Correction of no 3:
The impedance of a microphone for plug in power is set by the resistor used
to supply the plug in power, usually about 3-5 kOhms.
The correct way to squeeze out the best from a plug in power microphone is
to connect it to a higher voltage, say 9 volt, with a 15-30 kOms resistor,
(must be tested) and then lead the output signal via a condensor to the
input of the MD / Dat.
Klas.
At 06:27 2003-11-25 -0000, you wrote:
>I'll add my 2 cents:
>
>1) The plug-in-power can cause a loud crackling noise when the mic
>plug wiggles slightly or rotates. It may depend also on what mic you
>are using, and is probably more of a problem with dynamic mics as a
>variation of the resistance at the jack will cause the "plug-in-
>power" voltage across the mic element to vary. Therefore, you may
>find it necessary to add a blocking capacitor. I use a Panasonic FC
>27uF/25v capacitor. It fits inside the XLR connector and only causes
>a roll-off of 0.3dB at 20Hz measured with this model.
>
>2) Several news reporters have complained to me that this model has
>a noisy mic preamp. You will get better results with a high-output
>condensor mic instead of a dynamic, but as nature sounds are often
>of low intensity and need high gain, you should make sure that you
>get acceptable noise results with the combination of recorder,
>microphone, and subject matter. Eventually, I hope to do comparitive
>measurements to quantify the problem with different recorders.
>
>3) You may get better noise performance using a matching transformer
>(200 ohm input to "medium impedance" output), but this will depend
>on what input impedance the mic preamp is optimized for (which I
>haven't myself tested). Most consumer mics that would accept plug-in-
>power are likely to have a 600 ohm output impedance, which may be
>why (combined with the crackling problem) they recommend these mics,
>even though they are unsuitable for professional use.
>
>- Adam Liberman
>Liberman Sound
>
>Thanks,
>Adam
>
>--- In Vicki Powys <>
>wrote:
>>
>> Can anyone confirm if the Sharp minidisc MD DR7 (which may also be
>listed as
>> DR480) will only accept microphones that use plug-in power? The
>manual
>> suggests using only "mics that can be powered from the mic
>socket". What
>> would happen if you used a battery-powered mic such as a
>Sennheiser K6
>> series mic?
>>
>> Vicki Powys
>> Australia
>
>
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