp. I checked to see that the PT was still supplying adequate voltage, and it was. I didn't care for the sound and went back to 5881s.
The worst part was the tube grippers wouldn't open far enough to hold the KT66s, so I had to take them off while I had those tubes in there. The sockets gripped tight enough that the tubes never came loose.
If your amp has the springy steel tube grippers I would bother with changing the tubes.