Hi there. Wondered if anyone could solve this one: Son has just bought a Rega Brio R - great amp by the way. It works well with his Ipod and when driven direct via headphone out of his Sony laptop. However, when he plugs the laptop into power rather than using the battery he gets bad interference on laptop. I tried my Macbook through it and it's fine, powered or not. Just wondered if anyone might have encountered this and maybe had a remedy (we tried a different power cable and problem persisted). Thanks in advance.
Interference
- Thread starter paley
- Start date
sergeauckland
pfm Member
I've come across this a few times, and it seems to be a function of the power supply used. In each case, it was solved by changing the power supply to a different make or type, but another way is to use something like the Behringer UCA202 to extract the audio from the USB port and not use the laptop's headphone output at all.
Our radio Presenters often use their laptops to play music on their shows, and we had a lot of trouble with this before putting the UCA202 in the studio. Since then, not had a single instance of buzz/hum from laptops.
S.
Our radio Presenters often use their laptops to play music on their shows, and we had a lot of trouble with this before putting the UCA202 in the studio. Since then, not had a single instance of buzz/hum from laptops.
S.
That looks interesting and totally cheap Serge. Is the optical out clean?
martin clark
pinko bodger
The problem is the SMPS power brick supplied with the laptop, as noted by Serge.
Some have a hard bond to mains earth, some do not, some are intentionally 'leaky' in this regard; all of them inject varying to large amounts of common-mode noise - which may or may not play well with what the laptop is plugged into.
There are fixes but an optical interface guarantees it.
Some have a hard bond to mains earth, some do not, some are intentionally 'leaky' in this regard; all of them inject varying to large amounts of common-mode noise - which may or may not play well with what the laptop is plugged into.
There are fixes but an optical interface guarantees it.
sergeauckland
pfm Member
I don't know about the optical output as we don't use it, but as it's trivially easy to get an optical S-PDIF from a USB output, I would be very surprised if it was anything other than clean.
S.
Cereal Killer
432
Try removing the earth connection to the SMPS. I have two for the same laptop, with and without. Noise disappears without an earth.
martin clark
pinko bodger
..because that's one way of breaking a very noisy loop created as post #4.
Downside is - thanks to Y-class caps in the SMPS you may get a bit of a 'sting' off the laptop at any time it isn't connected to earthed audio equipment...
Downside is - thanks to Y-class caps in the SMPS you may get a bit of a 'sting' off the laptop at any time it isn't connected to earthed audio equipment...