Thoughts on Tube vs SS amplification for Sony SS AR1s

BTW I know the Luxman is rated at 20 watts. However it is rated at  14 w at 4 ohm load. The Luxman produces its lowest power right in the rsgion where the Sony actually dips even lower to 2.7 ohm!!! So one would expect less than the 14 watts at this very low level. Fascinating outcome with this amplifier.
Charles

atmasphere,
Thanks for your response. In light of the excellent sound quality sfmorris described with the Luxman and Sony pairing, your explanation makes considerable sense. One can’t help but notice the contrast to what George and erik_squires concluded per citing the Stereophile review test measurement results of the Sony speakers. I can understand their respective responses given the test bench numbers. 

Specifically the impedance behavior in the bass and lower midrange (Sub 3 ohm and steep phase angles) frequencies. You’d certainly predict the high current Accuphase to trounce the Luxman. This was far from the case. This has been a very insightful thread. Thank you sfmorris for sharing your very interesting listening experiences.

@atmosphere thank you for your informed comments as an experienced electrical engineer and manufacturer of highly regarded audio components.
Charles

atmasphere,
You have more knowledge and experience in this realm than I. If you say that the need for high current is "overblown" I’m sure you have the evidence to substantiate that position. It’s just that the need for high current is nearly axiomatic by many posters on this forum when discussing driving speakers such as the ’challenging ’ Sony SS AR1. Purely out of curiosity and to gain further knowledge my question simply is how does the 14 watt (Tubed) Luxman accomplish this feat?

Earlier in this thread several posters said sfmorris didn't know what he's missing with his Sony's until heard driven by a powerful high current  solid state amplifier.  Ironically they were right but not as they would have  expected.. 
Charles 

atmasphere,
I understand your point and the significant importance of the output transformer. In threads discussing tube amplifiers I consistently advocate the undeniable need for high quality transformers if one is seeking excellent sound quality from tube powered amplifiers. 

My point is if you look at the Sony SS AR1 speaker measurements they are as George and others have rightly noted, a ’challenging ’ speaker load given its impedance curve and phase angle characteristics. Armed with this knowledge the last thing you’d recommend is a 14 watt tube amplifier.

The low watt tube Luxman is doing something obviously good that can’t be surmised from assessing its measurements or those of the Sony. So again, how is this gross mismatch (Via documented measurements for both products) able to produce such high quality sound? Something is occurring that isn’t accounted for with supporting test bench numbers.
Charles

No doubt that damping factor (DF) is an important variable that affects and influences the performance of an amplifier and speaker pairing. I have to imagine there are other factors at play as well. By every reasonable and trusted test bench metric the Accuphase should ’clearly’ be a far more compatible  matching amplifier for these Sony speakers than the Luxman.

Assuming that the Accuphase isn’t defective in some manner, one has to ask what’s going on? How is it possible/explainable the tubed 14 watt (Into 4 ohms) Luxman so convincingly sounds better driving the current demanding difficult impedance Sony than the (Much) higher power/current Accuphase transistor amplifier?

Can it all be written off as merely subjective preference? If so it’s fascinating that this can occur in light of test bench measurements that would suggest a far different outcome. One has to ponder that there are things listeners can clearly hear that (At least for now) aren’t being measured or maybe can’t be measured.
Charles

The Accuphase e650 specs 30 watt class A at 8 ohms
60 watts at 4 ohms
120 watts at 2 ohms.

The Marantz is (claims)  300 watts at 8 ohms
600 watts at 4 ohms
No specs given for 2 ohms.

But what can you surmise from these listed specs ? 
The Luxman could very well be single digit watts into 2 ohms yet it sounds very good to sfmorris.
The Parasound Halo amplifier George recommended earlier is readily available and reasonable cost ( And probably can be gotten with a return clause). 

Curious how the Parasound Halo with ample current (per George)  would fare against the Luxman head to head driving the Sony's. All that matters is which would sound better to sfmorris. Superior sound is the pertinent objective. 
Charles 

George, 
Again from a pure technical analysis you are absolutely right in referring to the Sony speaker as a "pig of a speaker" given its extremely demanding need for current delivery.  How in the world does the low watt tube Luxman produce wonderful sound paired with this very difficult speaker load?  Can it be explained by the assumption that the Luxman has superb quality output transformers and power supply section or is it more complex than that? Really intriguing how this is pulled off.
Charles 

sfmorris,
In your opening post you wondered if you don’t know what you’re missing regarding the sound quality (SQ) of your Sony speakers. According to George and jsautter the answer is a resounding yes! You don’t know what you’re missing. George provided legitimate technical test measurements to make a very strong case.

Based on the Stereophile Sony  measurements your Luxman tube amplifier is weakest ( decreased power of 14 watts/4  ohms i.e. lower speaker impedances) right in the range where the Sony speaker is most demanding of an amplifier.  . That’s quite the dichotomy it would seem. What’s fascinating is despite clear technical evidence that the Luxman should fail in miserable fashion, it sounds terrific according to you. I don’t doubt what you hear.

How is this apparent contradiction possible? How can what one hears be so contrary to what verified measurements would predict? sfmorris it would be undeniably interesting if you could get an amplifier (or very similar type ) suggested by George and compare directly to the 14 watt Luxman.

Would the technically corrdct/preferred powerful high current transistor amplifier expose shortcomings of the Luxman while effortlessly driving the Sony’s to new heights of sonic capability? Or would those 14 tube watts continue to impressively make beautiful music and possibly outshine the more powerful competitor? This listening comparison would be very insightful and informative.
Charles