Scott and all:
"Impedance mismatch"..?
No designs today have low input impedance. The input impedance of a recorder
is always 2-10 kiloohms. I know SQN had a transformer input on some
pre-amps, but that was long ago.
This is the one and only principle for impedance matching: The input
impedance must be much higher than the output impedance.
All recorders / mic amplifiers today have an input impedance around 2 - 10
kOhms.
The problem for all you guys using ME-series, is mainly because the mic is
made to handle pop-music. For the birder, the output is too low. A
transformer will boost the voltage.
Using such a transformer will not lower the noise, unless the mic amplifier
is noisier than the microphone. No recorders today have such noisy mic amps.
Using a ME-mic into the HHB, I'm sure it is the mic noise you hear.
Klas.
At 08:09 2002-05-28 -0400, you wrote:
>John and Walt, thanks for a great evaluation of Hhb performance. This is
>meat and potatoes stuff for all of us, but especially the birders. John,
>is there any kind of impedance mismatch between the Senn 67 and the
>input on the Hhb? I was never a believer in the Mineroff pre-amps
>because of their noise level. I solved the problem by using a matching
>transformer between the TCM-5000 and a Senn 88. When the Senn 66 became
>available, I found that the transformer wasn't necessary any more
>because the mike impedance of the 66 was much lower than the 88 (I
>believe that the difference was 150 vs. 200 ohms as opposed to 150 vs.
>300 before). Your thoughts?
>
>Scott Connop
>
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