SDS-200 Headphone Out to Aux In issues

[AKJohnny]

Has anyone else tried plugging their SDS-200 headphone out jack to an Aux in in their car (or other audio device) via a 3.5mm stereo audio patch cable? I have major noise (excessively loud hiss sound) when doing this. I've tried multiple different brand cables (that all work fine & without any noise on my SDS-100).
Using headphones or earbuds via output jack works fine, there is No noise. But when going out to a device input, bad noise.
Can someone else test this so I know whether it's just me? Thanks!

 

[tkowalik]

Yes, there is an incredible hiss using this method. The novice engineers (me) and pros are methodically searching for the root cause. We have it narrowed down. Stay tuned.

 

[AKJohnny]

Ugh! Just when I thought mine was pretty acceptable compared to others. This is a deal breaker since I wanted to mount in vehicle and connect this way.

 

[tkowalik]

Ugh! Just when I thought mine was pretty acceptable compared to others. This is a deal breaker since I wanted to mount in vehicle and connect this way.

There will be a fix and can almost guarantee it will be simple.

 

[letarotor]

Have you tried using the external speaker jack on the back of the scanner? There is likely always going to be an impedance mismatch if I understand things right. It's like when you used to try to plug Radio Shack handheld scanners around the late 90s / early 2000s into an amplified speaker. You would get horrible hum or high-pitched noises or just a super low volume most of the time.

Even though what you're trying may work, I don't think the headphone jack is actually made for use in the way you sound like you're trying to use it. I don't know if it's a difference in ohms or just what the technical reason is but this has been a common issue in scanners as long as I can recall when using the headphone jacks for an audio connection other than headphones. And especially on handhelds. There are differences between the external speaker out jack and the headphone jack.

Brian (COMMSCAN)

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[AKJohnny]

Have you tried using the external speaker jack on the back of the scanner? There is likely always going to be an impedance mismatch if I understand things right. It's like when you used to try to plug Radio Shack handheld scanners around the late 90s / early 2000s into an amplified speaker. You would get horrible hum or high-pitched noises or just a super low volume most of the time.

Even though what you're trying may work, I don't think the headphone jack is actually made for use in the way you sound like you're trying to use it. I don't know if it's a difference in ohms or just what the technical reason is but this has been a common issue in scanners as long as I can recall when using the headphone jacks for an audio connection other than headphones. And especially on handhelds. There are differences between the external speaker out jack and the headphone jack.

Brian (COMMSCAN)

Sent from my SAMSUNG-SM-G930A using Tapatalk

Yes, tried external speaker jack and experience the noise many others complain about. Different than the front headphone hiss, but just as annoying. All the scanners that have headphone out in my signature have worked fine with the headphone out to aux in with my vehicle. So this is the only scanner giving me issues. Thanks though.

 

[AKJohnny]

There will be a fix and can almost guarantee it will be simple.

Hope you're right, but if it doesn't happen within the next 10 days, it goes back to the seller.

 

[KE5MC]

I don't know about the SDS200, but on other Uniden models the external audio jacket common side was not common to the radio. It was a balanced push-pull output expecting the item plugged into the jacket to be isolated/floating. Another thread I saw asked and answered what the audio stage device was for the 200. I recall it was an LSI DSP device, but nothing about the following stages of output. If they are using the same output driver circuit then the common of the 200 power input and the common from your audio system is messing with the not common of the 200's audio output. Another possibility is I don't have a clue what is causing your noise problem.
Good Luck,
Mike

 

[RF23]

I think ALL Uniden headphone and speaker jacks are MONO. Therefore, you might try a mono cable or get a mono to stereo adapter and see if that helps.

 

[buddrousa]

Yes and this is what I use all my 996p2's 15's 436 sds100 makes for nice clean audio
Pyle PLGI35T 3.5MM / 1/8'' Stereo Audio Ground Loop Isolator 68888993289 | eBay

 

[doctordialtone]

Yes and this is what I use all my 996p2's 15's 436 sds100 makes for nice clean audio
Pyle PLGI35T 3.5MM / 1/8'' Stereo Audio Ground Loop Isolator 68888993289 | eBay

Yes! That will do the trick! Isolation is the key!

 

[AKJohnny]

Yes and this is what I use all my 996p2's 15's 436 sds100 makes for nice clean audio
Pyle PLGI35T 3.5MM / 1/8'' Stereo Audio Ground Loop Isolator 68888993289 | eBay

I get the hiss while connect in home on ac power. Haven’t tried out in car yet. With that said, do you believe this would cure the hiss sound? I’ll give it a shot if you think so.

 

[AKJohnny]

I think ALL Uniden headphone and speaker jacks are MONO. Therefore, you might try a mono cable or get a mono to stereo adapter and see if that helps.

I could swear I remember reading something about the sds100 where UPMan said that was stereo. I tried so many cables last night and can’t remember for sure, but I think one was mono. I’ll double check.

 

[SteveSimpkin]

I get the hiss while connect in home on ac power. Haven’t tried out in car yet. With that said, do you believe this would cure the hiss sound? I’ll give it a shot if you think so.

I think there is a good chance this may help. The other thing to try is to turn the scanner volume up fairly high and turn the radio's volume down.

 

[SteveSimpkin]

I could swear I remember reading something about the sds100 where UPMan said that was stereo. I tried so many cables last night and can’t remember for sure, but I think one was mono. I’ll double check.

IIRC the headphone output is designed for stereo headphones or earbuds. Therefore it is wired as a " "stereo" jack. I think it feeds the same audio to the left and right outputs.
I believe the speaker jack on the back is wired as a mono jack to drive a single speaker.

 

[Ubbe]

The SDS200 are probably done the same way as a BCD536HP and it has the earphone jacks left and right signals, the tip and middle ring, connected together and the sleeve are floating and are not connected to the scanners ground. It's probably taking its signal from the loudspeaker jack thru some resistors to lower the audio level and those will also work as a shortcircuit protection.

The loudspeaker jack in a BCD536 are only using the tip and sleeve in a stereo connector and are directly DC connected to the amplifier and both have a 3.7 volt so do not connect either to scanner ground. The amplifer IC should have internal protection for excessive currents and shortcircuits but you'll never know what could happen when you ground the signal.

/Ubbe

 

[fxdscon]

I think ALL Uniden headphone and speaker jacks are MONO. Therefore, you might try a mono cable or get a mono to stereo adapter and see if that helps.

Headphone jacks are stereo on all our scanners. EXT SP jacks are mono.

 

[AKJohnny]

Yes and this is what I use all my 996p2's 15's 436 sds100 makes for nice clean audio
Pyle PLGI35T 3.5MM / 1/8'' Stereo Audio Ground Loop Isolator 68888993289 | eBay

Thank you. This solved my issue. I just wonder why none of my other scanners require this. Either way, clean audio now.