Thanks for the rundown on your experiences and the radio shack number, Vick=
y.
I've done one test with A96F "stock." It produced +3.9dB gain (from
nt1a->art phantom->NH900 to nt1a->art phantom->A96F-> NH900 Maximum
gain). I do detect some noticeable changes in tonal quality and
perhaps noise difference too. I'll change the A96F to the "150 ohm"
setting, run more tests, then do a report with sonograms. Rob D.
Rob D.
At 7:07 AM +1000 6/17/06, vicki powys wrote:
>Re impedence matching, for what it's worth I've successfully used a Tandy
>impedance adapter with a Sennheiser ME67 mic going into a Sony Walkman WMD=
6C
>cassette recorder, (the recorder is ancient but I carry it on longer trips
>as a backup for DAT). The sound to the walkman is definitely louder using
>the adapter, and it also serves to connect XLR mic to the mini-plug walkma=
n.
>The impedance adapter brand was 'Archer' "Lo-Z balanced to Hi-Z unbalanced=
"
>274-016. Maybe they don't make them any more, but they were relatively
>inexpensive. The transformer had female XLR to quarter inch pin so I need=
ed
>to get an inline RCA adapter, then made up a lead RCA to minijack. Works
>with stereo too, using 2 adapters. The cassette recordings were definitel=
y
>better when using the impedance adapter, maybe 6-10 db gain.
>
>Vicki Powys
>Australia
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>on 10/6/06 3:54 PM, oryoki2000 at wrote:
>
>> I have read conflicting points of view about impedance matching:
>>
>> 1. Matching the impedance of the mic output to that of the recorder
>> input reduces the power lost when a signal is transmitted. The result
>> is a louder recording without needing to boost the signal through the
>> recorder's preamp. For a brief discussion, see:
>>
>> http://hyperphysics.phy-astr.gsu.edu/hbase/audio/imped.html#c4
>>
>> 2. Modern transistor designs (meaning any audio device made since the
>> 1980's) use voltage transfer rather than power transfer. Voltage
>> transfer is actually improved when there is a large difference in
>> impedance between mic and recorder. So matching impedance will reduce
>> the volume of a recording.
>>
>> http://www.shure.com/ProAudio/Products/us_pro_ea_imepdance
>>
>>
>> Perhaps these two points of view are not mutually exclusive. I have
>> little understanding of the physics and electrical engineering
>> principles involved here. In my limited experience, however, I find
>> impedance matching to be a valuable way to gain some volume without
>> adding extra preamp noise.
>>
>> The impedance of my Sennheiser ME62 is 200 ohms. The impedance of a
>> Sony minidisc recorder is about 2000? 5000? ohms. (If I remember
>> correctly, Sharp minidiscs have a mic input with 10,000 ohm
>> impedance.) When I use a Shure A96f impedance matching transformer
>> ($40) to raise the ME62 output to 2500 ohms, the minidisc records a
>> considerably louder signal.
>>
>> A member of this list had similar results by employing the Hosa
>> MIT-156 impedance transformer ($20). This device is also calibrated
>> for 600 ohm mic output and 2500 ohm recorder input.
>>
>> Both cables have the added advantage of having an XLR female connector
>> on the mic end, and a 3.5mm male connector on the recorder end. So
>> either cable will let me connect a pro mic to the minidisc recorder.
>>
>> --oryoki
>>
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>>
>> "Microphones are not ears,
>> Loudspeakers are not birds,
>> A listening room is not nature."
>> Klas Strandberg
>> Yahoo! Groups Links
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>
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>"Microphones are not ears,
>Loudspeakers are not birds,
>A listening room is not nature."
>Klas Strandberg
>Yahoo! Groups Links
>
>
>
>
--
Rob Danielson
Peck School of the Arts
University of Wisconsin-Milwaukee
http://www.uwm.edu/~type/audio-art-tech-gallery/
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