Laptop charger add - improves sound!? - Page 1
Forum section: electronics / general

author: LeoTech
author_rank: Regular Contributor
timestamp: October 09, 2019, 07:11:19 pm
content: Hello,Is it just me, or is something wrong here?A DC Line noise filter, that improves sound? In a laptop charger?Did I miss something, or is this just BS/clueless marketing?Leo

author: Halcyon
author_rank: Unknown
timestamp: October 09, 2019, 07:43:29 pm
content: I'd say it's just poor translation into English and/or a complete lack of understanding of what "noise" it's referring to.

author: drussell
author_rank: Super Contributor
timestamp: October 09, 2019, 08:00:13 pm
content: Quote from: Halcyon on October 09, 2019, 07:43:29 pmMost likely no understanding that it is stopping RF noise from escaping, not AF noise coming in.

author: SiliconWizard
author_rank: Super Contributor
timestamp: October 09, 2019, 09:36:34 pm
content: LOL. This is not a "line filter", merely a ferrite clamp to pass radiated emissions tests.To be fair, they also cut down some amount of conducted noise.EDIT: Note the creative addition of (99.99% likely) fake wire pass-throughs on each side of the clamp, to make it look as though it could indeed be some kind of "inline" filter...(I'm amazed at how some chinese manufacturers, for instance, are creative with those fake pass-throughs.)For that to have a sizeable effect on "sound quality" though, the audio section of the laptop should probably have to have been designed with an engineer's feet.Selling this has a "bonus" is completely misleading anyway, since manufacturers only add ferrite clamps to cables when they are FORCED to after EMI testing, not out of good will.EDIT2: Given the very probably use of fake pass-throughs, it may also be very possible that the ferrite clamp is not even a ferrite clamp, and may contain absolutely... nothing inside the plastic shell. Would be fun to buy one just to check... and post your result here.

author: james_s
author_rank: Super Contributor
timestamp: October 09, 2019, 10:47:17 pm
content: I suppose it could help reduce audio hiss picked up by the amplifier driving the speakers in the laptop. I agree with the other post though suggesting that it's probably just a poor translation where RF noise became "sound".

author: Deodand2014
author_rank: Regular Contributor
timestamp: October 10, 2019, 01:21:11 am
content: I've got a Samsung SyncMaster BX2331 that needs a 12v 3amp external supply and I'd been running it off a 'wall wart' which meant the audio jack was unusable due to audio noise generated by the power supply. Recently I got my hands on a 'brick' power supply of the right voltage with the ferrite on the output line and the audio jack on the monitor is now useable because either the extra filtering in the 'brick' or the ferrite has removed the line noise.But that's the only kind of audio improvement a ferrite could produce.

author: drussell
author_rank: Super Contributor
timestamp: October 10, 2019, 02:14:06 am
content: Quote from: Deodand2014 on October 10, 2019, 01:21:11 amThat sounds more like a ground loop issue unless that wall wart was totally unfiltered "DC" with 90% ripple rather than RF noise being filtered in OR out. Was the noise your typical 100/120 Hz hum or were you actually hearing hissing noises from a switching-converter type wall wart? (That would really still be poor filtering of the power rails in the supply rather than RF escaping.)The ferrite on a power lead is normally for stopping conducted EMI from coming back OUT of the device and radiating, not stopping it from going into the device from the power supply.

author: amyk
author_rank: Super Contributor
timestamp: October 10, 2019, 12:09:24 pm
content: Reminds me of this:http://www.hisdigital.com/un/product2-388.shtml