Hi,

I noticed that there is a low frequency hum when I connect the RCA LFE connectors from the triton Ref to my amp.
Problem is always when you have 2 prong devices mixed with 3 prong devices which can then cause ground loops.
I now wanted to ground all my Hifi devices to the same ground rail.
For this, I was planning to connect a ring crimp connector to the shield of the RCA input on the speaker.

Would that be ok or would you recommend to rather connect it to a screw of the speaker?

Cheers!
Chris

Hello Chris,

Before doing anything else, I suggest you try the following approach.

1. Disconnect all speaker and LFE RCA connections from your two Reference Speakers. Disconnect the Reference Speakers LFE amplifier power cords. Disconnect all other cables from the amplifier.

2. Connect the speaker cable from the amplifier Left Channel output to the Left Reference speaker inputs. Listen for LF Hum ("LFH").

If you have LFH, then your problem is likely in the amplifier.

3. If no hum, add the amplifier right channel output speaker cable to the Right Reference speaker inputs. Listen for LFH.

4. If no LFH so far, then connect the LFE amplifier RCA output to the Left Reference LFE Connector. If LFH, then try a different RCA type cable and repeat the process.

5. If no LFH, then connect the Left Reference LFE power cord, wait for the Reference Amp to settle down and listen for LFH. If LFH appears, disconnect the Left Reference LFE power cord, then connect the Right Reference LFE Power Cord and listen for LFH.

If LFH is present in only one of the Reference units, swap the power cords between the Left and Right Reference speakers. If the LFH travels with the cord, then you probably need a new Reference power cord (contact dealer or GE).

If no LFH, repeat the above step 5, etc. with the Right Reference speaker.

6. If you have no LFH with a single RCA cable connected to one of the Reference LFE inputs and both Reference LFE amplifier systems operating, then move the LFE RCA cable to the other Reference LFE input and listen for LFH.

If no LFH after all above experiments and assuming that your amplifier has only a single LFE output, consider how you are splitting the LFE signal from the amp to the two Reference LFE inputs and devise a test to determine whether or not your splitting technique is introducing the hum.

If your amp has two LFE outputs, repeat above tests as necessary to determine whether or not the amplifier second LFE output is the culprit, or possibly using both outputs together introduces the LFH.

Bottom line: Most likely causes are: Reference power cord or internal grounding issue; cable ground issue; amplifier grounding issue. Least likely cause in my opinion would be mixture of two and three prong power cords causing a ground loop.

But, if you still suspect the 2-3 prong cause, try plugging both Reference power cords and the amplifier cord into a common power strip.

Hope this helps,

Art

Hi,

thanks for the detailed reply.
To clarify my setup. I have PSA M700 power amps which are connected to the speaker cables.
Only in case I want to use my speakers for home theater, I turn on my Marantz AVR which has the LFE cables connected to its 2 LFE outputs.
I think the AVR is the problem because it only has 2 prongs and might have a different potential than the other ones. The more expensive gear usually has 3 prongs while the consumer electronics like TV, AVR, BluRay only have 2. (not always true but often)

I will go through the checklist and post the results.
Thx
Chris

I think you will be able to isolate the problem by implementing the concepts I presented in my previous response. I would be surprised to learn that your problem is related to two prong versus three prong power cords. My system has a mixture of two and three prong power cords and requires two multi-tap AC adaptors to accommodate the various power cords. I do not have any hum issues.

I would focus on the LFE RCA cables. A poor ground connection would probably cause a hum.

Best of luck in locating the source of the problem.

Art