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60 Hz Noise Reduction

How do I eliminate 60Hz hum from my audio system?

HISTORY:
I recently purchased an Acurus A200 to increase the volume level of the front channel of my second system. When I connected the unit I noticed a 60Hz hum coming from both front speakers. I'm thinking the new set up has created a ground loop, or the units with no AC ground plug (2 prong AC plug) have a floating ground. The 2 prong AC units are Denon AVR3805, and Velodyne ULD15. So I would like to get some ideas of things I can do to eliminate the 60Hz hum This set up is a hodge podge of equipment left overs from the past.

OLD SET-UP (No 60Hz Noise)
Denon AVR3805 driving front, center, and surround speakers.
Denon preamp out to ULD15 controller/amp driving ULD15 sub.

NEW SET-UP (60Hz Noise)
Denon AVR3805 reciever which powers center, and surround speakers which are Monitor Audio bookshelf speakers. Denon pre-amp out to ULD15 Series II controller/amp driving Velodyne ULD15 sub. ULD RCA output to Acurus A200 amp input driving Monitor Audio GS10 for front.

Ideas Appreciated
Aaron
aweaver555

Showing 4 responses by aweaver555

aweaver555 OP
5 posts
 
Hi Rudd,
no cable box just TiVo.
Wow I would have never thought about low frequency noise coming from a cable box.

Just curious where did you place the jensen transformer, and which model for future reference.

Thanks Again
Aaron
aweaver555 OP
5 posts
 
Great article on noise isolation/elimination very helpfull.
I think I nailed it by attaching earth ground to Denon Receivers chassis ground.

Definetly will keep the Jensen ISO MAX CI-2RR isolation transformer for any future noise issues.

Thanks So Much
Aaron
aweaver555 OP
5 posts
 
Denon Chassis Ground
yes the Denon has 2 prong polarized AC plug.
I'm assuming that if I connect the chassis to AC ground instead of earth ground it would cause the same EMI/RFI noise problem. or worse correct?
I ordered the Jensen ISOMAX CI-2RR, and will install, and remove the earth ground from the Denon reciever chassis.

TiVo/Cable Loop
The Cable TV, and TiVo coxial are not connected to the Denon unit. However from these treads I'm going to connect the coxial cable through the isolation coax line in the Panamax power management system.

Thanks Again
Aaron
aweaver555 OP
5 posts
 
Hi Jim,
Well I don't believe it, but I disconnected the house cable line, and the noise went away. This line goes to a 4way splitter which supplies the TV, TiVo, and VCR/DVD.
I believe the splitter has a DC pass through.
I reconnected the house cable with none of the devices connected, and then reconnected seperately to determine which device was the source. Unfortunately when any single device is connected the noise returns.

When I do any of the following the hum goes away.
1-AC ground video splitter.
2-House cable through Panamax coax Isolation line.
3-AC ground denon chassis. (not a good solution)
4-drive front speakers with denon only.
For items 1 thru 3 there is a very very low level high frequency noise almost impossible to hear.
I'm wondering are items 1 & 2 good solutions, and what should I do about the residual noise?

Please note the TiVo, Wii, Playstation, and xbox go to a Philips AV switch that outputs to a 720 upconverter, which than supplies an hdmi signal to the TV. The TV supplies a digital audio to the denon reciever. Not sure if that helps.

Thanks Again
Aaron
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