Rolling KT150s in Primaluna hp integrated

jb
I totally get your excitement, I have been in the same boat with the PL HP Integrated and rolling the stock PL pre 12AU7s to NOS Mullards/NOS Brimars and the EL34--> KT88s. 

As you said, swapping out the first 2-4 pre tubes makes critical sound changes, for the better for sure. I have floor standing speakers, so my next move would be to move up to the KT120s and keep the Mullards in the first two inner pole positions of the pre tubes, followed by the Brimars, then the 2 stock tubes. Since the KT120s would spread out its energy toward the highs/low, the Mullards would fill in the mids nicely.

But alas, I live in a place without AC that gets so hot in the summer that tubes are now "temperature-prohibitive". I will be having to sell the HP integrated to go to Class D ... scary.

1graber2

Same here.  I am planning to get a PL HP w/KT150 but my concern is the temperature.  Summer in Los Angeles can be as high as 107F.  Can you guys share your experience on how hot the amp gets with those tubes?  Many thanks!

Can you guys share your experience on how hot the amp gets with those tubes?  Many thanks!

From the EL34's 6amp to the KT150's 8amps there will be substantial heater temperature dissipation, if the heater voltage stays at 6.3v and doesn't sag under the extra load that the 150's will put on the filament supply.

Cheers George  

There is no issue with the load imposed by the 150s in this amp. The manufacturer endorses after it did significant testing before doing so.

The power transforners on this amp are massive. That’s why it weighs 60 plus lbs.

With respect to room heating, I live in Chicago so we see all sorts of temperatures from 10 below to 95 to 00 every year. Smaller EL 34 Tubes in their substitutes do not cause too much significant heating in the summer months. But it is definitely noticeable. I went the route of buying a class D amplifier last summer and moving the prima Luna to the basement.

Let me just say that after six months, I sold the class D amplifier and brought the prima Luna back up. I don’t know when I’m going to do this summer. The sound is to to die for so I’m just not sure. I might not care s out the heat. Or, I’ll buy a nice used integrated.

I didn’t have the opportunity to audition all different makes of class D amps. But the one that I did evaluate was not able to impress me long-term.

"The sound is to die for", different amp(s), same result, Jbhiller, I agree. The KT-150 tube is the difference. Temperature effect would depend on many factors, room size, amps, local, season, etc not withstanding George's technical considerations.