Agree, Raimund.

Like I said, I would have liked to know which load he used at the
input, this guy who presented the curves about increased noise.
It is so easy to make incorrect measurements. Using a load resistor
would not even be considered theoretically "wrong". Therefore I want
to HEAR such a difference.
I can even imagine that the current regulator can make different
noise at different loads! If one fet needs 0,25 mA and you parallel
two of them, it is 0,5 mA and another situation.

I'll be back when I know.

Klas.


At 12:05 2009-07-05, you wrote:
>Klas Strandberg <telinga@...> wrote:
> >
> > Could be an overlooked thing...
> >
> > For the ones who donŽ't know about the principals of a pip circuit,
> > have a look at telinga.com / whitepapers / this is plug in power.
> >
> > I wouldn't worry if, like in the old days, a resistor was used to
> > give pip voltage. But it isn't, it seems: For some reasons, perhaps
> > to increase input impedance, (?)
> > a current generator is used.
> > This may cause noise. On the other hand it could also lower the
> > noise, compared to a battery and resistor...
> >
> > The tests I made last night with the LS-10 didn't show any
> > difference. But I had some difficulties setting the reference tone
> > because of insects.
> >
> > I'll be back when I know for sure.
> >
> > You noise measure people, Rod, Raimund, e.t.c. what do you think?
> >
> > I mean, - for the mic-fet it doesn't matter if it's running on pip
> > voltage or a battery.
> > So what could cause the recorder to start generating low freq. noise
> > internally?
> >
> > Klas.
>
>Hi Klas,
>
>I also noticed the increased levels of noise caused by the activated
>PIP voltage option on the various recorders that I have tested
>(using a 150 ohm termination resistor).
>
>I would also think that this additional (pink) noise is probably
>caused by a current generator inside the recorder.
>
>However, I guess that this increased PIP noise is not relevant when
>using a typical PIP microphone, which itself usually also exhibits a
>higher inherent noise level that probably masks this current
>generator noise. This would most likely also apply for your quieter
>Telinga PIP mics as long as they provide a sufficiently high
>absolute output level.
>
>In any case, it would be safe to switch off the PIP voltage option
>when using self-powered microphones such as the Sennheiser K6/ME6x
>series models for instance.
>
>Regards,
>Raimund
>
>
>
>
>
>
>
>
>
>
>
>
>------------------------------------
>
>"While a picture is worth a thousand words, a
>sound is worth a thousand pictures." R. Murray Schafer via Bernie Krause
>Yahoo! Groups Links
>
>
>
Telinga Microphones, Botarbo,
S-748 96 Tobo, Sweden.
Phone & fax int + 295 310 01
email: telinga@...
website: www.telinga.com


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