[sdiy] LDO / switcher?

[mark]

Some of the most expensive Hi-Fi in the world - Linn in scotland use
switching supplies on all their Hi-Fi equipment.

It's just a matter of sensible design. Most switchers run in the order of a
100kHz plus so they are well out of the way.

In my day job we use switchers on tuners and frontend receivers that sniff
signals at 47-2.2GHz down in the order of mV. It is very rare switching
noise causes an issue - theres more chance that the 400Hz from the 7seg
display or 15625Hz from the video causes disturbance. Most noise can be
removed with a decent pi filter cct and more importantly a sensible
power/ground layout.

Linear regs do work - we do use them occasionally on ultra sensitive vco
tank ccts.

I think it's just a myth generated by those who love to dissipate lots of
heat and power in a lovely linear (read analogue) power supply - rather than
a nice efficient switcher (read digital) power supply.   <ducks and runs>

Cheers

mark

-----Original Message-----
From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl] On Behalf Of Bert Schiettecatte
Sent: 20 April 2006 15:01
To: synth-diy
Subject: [sdiy] LDO / switcher?

hi all,

I am relatively new to complicated power supplies and I remember a post
somewhere about not using switching power supplies for audio circuits, and
that using a linear regulator for an audio section of a circuit might not
filter out all the noise on the power rails... is this true?

Thanks!
Bert