Yes, you are correct. For ClassB there should be four 560R 2W resistors and for ClassA two of 1k1 2W resistors are enough, but if you want to combine ClassA and ClassB in the same amp (like active speakers) then use four 560R resistor even for ClassA.
I will edit BOM accordingly and will put correction note in first post.
Damir
Hi to ALL and two questions.
1. How much phase shift at 20 kHz, at 1 watt.
2. Can you make a THD+N graph like this? Rotel A11.
1. Less then 1 degree and it depends of input LP filter.
2. No
That is very good, Damir, outstanding...... there is some belief that low phase shift maintains image integrity at very high frequencies, but there are other influences I believe.
I have a feeling that the very curvy transfer function at very low drain currents on latfets leave to the inactive device in AB remains on for longer than hexfets, which turn off around 2-4V off crossover even at higher bias quiescent. This might explain a smoother sound, less harshness, with latfets. With high Iq is might be as high at 15V above and below crossover, and this means a lot of headroom in Class A.
Thoughts?
Hugh
I have a feeling that the very curvy transfer function at very low drain currents on latfets leave to the inactive device in AB remains on for longer than hexfets, which turn off around 2-4V off crossover even at higher bias quiescent. This might explain a smoother sound, less harshness, with latfets. With high Iq is might be as high at 15V above and below crossover, and this means a lot of headroom in Class A.
Thoughts?
Hugh
Hugh, you have much more experience in the way to recognize what makes smother less harsh sound, and you are probably right.
I am more on engineering side, with much less listening experience.
Damir
Feedback
Aksa Lender P-mos Hybrid Aleph (ALPHA) Amplifier
by AKSA
Lateral CFA 120W - BSA, how much feedback? Less or more 29 dB?
Aksa Lender P-mos Hybrid Aleph (ALPHA) Amplifier
by AKSA
Lateral CFA 120W - BSA, how much feedback? Less or more 29 dB?
Several technics can have same result. Same technics can have different result. It is depend of the implementation. If you have deep knowledge of engineering, you know it. Unless you just doing trial-error design.
If we are not interested why the trial-error work, then this is not engineering. After we gained the knowledge we can use those knowledge for future use.
You know how science and engineering was developed. It is no secret.
Three years ago, my friend said the best SS amplifier should use latfet. He built one. At local audio community we met. He bought his amp and I bought my amp. My amplifier used all BJT. After we compared them, he almost not believe that my amp sound better in all aspect. He made his opinion because he never found all BJT's amp sound better than latfet's amp.
I do not believe there is only ONE WAY (ex. particular topology, special components) to make good sounding amplifier.
I do not believe there is only ONE WAY (ex. particular topology, special components) to make good sounding amplifier.
Brought. For a moment I thought you bought his and he bought yours, which is confusing
Sorry
My English is not good enough.
Hey, I got some of my improvements through trial and error like cleaning my incredible dirty electrical grid. I still can not find a logical explanation about one (the 150 kHz ferrite after a coil, in the KEF Q100 woofer, with first order crossover), something that bothers me!
- End off topic -
- End off topic -
So, what the problem? If you do not understand, it does not mean all people do not, either. Scott Wurcer said, it is design by accident.
You can always learn, and all people, too.
Bimo,
I can see where you are coming from, but I do not fully agree. I think much science comes from serendipity - design by accident - and I think there are many examples, particularly where art meets engineering like audio, when techniques are not fully understood. Creativity comes from 'what if....' as well as from 'if this rule works, then this will follow.......'
We are on the same page, however, but never lose your humility.
Hugh
I can see where you are coming from, but I do not fully agree. I think much science comes from serendipity - design by accident - and I think there are many examples, particularly where art meets engineering like audio, when techniques are not fully understood. Creativity comes from 'what if....' as well as from 'if this rule works, then this will follow.......'
We are on the same page, however, but never lose your humility.
Hugh
I agree about creativity. We never understood all, but we try to prefect our knowledge.
I proved your design philosophy worked to some people. Thank you, I learn a lot from you. But I also learn from other, like Dadod, Bonsai, Scott Wurcer, John Curl, Nelson Pass, etc. I read a lot of books about audio amplifier.
It is fun to learn something new. But, sometime some people too arrogant to appreciate new idea like OITPC compensation. They never really analyze this compensation or try to build it, but they judged: it is not important or not good enough.