Primaluna Prologue One power tube rolling

I was going to suggest you try Telefunken 12AX7's but the Amperex are very similar (BTW, you don't HAVE to buy "Bugle Boys". All the Amperex/Holland tubes are the same, and they made them for a multitude of other brands/manufacturers: Hewlett Packard, Eico, Fisher, Electrohome, even Mullard -- if you look on Ebay, you'll see what I mean)

If you really want a big (and pleasant) surprise get some NOS (ca. 1958) RCA longplate, blackplates. The best 12AX7 I've heard, and maybe the best 12AX7 ever made (see discussions on AA.)
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FWIW, I use EI 12AX7A Elites w/grey plates very similar to Tele's and combined with SED EL34's produces a very smooth, reasonably detailed sound. Personally I'd save my long green type NOS's for more critical applications. But, if you've got extra dough, what the heck! :-)

I have the Prima Luna 2 integrated and Prima Luna 5 power amps. When I upgraded preamp tubes, Kevin Deal (Upscale owners) suggested NOS 12AU7 Sylvanias and 12AX7 Mullards. Excellent upgrade.

As for the power tubes, it is recommended to only use the EL-34 with the P1 (look at Upscale Audio's web-site). The P2 supports tube rolling.

Regards, Rich

Any suggestions on tube replacment for the Art Channel Pro...Thanks

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!