Ha ha thanks for answering the question, but if you are answering the question with a guess based on mistaken assumptions I'm not sure that my response was out of line. If you don't have the technical background to answer the question, maybe just remaining silent would be a better plan.
Class A amps do NOT "require" class A regulators in their power supplies. That's just silly. Nelson Pass designs some of the most respected class A amplifiers in the world, and the highly-regarded "Aleph" series amps don't use ANY regulation in their power supplies, much less class A regulators.
>>...
if it was it would be advertised like Kingwa's class A amps (phoenix, c-2.1) ...<< Um, where is the Phoenix advertised as having Class A audio output stages? I don't see "class A" used anywhere except when discussing power supply regulation. So, that means the Phoenix is NOT advertised as having Class A audio outputs.
As far as "running a LOT warmer," this depends on what you mean by a LOT. The output stages are rated at 14 watts or so. That would mean, in class A, the output stage would be dissipating at least 14 watts. There are 4 output devices per audio channel, so each device would be dissipating at least 3.5 watts; probably more like 4.5 watts in a real-world design. 4.5 watts is not enough heat to make those fairly large heatsinks HOT, just moderately warm. So, checking the temp of the heatsinks is not going to tell you if it's class A or not.
There are two ways to tell if the NFB-10es output stage is class A:
- Measure the bias current of the output transistors and compare that figure against data published by the transistor's manufacturer.
- Ask Kingwa.
I have opted for (2.) So, we'll see if he replies.
When I asked the question, I was thinking that there must be someone who had already asked Kingwa and knew the answer.
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Well the amplifier isn't class A anyway. If it was it would be advertised like Kingwa's class A amps (phoenix, c-2.1) and run a
lot warmer. Also, I was under the impression that a class A output stage required a class A power supply so my previous answer should have already been adequate. There's no need to act like I'm an idiot when I'm answering your question.
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Does anyone know if the output stage of the NFB-10 is Class A? I assume it is, but.....
I could ask Audio-Gd I suppose.
somestranger26 replies:No. It is linear. See their
Frequently Asked Questions page
??? That FAQ talks about the POWER SUPPLY. I am curious about the AMPLIFIER output stage- the transistors that actually drive your headphones. They can be Class A, Class AB, Class B or Class C - those are the defined "classes" of analog amplifier. There is no amplifier class defined as "linear." (Class D, Class H, Class T etc are really not amplifier classes at all- they are different types of amplifiers altogether.)
FYI- The "linear amplifier" of CB and Ham radio is actually a Class C RF amplifier designed to amplify amplitude modulated or single-sideband modulated radio carriers- not at all related to anything in high-end audio gear.
