No, problem was my soldering ( I used some flux, which was conductive for high frequencies ) . After building new pcb, everything worked perfect ( and still working, two years later ).
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thanks 🙂
What is the Wattage @ 4E load?
and what is the input voltage Vpp max?
and how is the sound quality?
pls comment.
Thanks in advance.
Using M-Tech's provided LTspice simulation I tried to get frequency response of the amplifier. its nowhere linear. Can somebody here please help me to understand this. or correct me if I am wrong. I have attached PDF of the response graph.
To get freq response, the modulator (and every switch-mode) stage should be replaced by its equivalent gain. This gain roughly equals to peak-to-peak output voltage (of the modulator) divided by dV/dt on its input during comparation, multiplied by switching frequency *2.
Hi,
Anyone got pcb layout for this amp, i`ve test on ltspice with file provide here, seems interesting, what u think if i do test this circuit with multisim using TL071 and LM311?
Regards.
Azmi
Anyone got pcb layout for this amp, i`ve test on ltspice with file provide here, seems interesting, what u think if i do test this circuit with multisim using TL071 and LM311?
Regards.
Azmi
Simple Class D
I mounted this amplifier there what uses mosfet channel P and channel N.
The same thing has the best quality of sound when the volume of sound is quite low, to increase a little, already begins to distort.
I do not know what it can have of missed with him:
it looks at the scheme http: // img404.imageshack.us/img404/297/classdamplifier1.jpg
Because I see in this scheme, only it has a point of the circuit where it is possible to work the polarization of the sign of sound, 3 of the LM393 is there in the pin
I mounted this amplifier there what uses mosfet channel P and channel N.
The same thing has the best quality of sound when the volume of sound is quite low, to increase a little, already begins to distort.
I do not know what it can have of missed with him:
it looks at the scheme http: // img404.imageshack.us/img404/297/classdamplifier1.jpg
Because I see in this scheme, only it has a point of the circuit where it is possible to work the polarization of the sign of sound, 3 of the LM393 is there in the pin
Can you tell me what is the current and supply voltage used?
what is the signal input level?
any component heating up?
made sure input audio signal is not riding on DC signal.
the link is not opening here pls can toy post the classdamplifier1.jpg?
what is the signal input level?
any component heating up?
made sure input audio signal is not riding on DC signal.
the link is not opening here pls can toy post the classdamplifier1.jpg?
Power supply of amplifier +42V / -42V
Power supply of LM393 : =12 /-12
power mosfets are heating up. At the moment they are without radiator
the level of signal in the entrance is well low, only some Mille volts
the sign of the entry is of the personal computer
Power supply of LM393 : =12 /-12
power mosfets are heating up. At the moment they are without radiator
the level of signal in the entrance is well low, only some Mille volts
the sign of the entry is of the personal computer
Albert.... I am too building the same type . there is little difference. did you confirm the value of filter coil? did u check it on meter? then try small modification. open one end of zener diode of 15v(connected to gate). connect other zener of 4.7v back to back in series. and check if it works well... do this for both side
I did the next modifications:
Instead of using a capacitor of 220pF, I used other of 150pF
Instead of using transistors 2N5551 and 2N5401, I used transistors BC327 and BC337
The transistors do BC327 and 337 work well in this circuit?
Can I do an inductor of filter with nucleus of air?
How it will calculate nucleus of air?
Is this filter of exit very critical in the functioning of the circuit? Is the right value necessary or other values work?
Instead of using a capacitor of 220pF, I used other of 150pF
Instead of using transistors 2N5551 and 2N5401, I used transistors BC327 and BC337
The transistors do BC327 and 337 work well in this circuit?
Can I do an inductor of filter with nucleus of air?
How it will calculate nucleus of air?
Is this filter of exit very critical in the functioning of the circuit? Is the right value necessary or other values work?
An externally hosted image should be here but it was not working when we last tested it.
The voltage of the sound in the output of amplifier, does not exceed 0,6V with good quality of sound.
When I increase the level of sign in the input, the voltage in the exit of the amplifier remains to same, distorting Excessively
When I increase the level of sign in the input, the voltage in the exit of the amplifier remains to same, distorting Excessively
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Instead of using a capacitor of 220pF, I used other of 150pF.
I don't see much of problem.
The transistors do BC327 and 337 work well in this circuit?
The frequency typically don't go above 330KHz so most small power transistors should not be problem.
If you use Air core inductor the length of wire would be long compared to ferrite core. resulting in more series resistance which is not desired. And also its size would be bigger.But if you still want to, I can give you details. The core material is not your problem for distorted sound. I very much doubt Inductance value.
when the switching transistor unfairly heats, it indicates that the transistor is not getting completely on. but what you have shown in the new gate driver circuit should solve the problem(new circuit uploaded by you).
One more point to be taken care of is the 12V regulating zener. re-calculate it s series resistor. wattage of zener required.(currently this is not the problem but check how bad zener heats.)
and I had asked what is the inductance of the coil used on your. higher inductance could be a problem.
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new gate driver circuit did not resolve the problem
new gate driver circuit did not resolve the problem.
The voltage of the sound in the output of amplifier, does not exceed 0,6V with good quality of sound.
When I increase the level of sign in the input, the voltage in the exit of the amplifier remains to same, distorting Excessively.
what might cause this problem?
new gate driver circuit did not resolve the problem.
The voltage of the sound in the output of amplifier, does not exceed 0,6V with good quality of sound.
When I increase the level of sign in the input, the voltage in the exit of the amplifier remains to same, distorting Excessively.
what might cause this problem?
Friend, I am over and again asking and also indicated that tell me what is the exact inductor value you have used?
Emule,
please read the above properly. also I have indicated that driver circuit could be responsible for heating of transistor.
Albert,
As a good practice you should post here what did you do to get it working. What corrections did you do to make it working. Cause when members are putting good efforts for you. They expect complete reply from you.
I'm using 30uH + 680nF for output filter. Inductor is wound on EF25 core ( air gap is 1mm ).
Albert probably had some pcb errors.
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M-tech,
Thats very much possible. but again, things sound ok when input is low. I could simulate that distortion (ofcourse using LTspice) when inductor value goes high. So I had big doubt if the problem is with the Inductor.
Thats very much possible. but again, things sound ok when input is low. I could simulate that distortion (ofcourse using LTspice) when inductor value goes high. So I had big doubt if the problem is with the Inductor.
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