Pass Labs INT 60 VS. Primaluna Dialogue Premium HP VS. Arcam A49

Scott, thanks for your inputs. Here is a corrected link to Mr. Potis’ review of the Carissa:

http://www.6moons.com/audioreviews/artaudio2/carissa.html

Interestingly, it is described in the review as being a "no negative feedback" design, but having an output impedance of 1.2 ohms, which is on the low side for a zero negative feedback SET design. While at least in its present version it is described at the Art Audio UK site as incorporating 9 db of feedback, which is a substantial amount, that would tend to reduce output impedance significantly. Both references, however, indicate that maximum power capability has been sacrificed somewhat in order to "double available current" in comparison with traditional designs.

All of these indications (1.2 ohms output impedance, 9 db of feedback, doubled current capability) are consistent with low output impedance, certainly in comparison with most SET designs, and in comparison with JA’s measurements of the PL Dialogue Premium, and I suspect also in comparison with the PL Dialogue Premium HP. (I would assume that the reference to a 10 ohm output impedance that is provided at the Art Audio UK website refers to optimal load impedance, rather than to amplifier output impedance).

In contrast, the interaction of an "unusually high output impedance," such as Scott described for his former 60 watt tube integrated, and a speaker impedance that is low in the bass region and higher at other frequencies, will produce exactly the results he described ("very weak lower mids and bass"), compared to the results most well designed solid state amps (and many other tube amps) would have provided.

BTW, I was one of those who suggested caution regarding the Cary tube amplifier in the thread Charles referred to. I did note in my post in that thread, however, that the output impedance of the Cary amp was unspecified, as was the corresponding damping factor (damping factor and output impedance are inversely proportional), and that measurements of those parameters did not appear to be available.

Also BTW, in saying all of this I’ll add that like several of those who have posted above I personally am firmly in the category of being a fan of tube power amps. But I am also not a risk-taker when it comes to questionable pairings.

Best regards,
-- Al

@almarg 

Thanks for correcting the link. For some reason I had a hard time posting it and did not know that it was not correct/working.

Cheers,

Scott

I own a number of amps all except one that I can think of are Tube Amps.  I am firmly committed to them but only with reasonable speakers .  I decide what reasonable is, somewhat arbitrarily .  If I owned Sashas, I would use solid state. 
That said I do own or I should say am trying to retrieve, two powerful tube amps.  A Jadis DA-60 with 8 KT-88 (Gold Lion), rated at 60 watts but that is not likely the true output which I believe is higher.  I also own a pair of Opera Consonance Cyber 800 monoblocks with 4X EH fat bottle 6CA7 each.  Rated at 78 watts. 
Still I wouldn't think they would be a good match , the Cyber 800s are truly exceptional for there pedigree, nonetheless, I just don't know?
Perhaps a cautious audition 
So to keep it related to this thread, I would choose the pass which I have heard and think is superb.

The best comparison to the Prima Luna is the INT 30. I'm an ex tube freak who finds class A to be a bit sweeter if paired correctly. My Accuphase E600 is noticeably sweeter than any tube amp I've heard though my Harbeth's.

The Pass Labs dealer says the INT 60 will work tremendously with my Sasha 1's. He says there will be a huge difference from my Arcam A49. The Arcam A49 has the power and is very good and my Arcam dealer says I would need to spend over 13K to really make a difference. My Primiluna Dialogue PREMIUM HP dealer says this tube amp will better the Arcam and the Pass Labs & will work incredibly well with the Sasha's. Since I have to order the units I have no way to try them out with the Sasha's. Wilson Audio believes the Primaluna Dislogue PREMIUM HP would work very well, as well as the Arcam & the Pass Labs.