HI All,
Entered coach last week and heard a low-level buzz in speakers. Turning the Receiver/Amplifier off (or disconnecting 110v) stops the noise.
Ideas?
Thanks for your help!
Don
If the receiver has a ground lug on the back, as many older units did, try grounding the unit.
I checked the back of the Receiver/Amplifier and checked the wiring diagrams. There is no dedicated ground. I called the people that installed my home theatre, and they think that likely it is not the Receiver/Amplifier but may be something else electrical. Can't think of what it might be. Will be checking 110v connections to make sure they are tight. Any other ideas?
Don
What was the source selected (CD, radio, etc)? If you change the source, does the hum go away?
Does the power connector have a 3-pin plug with a ground or just a 2-pin?
What has changed or been installed since the hum was not noticeable until now? New TV? Ran some new wiring, etc?
Some inverters will introduce noise. Is this from shore power? Several other possibilities. See here: https://www.techhive.com/article/582313/how-to-get-rid-of-hum-and-eliminate-other-noises-from-your-audio-and-video-systems.html''
Any reason for the old receiver? Newer 12V head units are cleaner and HD FM/AM is an option. HD FM does sound a lot better. But I love the look of some of the legacy receivers.
Pierce
Might try turning off all 120Volt power. There may be some sort of motor or faulty unit that puts out a small signal . Unplug the battery charger , etc.
Look close at anything with a transformer.
After that ,I would power the radio with a separate battery.
Changing the source does not change the hum.
The power connecter is a 2-pin plug.
Turned off all circuits one by one via 110v breakers. No change in buzzing. Home theater system is 110v only (no 12v).
Maybe get a small surge protector to use in front of the connection to the coach?
Plug something else into the plug electronic that has a speaker connection or try a cord from a different source.. Like mentioned the ground could have an issue but probably a bad receiver (its old).
Probably time for a new one... I always tell myself "Its outdated" and buy a new one lol.. Has worked so far and I have limited problems.
What has changed or been installed since the hum was not noticeable until now? New TV? Ran some new wiring, etc?
Is there a ground screw on the back anywhere?
I removed the head unit 2 years ago and put in a pioneer system that the previous owner had left with the coach. This is in the dash 12 volts. I put MB court speakers where the old Bose speakers were and the one that is above the kitchen counter buzzes from time to time. I have not been able to figure it out and it does it. Even sometimes when the power is off. The head unit goes through a pioneer amplifier located underneath my jackknife sofa where I also have a new subwoofer where the old bose unit was. Haven't been able to track it down. It's annoying but when I turn off the head unit of course it goes away. I'm suspecting some loose wiring is causing it but I don't know for sure.
12V car stereo head units are terrific and the higher end models have HD FM.
You can put your entire library on a flash drive. Best is FLAC or ALAC where there is no loss compared to a CD. Most all head units have USB in on the back and front both as well as a mini jack input from a phone, tablet or laptop.
Apple Music is inexpensive, especially if you share it with other family members. Google has a like service. You do need internet for this.
If you come out of a laptop, you can set the sound stage width, equalize, select analogue sound, etc, etc.
Use a flash drive to send the music to your head unit, video to your 4K TV.
Or, just use a smart phone, laptop, etc to go directly into a 12V amplifier for 2 or 4 channels plus woofer. No need for a head unit and it will still do Siri, etc.
I have a Kenwood single DIN (size) It has a great sound but the display is not as readable as it should be. Having good visibility is very important. If you have an older Foretravel, you may be limited to a single DIN size or a larger motorized screen. Later Foretravel have room for a double DIN.
I've led a Big Band for many years plus I run the sound board with a MacBook Pro into a $300,000 sound system several times a year. Photo taken about an hour before curtain.
Monsoon planar speakers are hard to beat for everything above 500Hz. Flat, small, they don't take up much room. They are out of business but in high demand today. You can hear the difference even with elder ears. OK, they are not Altec horns but our computer room or U300 does not have the room either.
Good to study and plan well before you buy. Read customer reviews on Amazon for the best information. Lots of great equipment available on FB Marketplace so you don't have to spend a lot of cash.
Pierce
A couple of months ago I changed the motorized Winegard batwing to a Winegard Razor automatic. Simply unplug the wiring on the roof and plug into new unit. Has worked OK. Buzzing started about a month after the antennae change. I don't believe that it is related. No other changes.
No ground screw that I can see. Not illustrated in wiring diagrams.
Is the Winegard batwing connected to this receiver? If so, disconnect and see if that affects the hum.
If not, start disconnecting source inputs until you find what is giving the hum. If you're down to nothing but the unit and speaker wires, time to replace.
A hum in a speaker: the first thing to look for is a bad wiring connection, everything may work but the bad connection can cause a hum.
My first instinct is to ask, Does the system have a powered Sub-woofer?
This will help to block noise injected by other AC circuits. And it's cheap as chips. Choke coil (https://palomar-engineers.com/rfiemi-solutions/AC-Power-Cord-Choke-Power-Cord-120VAC-RFI-Range-1-30-MHz-28-dB-Noise-Reduction-15-Amp-p439676105)
Ended calling a local AV expert who was willing to work on a motorhome. Determined that the receiver itself was bad. He recommended trying to find a used/refurbished unit. He thought that likely I could find 1 on Ebay. Lucked out and found 1 for $125. Installed within a week and has been working OK since. In the process, determined that the remote turned all components on but did not turn off AV Receiver/Amplifier or Direct TV satellite box. Likely both have been on for months (if not years). Just have to remember to turn off manually until I can figure it out.
It's a Hobby!!
Don
Plug them all into a single powerstrip and turn off powerstrip when you want things off to conserve inverter battery or when extended time not being used. All devices have live, active components when turned off, especially satellite receivers that are almost fully on ready to record shows.
Don very likely it had a bad filter capacitor in the power supply. New used one may last for years, they live in a harsh environment and are actively going threw a continuous earthquake
Scott