g.costanza
New member
- Location
- usa
Wondered if u guys could help with these humming subwoofer amplifiers that apparently don't know the words
I'll stick to the facts I know...
I bought two new JAMO powered J110 subwoofers that are near clones of the Klipsch R110/112/115 family. Same plate amps between JAMO and Klipsch versions depending on woofer size. They have 2 prong power plugs.
Denon Receiver has a 3 prong power plug.
I previously had a pair of DIY subwoofers on a single parts express BASH amp (3 prong plug) in the same spot as these new subs. Zero noise issues.
Using same single RCA coax cable connection on new subs as old setup.
JAMO subs do not hum until I connect the RCA cable going to the Denon.
JAMO subs also do not hum if I connect the headphone out jack of my iphone using a 3.5mm to RCA plug adapter.
I moved Denon and connected it to same wall outlet as the subs. No help. Still Hums.
I put a ground loop isolator on the RCA audio connection. No help. Still hums.
I tried a different RCA cable. Still hums.
I don't have "cable TV", so that can't b a hum source.
I used a FLUKE meter to check wall outlet. I get 120v from narrow HOT slot to wide slot, ground hole, and center screw. Normal.
I get 0v from wide COMMON/NEUTRAL slot to ground hole and center screw. Normal.
I used continuity setting of FLUKE and got "tone" between outer/ground ring of sub amp's RCA audio inputs JACKS to the screws, etc on the EXPOSED metal plate amps on subs.
I was then surprised to find that if I touched the screws, jacks, etc of the metal plate amp with a probe of the fluke on V~ setting, and the center ground screw on the wall outlet, I got 118v. Is that Normal? Touching the metal plate amp doesn't result in a shock. I didn't try touching the center wall outlet screw with my other hand, lol. Not sure what would happen.
The hum does increase or decrease depending on subwoofer amp volume knob setting, if that matters. When the RCA plugs are removed from the amps, I get no noise, regardless of volume setting.
Any ideas?
I'll stick to the facts I know...
I bought two new JAMO powered J110 subwoofers that are near clones of the Klipsch R110/112/115 family. Same plate amps between JAMO and Klipsch versions depending on woofer size. They have 2 prong power plugs.
Denon Receiver has a 3 prong power plug.
I previously had a pair of DIY subwoofers on a single parts express BASH amp (3 prong plug) in the same spot as these new subs. Zero noise issues.
Using same single RCA coax cable connection on new subs as old setup.
JAMO subs do not hum until I connect the RCA cable going to the Denon.
JAMO subs also do not hum if I connect the headphone out jack of my iphone using a 3.5mm to RCA plug adapter.
I moved Denon and connected it to same wall outlet as the subs. No help. Still Hums.
I put a ground loop isolator on the RCA audio connection. No help. Still hums.
I tried a different RCA cable. Still hums.
I don't have "cable TV", so that can't b a hum source.
I used a FLUKE meter to check wall outlet. I get 120v from narrow HOT slot to wide slot, ground hole, and center screw. Normal.
I get 0v from wide COMMON/NEUTRAL slot to ground hole and center screw. Normal.
I used continuity setting of FLUKE and got "tone" between outer/ground ring of sub amp's RCA audio inputs JACKS to the screws, etc on the EXPOSED metal plate amps on subs.
I was then surprised to find that if I touched the screws, jacks, etc of the metal plate amp with a probe of the fluke on V~ setting, and the center ground screw on the wall outlet, I got 118v. Is that Normal? Touching the metal plate amp doesn't result in a shock. I didn't try touching the center wall outlet screw with my other hand, lol. Not sure what would happen.
The hum does increase or decrease depending on subwoofer amp volume knob setting, if that matters. When the RCA plugs are removed from the amps, I get no noise, regardless of volume setting.
Any ideas?
