Hey guys, I thought I'd clear things up a little for you...
The ProLogue One along with the Four, Six, and new DiaLogue One are optimized around EL34 power tubes. However, you can also use 6L6GCs, KT66s, KT77s, 6CA7s, 6V6GTs, 7581s. We have had dozens of customers run 6L6GCs or KT66s with great results.
You can use KT88 & 6550 types too and they'll work just fine, however those tubes have higher dissipation, and require a slightly hotter bias to function optimally.
Since the ProLogue One, Four, Six, and DiaLogue One are optimized for the EL34, we do not recommend using KT88 types, but you can do so if you feel like experimenting.
Newbee, I am not sure exactly why you would experience what you did. I can say with confidence it was not the Adaptive AutoBias board. If it was, the problem would repeat itself, and typically would not take 12 hours to manifest. It could be one of the 6L6s had what we like to call a "hiccup" that may have manifested while playing, then dissipated once the tube cooled off.
Adaptive AutoBias is the main reason you can use a wide variety of power tubes. They don't need to be matched, and in fact, they don't even need to be the same tube type! You could have one EL34, one 6L6GC, one KT66, and one 6V6GT plugged into the ProLogue One, and Adaptive AutoBias will recognize the different tubes, and adjust itself accordingly so the amp is running at optimum levels. Now... it may not sound so good, but it will work!
This can be very helpful if you're having a little gathering and one EL34 craps out on you and all you have lying around are some 6L6s or KT88s.
Of course if you ever have concerns about whether or not a tube will work, feel free to shoot us an email and confirm. As with any piece of tube gear it's always better safe than sorry!
The ProLogue One along with the Four, Six, and new DiaLogue One are optimized around EL34 power tubes. However, you can also use 6L6GCs, KT66s, KT77s, 6CA7s, 6V6GTs, 7581s. We have had dozens of customers run 6L6GCs or KT66s with great results.
You can use KT88 & 6550 types too and they'll work just fine, however those tubes have higher dissipation, and require a slightly hotter bias to function optimally.
Since the ProLogue One, Four, Six, and DiaLogue One are optimized for the EL34, we do not recommend using KT88 types, but you can do so if you feel like experimenting.
Newbee, I am not sure exactly why you would experience what you did. I can say with confidence it was not the Adaptive AutoBias board. If it was, the problem would repeat itself, and typically would not take 12 hours to manifest. It could be one of the 6L6s had what we like to call a "hiccup" that may have manifested while playing, then dissipated once the tube cooled off.
Adaptive AutoBias is the main reason you can use a wide variety of power tubes. They don't need to be matched, and in fact, they don't even need to be the same tube type! You could have one EL34, one 6L6GC, one KT66, and one 6V6GT plugged into the ProLogue One, and Adaptive AutoBias will recognize the different tubes, and adjust itself accordingly so the amp is running at optimum levels. Now... it may not sound so good, but it will work!
This can be very helpful if you're having a little gathering and one EL34 craps out on you and all you have lying around are some 6L6s or KT88s.
Of course if you ever have concerns about whether or not a tube will work, feel free to shoot us an email and confirm. As with any piece of tube gear it's always better safe than sorry!