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Picking Up Radio Signal


Pete the bean

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I was getting a lot of hum from my UHL X3-2 when running UHL X3 direct to monitors. I also got hum from the X3 when running my live rig. I emailed UHL and was reassured the X3 has a top notch power supply and the hum problem is on my end. I added an EB Tech hum eliminator and that solved the problem.

 

I added a mixer my studio setup so I can connect my Yamaha CP1 and X3 to the monitors. Now I get the local punjabi station in the monitors. If I remove the CP1 from the board I still get punjabi music from the X3 signal chain.

 

If I pull the hum eliminator out of the chain and go X3 straight to the board I get a ton of noise in the signal but no punjabi music.

 

 

 

The X3 only has 1/4 inch output jacks. The cables from X3 to the board are 20 feet in length but I need the length to get from X3 to the board . The cables from the hum eliminator to board are 12 inches.

 

 

Any suggestions on what I need to do to get a clean signal to the monitors?

Yamaha CP1 UHL X3-2 QSC K10's
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It are a typical guitar problem.

Often with long cables, and a mix of effect pedals in the chain.

Perhaps you can temporary try shorter cables between the X3 to the board.

/Bjørn - old gearjunkie, still with lot of GAS
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HAHA...this happened to me once with my Fantom G6 except it was a religious Korean broadcast. I actually recorded it!

Korg Kronos 61 (2); Kurzweil PC4, Roland Fantom-06, Casio PX-350M; 2015 Macbook Pro and 2012 Mac Mini (Logic Pro X and Mainstage), GigPerformer 4.

 

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For a brief time, I would use a cheap Danelectro phaser pedal (purchased used for about $20) with my Wurlitzer. One time I brought it to a radio station gig, and to my horror, when I turned on the Wurlitzer, the station began broadcasting through the built-in speakers. I had to remove the Danelectro pedal from my signal chain. Haven't used it since... we'll see if it behaves better the next time I'm asked to cover No Quarter.

Samuel B. Lupowitz

Musician. Songwriter. Food Enthusiast. Bad Pun Aficionado.

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I would go with balanced lines as much as possible -- they are designed to phase-cancel AM RF interference. If the X3's outputs are balanced TRS, try running that to the mixer. If they are TS unbalanced, use a short cord (plural if running stereo) to a DI box and run balanced for the 20 feet to the mixer.

 

Also, if the monitors are powered speakers, stick with balanced lines; it they're passive speakers, run balanced line from mixer to the amplifier.

-Tom Williams

{First Name} {at} AirNetworking {dot} com

PC4-7, PX-5S, AX-Edge, PC361

 

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I would second the troubleshooting suggestion of short high quality cables.

 

If that solves the problem, even if you don't have balanced outs, try higher quality long cables. There is a very wide variation in cables. First, the dielectric strength and configuration of the cable/shield. Cables can have capacitance. I've had guitar cables going to an amp where, because of the capacitance of the cable, you could step on it and hear a pop in the amp. Stepping on it squeezed the insulator and if you've ever studied parallel plate capacitors, the change in insulator (by squishing it to a smaller distance) changes the capacitance.

 

Well, RF antennas and circuits use capacitance among other things to tune in the frequency.

 

None of this would matter with proper shielding. I've seen cables range from as little as 55% spiral shield, to 95% braided shield, to 100% foil shield (with a drain wire). The shield with proper grounding will block out all RF interference.

Dan

 

Acoustic/Electric stringed instruments ranging from 4 to 230 strings, hammered, picked, fingered, slapped, and plucked. Analog and Digital Electronic instruments, reeds, and throat/mouth.

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I no longer use OTS cables and I build my own. My cable choices are Canare L-2B2AT with 100% foil shielding plus drain wire for internal rack wiring, or Belden 8410/8412 with 95% braided shielding for outer cabling. Never had RF issues with my DIY cables.
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Years ago my Motion sound Pro3T would pick up a radio station which was down the road from one of the clubs we played. I believe I narrowed it down to the tube in the MS. Never was able to eliminate it.

57 Hammond B3; 69 Hammond L100P; 68 Leslie 122; Kurzweil Forte7 & PC3; M-Audio Code 61; Voce V5+; Neo Vent; EV ELX112P; GSI Gemini & Burn

Delaware Dave

Exit93band

 

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If you are too close to a station, especially a high-power one, the electromagnetic field can be strong enough that the only way to eliminate pickup is to get further away.

While I was CE of a local TV station, at a time when the 25KW transmitter was on-site; we had problems with video buzz in the studio microphones. Even using Belden with 100% foil shield and drain wire didn't get rid of it. Had to get some special RCA cable that had the foil shield, and that was inside insulation with an extra 100% shield around it. The outer shield was only connected to ground on the console end to provide a Faraday cage type shield.

Could have been fired over that one. Owner of the station would come down from up north and complain to me about the buzz. I contacted RCA Engineering and they recommended the cable, which was QUITE expensive. Ordered it, didn't get it. Owner came down again, asked me why it wasn't fixed. I told him that I had ordered the needed cable and that some idiot had cancelled my order (assuming it was someone in Purchasing). Turned out, owner cancelled it because of the expense. He told me that he would order it, but if it didn't fix the problem, I was gone. It DID fix the problem.

Some small victories are particularly sweet, and that was one.

Howard Grand|Hamm SK1-73|Kurz PC2|PC2X|PC3|PC3X|PC361; QSC K10's

HP DAW|Epi Les Paul & LP 5-str bass|iPad mini2

"Now faith is the substance of things hoped for, the evidence of things not seen."

Jim

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