Noise suppression and the yellow wire

[John Langford]

Is there an audiophile in the group? In the course of exploring the electronic bowels of my new (to me) boat I notice that the previous owner installed a Pyramid 20amp noise suppressor as part of the aftermarket car audio system. A couple of questions. Is this device necessary if I don't run the audio system when the engine is on? Second, does it draw much power? It seems to be powered from a small secondary breaker panel with 3 amp plug in fuses but I haven't been able to sort the whole scene out yet.

A related audio question. There seem to be two power connections to the am/fm/cd unit. One is the red wire which goes to a breaker on the main panel and the second is a yellow wire  which goes directly to the house battery connection on the main battery switch. Both are fused. What is the purpose of the yellow wire? Why is it connected directly to the main battery switch and is that the best way to do this? The readings on my e-meter suggest that even if the battery switch is turned to the starter battery, the power for the audio system continues to come from the house battery. Is the audio unit effectively being powered through the yellow wire?

Cheers
John

[Jim Price]

I am not an expert, but I recently upgraded the audio on Lady Di and the "yellow" wire to battery for continuous voltage is to keep settings memory intact.  Since units are basically car type anyway, that is the same on your auto, small voltage hot wire to keep stations set, security codes, etc.  You don't have to use but you will never have a radio pre-set.

 :confused:  I also have noise question.  I have to kill Truecharger when on shore power if playing radio.  Stations are interfered with and Admiral gets upset.  Is there something that can be added to radio circuit that eliminates the noise??

[Mike and Theresa Vaccaro]

John,

Jim's right about the additional power (yellow) wire, only maintains the memory features.  Keep in mind, that this will always place a drain on the batteries, albeit a very small one.  

If you don't have a noise problem, then you don't need a suppressor.  Typically, the source of noise is a battery charger located relatively close to the stereo.  Most solid state chargers (e.g., Guest Bluewater, etc.) don't cause RF problems.  Other, larger types may.  For example, Charles produces two high capacity lines, one of which (the "bargin" version!) does not include RF protection.  RF can also be produced by induction motors on board--typically an inexpensive fan motor.  Alternators are also a possible source of noise.  The bottom line, if you listen to the radio and there's no noise, you're good to go!  Another option is to limit the source to CD's or tapes--much less likely to have a noise problem with a local signal source (but still possible).  If the previous owner installed a suppressor, there was probably a reason for it and no harm maintaining it.  One way to determine amperage draw is with an appropriately installed amp meter, another is to check the label on the component.  If it doesn't list draw in amps, it should in watts--then you can do the math.

Life is good when you can get around to sorting out the stereo vs. electrical, fuel, rigging, steering, etc.!!!  I've found beer to be beneficial during this type of introspection...

Cheers,

Mike

[BillR]

I'm having the same noise problem with the Truecharge battery charger.  Pain.

[Ben]

I also have very bad noise problems with the Truecharge unit, in fact I can not use the radio unless the Truecharger is turned off!

[Mike and Theresa Vaccaro]

Might want to check with a car audio specialist to find out if there is a supression system that will work with the charger on.  If anybody would have a solution, that would be the place to look.

May or may not be practical, and another reason why a good charger is so expensive!

Best of luck,

Mike

[John Langford]

Since I started this thread I should report that the Pyramid noise suppressor does deal effectively with any noise that might emanate from the ProMariner Flyback Charger. I am planning to disconnect the suppressor and check radio performance with the charger, Espar system etc. Will report back.

What a nuisance about the Truecharge. It was going to be my new charger when the Flyback packed in. I understood it was the best charger on the market.

Cheers,
John

[Jim Price]

Be interested in your testing, plus any additional info on how it is wired if test is conclusive.

Truecharge is great from charger experience. Absolutely no other interference on anything else.  It just happens to be attached under nav table and AM/FM radio is mounted in hanging locker cutout above nav table.  Actually only about 12" - 15" apart.  I also have a AC/DC TV sittng on top of locker above radio and it works fine.  I did not have any problems with old radio mounted on right hand side of shelf above AC/DC panel but it was crap anyway so who knows.

[Stu Jackson]

John

Please don't base your charger selection on a little noise issue.  Your batteries are a lot more expensive, and an inexpensive noise suppressor is a lot cheaper than not getting a quality charger.  A lot, as noted, has to do with how close your charger is to your radio.

I get the same noise on my radio with my Heart Freedom 1500 Inverter/Charger, but only in charging mode, and my radio is mounted port side above the sliding doors under the deck, pretty far away from the charger under the nav station desk.  I learned to live with it, although I can't admit to being a true audiophile.  Then again, I'm rarely plugged in.  If it bugs me, and it has, I play a tape or a CD.

Get the good charger and get the suppressor.

Stu

[David Sanner]

You might try relocating your antenna to cut down on the noise.

I had the same problem with my Truecharge20 creating noise on some stations.  It turned out the PO had just stuck a basic automotive antenna in the area just below the electrical panel, about a foot from the charger.

I moved the antenna forward and that seemed to help some, at least for my radio. (I've heard that most radios built these days have some sort of noise suppression already built in to the power circuit)

If you're having noise when playing CD/tapes then you may have a problem different from mine and the noise is coming through your power source.

[Ted Pounds]

That's probably why I don't have a problem with my Truecharge - my radio is spliced into my VHF antenna at the masthead. Also, you might consider turning off the charger when playing the radio.  Unless you're living on the boat with the radio on all the time it shouldn't be a problem for the batteries.  Just don't forget to turn the charger on when the radio is off.  Just a few thoughts...

Ted

[Ted Pounds]

By the way, the one drawback of using the VHF antenna for the radio is that when I talk on the VHF the radio noise is REAL BAD.  :eek:

Ted

[kss1220]

Ted:

I also use the VHF atenna for the radio.  I added a coax switch and can manually turn it to which ever device I am using at the time. Obviously it eliminated any noise. It does not allow the use of both devises at the same time.

Kelly

[karista]

I also have the noise problem with the Truecharger, I moved it into the forward V-berth hanging locker, hoping that the distance to the radio would eliminate the noise level. It did not, also adding various filters/suppressors into the line did not help much. I contacted the Truecharge technical dept., they basically confirmed my situation and let me to believe this was a known common situation with this charger. I will probably look for a alternative charger next time, now I just turn it off when on the boat!
Bernd Mueller

[hdevera]

Bernd,

I have a West Marine (Heart)Inverter/Charger mounted underneath the sink and had no problems with radio noise.  Invertger/Charger work fine.  When it's time to replace your charger, consider this brand.