Thanks Al. Would you kindly clarify my understanding of the Voltage and Power Paradigm area just one more time.
At least with my tube gear, ARC publishes so-called output regulation stats. In the case of both the Ref 150 and VS-115, output regulation off the 8 ohm tap is +/- .8 db and probably 60% of that number off the 4 ohm tap. See Stereophile and Soundstage bench test reports.
Perhaps I am misinterpreting what the term "output regulation" means. So please help me here. Based on the explanations provided in the two magazines, I gather that output regulation relates to how closely a tube amplifier's voltage output will vary so that the amount of power (watts) presented to the speaker will correspond to the magnitude of the input signal, thus compensating for varying speaker impedances which change as a function of FR. In short, if impedance increases, voltage will also increase. This in turn will increase current. All of this is accomplished through NF.
As I understand the Voltage Paradigm, SS amps generally maintain constant voltage and increase or decrease power in response to speaker impedance changes. But here again, if a SS amp is asked to feed current into a high impedance segment of the speaker's FR spectrum, somehow the amp must increase its current output or else power (watts) will decrease. Here again, I would think that NF would throttle up or down as the case may be the amount of the amp's gain in order to compensate for these variations.
I surmise that since Voltage Paradigm amps naturally increase power in low impedance loads, it is easier for the SS amp to deliver current and ultimately power into the bass regions. In contrast, if presented with a high impedance segment of a speaker's FR spectrum, the amp will need to deliver much more current in order to "power" its way through the speaker's impedance mountain, and may choke. Again this is where NF comes into play ... I think.
If I am tracking so far, what I don't understand is how a so called zero NF amp (tube or SS) can properly respond to impedance values which change as a function of FR in order to maintain constant power through a speaker's FR spectrum. I would have guessed that some type of NF, either global or local would be needed. It would seem that the only way to avoid NF is to use a speaker that has extremely flat impedance curves and phase angles.
Btw, I was reading some of the tech data on the Ref 150. Can't say I understand it, but from what I gather, ARC has somehow directly coupled the power tubes to the output trannies in order to regulate power output. I don't know if this is just another term for local feedback, but that's as much as I understand. I recall ARC used the term partial cathode following, or something like that.
Sorry for getting back into the tech stuff again, but all of this touches on the OP's question and the area is confusing, albeit interesting, to this lay person.
At least with my tube gear, ARC publishes so-called output regulation stats. In the case of both the Ref 150 and VS-115, output regulation off the 8 ohm tap is +/- .8 db and probably 60% of that number off the 4 ohm tap. See Stereophile and Soundstage bench test reports.
Perhaps I am misinterpreting what the term "output regulation" means. So please help me here. Based on the explanations provided in the two magazines, I gather that output regulation relates to how closely a tube amplifier's voltage output will vary so that the amount of power (watts) presented to the speaker will correspond to the magnitude of the input signal, thus compensating for varying speaker impedances which change as a function of FR. In short, if impedance increases, voltage will also increase. This in turn will increase current. All of this is accomplished through NF.
As I understand the Voltage Paradigm, SS amps generally maintain constant voltage and increase or decrease power in response to speaker impedance changes. But here again, if a SS amp is asked to feed current into a high impedance segment of the speaker's FR spectrum, somehow the amp must increase its current output or else power (watts) will decrease. Here again, I would think that NF would throttle up or down as the case may be the amount of the amp's gain in order to compensate for these variations.
I surmise that since Voltage Paradigm amps naturally increase power in low impedance loads, it is easier for the SS amp to deliver current and ultimately power into the bass regions. In contrast, if presented with a high impedance segment of a speaker's FR spectrum, the amp will need to deliver much more current in order to "power" its way through the speaker's impedance mountain, and may choke. Again this is where NF comes into play ... I think.
If I am tracking so far, what I don't understand is how a so called zero NF amp (tube or SS) can properly respond to impedance values which change as a function of FR in order to maintain constant power through a speaker's FR spectrum. I would have guessed that some type of NF, either global or local would be needed. It would seem that the only way to avoid NF is to use a speaker that has extremely flat impedance curves and phase angles.
Btw, I was reading some of the tech data on the Ref 150. Can't say I understand it, but from what I gather, ARC has somehow directly coupled the power tubes to the output trannies in order to regulate power output. I don't know if this is just another term for local feedback, but that's as much as I understand. I recall ARC used the term partial cathode following, or something like that.
Sorry for getting back into the tech stuff again, but all of this touches on the OP's question and the area is confusing, albeit interesting, to this lay person.