~14 VDC between chassis ground and signal ground...

StalfoS · 5th May 2007, 02:51 AM

I built a power supply similar to this using two lm338 regulators. When I run just the PS, I get the correct voltages relative to ground, but when I attach my audiosector lm4780 board (parallel config) the voltages of +rail, ground, and -rail get skewed by 14 or so. If i connect the circuit common ground to the chassis i get blown fuses.

Does this sounds like a familiar problem to anyone? I have check my circuits over many times and everything seems correct. Any ideas?

AudioFreak · 5th May 2007, 08:47 AM

What voltage are your rails with nothing attached?

AndrewT · 5th May 2007, 08:55 AM

Hi,
I think you have a mis-wire somewhere.
Insert a mains light bulb in the mains supply to your PSU/amplifier. Then start measuring voltages without blowing fuses.

StalfoS · 5th May 2007, 08:26 PM

Quote:

Originally posted by AudioFreak
What voltage are your rails with nothing attached?

+/- 30VDC

5th May 2007, 02:51 AM	#1
StalfoS diyAudio Member Join Date: Jan 2005 Location: Vancouver, British Columbia	~14 VDC between chassis ground and signal ground... I built a power supply similar to this using two lm338 regulators. When I run just the PS, I get the correct voltages relative to ground, but when I attach my audiosector lm4780 board (parallel config) the voltages of +rail, ground, and -rail get skewed by 14 or so. If i connect the circuit common ground to the chassis i get blown fuses. Does this sounds like a familiar problem to anyone? I have check my circuits over many times and everything seems correct. Any ideas?

5th May 2007, 08:47 AM	#2
AudioFreak Warp Engineer On Holiday Join Date: Oct 2001 Location: Queensland, Australia	What voltage are your rails with nothing attached? __________________ - Dan

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5th May 2007, 08:55 AM	#3
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, I think you have a mis-wire somewhere. Insert a mains light bulb in the mains supply to your PSU/amplifier. Then start measuring voltages without blowing fuses.