Need advice on this...

[Benoit F.]

Hi,

I need +12V and -12V for a low power audio application(Less than 100mA). The
problem is that the power supply is a switching 12v and is not very stable.
I would need a 12v regulator, but it needs at least 15V to work. So, i'm
planning to use a voltage doubler, then a regulator for +12v supply and an
inverter for -12v supply.

Also, i saw two types of regulators, switching and linear. Which one of
these works the best for audio?

Thanks.

 

[Ban]

Benoit F. wrote:

Hi,

I need +12V and -12V for a low power audio application(Less than
100mA). The problem is that the power supply is a switching 12v and
is not very stable. I would need a 12v regulator, but it needs at
least 15V to work. So, i'm planning to use a voltage doubler, then a
regulator for +12v supply and an inverter for -12v supply.

Also, i saw two types of regulators, switching and linear. Which one
of these works the best for audio?

Thanks.

A switching PS can be as well regulated as a linear one, the advantage for
audio is if it is isolated, so you do not depend on a common ground. Best to
have a single switching supply with dual outputs. If you are using opamps in
your circuit, you do not really depend on a accuratly regulated supply
because of common mode suppression of the opamps. Modern switching supplies
are working on very high frequencies (>0.5MHz) and it is easier to suppress
these frequencies to accaeptable levels. A voltage doubler is certainly not
different from any switcher, neither is your "inverter" (whatever that is).
If you want linear regulators post a switching preregulation then use a
+/-15V supply and follow with low dropouts +/-12V linears. I doubt this
additional stage is of any benefit though.

--
ciao Ban
Bordighera, Italy

 

[John Popelish]

"Benoit F." wrote:

Hi,

I need +12V and -12V for a low power audio application(Less than 100mA). The
problem is that the power supply is a switching 12v and is not very stable.
I would need a 12v regulator, but it needs at least 15V to work. So, i'm
planning to use a voltage doubler, then a regulator for +12v supply and an
inverter for -12v supply.

Also, i saw two types of regulators, switching and linear. Which one of
these works the best for audio?

Thanks.

Switching regulators are inherently more efficient than linear
regulators because they convert one voltage to another, instead of
wasting the extra voltage. But they also involve large and fast
internal waveforms. However, if the switching frequency is above what
you can hear, they can be quiet powering audio equipment. Besides
that, since they contain filter components that contain their own
internal noise, that tend to be good at also preventing noise from
passing through from input to output, so in the noisy automotive power
environment, they can easily out perform linear regulation unless you
add much of the same filtering components to the linear regulator.
--
John Popelish

 

[Ben Bradley]

On Fri, 7 May 2004 00:26:55 -0400, "Benoit F." <nospam@spam.abuse.net>
wrote:

Hi,

I need +12V and -12V for a low power audio application(Less than 100mA). The
problem is that the power supply is a switching 12v and is not very stable.
I would need a 12v regulator, but it needs at least 15V to work. So, i'm
planning to use a voltage doubler,

What's the unregulated input (AC) voltage? Linear regulators will
run at higher input voltages (look at the data sheet to be sure) but
will unnessecarily dissipate a lot of heat and need a larger heat
sink.

hen a regulator for +12v supply and an
inverter for -12v supply.

Also, i saw two types of regulators, switching and linear. Which one of
these works the best for audio?

How quiet do you need the audio to be? If this is a microphone or a
phono preamp, then you definitely want to use a linear regulator. +/-
12V at 100mA is not much power, and a 7812 and 7912 regulators on
small heat sinks with 15 to 20 volts input will do fine.

It's possible to design a switching regulator that powers an audio
circuit without inducing (too much) noise, but it's much easier to
just make a linear supply, and at the low power level of a
preamp/volume/tone control type circuitry, linear is a no brainer.

Thanks.

-----
http://mindspring.com/~benbradley

 

[N. Thornton]

"Benoit F." <nospam@spam.abuse.net> wrote in message news:<CdEmc.32759$j11.603162@weber.videotron.net>...

Hi,

I need +12V and -12V for a low power audio application(Less than 100mA). The
problem is that the power supply is a switching 12v and is not very stable.
I would need a 12v regulator, but it needs at least 15V to work. So, i'm
planning to use a voltage doubler, then a regulator for +12v supply and an
inverter for -12v supply.

Also, i saw two types of regulators, switching and linear. Which one of
these works the best for audio?

Tell us the app, tell us the setup. Your description fails to do either of those.


Regards, NT