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Author Topic: AM Radio bleed out of the amp...  (Read 1570 times)

Jeff Bankston

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Re: AM Radio bleed out of the amp...
« Reply #20 on: October 22, 2020, 01:38:26 am »

thats the backup music if the band up and quits playing
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Jonathan Johnson

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Re: AM Radio bleed out of the amp...
« Reply #21 on: October 22, 2020, 07:09:10 pm »

I did see an interesting email as it went up the food chain:
Hi,
"I got this email from Frank. He has a good point. We had to use duct [sic] tape to hold the plug in, and it really should be a GFCI outlet. Could Jesus do this before the next service?"

Perhaps their electrician or maintenance guy is Jesus (pronounced hay-sooce).

Some keyboards offer balanced outs. If that one does, try using TRS balanced cables to the mixing console (or the amp, if it supports balanced inputs).
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Stop confusing the issue with facts and logic!

frank kayser

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Re: AM Radio bleed out of the amp...
« Reply #22 on: October 22, 2020, 11:01:26 pm »

Perhaps their electrician or maintenance guy is Jesus (pronounced hay-sooce).

Some keyboards offer balanced outs. If that one does, try using TRS balanced cables to the mixing console (or the amp, if it supports balanced inputs).


Of course it would be logical that their maintenance man is named Jesus (hay-soose). Further, I've only met four persons in the church, not including the maintenance man.  I'll just say the writing of which reads funny when attached to a church and asking for help. After all, the church prays to the Son of God, Jesus. It could be read figuratively - as in there's no money to get the work done, so we pray to Jesus for help and guidance.  It's like the song "Some say tomato, some say tomato, some say potato, some say potato".  Just as these lyrics lose something in writing, so would the not-so-divine request be without seeing it in writing.


I originally looked for balanced outs on the keyboard - no dice. 1/4" outs, with no mention of the jack being balanced/unbalanced. Amp is a <$100 Ibanez - works for what it is - certainly not high-end enough to have anything but the very basics i.e., no balanced ins.  Run what was brung.


thats the backup music if the band up and quits playing


Actually, not so much backup music as a replacement for the clergy - it's a Christian radio station.  There are enough of these funny coincidences associated with this church that it seemed planned.





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Daniel Levi

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Re: AM Radio bleed out of the amp...
« Reply #23 on: October 23, 2020, 01:48:12 am »

I would ask what keyboard is it?, not all keyboards tell you that they have balanced outs on them on the device, i.e. whilst my Motif XS7 does, I believe, but my Akai Miniak (Alesis Micron) and Generalmusic/GEM S2 does not (and even more confusingly the additional outs on the S2 are not balanced).
If you can find out/know what they keyboard is I can probably tell you if it has balanced outputs or not.
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Jerome Malsack

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Re: AM Radio bleed out of the amp...
« Reply #24 on: October 23, 2020, 10:51:29 am »

With unbalanced out and balanced out, behringer (ugh) has impedance balanced out 1/4 TRS on most of the mixers.  So from the opamp there is a resistor in line with the Tip. and an equal resistor on the Ring to shield.  and the shield to ground.  Giving you an impedance balanced out that will also work with TS unbalanced out.  The keyboards may be wired or connected this way but one has to verify with the company or open and inspect.  Most of the time I feel they only did the TS unbalance and the best answer for this is the short unbalanced cable into DI.

  https://www.sweetwater.com/insync/impedance-balancing/

« Last Edit: October 23, 2020, 10:59:00 am by Jerome Malsack »
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Jerome Malsack

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Re: AM Radio bleed out of the amp...
« Reply #25 on: November 01, 2020, 10:25:52 am »

Ok Frank,  How did things go on the second go around ?  Cold and wet guessing you did not go out. 

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frank kayser

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Re: AM Radio bleed out of the amp...
« Reply #26 on: November 01, 2020, 06:38:47 pm »

Ok Frank,  How did things go on the second go around ?  Cold and wet guessing you did not go out.


I sent you a synopsis of the result Saturday to your hotmail account.  The guts of which are here:

I've done some testing -
- My Mixer, RCF Evox, and Alto monitors are unaffected.
- Nothing leaking in via microphones.  Bob Heil did a good job with his PR22.
- As you pointed out, the two condenser mics were quiet.
- Leakage from Keyboard traced to 1/4" cords.  Too long.  I will use monitor off mixer instead.
- Guitar amp still has some broadcast noise - very near the noise floor.  We'll use shorter cords I know are newer and that have been handled with kid gloves.

The real bottom line is someone did a rain dance, and it was over before it began.  Next one in two weeks - weather permitting.

Thanks again for all you shared, and the offer of your amp rack/passive speakers Jerome.  That was a hugely generous offer.

Thanks to everyone else for helping me understand and sort out the problem.

frank
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Jerome Malsack

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Re: AM Radio bleed out of the amp...
« Reply #27 on: November 01, 2020, 07:52:44 pm »

Happy it was much improved and hope weather is better next time.
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Steve M Smith

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Re: AM Radio bleed out of the amp...
« Reply #28 on: November 02, 2020, 03:12:52 am »

In order to change RF to audio, it needs to be rectified. Dirty contacts can do this. They work much like the 'cat's whisker' detector in an old crystal wireless.


Steve.
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frank kayser

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Re: AM Radio bleed out of the amp...
« Reply #29 on: November 02, 2020, 10:48:18 am »

In order to change RF to audio, it needs to be rectified. Dirty contacts can do this. They work much like the 'cat's whisker' detector in an old crystal wireless.


Steve.

More goof info Steve.  I'll bring some Deoxit along.  Should be in my kit regardless.  FWIW, I find a .22 cal or .243 cal cleaning brush on a short rod perfect for lightly brushing the Deoxit into the 1/4" jacks.


frank
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Re: AM Radio bleed out of the amp...
« Reply #29 on: November 02, 2020, 10:48:18 am »


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