What amps are out there that are Class A, 50 wpc into 8 ohms?
This is NOT a buying advice question.
This is a purely theoretical question. A friend and I were trying to figure out what is available that is:
(a) Class A
(b) 50w into 8 ohms or better
My guess is that the answers will be Pass, Sugden, and then very very expensive things like Gryphon. I'm curious to see what folks come up with.
Just for fun.
Emotiva XPA-1 gen2 amp class A up to 60 watts @ 8 Ohms.
The CODA #16 (100 watts Class A, 150 watts total@8). The CODA is not much of a heater. Just warm to the touch.
The KRELL Duo 175XD (175 watts Class A). Westminster Labs (100 watts Class A). These 2 use a biasing scheme. The KRELL runs cool, I expect the Westminster Labs to be similar in temperature.
Check my virtual system for the Triode Audio of Japan TRX-M845 mono blocks. 50 watts Class A.
A few past NorCal USA units, old/new, +others:
Doing a Forte Model 3/1 50w Class-A conversion and various upgrades now with help from Jon Soderberg, local, he use to work at Threshold. VintageAmpRepair.org (new site)
Anything over 30-40 watts being sold as Class A is not pure class A, it’s class A biased. And the majority of the amps mentioned here are good examples. If Pure Class A is what you’re after (sounds alot better) don’t waste time with most of the amps mentioned here. And yes anything Pure Class can get pricey. Sugden and Pass might be the only exceptions, and they both make Pure Class A products. Most of Sugden’s product line is Pure Class A and it sounds superb.
The trade off to a Pure Class A amp and the sound it produces is the limitation of the wattage and it's ability to drive a wide array of speakers.
@jc51373 not true, the Belles SA30 was tested by a British Hi-Fi magazine and measured around 50w in true class A. I can believe that as the amp gets very hot.
SA 30 is a 30 watt amp (SA30= 30 watts) measure to 50 watts into 8 ohm load? You have a link for this article? If it’s 4 & 8 ohm loads you are referring to?
This statement is misinformation. If an amplifier is class A biased, its a class A amplifier. The output power has nothing to do with it.
Here are some simple facts about class A operation:
Class A simply means that the output device or devices do not shut shut off at any point during the waveform to be amplified.
A class A amplifier can be made of any power. We make one that is 500 Watts/channel (So the quote above doesn't make any sense).
The output impedance of the class A amplifier can be quite variable- depending on if the amp is tube or solid state and how much feedback is used.
On top of class A, if you are talking about tube amplifiers, there are three forms of class A: A1 in which no grid current flows, class A2 in which grid current is seen during part of the waveform, and class A3 (recently patented) in which grid current also flows.
Class A can be either single-ended or push-pull. It can be tube or solid state. Triodes and pentodes can be biased class A.
Any amplifier that is class A to a certain output power and then is in class B above that power is an AB amplifier, regardless of how 'enriched' the bias on the circuit actually is. IOW an amp that is class A to 50% of full power is an AB amplifier.
😁 What is safe to say is that it draws 120 Watts at idle.
This is a sort of 'who cares' thing since the point at which the amp goes from class A to AB isn't important; the amp is a class AB amp regardless. What is important is how well distortion is managed by the heavy bias (that's the reason for class A in the first place).
For about 15 years I had 3 Class A Amps.Two modified Threshold T-50's that were originally owned by a former Threshold employee. The amps were modified at Threshold to work as 90 wpc mono blocks. Also a classic Forte 4A 50 wpc amp. If you can find one on line pick it up. Always regretted selling that amp.