Rolling KT150s in Primaluna hp integrated

@georgehifi as you said, the bias can change the heat. that is why PrimaLuna has a "self-bias" to not run the tubes as hot. we can argue over specifics, but it is the essentially the same concept, of ultimately, how hard the tubes are run. The bias of any amp will effect the tube heat, not just PL. it is the manufacturers call for self-biased units, but the owners call if manually biased. In any case, it is true that tubes will live different number of hours, eg 5k vs10k, depending on the supportive electronics/bias adjustments.

@tubegroover @georgehifi . sending your USED tubes in to be cryo'ed may not show clear difference in sound. this is b/c "cryo'ing" tubes essentially hardens some metal structures of the tubes. these structures, metal pieces, etc will harden over time anyway with use. 

So there would be a bigger difference b/w 2 NEW sets of tubes, one Cryoed and one NON-cryoed. But if you are sending in used tubes for cryo'ing, I would ask:
how many hours do they have on them? what is their expected life span in the particular amp you are using? eg, if a used tube has 4000 hours on it, and the life expectancy is 5000 hours, then it will already have been "broken in", in terms of the metal structures hardening. Sending it in to be crayoned with 4k hours would not make a significant difference IMO. 

1graber2111 posts03-10-2018 5:44am@georgehifi as you said, the bias can change the heat.

Ah no, I said the main source of heat from tube amps is from the heaters/filament it's circuit/transformer, the bias whatever it is, contributes a small amount compared to that.
Cheers George

Guys, FYI, Christiaan Punter did a review of fitting KT150s to a PrimaLuna and then compared it to other amplifiers including the ARC Ref 75SE.  Interesting outcome.

http://www.hifi-advice.com/blog/review/analog-reviews/amplifier-reviews/primaluna-dialogue-premium-t...

They used the Wilson Watt/Puppy 8"s for this review.
This statement by the reviewer is wishful thinking.
" Although neither the Wilsons nor the Franco Serblin Accordo’s are particularly power-hungry"

Stereophile test on the WP8’s:
"However, and also like its predecessors, the WATT/Puppy 8’s impedance characteristic demands the use of an amplifier that can deliver generous amounts of current. There is a drop to 2.2 ohms at 77Hz where the most power is needed. (fig.1)"
https://www.stereophile.com/images/archivesart/607WILFIG01.jpg

Combine that 2.2ohm with the -phase angle, and it could go down even below 2ohms. And with the PL’s you’ve only got 2 tubes to drive each speaker.

Cheers George

Reviving an old thread as I’m considering this very upgrade. I notice many reference buying their KT150’s on eBay. Meanwhile Upscale passionately states that their tubes are somehow blessed with a veritable dose of unobtanium and are well worth the higher price. The junk discarded by others are ebay fodder, or some such. 
 

Considering their impressive cost, is there merit to spending extra for the Upscale touch or is it just marketing?  Currently looking at $155+ per tube.