Tips for radio interference?

[northoak]

I tried some headphones and the radio interference doesn't show up but the high pitched whine still does. The only thing I can think of is that my headphones are stereo while the audio cables im using are 1/4 mono cables. I'm not sure if that is relevant but will probably go buy a stereo 1/4 cable and see if it helps.

My other thought is that maybe there is a ground loop even though my amps are plugged in on a different side of large room

thanks again

[KC9UDX]

Especially because they're on the other side of the room. That's the best way to create a ground loop. :)

The high pitch whine might be ever-present, but not reproduced by the inbuilt speakers. You may be able to eliminate it with a low pass filter, or simply with a tone control on an amplifier.

Try reversing the polarity of your amplifier cables. This may or may not be easy for you to do, it's easiest to do with a pair of alligator clip leads.

[Goff]

Radio broadcast bleed is very hard to erase if your location or instrument is plagued with it.

Short of building a Faraday cage good enough to filter out the interference over the building there isn't much that can be done at once if the organ is picking up broadcasts.

Once did a session at a recording studio. A nearby radio station's feed was coming in the headphones.
They tried putting a screen over the building but it didn't work. It would need to be everywhere, the doors, windows.

The only solution would be one would have to move. The radio station or the studio.

If a simple addition of a filter to the offending circuit in the organ is not easily done, then perhaps shielding the inside of the organ cabinet.

You might try what guitar players do and that is rotate the organ position in the room to see if you can get out of phase with the radio signal.

May also try, (wild guess) is a SHIELDED power cable.


BELDEN 19364 SHIELDED MAINS POWER


Asking a tech to find where the line signal to the internal amp is and securing it's a shielded line, fixing or replacing the length of wire?

Could be something as simple as a ground spot is loose or the shield around the electronics is not grounded well enough.

If that doesn't do it, maybe re-flowing all the solder joints on all the circuitry might chase that demon down.


I sold a lot of Teenie G's (TG-1) back in the 70's working for Capitol Music, a Lowrey dealer in Hayward Calif. Never encountered this.

Pat and Sandy DeBellis were managers at Capitol.

[northoak]

That's awesome you sold the tgs, back in the day, maybe I have one of your old sales since I'm nearby in Oakland!

[trobbins]

Can you clarify your audio path from organ to speaker where you hear the radio signal? It sounds like you are using an external amplifier/recording device and speaker, but you also identify three locations, and also identify that with only a power cable connected to the organ (no audio path cables connecting to other equipment) then you don't hear any radio through connected headphones?

[northoak]

The am radio interference ended up being a ground loop that was solved by plugging into the same power strip as the amp. I'm going to try running an extension chord because my amp is always behind our drummer and I'm out front, wish me luck.

the high pitched whistle is a lil hard to eq out and live and is present regardless of what amp I'm using. I'm wondering if there is some internal way to filter it out.

As far as my signal path goes, I'm going from my headphone jack on the Teenie geenie to a 200w Sun concert keyboard head which then goes via a 1/4 in speaker cable to a 2 by 12 cab.

I tried adding a three prong cable with the ground wire goin to the chassis of the power supply and then to the metal of the organ and the hum was terrible! So much for that idea. Probably going to try some alluminum tape for added shielding.

thanks for all the help! I definitely learned some things

[trobbins]

Are you saying the 'whistle' is just coming from the L50 when only headphones and power are connected ?

[northoak]

Turns out I spoke to soon! :-( The radio interference is still present but significantly quieter. We had practice last night and when I get loud enough to be heard over the drums and bass the radio is faintly present. The whistle is there when I use the headphone out to go directly into my amplifier head. I can't hear it with headphones but I imagine that is only because the volume is not pushed to an extreme by an external amp.

[trobbins]

Ground loop may cause the 'whistle' - especially if you can somehow confirm there is no 'whistle' when either using sensitive headphones, or using an optically isolated DI box, or recording to a battery powered device and then checking the recorded signal for whistle.

The radio may be a pickup from other cause than just the organ - such as the speaker wires letting some radio signal interact with the power amp - or the signal lead entering the amp. The time-honored suppression mechanism for those causes is a small ceramic cap from signal socket terminal to chassis, with cap leads as short as absolutely possible., and possibly a ferrite bead or two over the signal wire existing the socket in the equipment. Check the web for examples and generic schematics.

[ducrider]

Hello all, not sure if this is the correct place to post this, but here goes... I have an old (of course) Baldwin Cinema II home organ. It picks up a local FM talk station, and plays it through the internal speakers. It seems worse with certain stops engaged. For some time, moving the pedal board around seemed to cure the issue, but that s no longer the case, it comes through all of the time, just at varying levels of intensity. I'm not inclined to work on it myself, but if you could offer suggestions that I could pass along should I hire a repair person, that would be helpful!

[myorgan]

Ducrider,

Welcome to the Forum. From my quick perusal of this thread, it appears your solution would be similar to those already discussed. That said, however, I'm not (by any means) an expert on Baldwin organs. Please wait for our techs to weigh in, and they'll give you excellent advice based on their vast experience.

Again, welcome to the Forum!

Michael