BCD 536 connection to external amp

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ORE007

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Hello all,

I have been reading several threads on the external speaker output and the potential of damaging scanner. There has been talk about a Would an isolator like this Golvery Ground Loop Noise Isolator, Auido Humming Hissing Buzzing Noise Filter Eliminator for Bluetooth Car Audio, Home, PC Stereo System with 3.5mm or RCA Aux Jack https://www.amazon.com/dp/B076WKDH46/ref=cm_sw_r_cp_tai_pog3EbWGHWNRN work? I haven’t found a mono one so would a mono to stereo adaptor work?

The other option I might do is using an old iPhone and the app.

Reason is that in two counties around me they are changing to digital in a few months and I don’t want to replace 7 scanners throughout the house and instead using an amplifier with in-line volume controls.

Thank you for any replies or recommendations
 

prcguy

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A stereo to mono adapter may not work. If you need a mono one just get a 600 ohm audio isolation transformer, a 3.5mm male to female cable and cut it in half then solder each cable to the transformer. I would also put about a 100 ohm resistor across the radio end of the transformer to give a better load for the earphone jack. Total cost would be cheap.
 

n1chu

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Curious as to which threads you read that state possible damage to the scanner when using an amplified external speaker. To the best of my knowledge, as long as anything plugged into an external speaker jack does NOT provide a voltage or amp level greater than zero, the worst results experienced would be if the contacts were shorted together... which would produce no audio. So, how could any damage to the scanner happen?
 

Ubbe

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You can use a standard ground loop galvanic isolator. If used with speaker output it will be a mono signal, only audio at tip and sleeve.
If used with earphone output it will be stereo as tip and ring are connected together.

/Ubbe
 

ORE007

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Curious as to which threads you read that state possible damage to the scanner when using an amplified external speaker. To the best of my knowledge, as long as anything plugged into an external speaker jack does NOT provide a voltage or amp level greater than zero, the worst results experienced would be if the contacts were shorted together... which would produce no audio. So, how could any damage to the scanner happen?
It's an (very) old thread but Bcd536hp external speaker connection considerations and precautions is one. I guess it says that the amp might be damaged.
 

Ubbe

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It's an (very) old thread but Bcd536hp external speaker connection considerations and precautions is one. I guess it says that the amp might be damaged.
The ext loudspeaker signal goes between sleeve and tip and the ring are not used. The sleeve are not grounded to the scanners chassi or 12v ground, it is a floating signal that should not be grounded. That's the reason why the jack is totally isolated from chassi ground. No problem using a proper ground loop isolator.

It's same precations you often see at other places like car stereos, never ground any speaker leads.

/Ubbe
 
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