Are these tranzistors in wrong position or they are different parts?
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Please, is there any PCB design other than Juan Vargas' for AX-20P?
I'd like to build this amp, and some inspection before building is always welcome.
Also impressions and hints would be nice.
Thank you all.
I'd like to build this amp, and some inspection before building is always welcome.
Also impressions and hints would be nice.
Thank you all.
The amp doesn't oscilate but I have 28vcc on out on both chanels, some tranzistor is malfunctioning, i measured all of them, they seem ok. I'll be back with some mesurements when I get home.
I've done some measurements on final transistors:
The psu in +/-30v, and on the output is 28vcc
2sa1943
GND-B-29.6v , B-E -0.02
GND-C-30 , B-C- 0.04
GND-E-29.5 , E-C-0.03
2SC5200
GND-B-29.4 , B-E 0.02
GND-C-28.9 , B-C 0.02
GND-E28.9 , E-C 0.02
The psu in +/-30v, and on the output is 28vcc
2sa1943
GND-B-29.6v , B-E -0.02
GND-C-30 , B-C- 0.04
GND-E-29.5 , E-C-0.03
2SC5200
GND-B-29.4 , B-E 0.02
GND-C-28.9 , B-C 0.02
GND-E28.9 , E-C 0.02
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Measure voltage on input and VAS transistors... check diode polarity there is mistake in first post.
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Voltage reading taken incorrectly or written incorrectly.
2SA1943 collector should be negative -30v and 2SC5200 collector +30v from GND.
what psu you are using smps or transformer with bridge and filter caps.
Regards
Sonal
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They might be written incorectly, i'll be back with some measurements tomorrow. This problem is at one chanel the other one seems to work post #4547. My PSU is +/-30VCC
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Chanel one works, I replaced the fuses with 10R resistance and set to 115mv voltage drop., with input shorted I have 12mv on output.. I even made a sound test on a small speaker before I destroied it.
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Yes i see that is a beautiful pcb, but drawing a pcb isn't an easy way.Apex know this.
Most of good amplifiers are drawing haven fuses close way each other,i believe that isn't without any reason.This way (+,-,gnd traces close each other)minimize the EMI.
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