[Audio Empire]

On Tue, 23 Mar 2010 20:43:30 -0700, David Nebenzahl wrote
(in article ):

On 3/23/2010 5:40 PM Audio Empire spake thus:

On Tue, 23 Mar 2010 16:44:59 -0700, Ian Bell wrote
(in article ):

Audio Empire wrote:

On Tue, 23 Mar 2010 08:40:00 -0700, Randy Yates wrote
(in article ):

Is there ever a reason NOT to use a differential amplifier as
the first stage of a microphone preamp?

I really can't think of any instance where NOT using a
differential amplifier as a microphone input stage would, in any
way, be considered beneficial.

1. They provide no galvanic isolation (transformers do)

And this is important, when?

2. If they have phantom power connected to them, user cock ups an
destroy the input stage (transformers don't)

Most modern differential amplifiers are pretty well protected against that.
I
still wouldn't consider that an overwhelming reason to use transformers and
still think that the disadvantages of transformers outweigh the advantages.


Why are we even discussing microphone transformers here? (I guess this
is the Usenet version of "telephone".) I mean, the OP didn't mention
them; neither did they mention phantom power, yet everyone seemed to
jump to the conclusion that this would be a crucial consideration.

I'd say that since a differential amp practically eliminates common-mode
noise, there's no reason *not* to use one (which, after all, was the
question the OP asked).

Sheesh.




That's what I said. I only brought-up transformers as an alternative (after
all, they do replace diff amps in some designs) and to show that this older
technology was at once more expensive and less effective than are modern
differential amplifiers.