Humming from Ramsey 25B... - Christmas Radio/Music/Videos/etc. Read Only. No more posting. - PlanetChristmas! Forums. Read Only. We've moved to http://talk.planetchristmas.com - The Forums of PlanetChristmas have moved to http://talk.PlanetChristmas.com
I decided to check our transmitter from last year out...and it hums slightly between songs. Why is this? How can i fix it. It came put together when we bought it last year. I am a dummy when it comes to electronics...
It depends on where the Hum is coming from. Some people have complained that their Ramsey transmitters HUM and it is just how they are made.
You may want to buy a Ground Loop Isolator though to see if it helps you.
I have seen this Scosche one at Wal-Mart and it works pretty good. It will be in the Car Audio Department. I had a slight Hum on my transmitter and used this and it totally took it away. I have also used them many times when setting up sound systems and wanted to quickly get rid of the hum.
ChuckHutchings wrote: Try moving the transmitter around while you listen to it on the radio. There might be something in the environment causing the hum.
Try to keep it away from power lines and metal objects (like windows).
I have to keep mine elevated a few inches above the sill that it sits on or I'll get hum.
Yes try those first!
It is important to move your transmitter away from any computers or electrical sources. I have a 20' audio cable so I can put my transmitter far away from my laptop, electronics, or power sources.
If you still get hum, try the Group Loop Isolator.
Snow,
As Jeff said I too had a humm in the transmision background. The fix that worled for me was to replace the power supply that came with the unit. I purchased a "regulated" power supply from Radio Shack for about 18.00. No more humm.
macrosill wrote: Snow,
As Jeff said I too had a humm in the transmision background. The fix that worled for me was to replace the power supply that came with the unit. I purchased a "regulated" power supply from Radio Shack for about 18.00. No more humm.
Good Luck.
Would plugging the wall wart into a UPS accomplish the same thing?
What are you using to play music through your transmitter? Your computer? Which jack(s)? Knowing this will help, but here are some basic suggestions:
I would first look to your music recordings. Are they "clean" when played through something else? Even the silences between?
I would then look at your gain structure. Are you sending a weak signal to the transmitter, then having to turn it or your FM receiver up to get a decent volume level? Start with the strongest, cleanest audio signal from your playback source as possible. If this is your computer, you may need to adjust various voume levels. The best rule of thumb is that no one part of your audio chain should be "cranked" while others are set low. The "cranked" device will introduce noise that will just be passed along by the other parts of the chain.
The location of your transmitter is also another good place to look. Also the cables that are feeding the audio signal to your transmitter. If they are running parallel with power cables for a few feet, then you could likely pick up the 60-cycle hum from your AC power. Don't overlook where you've gotten power for your transmitter either.
Try moving the transmitter and listen. Try different antenna positions. Then try running your audio cables away from everything else electronic. Then try another power outlet/circuit in your house. You may end up with your transmitter only a few feet from where it was and your problem goes away.
Unless you just have hum in the silences of your recordings, the hum is most likely always there, it just isn't as apparent when music is playing.
ChuckHutchings wrote: Would plugging the wall wart into a UPS accomplish the same thing?
Only if there's some sort of line conditioning in the UPS.
I can usually minimize the hum to a barely-noticable level by making sure the power cord and the audio cord don't run parallel to each other, going to the transmitter.
I suspect to totally eliminate it, you'd have to buy a better power supply, as others have suggeted. But you can't notice mine unless I'm broadcasting silence and then you crank things way up...
I agree with Tim. I have a Ramsey FM30 and I have it near the PC. But the audio and power cables go in two different directions. The hum is barely noticable.
The regulated PS is the way to eliminate it though.
I built my FM30 and found that the connection between the case and the circuit board was slightly loose, when I moved the board around the hum would change intensity. The cause of the hum was due to a poor case to circuit board ground connection. I installed some copper braid (solder wicking wire) on both sides between the board and case to snug up the connection. This cured all humming issues. I run my transmitter everyday listening to my mp3's or audio streaming on the shop stereo, while doing important work (playing with my toys) and I've not had any other issues.
tfischer wrote: I can usually minimize the hum to a barely-noticable level by making sure the power cord and the audio cord don't run parallel to each other, going to the transmitter.
