BCD536HP mono rear headphone jack to car stereo?

Status
Not open for further replies.

J805

Member
Joined
Nov 10, 2018
Messages
35
Location
Camarillo, CA
All,

I have a BCD536HP and I'd like to run an audio output from the rear headphone jack to a 1/8" stereo input on my car stereo. This works fine on my SDS100, however on the 536, I only get audio to the right channels on my stereo, not the left. In reading further, it appears that the rear jack is a mono output used for a single external speaker? Could I just use a mono to stereo adapter to split my audio to both channels on my car stereo? Or will this mess anything up?

80032

Thanks
 

J805

Member
Joined
Nov 10, 2018
Messages
35
Location
Camarillo, CA
Cool, thanks guys. I figured it would be ok but just wanted to clarify.

I know the front jack on the 536 is stereo, but I want all my cables coming off the back so it looks cleaner.
 

tvengr

Well Known Member
Joined
Feb 10, 2019
Messages
10,321
Location
Baltimore County, MD
Do not use a mono plug on the SDS or X36HP scanners. You are shorting out half of the audio amp and may damage the scanner.
 

J805

Member
Joined
Nov 10, 2018
Messages
35
Location
Camarillo, CA
Do not use a mono plug on the SDS or X36HP scanners. You are shorting out half of the audio amp and my damage the scanner.


But the rear jack is mono on the 536 and meant for a single external speaker which does not come with a male stereo plug.

???
 

tvengr

Well Known Member
Joined
Feb 10, 2019
Messages
10,321
Location
Baltimore County, MD
Look at the Uniden BC23A amplified speaker. It has a stereo plug on it. The tip and sleeve feed an isolation transformer inside the speaker. The output from the ring is not used.
 
Joined
Apr 18, 2009
Messages
6,280
Location
CT
I feed a 996XT and 325P2 into Stereo PC speakers without a problem.

Audio comes out of both speakers.
 

tvengr

Well Known Member
Joined
Feb 10, 2019
Messages
10,321
Location
Baltimore County, MD
To my knowledge, the 996XT and 325P2 both have mono outputs. A mono plug will not damage the scanners. The BCDx36HP and SDS100/200 use a different audio output design. Look at some of the articles from Upman regarding external speakers. The scanners use a BTL audio amp. If you hook it to an external speaker, you use a stereo plug. You have a balanced audio output from the tip and the ring. When the tip goes positive, the ring goes negative by the same amount and vice versa. If you use a mono plug, you are shorting the ring output to the sleeve which may damage that half of the amplifier. That is why the Uniden BC23A amplified speaker has a stereo plug. If using an unamplified speaker, you take the output from the tip and the ring using a stereo plug. If you take the output from the tip and sleeve or ring and sleeve, you are getting only 1/2 the voltage and 1/4 the power.
 

J805

Member
Joined
Nov 10, 2018
Messages
35
Location
Camarillo, CA
So then why do I only get sound out only my right channel when I plug my headphones in or my car stereo input? When I plug those into my SDS100 I get sound from both channels. Everything I have read in other posts says the 536 rear output is mono and the front output in stereo. I get sound from both left and right when using the front jack.
 

tvengr

Well Known Member
Joined
Feb 10, 2019
Messages
10,321
Location
Baltimore County, MD
I just did a check with a couple of 536's and 2 cables. The audio output seems to be from the tip and sleeve. There is very little output from tip to ring. This is totally different from the headphone output on the SDS100, which is balanced audio between the tip and ring. I may be wrong about the speaker jack being stereo. I am going to have to do a further investigation.
 
Last edited:

J805

Member
Joined
Nov 10, 2018
Messages
35
Location
Camarillo, CA
I just did a check with a couple of 536's and 2 cables. The audio output seems to be from the tip and sleeve. There is very little output from tip to ring. This is totally different from the headphone output on the SDS100, which is balanced audio between the tip and ring. However, Upman warns about shorting out the amp using a mono plug. I am going to have to do a further investigation.

If it's only the tip and the sleeve, this sounds like mono? I ordered one of those adapters, I will try it real quick just to see. I imagine it's either going to work or it's not.
 

fxdscon

¯\_(ツ)_/¯
Premium Subscriber
Joined
Jan 15, 2007
Messages
7,392

.
 

tvengr

Well Known Member
Joined
Feb 10, 2019
Messages
10,321
Location
Baltimore County, MD
Headphone jacks are stereo on all our scanners. EXT SP jacks are mono.

Uniden "Big Daddy" Product Ninja

Thank you fxdscon and Upman! I stand corrected.
 

kruser

Well Known Member
Premium Subscriber
Joined
Nov 25, 2007
Messages
5,056
Location
W St Louis Cnty, MO
The problem is the fact that the sleeve is NOT grounded to the radio chassis in these never models. Both sides of the mono jack float from ground.
In older designs, the sleeve was always at ground level. That changed with the BTL design.

With the BTL design, the sleeve or tip cannot be grounded.

Using an output from the rear speaker port into an external input that has a grounded sleeve will short half the audio unless you build an isolation circuit that can handle speaker level audio or a simple isolation transformer (ground loop isolator) if trying to use the output as line level into an external amplifier.

One can also hook just one wire to the tip or sleeve and the other to a chassis screw and the amp will give you half the power for an external amplified speaker or typical line level grounded input. This is usually just fine and produces plenty of audio.
External speakers that have mono plugs work just fine as neither side is grounded at all.

There have been several threads on this subject in the past including one with circuit diagrams that someone put together so people will not destroy the BTL amp in their radios.

Also, the rear jack is Speaker level and NOT headphone level.
 

zzdiesel

Member
Joined
Mar 17, 2006
Messages
2,012
Location
Kennett / Dunklin Co, Mo.
All,

I have a BCD536HP and I'd like to run an audio output from the rear headphone jack to a 1/8" stereo input on my car stereo. This works fine on my SDS100, however on the 536, I only get audio to the right channels on my stereo, not the left. In reading further, it appears that the rear jack is a mono output used for a single external speaker? Could I just use a mono to stereo adapter to split my audio to both channels on my car stereo? Or will this mess anything up?

View attachment 80032

Thanks
Where to buy this 50 cent adapter?
 
Status
Not open for further replies.
Top