I would second Klas's comments about using low voltage regulators and
inverted to current regulators. All designs are a mess, generating a
lot of noise that is very difficult to isolate. These small devices
are also stuck using tantalum caps or other, less than ideal, types.
The ME-66 did get it right for running off 1.5 volts and I always use
the mic supply with my K6 and not P48. It seems to be one of those
things that is hard to achieve but once you get it right you got it
right for ever.
Rich Peet
hope to be home and recording within the next 2 weeks as I have had
enough fun outside of recording lately and have a serious yearn for a
frozen wetland during a blizzard.
--- In wrote:
>
> Klas, you wrote:
>
> >Note that unless you are going to run microphones with output
> >transformers, you don't need to use matched 1% resistors.
>
> Yes, it would perhaps be OK to use less precise resistors. However,
a good
> match would also preserve a proper balance of the two input rails of the
> differential microphone preamplifier. Unmatched resistors would
degrade the
> "common mode" rejection capabilities of the recorder. This means that
> external noise interference would be canceled out less effectively.
>
> This kind of balance should also be preserved within the microphone
or in a
> dummy microphone circuit for noise test purposes. So, a test circuit
that
> employs an unbalanced connection scheme might produce worse results
than a
> balanced microphone. Noise originating from the phantom power circuit is
> usually a common mode signal that can be reduced by the balanced
> preamplifier input.
>
> Klas, this is the reason why I would not over-estimate the bad
results you
> got in your test on the MT2496 phantom power. At least the phantom
power of
> my own MT2496 is sufficiently clean for operating my phantom-powered
(and
> balanced) K6P/ME66 microphone.
>
> Raimund
>
> --
> Highspeed-Freiheit. Bei GMX superg=FCnstig, z.B. GMX DSL_Cityflat,
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>
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