[sdiy] Direct Injection box? (balanced v. unbalanced)

[harry]

No... it can be done by two opamps that output a non-inverted and an inverted
signal... Some opamps have two complementary outputs built in, but they are
sort
of rare.

Transformers have poor low frequency response that NEVER goes to DC...
they can pick up magnetic fields unless properly shielded (usually included in
the
manufacture, and expensive... better = more $$$)...

But they can provide total galvanic isolation... sometimes important.

Almost all balanced inputs can be driven by a single ended source with
slightly
less noise rejection... you would noy notice unless the cable was very long...

H^) harry

Alex Dickey wrote:

> > A direct box (for bass or guitar) usually converts from single
> > ended to balanced output, and provides attenuation to go into the
> > microphone input of a mix console. Isolation is usually a
> > feature, as is the
> > ability to separate the grounds. Very often an audio transformer is
> > involved.
>
> i was wondering about this the other day, i.e. balanced inputs vs.
> unbalanced inputs.  is the conversion done exclusively with a transformer?
>
> alex