I am very excited about the result of this amplifier, in every respect.
Simply draw an envelope curve, determine 2 to 3 watts - and now set the quiescent current to 560mAdc.
But perhaps Nico R. is just joking.
Why would I be joking? I have been developing this kind of stuff for some 50 years. Tubes as well. Maybe you should check the mathematics of distortion. Besides class A distorts very differently from class AB. In class A if you do not hear it or recognise it, it is not there. Class AB you can hear both cross-over and IMD far earlier than harmonics simply because they are dissonant. During music playback distortion unless grossly nonlinear amplification is very difficult to decern.
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I found how to block htb, now my irritation will go away. Just looking at his profile, he comments on threads every minute. He has either nothing else to do or using a robot or pre-prepares his comments ahead of time.
Sounds very nicely clear and detailed over headphones. Congratulations 👍
Are the fans set up to blow all the time or activate based on temperature..
Thank you! @drjlo
The fans are set to work continuously based on the temperature and they never stop based on the controller that has an audible alarm if their speed decrease too much. I chose this one for this reason.
I have also another controller where the fans operate based on the temperature and stop if the temperature drops 2 or 5 degrees from the limit you have set for them but no audible alarm for their speed
Its a mobile recording....
The fans are set to work continuously based on the temperature and they never stop based on the controller that has an audible alarm if their speed decrease too much. I chose this one for this reason.
I have also another controller where the fans operate based on the temperature and stop if the temperature drops 2 or 5 degrees from the limit you have set for them but no audible alarm for their speed
Its a mobile recording....
I got one side working. Sounds good and will play with it after I get the other side working. Both sides are running 28.5v rails. Admittedly when I hooked up the npn to the side that isn’t working properly I had the gate and source on wrong sides. When I switched them back I got the funky measurement on the transistors. Any Ideas?
In a nutshell:
How is Nikos supposed to reduce the quiescent current of the power amplifier linearly while listening to music and suddenly find a lower point at which the sound becomes bad.
@AKSA
Have you changed the circuit so that we can turn a trim potentiometer to set an exact quiescent current (at wish)?
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That's why I say you're probably kidding us or not looking at the circuit in detail, dear Niko Ras. AN39 cannot be adjusted during operation (in therms of the idle current). At least not in a practical sense. Or should Nikos resolder a battery of resistors (under power /mains) ?
But maybe I missed the latest iteration of the AN39(?).
@Nikos,
your build looks and sound beautifully - be happy with your nice Amplifier.
greetings,
HBt.
How is Nikos supposed to reduce the quiescent current of the power amplifier linearly while listening to music and suddenly find a lower point at which the sound becomes bad.
@AKSA
Have you changed the circuit so that we can turn a trim potentiometer to set an exact quiescent current (at wish)?
#
That's why I say you're probably kidding us or not looking at the circuit in detail, dear Niko Ras. AN39 cannot be adjusted during operation (in therms of the idle current). At least not in a practical sense. Or should Nikos resolder a battery of resistors (under power /mains) ?
But maybe I missed the latest iteration of the AN39(?).
@Nikos,
your build looks and sound beautifully - be happy with your nice Amplifier.
greetings,
HBt.
Very good point, HBt. 👍
Given that:
- the quiescent current going through the mosfets is adjusted by changing the value of extremely small-value resistors (in my case - with the 4R circuit - from 0.12R to 0.15R) and
- these resistors get red hot 😱
... it is hard to imagine there is a pot that could fulfil the requirement!
Use the wire wound pots that was popular in front and back speaker control for vehicles, they were about 15 watt rated and low value. The pic is from Noble. You can place a fixed resistor in parallel to make very small adjustments.
Well....I did some tests and today with parallel resistors 0.22Ω=0.11Ω the quiescent current was fixed at 3A and the other channel at 2.65A.....i believe i stay at 3A
.... finally .
.... finally .
If they were used for spkr control in cars - I suggest they would be up to 3 or 4 ohms, max. So not so good for changing between 0.1 ohm and 0.2 ohm.
And how do you exactly match two of them (to equalise L & R channels)?
Know anything about paralleling resistors. You can adjust the value exactly. This is school maths. Obviously to adjust two you need two calibrates multimeters. Use two light bulbs and adjust for the same brightness, or two motors and adjust for the same speed, or place two fingers on them and adjust for the same temperature....... 😴 I will think of some more less scientific ways.
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Parallelling resistors - why would you want to do that? 😵
You know, right, that electrons travel through different-value resistors at different speeds (the higher the value ... the slower the speed)? So if you parallel 2 resistors of different values ... you get a blurred signal out of the parallel pair.