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

Unsound, 
That's a fair point but I don't believe that Wilson would offer that advice in a generic manner for the sake of politeness and not wanting to offend. Given that they have used tube amplifiers during presentations and there's ample feedback from Shasha owners who've happily used tube amplifiers. 

I'm left to conclude that both tube and transistor power amplifiers can and have been used successfully.  As is always the case it is depends on what type of sound character and presentation a listener seeks. I'm well aware of the speaker's test measurements yet also recognize the very good outcomes attested to from the use of an appropriate tube amplifier in numerous systems. 

This and other forums are replete with experiences of happy Shasha/tube amplifier owners (and SS amplifier owners  as well).
Charles 

Charles1dad,  I'm not trying to make this a tube vs. ss debate, even many ss integrateds would be challanged by the sub 2 Ohm load coupled with a difficult phase angle. 

Oops, I meant to add..... We sometimes think that the greatest amount of care goes into show demonstrations, when in reality often times systems are cobbled together at the last minute from borrowing components from local dealers located near the shows.

Kenepeters, The only integrated on your short list that actually specs being capable is the T&A. I'm confident that there are a few more. I believe Dan Dagastino'd integrated might qualify.
I haven't heard  all of the vast amount of amps on the market. When I make a short list, I begin by eliminating those that could be technically compromised, and then choose the ones from that list based upon what I just plain like, and of course price/value.

I don’t doubt that some tube amps would do very well with this speaker. The ARC REF series would seem like good bets, for example, due to their combination of low output impedance (for a tube amp), robust power supplies, and other characteristics.

However, **if** the output impedance of the Dialogue Premium HP is not considerably lower than the output impedance of the non-HP version (as described in the Stereophile measurements I linked to earlier), and given the speaker’s impedance characteristics as shown in Stereophile’s measurements which Unsound linked to earlier (showing an impedance between 2 and 3 ohms for frequencies between about 60 Hz and 300 Hz, where a lot of music contains a lot of energy, while rising to considerably higher values in the mid-range and treble regions), the result of those impedance interactions **will** be weak bass and over-emphasized mids and highs, ***in comparison with the tonal balances that would result with many other tube amps and most solid state amps.*** The degree to which that effect on tonal balance occurs will be dependent on the output tap that is used and on whether triode or ultralinear mode is used. But it would be a significant effect in all of those cases (if, as I said, the amp’s output impedance is not considerably lower than that of the non-HP version).

That follows from basic EE circuit analysis principles, which of course cannot predict a lot about what we hear or don’t hear from our systems, but can certainly predict some things, including what I said in the preceding paragraph.

Whether or not the resulting sonics would be appealing to some listeners in some rooms is another matter, of course. But why take the risk, unless a meaningful and extended audition in familiar circumstances is possible? And even then, why invest the time that would be required for such an audition, when other candidates can always be found that would not have this issue?

And as Unsound said (rightly, IMO) in his recent posts:

What will work, and what will work best are different things.

When I make a short list, I begin by eliminating those that could be technically compromised....

Best regards,
-- Al