speaker buzz

Archived from groups: rec.audio.tech (More info?)

Chris wrote:

> Hi I'm new to the group and a newbie at wiring stereos so please bear
> with me. On my boat I installed a new Kenwood receiver and a new Sony
> CD changer. Connected to an older (6 yr.) Kenwood equalizer ans Sony
> 3040 that's the name amp. I've installed new speakers outside, checked
> and upgraded all my speaker wires and connections but there is a buzz
> in both sets and wasn't there in the old system. I've connected a
> ground wire from the stereo power neg busway to a copper strip which
> runs all thought out the boat. I've checked the resistance on the
> copper by setting my meter to 20K touch both prongs together and get
> 0.03 rating. I then placed both prongs on the copper wire and the
> resistance reads 0.03 but still the buzz. If I disconnect this #16
> ground wire it of course gets louder. I've tried a heaver ground wire
> #8 no change still the buzz.The power wires +/- to the amp are #8
>
> Where next do I get better RCA cables than Radio Shack and if I need a
> separate ground for the amp where do I attach it....to one of the
> mounting screws holding the amp to the boats wood interior? The buzz
> is making me crazy trying to get rid of it in both the radio or CD's.
> I've also turned off at the panel board all other items, no motor and
> still the buzz. Today I cleaned and tightened all battery connections
> you guess it still there

Can we assume you have an inverter on the boat that supplies 120VAC to
the stereo system? Have you tried plugging this system into normal mains
and is the buzz still present or not?

My guess is that you have an inverter which does not supply clean enough
power for your stereo system. If true, the question is does the buzz
come from RF interference or the power directly. You may be able to
filter the power but are not likely to get rid of RF.

If you are using an inverter, consider buying a higher quality unit.

Archived from groups: rec.audio.tech (More info?)

>The system is 12volt setup for a car and the inverter on board is top
>of the line but not even on. I think the problem is somewhere in the
>ground or from the amp just need some advice to where else I should
>search...

Does the problem exist only when you're hooked up to dockside power,
and have a battery charger operating?

Many chargers put a rather ragged voltage waveform into the battery...
the charger's output is not regulated. The buzz could result from the
voltage/current pulses on either the "hot" wire, or on the ground.


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Archived from groups: rec.audio.tech (More info?)

In <2e0deff0.0504271844.2efd2894@posting.google.com>, on 04/27/05
at 07:44 PM, cmlove2003@yahoo.com (Chris) said:

[ ... ]

>Where next do I get better RCA cables than Radio Shack and if I need a
>separate ground for the amp where do I attach it....to one of the
>mounting screws holding the amp to the boats wood interior?

Attaching to the wood will not be productive. Better cables *MAY* help,
but probably not in this situation. Hold off on new cables.

>The buzz
>is making me crazy trying to get rid of it in both the radio or CD's.
>I've also turned off at the panel board all other items, no motor and
>still the buzz. Today I cleaned and tightened all battery connections
>you guess it still there

Make sure *ALL* of your electrical and electronics are off -- including
any "high tech" lamps that may be using an inverter or dimmer and your
computer. Disconnect your dockside umbilical -- especially the ground
wire. Run the stereo from the battery. Hopefully, there will be no buzz
and you can bring devices online one by one till you find the trouble
maker(s). In rare cases the problem source could be in your neighbor's
boat or a nearby radio or radar transmitter.

Fabricate a "shorting plug" from an old interconnect cable by twisting
the shield and center conductor together. Plug this into the power
amplifier's input and listen to the system. Once we've proven that the
amplifier is not creating the buzz, we know that external items
contribute to the problem.

Is this only a dockside problem? If so, do you have a cable TV
connection?

Probably, this is a "ground loop" problem. Ground loops are like an
argument -- one person cannot have an argument, it takes two or more.
And, like the argument, it can be difficult to get to the root cause of
the issue.

Your audio system should be connected to the boat's "ground" at a
single point. Don't use the ground to connect one side of the speakers.
By "audio system" I mean anything connected to the stereo. This
includes an external radio antenna that may be connected to the ground,
a computer, a TV ... anything with a metal connection to the stereo. In
some situations you may need to run a separate ground wire back to the
battery.

But first, make sure the amplifier is quiet when you use the shorting
plug.

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