NEWBIE Question : Why do I have a "bbzzz" in my loudspeakers with some interconnects on not with others ?

[PenguinMusic]

Hi,

Hope this is the right place to post my question.

I havea home-cinema 5.1 set-up.
The rear speakers are active tri-amplified Linn Kaber loudspeaker.

To power then I have a long run (about 10m) of interconnects that go from pre-amp to the so-called "Tunebox".
The tunebox is a an active filter that separates sound in treble, mid and bass so each speaker is amplified only with it's own range of frequency.

The Tunebox feeds 3 SMSL SA-98e power amplifiers.
One handles treble, one mid and the last one bass.

Now, when I use some interconnects that go from the Tunebox to the power amplifiers, I get a really loud "bbbzzzzz" in the loudspeakers even when not playing anything at all.
With some others, I still have that, but really low.
And with other cables, I have nothing at all...

Any explanation on this ?
Can RCA interconnect (or should they) have some shielding or something ?

Thanks a lot for your thoughts.

 

[Blur]

Some RCA cables have better shielding for sure, but most of the time it’s as simple as the dimensions of the plug and how it mates with your gear. If it’s too shallow or has too small of a diameter then the grounding will be poor or non existent.

 

[PenguinMusic]

Some RCA cables have better shielding for sure, but most of the time it’s as simple as the dimensions of the plug and how it mates with your gear. If it’s too shallow or has too small of a diameter then the grounding will be poor or non existent.

Hi,

Thanks for your answer.
So the problem is not the cable, but the connectors ?
That makes sense indeed.

So that is why the cables I made myself with decent cable but top connectors may be the ones producing the lowest "bbbzzz" in the loudspeakers ?

Regards.

 

[Zek]

Your cable must be double shielding and have firm connection, for such a long length.

 

[PenguinMusic]

Your cable must be double shielding and have firm connection, for such a long length.

Hi,

The long run cable that goes from pre-amp to Tunebox is not the problem.
If I remove it, the "bbbzzz" remains.

So the problem is in the link between the "Tunebox" and the power-amps.

And there the used cables are rather short ones (from 75cm to 1.5m).

Regards.

 

[mansr]

Some RCA cables have better shielding for sure, but most of the time it’s as simple as the dimensions of the plug and how it mates with your gear. If it’s too shallow or has too small of a diameter then the grounding will be poor or non existent.

Gently pinching the ground ring on the plug with a pair of pliers can help with this.

 

[PenguinMusic]

Gently pinching the ground ring on the plug with a pair of pliers can help with this.

Hi,

Cool... I will try that. I have several interconnect cables, so if one is lost it isn't that bad.

Regards.

 

[PenguinMusic]

Hi,

It seems the problem is with the power supply.

As I said already, the 3 amps are hooked into an active filter for active tri-amplification of the speakers.

So :
- 1 amp is used to power treble
- 1 amp is used to power mid
- 1 amp is used to power bass.

Now, on powering on the amps, I had that really loud "bbbzzzz" in one speaker.

I shut down the amps successively and found the culprit.
It was the one powering the treble.

So I switched the power supply between treble and bass dedicated amps.
After the switched, the "bbbzzz" came from the mids... while the treble were now inaudible.

To make sure I switched the power supply from the mids to the bass dedicated amp.
Now the "bbbzzz" was in the bass drivers.

And finally, I reset everything to the original config...
And "bbbzzz" came from Treble again.

So I definitely think that one of the power supplies is defective and produces something like a "ground loop".

I am in touch with Massdrop support to see what they work out to solve the issue...

But of course if any of you would have an idea, I'd be a taker