Tube Amps Watts vs SS amp

Wow, what a thread!  OP, there is a ton of misinformation here.  Read some articles by experts to get an answer to your question.  I'm not an expert but I do know that with a tube amp, it isn't about the wattage, it's about the output transformers, and their bandwidth and power output.  

But, the real question you are asking is about those particular speakers with tube amps.  This is the right answer! 

05-07-2019 9:17amyogiboy2,778 postsYou are better off using that speaker with solid state. It is not an easy speaker to use with tubes!
http://www.thevintageknob.org/acoustic_research-AR9.html

As it happens, I have a Primaluna HP Integrated tube amp that I love, and think sounds fantastic with every speaker I've heard with it.  It puts out close to 100 watts with KT150 tubes.  

However, a local friend invited me over to listen to his AR9s.  He has them connected to vintage NAD mono blocks and they sound great in his room!  But, he is thinking about updating his amps to tubes.  His dealer brought over a Primaluna HP Integrated to listen with his speakers.  

It was not a good match.  I don't know the technical reason - it was definitely plenty of output power.  But the bass was kind of flabby and weak, and overall the speakers sounded flat and uninviting.  I was shocked.  This amp has never sounded so poorly with any speakers I've heard.  

The dealer wanted to bring something else along to listen to.  So, he connected an Anthem STR 200 wpc integrated, with room correction, and the speakers sounded much better.  Tight bass, smooth overall sound, and really good overall.  

Hooking the NADs back in the mix (I think they are 200 wpc) and the sound was very similar to the Anthem.  The speakers sound fantastic.  Deep, taut bass, wonderful midrange, just fantastic.  I was shocked that the SS both beat the PL.  The NAD and Anthem had very similar sound signatures, and worked very well with these speakers.  He decided to keep the NADs and save his $4500.  Instead he had the NADs refreshed with new caps, etc.

Point is, as pointed out by @yogiboy these speakers aren't a good match for tubes.  At least not Primaluna tubes, which I consider to be top notch equipment.

Soundermn 5-10-2019
His dealer brought over a Primaluna HP Integrated to listen with his [AR9] speakers.

It was not a good match. I don’t know the technical reason - it was definitely plenty of output power. But the bass was kind of flabby and weak, and overall the speakers sounded flat and uninviting. I was shocked. This amp has never sounded so poorly with any speakers I’ve heard.

I would expect that a major reason for that is the relatively high output impedance (and correspondingly, the relatively low damping factor) of that amp. Some PrimaLuna amps have output impedances that are much higher than average even for a tube amp. But even if (as appears to be the case) the amp in question was the PrimaLuna DiaLogue Premium HP model that was reviewed by Stereophile here, and even though JA noted in the measurement section of the review that "these impedances are significantly lower than with other PrimaLuna amplifiers I have measured," the amp’s damping factor (corresponding to the measured output impedances divided into the 4 or 8 ohm rating of the corresponding tap) is just slightly greater than 3!

In the first of my posts dated 5-8-2019 in this thread, in which as you also did I tried to focus on the OPs issue rather than on generalities about tubes vs. solid state, I had suggested to him that although I couldn’t find an impedance curve for the AR9 (which probably would have allowed a more precise judgment to be made), if he were to go to a tube amp it should be one having a damping factor of at least 8.

Regards,

-- Al

The tubes vs SS discussion should focus more on the type of music one prefers rather than the technical merits of each amp. I have multiple tube and SS amps that I interchange frequently. If you primarily listen to Jazz, voice, acoustic music of any kind there is nothing better than a quality tube amp.

The only time I would caution someone about moving toward tubes is if they primarily / exclusively listen to rock & roll at higher volumes. i don’t feel the benefits of tubes are realized in that case.

This is one of the more common myths in audio- that somehow, tubes or transistors (or loudspeakers) have some sort of taste or are better somehow at a certain genre of music. This idea is entirely false- what makes an amplifier or speaker good at one genre is precisely what will make it good at an entirely different genre. IOW an amplifier that is 'best' at rock will also be 'best' at everything else (whatever 'best' means...).