On Thu, 16 Mar 2006 11:17:50 GMT, "housetrained"
wrote:

Is this the reason why one of my amps has its own power supply. A separate
box that sits next to the pre-amp and transforms the mains into DC?

All amps have their own power supply that does exactly this. Whether
it is in the same box or not is entirely immaterial.

d

Pearce Consulting
http://www.pearce.uk.com

"Don Pearce" wrote in message

On Thu, 16 Mar 2006 11:17:50 GMT, "housetrained"
wrote:

Is this the reason why one of my amps has its own power
supply. A separate box that sits next to the pre-amp and
transforms the mains into DC?

All amps have their own power supply that does exactly
this. Whether it is in the same box or not is entirely
immaterial.

True for power amps, but not necessarily true for every kind of audio gear.

Rane, a U.S. pro audio gear manufacturer with a very solid reputation for
conservative technology claims that some of their gear (like mic preamps)
showed a SNR advantage when the power transformer was moved out of the box
and into a big plastic wart on the power cord.

http://www.rane.com/rap.html

Reasons to use external pwoer supples:

"Better Audio Performance. Removes the hum source, i.e. the AC line
transformer and all primary circuits resulting in quieter noise performance,
without the usual (and annoying) 50/60 Hz and 150/180 Hz hum components."

Rane, a U.S. pro audio gear manufacturer with a very solid reputation for
conservative technology claims that some of their gear (like mic preamps)
showed a SNR advantage when the power transformer was moved out of the box
and into a big plastic wart on the power cord.

http://www.rane.com/rap.html

Reasons to use external pwoer supples:

"Better Audio Performance. Removes the hum source, i.e. the AC line
transformer and all primary circuits resulting in quieter noise performance,
without the usual (and annoying) 50/60 Hz and 150/180 Hz hum components."


More bollockx.

**** poor design then, if their having those problems.

This "wall-wart" caper is more to do with complying with different regs
in different markets.....
--
Tony Sayer

"tony sayer" wrote in message

Rane, a U.S. pro audio gear manufacturer with a very
solid reputation for conservative technology claims that
some of their gear (like mic preamps) showed a SNR
advantage when the power transformer was moved out of
the box and into a big plastic wart on the power cord.

http://www.rane.com/rap.html

Reasons to use external pwoer supples:

"Better Audio Performance. Removes the hum source, i.e.
the AC line transformer and all primary circuits
resulting in quieter noise performance, without the
usual (and annoying) 50/60 Hz and 150/180 Hz hum
components."

More bollockx.

**** poor design then, if their having those problems.

Mic preamps for audio production are a more stringent environment than say,
RIAA phono preamps. RIAA MM phono preamps have 40 dB gain at 20Hz, but their
noise bandwidth is only 50 Hz. Mic preamps typically have up to 60 dB of
gain, and a minimum of 20 KHz noise bandwidth, usually far more.

This "wall-wart" caper is more to do with complying with
different regs in different markets...

That, too.

In article , Arny Krueger
writes
"tony sayer" wrote in message

Rane, a U.S. pro audio gear manufacturer with a very
solid reputation for conservative technology claims that
some of their gear (like mic preamps) showed a SNR
advantage when the power transformer was moved out of
the box and into a big plastic wart on the power cord.

http://www.rane.com/rap.html

Reasons to use external pwoer supples:

"Better Audio Performance. Removes the hum source, i.e.
the AC line transformer and all primary circuits
resulting in quieter noise performance, without the
usual (and annoying) 50/60 Hz and 150/180 Hz hum
components."

More bollockx.

**** poor design then, if their having those problems.

Mic preamps for audio production are a more stringent environment than say,
RIAA phono preamps. RIAA MM phono preamps have 40 dB gain at 20Hz, but their
noise bandwidth is only 50 Hz. Mic preamps typically have up to 60 dB of
gain, and a minimum of 20 KHz noise bandwidth, usually far more.

Arny surely your not saying that they can't design a mic amp without a
built in AC PSU now are you?....

This "wall-wart" caper is more to do with complying with
different regs in different markets...

That, too.



--
Tony Sayer

"tony sayer" wrote in message

In article
, Arny
Krueger writes
"tony sayer" wrote in message

Rane, a U.S. pro audio gear manufacturer with a very
solid reputation for conservative technology claims
that some of their gear (like mic preamps) showed a SNR
advantage when the power transformer was moved out of
the box and into a big plastic wart on the power cord.

http://www.rane.com/rap.html

Reasons to use external pwoer supples:

"Better Audio Performance. Removes the hum source, i.e.
the AC line transformer and all primary circuits
resulting in quieter noise performance, without the
usual (and annoying) 50/60 Hz and 150/180 Hz hum
components."

More bollockx.

**** poor design then, if their having those problems.

Mic preamps for audio production are a more stringent
environment than say, RIAA phono preamps. RIAA MM phono
preamps have 40 dB gain at 20Hz, but their noise
bandwidth is only 50 Hz. Mic preamps typically have up
to 60 dB of gain, and a minimum of 20 KHz noise
bandwidth, usually far more.

Arny surely your not saying that they can't design a mic
amp without a built in AC PSU now are you?...


It's not a matter of not being able to design an acceptable preamp with an
internal transformer, its a matter of the ultimate performance of similar
preamps that differ only in the location of the power transformer.

In article , Arny Krueger
writes
"tony sayer" wrote in message

In article
, Arny
Krueger writes
"tony sayer" wrote in message

Rane, a U.S. pro audio gear manufacturer with a very
solid reputation for conservative technology claims
that some of their gear (like mic preamps) showed a SNR
advantage when the power transformer was moved out of
the box and into a big plastic wart on the power cord.

http://www.rane.com/rap.html

Reasons to use external pwoer supples:

"Better Audio Performance. Removes the hum source, i.e.
the AC line transformer and all primary circuits
resulting in quieter noise performance, without the
usual (and annoying) 50/60 Hz and 150/180 Hz hum
components."

More bollockx.

**** poor design then, if their having those problems.

Mic preamps for audio production are a more stringent
environment than say, RIAA phono preamps. RIAA MM phono
preamps have 40 dB gain at 20Hz, but their noise
bandwidth is only 50 Hz. Mic preamps typically have up
to 60 dB of gain, and a minimum of 20 KHz noise
bandwidth, usually far more.

Arny surely your not saying that they can't design a mic
amp without a built in AC PSU now are you?...


It's not a matter of not being able to design an acceptable preamp with an
internal transformer, its a matter of the ultimate performance of similar
preamps that differ only in the location of the power transformer.




Sounds to me like their passing off the nuisance value of a wall wart
supply as some sort of benefit!.....
--
Tony Sayer

Hi,

"Arny Krueger" wrote in message
. ..
"tony sayer" wrote in message


Arny surely your not saying that they can't design a mic
amp without a built in AC PSU now are you?...


It's not a matter of not being able to design an acceptable preamp with an
internal transformer, its a matter of the ultimate performance of similar
preamps that differ only in the location of the power transformer.

Is that what they mean by "thinking outside the box"?

I'll get my coat.

Regards,

Glenn.