Double down, good or bad?

Unsound, we got a Golden Ear Award for our MA-1 driving a set of Apogees. This is a zero-feedback tube amp BTW.

Kirkus, its clear to me that your perspective is that of the Voltage Paradigm. As to papers on the subject, one was written by one of the designers at EV. The way tube amp manufacturers were getting their 'output impedance' down was by adding feedback- to the detriment of the resulting sound quality. The HK Citation 2 is a good example- a fair amount of feedback, used to reduce the distortion imposed by the AB pentode-based transformer-coupled output section. Despite that though, the amplifier fails to double power as the load impedance is halved. And we are not talking about clipping!!

clipping power is precisely what this thread, and "doubling-down" is all about. What I'm confused about is why you seem to be discussing clipping-power specifications and output-impedance specifications as if they're interchangable . . . or at least a common debate. They're not.

I am not discussing clipping at all, nor do I see clipping power as interchangeable with output impedance- no idea where you got that.

FWIW the 'Grand Conspiracy' thing you mention seems to me an example of adding meaning where none existed prior. All I am pointing out is what is causing the tube/transistor debate, the objective/subjective debate and the equipment matching conversation- they are all the same thing. There is a secondary conversation regarding the rules of human hearing/perception, wherein I contend that it is important to understand those rules and adhere to them as design principles. FWIW, that, for the most part, is not happening in audio.

Ralph, as I said, "it would take a hell of a tube amp...":-) Now if they were Scintillas, I'll recant my earlier post.

Unsound, I've heard a set of our MA-1s driving the old Full Ranges, which were one ohm (we used a set of autoformers that had one ohm taps). There is an old TAS review which mentions that from the early 90s as the speakers were owned by a TAS reveiwer.

Seems to me Paul Bolin used Duetta Signatures.

Best Thanksgiving and holiday wishes to all . . .

I am not discussing clipping at all, nor do I see clipping power as interchangeable with output impedance- no idea where you got that.

Atmasphere, here's where I got that . . . quoting from your "white paper" that started this whole thread:

Let's say you have a high quality 150/channel transistor amp. 150 watts into 8 ohms, a reasonable amount of power, but if you have a four Ohm speaker its 300 watts. Nice. Into 2 Ohms, if the amp doesn't blow up or current limit, 600 watts. So what does the amp produce driving 16 Ohms? 75 watts. Into 32 Ohms its only 35 watts! . . .

. . . This is what the right OTL can do into these impedances: 150 watts into 8 ohms, 145 into four (less than 1/2db difference), about 80 watts into 2 ohms, but into 16 we have 149 watts, into 32 ohms 145 watts . . .

Are you not, in all the wattages above, referring to the maximum power available, BEFORE CLIPPING, into various resistive load impedances? If not, to what are you referring? And from these specifications, you conclude:

Thus there is no way that a transistor amp can be described as linear if it is subject to these problems and that is one of the reasons why transistor amps produce so many amusical colorations. The reason has to do with the vanishingly small output impedance of the transistor amp

In your Power Paradigm "white paper", the same conclusions are made:

Let's say you have a high quality 150/channel transistor amp. 150 watts into 8 ohms, a reasonable amount of power, but if you have a four Ohm speaker its 300 watts. Nice. Into 2 Ohms, if the amp doesn't blow up or current limit, 600 watts. So what does the amp produce driving 16 Ohms? 75 watts. Into 32 Ohms its only 35 watts! This could result in serious problems were the speaker a typical electrostatic, where such impedances are common in the bass frequencies. This explains why transistor amplifiers are usually such a poor match for electrostatic speakers.

No, these power ratings say absolutely NOTHING as to why an amplifier may be a good or a poor match for an electrostatic speaker. Or do you mean output impedance here as well?
Can you not see that you use the concepts of maximum clipping power and output impedance interchangibly, or you feel that one is an accurate indication of the other?

Kirkus, its clear to me that your perspective is that of the Voltage Paradigm

Actually, I don't feel personally polarized on any of these issues . . . I find it far more interesting to try to work to understand the actual correlations between circuit design, measured performance, and perceived quality of sound reproduction. And to this end, it seems obvious to me that factors such as output impedance, maximum power vs. load impedance, type of feedback employed, and circuit topology are best considered and analyzed individually, rather than as a group or belief system.

Ralph & Kirk,

I think that the confusion (or lack thereof) between power at the clipping point and output impedance comes down to what I said in my post dated 11/24. It is important to clearly maintain a distinction, in discussions such as we have in this thread, between doubling down of an amplifier's RATED power output into 4 ohms vs. 8 ohms (which is what this thread was originally about, and which amplifiers having very low output impedance may or may not be able to do), and the fact that ANY amplifier having very low output impedance WILL deliver double the power into a 4 ohm speaker impedance vs. an 8 ohm speaker impedance, provided that it is not driven to the point where its output is limited by clipping or other factors.

Best regards,
-- Al