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