8000dle Left/right spkr out protocol

greg
Posts: 8
Joined: Sat Nov 11, 2017 7:50 pm

8000dle Left/right spkr out protocol

Postby greg » Fri Nov 24, 2017 4:47 pm

New radio, rear speaker out 1/4" jacks apparently require stereo plugs as mono plugs short the audio out amps.
On initial setup, I just plugged in a set of computer mon units that used mono jacks.
All that was heard was popping thru the spkrs.
Headphone front jack worked fine.
Pulling the rear plugs part way out restored audio to both sparks.
The manual does say vaguely to use stereo spkrs.
Don't know why the rear panel jacks are ring/tip/sleeve wired.
Can the 2w output amps survive a dead short?
Amazing...
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w-u-2-o
Posts: 1142
Joined: Fri Mar 10, 2017 1:47 pm

Re: 8000dle Left/right spkr out protocol

Postby w-u-2-o » Fri Nov 24, 2017 7:42 pm

The reason that they are wired that way is because neither leg of the output of the 3W stereo speaker amplifier integrated circuit can be attached to ground. However, I agree, I would never have chosen to use a TRS connector for that connection. As rugged as it might be, and as convenient as it might be to arrange to terminate some shielded speaker wire, it nevertheless just begs for mistakes to happen, and they do all the time.

To understand the capability of the amplifier IC, go to the schematic section of the forum here and download any of the available radio schematics (the 8000 is not yet available). They all use the exact same parts and circuit for the CODEC and amp ICs. Then you can look up the datasheets, etc.

Just to confirm what the manual says: tip and ring connect across the speaker coil, shield connects to nothing but shield in the cable, if it has any.

If it was me designing it (and it wasn't!) I would have used some chassis isolated RCA connectors, or even some screw terminals.

73,

Scott

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