Hi all,
I've been using a dual mono Aikido preamp into a SS amp(SKA) and it sounds terriffic. I also included an AC line filter as part of the build, it is dead silent, no hum or hiss under normal circumstances. However recently I remodeled my kitchen and added some LED under cabinet lights, they are powered by 12 vdc switching power supplies that are located remotely in a closet above the kitchen on the second floor. The preamp is located in a room next to the kitchen on the first floor. When I turn on the undercabinet lights I get a low hum that sounds like a ground loop hum from the preamp, if I turn off the lights the noise dissappears. This doesn't occur with a SS preamp. Does anyone have any idea why this is happenning or if there is a solution (besides not using the lights 😉)
Thanks,
PJN
I've been using a dual mono Aikido preamp into a SS amp(SKA) and it sounds terriffic. I also included an AC line filter as part of the build, it is dead silent, no hum or hiss under normal circumstances. However recently I remodeled my kitchen and added some LED under cabinet lights, they are powered by 12 vdc switching power supplies that are located remotely in a closet above the kitchen on the second floor. The preamp is located in a room next to the kitchen on the first floor. When I turn on the undercabinet lights I get a low hum that sounds like a ground loop hum from the preamp, if I turn off the lights the noise dissappears. This doesn't occur with a SS preamp. Does anyone have any idea why this is happenning or if there is a solution (besides not using the lights 😉)
Thanks,
PJN
which ac line filter? are you using a premade one?
if so, try grounding the case of the ac filter to the 3rd prong ( f.e. ground).
If not, you may have to isolate the signal ground from eath ground.
if so, try grounding the case of the ac filter to the 3rd prong ( f.e. ground).
If not, you may have to isolate the signal ground from eath ground.
also, if the electrical outlet in the kitchen has the wires poked in the back, turn off breaker, and move the wires to the screw terminals. weak neutral connection will cause some power supplies to impress noise on the AC line.
LED Drivers are switching devices -- i have similar issues (higher frequency) with a Phillips Lumiled fixture and a receiver -- and the dutchies aren't particularly helpful in answering questions -- pleading the 5th as it were.
Preamp needs a complete metal surround, the cabinets of the various devices have to be linked together and returned to a common ground. If you're using XLR's make sure that Pin 1 issues are resolved.
Preamp needs a complete metal surround, the cabinets of the various devices have to be linked together and returned to a common ground. If you're using XLR's make sure that Pin 1 issues are resolved.
Hi all,
Thanks for your input. The line filter is a design by Jon Ritch and is part of the build. It's a typical filter design using caps and chokes. The preamp is in a wood case with a perforated metal top. No XLR, single ended in & out. I'll try putting a grounded metal enclosure around it to see what happens.
The LED folks also lied to me and told me point blank that the drivers(psu) were dimmable, it turns out they aren't.
PJN
Thanks for your input. The line filter is a design by Jon Ritch and is part of the build. It's a typical filter design using caps and chokes. The preamp is in a wood case with a perforated metal top. No XLR, single ended in & out. I'll try putting a grounded metal enclosure around it to see what happens.
The LED folks also lied to me and told me point blank that the drivers(psu) were dimmable, it turns out they aren't.
PJN
Parenthetically, there's are some troubling issues with the types of wall-plate dimmers for different LED fixtures -- you can't just pop one from Home Depot in there, you've got to look at the manufacturer's datasheet.
All of these little switching supplies are the bane of our existence -- there's no respect for FCC Part 15 rules.
All of these little switching supplies are the bane of our existence -- there's no respect for FCC Part 15 rules.
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