[App_rpt-users] Noisy Quad PCI audio

Bryan D. Boyle bdboyle at bdboyle.com
Tue Jan 24 15:20:36 EST 2012

On 1/24/12 2:46 PM, Jim Duuuude wrote:
> I guess you could always apply a 1:1 600 Ohm isolation transformer. You can even
> get one of those at Radio Shack (still).

Keeping unbalanced audio or other signal paths clean is such a pain...

Isolation xfmrs are a good thing.  If cellphone shack doesn't have 
them...IIRC Mouser, Digikey, even Broadcast Supply Warehouse, and some 
ham bits-and-pieces places (there are still a few left...) will.  They 
should NOT be expensive, nor massive (like the old Weco 666 repeater 
coils...).  I bought a box of them a couple years ago when I was 
building my streaming radio station, and, even between balanced audio 
sources and my console, I dropped them in on the back of my patch 
panel...just in case (and the audio chain meets the old FM proof of 
performance specs, so...).

Basically you are more prone to have noise issues if you have multiple 
pieces of equipment where the grounds are at different voltage 
potentials between different pieces of equipment (like being plugged 
into different wall outlets or power strips).  Don't discount the noise 
that switching supplies or wall warts can spew onto lines, nor noisy 
muffin fans on amplifiers (have this problem on a Henry amp right now), 
florescent lights, HT chargers...the list is long where it could be 
coming from, not to mention a/d device issues.

In this world, you must be oh so smart or oh so pleasant.
Well, for years I was smart. I recommend pleasant.
You may quote me.

Sent from my MacBook Pro.

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