[LAU] OT: Phantom power and my acoustic guitar

Fons Adriaensen fons at kokkinizita.net
Sun Jan 25 12:38:21 EST 2009


On Mon, Jan 26, 2009 at 01:28:32AM +0800, Ray Rashif wrote:

> As long as it's balanced, there won't be any issue.

That is *absolutely not true*. Any website that
claims that you can safely connect a phantom
powered mic input to any balanced output is
providing very bad advice to its readers.

It depends on *how* the preamp output is balanced.

If it has a transformer to balance the output
there will be no problem.

If it is 'actively' or 'electronically' (!) 
balanced it depends on the if the designer
has allowed for phantom power or not. In
many cases the answer is *no*.

If DC-coupled the PP may just destroy the
output stages (transistors or opamps) if
they are not specified to survive the
voltage.

If condenser coupled the PP will typically
reverse-bias electrolytic condensers, again
destroying them, maybe not immediately but
they will die at some point.

Ciao,

-- 
FA

Laboratorio di Acustica ed Elettroacustica
Parma, Italia

O tu, che porte, correndo si ?
E guerra e morte !



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