switching or linear power supply for +48? (phantom only)

arkestra · Post by **arkestra** » Sun Jul 20, 2008 4:04 pm

switching for 48 (phantom) only should be ok right? im using linears for the psu for the pres in a rack. want to put the switching 48 in there too. any thoughts on this? anyone tried this combo before?

RefD · Post by **RefD** » Mon Jul 21, 2008 6:21 am

IIRC, switching supplies throw alot of garbage into the world in the way of RFI and it shows up in the audio as noise.

IOW, bad idea to use them for audio applications.

anyone (RodC for instance) care to check me on this?

Nate Dort · Post by **Nate Dort** » Mon Jul 21, 2008 6:39 am

I'd agree with that statement. The only place I would use a switching power supply in a piece of audio gear is for non-audio applications. Maybe to power some signal-switching relays or to power some LEDs, but only if they have their own isolated ground paths away from audio ground. Definitely don't use them for phantom, as that voltage travels down the same copper as the audio and those 6.81k resistors at each leg aren't going to smooth out whatever garbage the PS is putting out, and with the amount of gain in a mic pre you're just going to amplify that noise.

RodC · Post by **RodC** » Mon Jul 21, 2008 6:41 am

I try to avoid switching because of the noise.

If you have any voltage you can usualy fab some kind of supply for phantom.

After all kinds of Preamps without phantom I finaly gave up and got myself a 6 channel supply. It became a real hassel trying to figure out how to get phantom to each, plus depending on the design the would all vary a bit.

Brian · Post by **Brian** » Mon Jul 21, 2008 9:45 am

How do the new designs of poweramps such as the Crown Itech series use them?

RefD · Post by **RefD** » Mon Jul 21, 2008 9:55 am

Brian wrote:How do the new designs of poweramps such as the Crown Itech series use them?

my my guess is probly alot of additional hardcore ripple suppression filtering as well as hefty internal RF shielding between supply and audio path.

Brian · Post by **Brian** » Mon Jul 21, 2008 9:56 am

,,,,,,,,,,,, and with all that, it's 25 to 75 lbs lighter to carry.

RefD · Post by **RefD** » Mon Jul 21, 2008 9:57 am

Brian wrote:,,,,,,,,,,,, and with all that, it's 25 to 75 lbs lighter to carry.

but how does it sound?

Brian · Post by **Brian** » Mon Jul 21, 2008 10:01 am

AWESOME!

RefD · Post by **RefD** » Mon Jul 21, 2008 10:03 am

Brian wrote:AWESOME!

congratulations.

do the needful.

then click the button below.

you will be intimated shortly.

Andy Peters · Post by **Andy Peters** » Mon Jul 28, 2008 12:21 am

arkestra wrote:switching for 48 (phantom) only should be ok right? im using linears for the psu for the pres in a rack. want to put the switching 48 in there too. any thoughts on this? anyone tried this combo before?

The answer is: it depends. You can do a proper design and have a quiet-as-you-like switchmode power supply.

And you can fuck up a simple linear regulator and have it hum for days.

-a

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switching or linear power supply for +48? (phantom only)

switching or linear power supply for +48? (phantom only)

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