Tube Amps Watts vs SS amp

wow lots of GOOD INFO, Thanks

Lots of bad info and misinformation too...

Atmasphere, thanx for the article. For certain humans are extraordinarily change resistant. That is an unusual perception for an engineer. Those that embrace change are the pioneers like Tesla, Ford, Musk and others less well known. Too bad non of them are politicians.
Under the power paradigm you want speakers of steady impedance and relatively high efficiency. How does Soundlabs achieve this with an electrostatic loudspeaker. My Acoustats drop perilously low at high frequencies. I had to put a1 ohm series resister on the primary to prevent my amps from overheating. I removed the stock transformer drive and put one large 1:100 Sowter transformer on them resulting in this behavior. Conversely I always shied away from McIntosh amplifiers because they used transformers. I am not sure how they use feedback but it would appear they applying the objectivity principle. I am sure you prefer not to make comments on other companies amplifiers but how do you think this affects their sound versus standard voltage driven SS amplifiers. My final question is, how do you keep your amps power driven without transformers. 
I have long forgotten what boxes sound like;-)

Atmasphere, one more series of questions. The Sensitivity measurement in db/1watt/1meter, is this measured with white noise? Does this really tell you how the speaker will perform with music? Is "music sensitivity"
frequency dependent. I roll off my speakers at 125 Hz 48 db/oct. My assumption has always been that the efficiency of the speaker increases because it would require less power to reach a certain volume than if I ran it full range. Is the correct or am I deluding myself? The sensitivity has not changed but efficiency increases?
The Soundlab Magestic 845 has a senstivity of 89db/1watt/1meter.
This means that it would take 128 watts to get to 110 db. This is the loudest playing music I would ever go. The MA 2 has sufficient power to do this. How would the MA 3 sound better. Some would argue that music being dynamic has peaks that go much higher than the steady state volume requiring much more power to handle without clipping.
Music obviously has peaks like the snap of a snare drum but are these peaks that much higher? The power required does increase
geometrically. The MA 3 will go about 4 db louder than the MA 2. Does this headroom make a difference?

In this particular case the 87 db spec is stated to be based on an input of 1 watt, rather than on an input of 2.83 volts. Also, as I mentioned in my previous post the brochure for the speaker states that an input of 8 watts results in an SPL of 96 db at 1 meter, which is consistent with 87 db/1 watt/1 meter. So if those numbers are accurate the efficiency is 87 db, rather than 84 db.

@almarg

Apparently it matters where you look. The specs I found stated 4 ohms and 87 dB Sensitivity; since the sensitivity spec is a voltage spec and not power, this translates to an efficiency as I stated. I’ve seen speaker manufacturers confuse efficiency and sensitivity before; is this one of those cases?

Under the power paradigm you want speakers of steady impedance and relatively high efficiency. How does Soundlabs achieve this with an electrostatic loudspeaker. My Acoustats drop perilously low at high frequencies.

@mijostyn Actually a steady impedance is not required of either paradigm. What is required is best put as the designer’s intention- and the behavior of the technology. In the case of ESLs, the impedance curve is based on a capacitance rather than a driver in a box (with its consequential resonance). On this account, ESLs have an impedance curve that essentially decreases as frequency increases. The Sound Lab for example is about 32 ohms in the bass but only 1.5-3.0 ohms (depending on the position of the Brilliance control) at 20KHz. The impedance curve of a box speaker maps out its efficiency with respect to frequency; with an ESL the efficiency remains constant despite its impedance.


One sign of a speaker that is a Power Paradigm device is that it will have controls in the crossover- like you see in the Sound Lab, but also like you see in vintage speakers like Altec, JBL, KLH and so on. These controls are not there to adjust the speaker to the room (although they are often used that way) they are there to adjust the speaker to the voltage response of the amplifier, which is an unknown. In the Voltage Paradigm the voltage response is a given; the idea was pioneered by MacIntosh and ElectroVoice in the late 1950s to assist with plug and play. The problem is to do so audible distortion in the form of brightness is usually introduced by the operation of the feedback loop in the amplifier, and one has to come to terms with the simple fact that no loudspeaker is actually flat in frequency response- so getting ’flat response’ is a bit of a red herring.


Add to that the fact that the ear/brain system interprets distortion as tonality (which is why we perceive the distortion added by feedback as brightness), often favoring it over actual frequency response, and you have a situation where you can often achieve greater neutrality without feedback. Crazy world, but we really can’t change how our ears perceive sound except by damaging them. So it seems pragmatic to come up with engineering solutions that take the human ear/brain hearing perceptual rules into account rather than ignoring them!