Hello, I recently designed a power amplifier with capabilities of around 120W. The problem came as I connected the speakers and turned it on. What happened was the speaker started moving and making noise without any input signal. I also measured the voltege between speaker terminals and my multimeter showed the same voltage that was on the positive output of the power supply, sience Im using dual polarity type psu.
I hope someone here has some insight on the topic, it would be really helpful.
I hope someone here has some insight on the topic, it would be really helpful.
Is this a guessing game? Seriously, nobody can shed light on a problem without any relevant info. So what's the design (schematic)? How was it built (pictures)? What were the specific test conditions? Etc.
It's the equivalent of "I made this thingamajiggy and it doesn't work...tell me what's wrong" without providing anything to go on.
Mike
It's the equivalent of "I made this thingamajiggy and it doesn't work...tell me what's wrong" without providing anything to go on.
Mike
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A new DIY amplifier should always be checked with test equipment first, before connecting speakers to it.
Especially if it is a new design, and not a kit. The speakers can be damaged otherwise.
Especially if it is a new design, and not a kit. The speakers can be damaged otherwise.
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dc on the output the same as positive power supply should never be connected to the speaker
its likely some dead transistor
120 watt amp is probably running +/-45 volt supply, or higher, typically
niko58 did not share that with us
that would make woofers membrane jump on the floor
when I test new amp (i do not design any, just copy), I use cheap small fullrange, even that often cap protected
we need pictures, niko58, post lots of pictures
niko58 did not share that with us
that would make woofers membrane jump on the floor
when I test new amp (i do not design any, just copy), I use cheap small fullrange, even that often cap protected
we need pictures, niko58, post lots of pictures
Its runing on +/- 60V, Im using dummy speakers so no worries about blowing them up. Ive came to the same conclusion that one of the lateral MOSFETs probbably SJ162 is faulty.
Ive measured Source to drain about 200, then I went and measured drain to source and both of the two PMOS Im using started filling up, one of them came to the value of 2000 and then showed an open circuit, however the other one didnt. It just stayed rock solid at just below 2000.
This doesnt seem okay to me, but Im no pro so thats why Im here.
Hope you can tell me something with the data I gave you.
Ive measured Source to drain about 200, then I went and measured drain to source and both of the two PMOS Im using started filling up, one of them came to the value of 2000 and then showed an open circuit, however the other one didnt. It just stayed rock solid at just below 2000.
This doesnt seem okay to me, but Im no pro so thats why Im here.
Hope you can tell me something with the data I gave you.
Let me get this straight. You designed it but have no circuit and are no pro, that's why you are asking for help. Did i get it right?
A single 2SK1058/2SJ162 pair at +-60V is bound to fail quickly with 8ohms speakers and immediately with 4ohms ones.
A double pair would be safer in both cases at +-55V.
A double pair would be safer in both cases at +-55V.
