Battery hum distorting sound when put through a mixing desk.

philius

have a bit of a problem with a laptop, in that the power adapter makes a hum when i run the laptop through a mixing desk.
This obviously is a problem.

i know some adaptors do this and some dont, but basically does anyone know of a type that doesnt

Thanks.

subway

dont know any,
but ive had them same problem and the solution i found was either
a)
dont plug the laptop and amp into the same extension cable
b)
use one of these
http://www.maplin.co.uk/Free_UK_Delivery/Ground_Loop_Isolator_33172/Ground_Loop_Isolator_33172.htm

hth

philius

Oh, that maplin thing looks great. Yeah it never happen with my last two laptops but i guess its just the way things are with some machines

as a side point, do you reckon it would happen through an external sound card?

Darth Maul

try to find a 3 pin adaptor, ie one with an earth pin, most Laptop power supplies now only have 2 pins, but the 3 pin ones (usually compaq ones have 3) are much better for this, found that some of the universal ones are the worse culprits, so try to use the original one if possible

And no an external sound card won't hake any difference.

Karoma

The "GROUND LOOP ISOLATOR" looks like it would do the job.

Cheaper,possible,solution: I've never found a need for absolute quietness, but I've found adding one of these (I cannot remember the name of them) helped reduced a lot of interference before (You may have a spare one from a camera or camcorder..)

Emerson

Are the laptop & mixer on the same plug board?

I was doing a gig a few weeks ago and we were having that problem. They guy trying to explain to me the grounding needs to match in both appliances.

I think both need to be on the same adapter.. or maybe it was different adapters. Try both!

wheresmybeaver

I use some external Creative soundcard thingy (about 30 quid) when I'm recording guitar etc with my laptop, it bypasses the humming and has better latency too etc (probably because it runs off USB power and not the mains). But before I used the external card I had that irritating hum. Might sound stupid, but what I used to do was unplug the laptop and run it off the battery for the duration of the recording; ie it was the ac adapter creating the hum. Probably not a good solution for you bein connected to a mixer tho..

philius

Emerson wrote:

Are the laptop & mixer on the same plug board?

I was doing a gig a few weeks ago and we were having that problem. They guy trying to explain to me the grounding needs to match in both appliances.

I think both need to be on the same adapter.. or maybe it was different adapters. Try both!

No they were running of seperate plug boards.

Will try the maplin thing first, and if that doesnt fix it i will work something out after.

Plugging out the laptop is a solution, but i need to keep it open for rehersals, which are minimun 4-5 hours, and 1-2 hours of bat time just wont cut it.

Cheers for all answers

philius

just an update on the battery thing, i tried the maplin solution

http://www.maplin.co.uk/Free_UK_Deli...ator_33172.htm


and it works perfect.

Problem solved.