What are the most powerful Pure Class A Amplifiers ever made?
- Thread starter caesar
- Start date
Most I see top out in the 100w range. Even 200 watters are very rare for all class A. Twin power line inlets the giveaway. Boulder is the only one I can think of that claims true class A all the way, not sliding into AB somewhere along the line. Was the BAT VK-600 pure class A? Those were twin PC affairs.
Interesting & I am not doubting you.
Does any amplifier deliver 300 w REAL class A from NON standard AC [or DC] installation /// 220v, 440v, 3 phase, High Voltage DC generator ?????
Thank you,
zz
Nelson Pass makes great amplifiers.
I read the manual on the XS300. I initially copied 2 paragraphs, but deleted them due to ?copyright issues? - maybe.
The pdf manual is easy to download & read.
Near the end the meter is mentioned & and I will quote here: "when the output current of the amplifier exceeds the Class A bias
setting, you will see the needle bounce upwards."
"exceeds the Class A bias"
Great amps / I am not solid state technical enough to continue.
zz.
Yes, it is my understanding that these Pass amp ratings are for Class A power before they go into Class A/B. My XA160.5 for instance has 160 watts of Class A into an 8 ohm load and 320 watts of Class A into a 4 ohm load. But they have much more additional power once they leave Class A. The XA30.5 was measured by Stereophile and found to have something like 130 watts of total power in Class AB, but at least 30 watts of Class A into 8 ohms. I can't remember the exact number, but the rating was found to be very conservative.
The XA.5, XA.8 and XS series each deliver their full rated power as Class A into 8 ohms, double that into 4 ohms. They have an additional 6 dB of A/B power (or slightly more) available above that rating.
someone once told me that typically most pure Class A amps are pure Class A into their 8ohms loads, and will double watts into a 4ohm load, but the amount that is still Pure Class A actually HALVES...so a 100watt/channel Class A amp will be 200watts into 4ohms, but 50 watts of that is Class A.
I am NO techie, so thanks for any clarifications here.
Why not? Theoretical class A efficiency at nominal impedance is 50%. Even if you degrade it by 20% almost any standard AC installations can supply 750 watts. But it will heat a lot.
Yes, the KRS 200. Some people used 4 mono amps to power the Apogee Scintilla - almost 1000 lbs of amplifiers!
Yes, it is like that. The only correction I would do to the sentence is " and can probably double watts into a 4 ohm load" .
Quick note on Boulder (and Krell). They now have dynamic biasing so that if you are playing at low volumes, they don't suck out the huge currents that standard class A uses. They have an algorithm that then has to anticipate when to dial this up or down.
Others with more technical background can answer with science. All I can say is my 160watt pure class a dual mono amp weighs 176lbs as it is. That's big and heavy enough! And with 95db speakers, I seriously doubt I am leaving class a at any time. That said, I could see where some might wish for more depending on room size and speakers.
Similar threads
 | Steve Williams Site Founder | Site Owner | Administrator |  | Ron Resnick Site Owner | Administrator |  | Julian (The Fixer) Website Build | Marketing Managersing |