I suspect to totally eliminate it, you'd have to buy a better power supply, as others have suggeted. But you can't notice mine unless I'm broadcasting silence and then you crank things way up...
-Tim
The other way you can do it, (as most wallwarts don't use the best filtering!), is to install a simple common mode choke. The easiest thing to do is to get a ferrite core (a circular ring/clamp on device which you can get from elecrtical supply houses, and even one or two varieties from R Shack) that goes over the power supply lead to the radio.
For the frequencies we are dealing with (as far as 60 cycle hum goes), wrap about 7 turns of your power cable through the choke, and that should help, if the power supply is the source..
While you can compensate by increasing the audio level into the radio (and decreasing the level internally via the pots for the L & R audio channel inputs in the transmitter), that does not remove the problem, it only masks it).
Another tip I remember reading from the Ramsey site -- if possible, hook up a battery source to the Ramsey tramsmitter. You need a 12V source, which could be done by placing 8 standard cells (e.g. AA, C, or D) in series, and connecting them to the back of the Ramsey. Batteries are a pretty good clean power source, so if you still get hum from them, your problem isn't the power supply. If the hum does go away, try some of the other suggestions mentioned, such as Greg's choke.
Good luck,
-Tim
Last edited on Saturday September 1st, 2007 10:07 pm by tfischer
tfischer wrote: Another tip I remember reading from the Ramsey site -- if possible, hook up a battery source to the Ramsey tramsmitter. You need a 12V source, which could be done by placing 12 standard cells (e.g. AA, C, or D) in series, and connecting them to the back of the Ramsey. Batteries are a pretty good clean power source, so if you still get hum from them, your problem isn't the power supply. If the hum does go away, try some of the other suggestions mentioned, such as Greg's choke.
Good luck,
-Tim
Normal battery cells are 1.5v Tim, not 1v. You would need 8 cells, not 12.
oldcqr wrote: tfischer wrote: Another tip I remember reading from the Ramsey site -- if possible, hook up a battery source to the Ramsey tramsmitter. You need a 12V source, which could be done by placing 12 standard cells (e.g. AA, C, or D) in series, and connecting them to the back of the Ramsey. Batteries are a pretty good clean power source, so if you still get hum from them, your problem isn't the power supply. If the hum does go away, try some of the other suggestions mentioned, such as Greg's choke.
Good luck,
-Tim
Normal battery cells are 1.5v Tim, not 1v. You would need 8 cells, not 12.
12 cells = 18v
D'oh. Total typo on my part. I'll fix it above.
Thanks for the catch,
-Tim
Last edited on Saturday September 1st, 2007 10:07 pm by tfischer
I've watched this thread with interest since I also own a Ramsey FM25B and have had constant buzzing on my unit as well ever since I built it from a kit last year.
I've tried a lot of suggestions to fix it, including different power supplies, more filtering, re-routing of cables, etc. I haven't tried the battery test yet, maybe I will.
In the end, I guess fiddling around with things (especially cables) did make it a little bit less "Buzzy", but the buzz is still there. Especially louder during the silence between songs, almost as if an AGC circuit was kicking in and raising that gain up with no signal input.
I was so dissatisfied with the FM25B that I ended up not using it and reluctantly purchased a Ramsey FM100 (based on a recommendation). While others have posted on here and said that the two transmitters share the same circuit design, I can tell you that the FM100 sounds better and doesn't have any of this associated hum.
I have no idea why some folks have trouble with their FM25B and others don't, maybe they don't notice the hum? At this point, I think it's part of the design of the transmitter.
Has anyone ever been able to completely make the hum go away? I'd like to hear what you did to accomplish that...
Thanks, Randy
Last edited on Saturday September 1st, 2007 10:37 pm by Randy
![:]](/images/emoticons/big_grin.gif)
