I just built the Silicon Chip 150w into 8 ohm Class D amplifier.
I am using it to replace the amplifier that blew up in my Subwoofer (Sony SA WM40).
After building the kit i triple checked all components as well as the DC voltage check points on the board and all was well.
Problem i have is twofold, firstly output is too low, even when i turn the subwoofer output of many Denon amp up to full (+12db).
Secondly, the amp is creating like a woodpecker sound out of the subwoofer occassionally, so i cant use it.
I dont own a CRO so does anyone know how i can check the circuitry with a multimeter alone ?
Cheers
Digger.
I am using it to replace the amplifier that blew up in my Subwoofer (Sony SA WM40).
After building the kit i triple checked all components as well as the DC voltage check points on the board and all was well.
Problem i have is twofold, firstly output is too low, even when i turn the subwoofer output of many Denon amp up to full (+12db).
Secondly, the amp is creating like a woodpecker sound out of the subwoofer occassionally, so i cant use it.
I dont own a CRO so does anyone know how i can check the circuitry with a multimeter alone ?
Cheers
Digger.
A picture and circuit diagram would be useful.
The woodpecker sound could be the circuit resetting as it thinks there is an overload.
The woodpecker sound could be the circuit resetting as it thinks there is an overload.
sorry I have deleted the schematic as it was copyright 2012 Silicon Chip.There was some discussion on this amplifier a couple of years ago when it first came out.
I am guessing it is not possible to fault find without a CRO and some better test equipment thaa a pretty Yellow Fluke multimeter ?
http://www.diyaudio.com/forums/parts/223104-classic-d-new-class-d-amp-silicon-chip.html
cheers
Digger
I am guessing it is not possible to fault find without a CRO and some better test equipment thaa a pretty Yellow Fluke multimeter ?
http://www.diyaudio.com/forums/parts/223104-classic-d-new-class-d-amp-silicon-chip.html
cheers
Digger
It seems we initially deleted the schematic in that thread, and then re-instated it. I seem to vaguely remember that we emailed silicon chip to enquire about whether it was ok to have the schematic online, I don't think we got a reponse, but anyone who wants to see the schematic follow the link.
Digger, I'm not at all familiar with Class D amps, but I would look at the kit instructions which hopefully have a reprint of the original article and see which components set the gain. double check that you have the right value resistors in those positions, and also for bad joints there.
The woodpecker sound may be a fast motorboating (a low frequency oscilation) This also could be caused by a bad joint, or maybe a solder bridge from one track to another.
Tony.
Digger, I'm not at all familiar with Class D amps, but I would look at the kit instructions which hopefully have a reprint of the original article and see which components set the gain. double check that you have the right value resistors in those positions, and also for bad joints there.
The woodpecker sound may be a fast motorboating (a low frequency oscilation) This also could be caused by a bad joint, or maybe a solder bridge from one track to another.
Tony.
Cheers Tony,
Yes, fast motorboating is a way to describe it. Seems to occur during quiet moments when the subwoofer shouldnt be working or should be just murmuring in the background.
I will check resistor values and look for solder problems on the weekend.
But my soldering is usually quite good as i learnt in the early 80's from a HRHS course that was originally designed by Nasa for the Apollo Missions.
I have solved the low output by turning down the db for all of the surround speakers and turning up the LFE output to the subwoofer.
Cheers
Digger
Yes, fast motorboating is a way to describe it. Seems to occur during quiet moments when the subwoofer shouldnt be working or should be just murmuring in the background.
I will check resistor values and look for solder problems on the weekend.
But my soldering is usually quite good as i learnt in the early 80's from a HRHS course that was originally designed by Nasa for the Apollo Missions.
I have solved the low output by turning down the db for all of the surround speakers and turning up the LFE output to the subwoofer.
Cheers
Digger
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