Bottlehead Forum
Bottlehead Kits => S.E.X. Kit => Topic started by: Dr. Exotica on December 30, 2012, 10:42:43 AM
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The past few days I've been tweaking my SEX amp. One of the things that I've noticed is that sometime when I rub my finger across the chassis plate, I've observed some low voltage current on my finger as I drag it across the chassis plate (a strange vibration of sorts). I was curious if I was imagining things, so I tried measuring the voltage between the chassis plate and earth (in a wall outlet). It measured somewhere around 10 volts. This left me scratching my head.
This morning, when I was lying in bed, I think that I figured it out.
The power supply caps have bleed resistors. After powering on the amp and measuring voltages, I would power it down and unplug it. My conjecture is that by unplugging the power cord quickly after the amp being powered up, the PSU bleed resistors resulted in some voltage (?) being transferred to the chassis plate, rather than ground (actually, everything became equipotential). Subsequently, when I rubbed my finger across the chassis plate when it was unplugged (and I was in bare feet), I observed some low voltage current.
Am I on crack, or was there a real voltage potential based upon my quick disconnect of the power cord?
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The power supply and the chassis are tied together, so this should not happen.
To be sure, I would tighten down on the #8 screw back by the IEC inlet, as well as the screws that hold the front two terminal strips to the chassis.
-PB
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You might also check the voltage (if any) between you and the wall socket ground. :^)
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Also check the polarity of your power cord.
shreekant