Radioshack Wall Wart Noise

[mpcarlino]

I apologize if this has been discussed elsewhere, but I really don't have the time to search the forums for it at the moment. Just putting it out there to see what I get.

I recently picked up a Radioshack 273-1766 6v 800mA wall wart for my BCD396T after the stock wall wart died on me. I noticed a significant increase in noise regardless of station. Even P25 transmissions have this background noise. It's not bad (but still noticeable) when using the internal speaker, but the noise when using headphones is much more severe; almost overcoming the voices in the transmissions. This was tried in two entirely different locations, and battery operation yielded the clean sound I expect. I know battery power is always cleaner, but this was almost to the point of inaudibility.

Has anyone used this particular unit for power on any scanner? I'm not sure if it's regulated (or if an unregulated unit would be so much noisier than a regulated unit), but the advertised "hash noise filter" isn't filtering anything at all. Any recommendations? Should I use some sort of inline noise filter, or consider another power supply?

Thanks!

 

[WisconsinRailfan]

same issue here, I tried several different outlets in the house, same issue. So now I just have a spare set of rechargeable batteries. BTW I have a PRO97.

 

[n211cr]

Ditto with the same adapter with a Pro-99. Its not real noticeable over the speaker but the headphone jack gives a nasty 60 cycle hum. I never looked too much into a solution just used it to charge the batteries.

 

[DickH]

... Should I use some sort of inline noise filter, or consider another power supply? ...

If you have a surplus electronics store in your area, they should have piles of surplus computer power supplies. They are well filtered with complete absence of 60-cycle hum.
12 volt units are not common, but some have two 5v outputs. If you wire them in series, the resulting 10 volts will run your scanner nicely. If the current rating is high enough you will be able to run several scanners from the same power supply.
It shouldn't cost more than $10 for something usable.

 

[mpcarlino]

If you have a surplus electronics store in your area, they should have piles of surplus computer power supplies. They are well filtered with complete absence of 60-cycle hum.
12 volt units are not common, but some have two 5v outputs. If you wire them in series, the resulting 10 volts will run your scanner nicely. If the current rating is high enough you will be able to run several scanners from the same power supply.
It shouldn't cost more than $10 for something usable.

I actually have quite a few PSUs lying around from various builds and upgrades, but what I'm looking for is a portable solution for when I take my scanner to my cottage or to the library (with headphones, of course). The thing is, the stock wall wart was fine. There was some noise as is generally so with anything AC-based, but it was perfectly fine. I have a crap-o variable voltage wall wart from wallyworld to power my 250, and I haven't noticed any noise problems with that one, either. It's only rated at 300mA, though, and I'm not interested in having to replace that one as well.

I might just have to fork over the $25+s&h for a replacement stock from uniden, and wait for it to crap out again. Everything's made like garbage.

Anyone have a preferred source for wall warts?

Thanks for all the help so far.

 

[DickH]

... I have a crap-o variable voltage wall wart from wallyworld to power my 250, and I haven't noticed any noise problems with that one, either. It's only rated at 300mA, though, and I'm not interested in having to replace that one as well.

300mA should be fine. I doubt that scanner draws much more than 150mA. Try it and if it overheats, don't use it. If it's too warm to hold comfortably, it's too warm.

 

[scanrrman]

I have this same problem but it's not constant. Usually happens when I plug it in and power it on. It sounds like a buzz that comes out with the key beep. I hear it in P25 voice transmissions too. I usually let it sit for a little bit and then check it again to make sure it has stopped. Almost like it has to warm up a little bit.... I usually just keep hitting the volume until I hear it stop. Don't like to let it continue throughout the night. I just program a new 396 for someone and they have new AC adapters now. I was thinking about ordering one thinking it would solve my problem...

 

[kb2vxa]

Why all the fuss here when you should be making a fuss at Rat Shack? If they sell you a defective product or one unsuitable for the intended purpose (unsuitable for merchantability is the legal term) you're entitled to replacement or your money back regardless of any guarantee. That's the law in most states, you'd be wise to invoke it.

 

[mpcarlino]

Why all the fuss here when you should be making a fuss at Rat Shack? If they sell you a defective product or one unsuitable for the intended purpose (unsuitable for merchantability is the legal term) you're entitled to replacement or your money back regardless of any guarantee. That's the law in most states, you'd be wise to invoke it.

That's part of my plan, but I need to find a replacement first. A replacement from them will more than likely suffer from the same problem (owing to the other reports of it here), so I guess the crux of my question was whether anyone had a recommended alternative.

300mA should be fine. I doubt that scanner draws much more than 150mA. Try it and if it overheats, don't use it. If it's too warm to hold comfortably, it's too warm.

I can try that if I can't find anything else, but whenever I've used a wall wart even moderately outside it's current rating, it works for a few days, and then quietly toasts itself. The other problem is it's lack of the proper plug size. I really don't feel like whipping up something that'll fall apart on the go. It does use an adaptaplug-like setup, but of course the pins are just different enough in diameter.

Thanks again for everyone's input.

 

[SCPD]

Hmnm I've had all RS wall warts on my scanner(s) since 1993 with no problems

 

[cjrjr507]

May I make a suggestion. If your having noise problems with wall warts
replace them with an desktop power supply. I used to have that problem with my old uniden wall wart and replaced it with an radioshack 3 amp desktop power supply unit. Cat. # 22-507 . Small unit and works great with no bloody hum at all. Or you can get larger amped unit if you have lots of scanners. For a plug for the scanner just chop off the wire on the stupid wall wort and use that, heh heh.

 

[mcema699]

I don't want to start a long discussion as its been hashed out on other threads here, so if you want to discuss pro's and con's please find the other threads and do it. For many reasons (see the other thread) Pro97 suggests a 9v supply. Don't know if this would make any difference in your line noise issue. Don't use 9v on the BC unless it says to.

Buy regulated supplies if possible.
I've used the RS walwarts as suggested by the manuals for their products for years and haven't noticed any line noise either.

The following is a rant, please do not reply. lol
If you're inclined to seek legal counsel over a $20 product, I think (I'm not a lawyer)RS might have beat you to the punch:

"EXCEPT WHERE PROHIBITED BY LAW, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE SPECIFICALLY DISCLAIMED: (1) FOR ALL 'AS IS' SALES; AND (2) UPON THE LATER TO OCCUR OF: [A] THE EXPIRATION OF ANY APPLICABLE EXPRESS WARRANTIES, OR 90 DAYS FROM DATE OF PURCHASE.

RadioShack is not liable for any loss or damage (including indirect, special, incidental or consequential damages), caused directly or indirectly by the products listed on this receipt. Some states do not allow limitations on implied warranties (such as warranties of merchantability or fitness for a particular purpose), or the exclusion of incidental or consequential damages, so the above limitations or exclusions may not apply to you. In addition, you may have other rights which vary from state to state. "

So check your state laws and have fun.
Maybe you should sue Uniden as well for not making a product that will work with any power supply on the market in the past, present or future.

 

[jonny290]

'over voltage' wall wart + 7805/7806/7809/7812 + filter/bypass caps is the cheapest way to solve this issue

bit of power dissipation but you can slap a heatsink on the reg NP