Hello,
Seeking a schematic for Proficient Audio Systems S12 Powered Subwoofer amplifier module.
Thanks in advance,
John
Yeoman
Member
Last Activity: 09-13-2021, 09:21 AM
Joined: 01-15-2015
Location: Atlantic City, NJ
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Schematic for Proficient Audio Systems S12 Powered Subwoofer?
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Re: SMPSU for Mackie SRM1801 rails seem too high
No the +20 is exactly +20. I took another look and with exactly 120 VAC at inlet the rails are plus minus 81.8 VDC. Maybe not a defect? At 110VAC the rails are at 75 VDC. Here are the rest of the schematics.... -
SMPSU for Mackie SRM1801 rails seem too high
Hello,
I was wondering if anyone here has experience with SMPS putting out a higher than normal voltage. I am working with a Mackie SRM1801 that blew out the audio amplfier section. The schematic shows 75 volt rails but I am measuring close to 85 volts. The PWM controller is a KA3532A. I am attaching schematic if you care to take a look. Is it possible for the PSU to work but not be regulating the way it should?
Thanks in advance!... -
Re: JBL PRX635 Schematics?
Ok I seem to have solved it. C180 and C181 on this PRX635 unit are 0.22uF instead of 0.47uF as indicated on PRX500 schematic and also as are in place on the MF amp and LF amp in unit in question. I thought that this might explain the 52.9 kilohertz at 2.25 Volts PP that was present at TP150 (modulator schematic) with no input signal and no load. When I tacked .3uF across existing C180 and C181 the oscillation disappeared. Does not appear to roll off high end significantly with the extra capacitance.Leave a comment:
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Re: JBL PRX635 Schematics?
Hello,
Walked away from this one for a bit. Thanks for the replies! Same amp as the prx500 series. The HF amp actually delivers audio to the compression driver however with no input signal and the speaker load removed r183 and r184 quickly get very hot. With a load connected the amp gradually heats up to the point of thermal shut-down.
Thanks Longbow I will take a close look at U165 and the related driver transistors. I suppose that if the mosfets are not switching correctly it could explain what I am seeing.Leave a comment:
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JBL PRX635 Schematics?
Hello,
I have an atypical problem with a JBL PRX635 amplifier.
The HF amplifier seems to be oscillating causing the unit to heat
up. The usual scenario with these units is replace shorted output mosfet devices. So I decided to change out the mosfets on the HF amp on the outside chance that it might cure the current draw, no change. If anyone out there has the schematics to share or has seen a similar problem with these class D amps please let me know.
Thanks -
Re: JBL PRX518S schematics
Fantastic!
Thank You.Leave a comment:
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JBL PRX518S schematics
Hello,
Anybody here have access to the schematics for the JBL PRX518S power amplifier module that you would be willing to share?
I have one in the shop with the typical shorted mosfet pair that I replaced but still does not power up.
Thanks in advance! -
Re: New Members - please post your introductions here
Hello,
Stumbled onto this forum searching for schematics, found them and here I am. Most of my repair work is with professional audio; power amplfiers, loudspeaker re-cones, instrument amps, etc. Between repairs and live sound system engineering I have been making a living at it since 1990. Thanks for forum that I could actually use!
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