In article , Dave Plowman (News)
wrote:
In article , Jim Lesurf
wrote:
Pretty common with computers of all types. You usually have to add a
decent sound card to get a decent audio output at the end of the day.

However that "sound card" can often be a USB one.

I was assuming it would be PCI, etc. Perhaps not possible on a laptop.

My experience has been that when using USB-powered USB audio devices with
a laptop they are often quieter if the laptop is being powered from its
batteries. Connecting and using the laptop's charger/mains PSU causes
noises. I also found with an old laptop that HD accesses also generated
audible noises on the audio.

The conclusion is that typical USB-powered USB Audio devices don't do a
good job of rejecting power rail variations. So they benefit from using
something that supply clean power. I found that one particular type of USB
hub from CPC was the best from a variety, and have used those since. If I
can recall/find the part number, I'll say.

But beyond that if you want good performance you really need to look for a
device that has its own dedicated power supply independent of the USB
power. The drawbacks, of course, being cost and the need for then supplying
that power.

Goes with my experience in testing and developing pre-amplifiers. I found
there that the PSU arrangements were very important and need to be
developed with care.

Jim

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