SDS-200 Speaker Noise Again like the 536HP

[weathermedic]

Was mentioned somewhere earlier in this thread. Depends on what type of external speaker you are using. I originally had mine hooked up to a Midland (very similar looking to the standard Motorola two-way radio external speakers used for years) and it had a very loud hum. I replaced that with a "generic" external communications speaker and the hum got noticeably lower. It's still there though. Of course the audio quality now suffers, as the Midland speaker is professional grade and projected a nice deep tone with transmissions. Waiting for my in line audio noise filter to arrive from Amazon today. Will let you know if that makes any difference.

 

[weathermedic]

I have always waited to order any new Uniden scanners until any issues with their new line of radios has been addressed. I did it with the 536. Most recently I waited to get a SDS100 until the battery issue was fixed and ordered mine with the new larger battery. This time I threw caution to the wind and ordered from the first batch, even though something told me to wait it out.

 

[KB4MSZ]

What I find to be the most disturbing about this issue is that some units have the problem and some don't. Those that do have varying degrees of loudness and even varying types of noise. A single issue of noise of the same type and volume wouldn't be so troubling.

 

[edweirdFL]

What I find to be the most disturbing about this issue is that some units have the problem and some don't. Those that do have varying degrees of loudness and even varying types of noise. A single issue of noise of the same type and volume wouldn't be so troubling.

Keep in mind that not everyone's ears work equally well, and the ambient noise of the environment you use the SDS200 in can sometimes mask the sound generated.

 

[tkowalik]

The sound is something not grounded on the front screen area. I'm getting close. I eliminated it once; trying to figure out what I did.

 

[tkowalik]

I pushed the top cover under the outside housing toward the screen as far as it would go and it GREATLY reduced the humming for me. Initially it was flush with the rear inside housing. If you put downward pressure on the inside top cover it also tends to reduce the hum.

I can now listen to headphones or an external speaker on the rear jack if I wanted and wouldn't be annoyed. The noise is still there but I have to literally hold the scanner making contact with my head to hear it whereas before, I could hear it from a couple of feet away. This may even be 'normal' noise now.

Maybe Uniden or someone else can take this info and start narrowing down where it's coming from?

 

[cxgy2]

Has anyone with the noise problem checked to see if the volume of the noise varies with the dimmer (backlight brightness) setting?

 

[maus92]

Keep in mind that not everyone's ears work equally well, and the ambient noise of the environment you use the SDS200 in can sometimes mask the sound generated.

Keep in mind that not everyone's ears work equally well, and the ambient noise of the environment you use the SDS200 in can sometimes mask the sound generated.

Yup, I just ran a test in my workspace with everything off, and I could hear the hum a bit farther away from the radio than when everything is up and running (with everything off, I could also hear the refrigerator one floor below.) I also noticed that the hum / noise changes tone when the radio writes major changes to the display. For example, the hum / noise is more or less steady when scanning through a system, but when radio scans the next system (along with "major" screen changes / updates) the tone of the hum / noise changes slightly.

 

[dfw1193]

I pushed the top cover under the outside housing toward the screen as far as it would go and it GREATLY reduced the humming for me. Initially it was flush with the rear inside housing. If you put downward pressure on the inside top cover it also tends to reduce the hum.

I can now listen to headphones or an external speaker on the rear jack if I wanted and wouldn't be annoyed. The noise is still there but I have to literally hold the scanner making contact with my head to hear it whereas before, I could hear it from a couple of feet away. This may even be 'normal' noise now.

Maybe Uniden or someone else can take this info and start narrowing down where it's coming from?

Maybe time for a solder jumper with 26ga wire between the housings.

 

[tkowalik]

Yup, I just ran a test in my workspace with everything off, and I could hear the hum a bit farther away from the radio than when everything is up and running (with everything off, I could also hear the refrigerator one floor below.) I also noticed that the hum / noise changes tone when the radio writes major changes to the display. For example, the hum / noise is more or less steady when scanning through a system, but when radio scans the next system (along with "major" screen changes / updates) the tone of the hum / noise changes slightly.

I put in headphones on the rear jack and started messing with the top inside plate and it makes a huge difference in loudness and pitch depending on if it's removed, partially removed, flush with back, pushed to the front, and whether you apply a little downward pressure. Doing any of those definitely changes it. What makes the biggest improvement is all the way to the front and some downward pressure.

 

[dfw1193]

Maybe time for a solder jumper with 26ga wire between the housings.

I remember some issue a while back with headphone jacks on uniden scanners that could be fixed by attaching a ground to one of the pins back in the pre dynamic memory days.

 

[tkowalik]

Maybe time for a solder jumper with 26ga wire between the housings.

I'm wondering if just scraping off that felt-like material between the housings so they make full contact wouldn't do the trick.

 

[dfw1193]

I'm wondering if just scraping off that felt-like material between the housings so they make full contact wouldn't do the trick.

Might try an alligator clip dual jumper to connect the housings before scraping it off.

 

[n2pqq]

It actually seems to help .

 

[m42duster]

This isn't A/C hum, ground loop, or anything else influenced from outside the SDS200. It sounds like CPU / processing noise.

Exactly what I was about to say.

 

[m42duster]

That is NOT HUM, that is audio from the cpu frequency oscillator (if it uses a multiplier) or an audio frequency created from the fpga chip when the unit scans, remember audio frequency range is 20hz through 28khz (or less for older) so if the scanner is scanning quickly at this range of cycles then its hearable with sensitive ears and somehow its bleeding into the audio amp ic chip, since thats what audio amp chips do they amplifier that frequency range, the reason it DOES NOT occur in the headphones in the headphone jack is the headphone output comes from the audio driver stage before the audio amp and this audio is not bleeding into the driver circuit just the audio amp circuit since it is so powerful of an audio amplifier.

Likely poor shielding in that area

 

[RF23]

Intresting that all the kings techs and engineers couldnt make it right with so much time for research, testing and development but release it to users who have had it less than 7 days and the issues cause appears to have been identified and probably within 2 days someone here will have a fix even though they voided the warranty by opening the unit.

I think the SDS200 has to have the outer case removed to be mounted in a Din sleeve to be put into the dash of the car. If true, then the warranty probably will not be violated by this action.

Also, a number of sites have claimed that the FTC has invalided manufacture’s claim of voiding the warranty by open the unit, but I have not confirmed this to be true.

 

[weathermedic]

The in line external speaker ground loop 3.5 mm adapter I just got from Amazon today not only succeeded in lowering the hum dramatically to the external speaker, it also lowered the audio substantially. Even with the scanner volume turned all the way up, the sound was low and a bit distorted. Guess I’ll keep that adapter for a rainy day for some other use at some point in time.

 

[KB4MSZ]

Also, a number of sites have claimed that the FTC has invalided manufacture’s claim of voiding the warranty by open the unit, but I have not confirmed this to be true.

Is this what you are referring to?
FTC Staff Warns Companies that It Is Illegal to Condition Warranty Coverage on the Use of Specified Parts or Services

 

[RF23]

Is this what you are referring to?
FTC Staff Warns Companies that It Is Illegal to Condition Warranty Coverage on the Use of Specified Parts or Services

Yes it is!
Now we all know!
Thanks!