Is the Pro 95 earphone jack stereo?

[rrman987]

I have been using an mono "earplug" for listening. For comfort. I tried a set of stereo earphones and pleasantly surprised both earpieces audible and voice was "centered" rather sounding out of phase far apart. The manual does not say anything about earphone types to use (other than the usual see your Rat Shack dealer for best earphones yada yada).
Is the Pro95 using a stereo jack so stereo headset will work as well as mono sets? Earphone jack barrel is grounda and the tip is for mono or a stereo earpiece, and the middle ring is for other stereo earpiece, so can't visualize electrically how both sides are working..
I will take the comfortable stereo though, rather than the former lopsided listening of mono earplug.

 

[gmclam]

The jack is wired in an interesting manner where you can plug in either a stereo or mono headphone. As you've discovered, you'll hear audio in each ear of a stereo headset. Of course it's the same audio which is technically not stereo. An interesting challenge comes when wanting to use the jack to feed audio to an external amplifier or computer input. What I've done then is obtain the ground from the antenna BNC and audio from the tip connection of the jack.

 

[rrman987]

I wondered if the earphone jack barrel was solidly grounded, so used an ohmeter to measure between the BNC shell and earphnone barrel and found there is a 480 ohm resistance between them. I sumise this resistor is to reduce earphone volume. Since I can't find a pro95 schematic (maybe its in a Mar A Largo super top secret folder??), I can't verify this or how the jack is wired for mono/"stereo" listening.

 

[a417]

It is not secret, sorry. You just need to improve your google-fu.



This is how the Pro 95 headphone jack is wired, almost identical to the Pro 92. This should help you visualize it electrically.

The NJM2070M (same as the 92) is a single channel mono audio amp, that can be verified from the data sheet.

 

[rrman987]

Thank you A417!! Certainly is unique way of accomplishing the mono/"stereo" connections. And I was correct in measuring 480 ohms between the earphone jack barrel and the BNC hard ground.
Interesting that The Shack didn't mention that either a mono single or dual headphones could work in pro 95 manual (or if there then I need better glasses).
Live and learn.
As far as Google-fu, I am lucky if I can type things straight with my hunt and peck typing, and then trying to frame my inquiry so I dont land at a XXX porno site!!

 

[rrman987]

An interesting challenge comes when wanting to use the jack to feed audio to an external amplifier or computer input. What I've done then is obtain the ground from the antenna BNC and audio from the tip connection of the jack.

I use a cable with mini stereo plug ends to connect the pro95 to the car's auxiliary audio jack so I hear the scanner out of both car speakers with no discernable problem. Of course my rooftop antenna is magnet so theres no hard car ground that might cause "weird" ground loop damage to scanner output or the cars sound system inputs. Scanner output in effect "floats" from cars audio system.

 

[a417]

The one you should be thanking is @pro92b , thanks to this thread.

 

[CB750]

I have been using an mono "earplug" for listening. For comfort. I tried a set of stereo earphones and pleasantly surprised both earpieces audible and voice was "centered" rather sounding out of phase far apart. The manual does not say anything about earphone types to use (other than the usual see your Rat Shack dealer for best earphones yada yada).
Is the Pro95 using a stereo jack so stereo headset will work as well as mono sets? Earphone jack barrel is grounda and the tip is for mono or a stereo earpiece, and the middle ring is for other stereo earpiece, so can't visualize electrically how both sides are working..
I will take the comfortable stereo though, rather than the former lopsided listening of mono earplug.

All communications broadcasts are Monaural. What you will receive is Bi-naural known as Mono x 2.

 

[rrman987]

All communications broadcasts are Monaural. What you will receive is Bi-naural known as Mono x 2.

There you go, I learned something new. Who sez you cant teach an old dog a new trick?