Double down, good or bad?

Kirkus, thank you for sharing your insight.

This is a very enightening thread. I have followed along as I used to be real SS die hard, considering even to delve into ultra ML or Classe stuff until I heard a pair of excellant tube amps that were designed to operate on 4 ohms, and drive low impedence speakers:

Push-pull mono output stages with new driver electronics for the output tubes. This all-new design improves the transient response with complex loads and reduces distortion - particularly when low impedance speakers are connected. Ideal for critical loudspeakers such as Martin Logan, Avalon, Audio Physik, Caldera, Isophon Vertigo and Europa.

Clearly, I can agree with Atmasphere on how a design is capable of perforimng such tasks as driving low impedance speakers, it is most likely the topology in that implementation that needs to be considered. My amps, the Octave MRE 130 are rated at 130, tested and reviewed at 140, but 100 watts into 8 ohms.

All I can say is with technology like that, I can drive easily a pair of B&W 800's in my 25x18.5 listening room with thunderous bass and more than enough volume to make it concert level. The addition of the so called "Super Black Box" and their promised benefits in bass control and 2-ohm stability. The Super Black Box has an additional 100 plus amps of current and capacitance. I am not sure how other companies would implement such a feature, perhaps larger power supplies, but this concept works with these amps.

I believe that that tube amp builders who design amps capable of driving low impedance speakers from the start are actually doing the audio community justice.



Ciao,
Audioquest4life

Audioquest4life:
I see a few posts back that you state the Magnepans are a difficult load to drive.
Not So. The impedance is pretty flat and at least for the 1.6s, the phase angle is moderate at worst. The only fly in the ointment is they seem to like current.
That being said, even my old Rotel RB1070 of 130x2 into 8 with NO 4ohm spec did well until pushed.

Stereophile measures phase / impedance but few manufacturers publish such data.

Magfan, I also find the Magnaplanars easy to drive.

Unsound, the TAS review using the Duettas did not use the autoformer, but in the case of the Full Ranges, without an output transformer of some sort, driving 1 ohm is difficult, even for transistors. Its not 'cheating'- its simply a tube amp that was able to do the job. The speaker otherwise is easy to drive.

Kirkus, I see now why we were not on the same page- I was referring only to my posts. You are right- the article is over-simplified. So I think we are really on the same page here. With regards to 'belief systems', what is happening in high end audio is tubes are effectively competing with transistors, and there are speakers (like the Wilson Watt/Puppy) that are more effectively driven by tubes than transistors and other speakers (like the B&W 802) that are more effectively driven by transistors.

People are constantly trying to mix the two technologies and in the process are flushing a lot of money down the loo.

The Paradigm paper seeks to expose why, and in the process also expose something that I regard as the Emperor's New Clothes- that aspect wherein products are made to look good on paper and ignore human hearing/perceptual rules; that whole thing that all of us are familiar with where the specs tell you nothing about how it sounds. IMO/IME we as an industry are measuring the wrong things, and there is little or no discussion about that!

I know of a neuro-scientist that has done studies of human hearing- he has found that when the audio playback system violates our perceptual rules, the processing of the sounds in the brain is actually handled in a completely different area!

Atmasphere,
Could you please elaborate a bit about the point in your last post where you say some speakers are more effectively driven by tubes and others by transistors. I do not see much written about this and am curious as to why. Thanks.