oryoki2000 wrote:
> John Moore wrote:
>
>
>>Would I experience [impedance mis-match]
>>if I used a Sennheiser ME67 with an
>>AIWA Minidisc Recorder AM-F70?
>
>
> The ME67 is a low-impedance mic, with an
> output impdeance in the 200 ohm range.
> The AM-F70 mic input is in the medium-
> impedance range, somewhere between 2000
> and 4000 ohms (I've seen both figures).
> The Shure A96F cable will raise the
> ME67 output to be closer to the range
> of the minidisc, resulting in louder
> recording without raising the level
> on the minidisc pre-amp.
Looking through the spec charts, I noted that the K6 powering module is
going to run the A96F above Shure's specs. Even though there are
numerous reports of this working fine.
As delivered the A96F is set on it's 600ohm winding. Shure specifies a
maximum of 1 volt for that winding.
If you were to modify the A96F according to Shure's directions to use
the 150ohm winding then the max voltage is rated at 0.5 volts.
The K6 powering module is rated as putting out a max of 2 volts.
Since nature recording tends to be on the quiet side it's probably ok as
the actual output out of the K6 will average much lower. But I expect if
this combo was used with continuous loud sound near the max SPL for the
mics, you might have problems. All depends on just how much pad Shure
allowed in their specs.
The K6 powering module also expects to see a minimum terminating
impedance of 1000ohms, not 600. This also seems to be the standard for
the MKH mics.
It all makes you wonder just what mic Shure was designing for. The 2500
ohm output end of the A96F sounds right for the minidisc.
Walt
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