Someone wrote:
>I would connect the tip and ring together at the mini-plug end, so
>the mike will feed both channels.....
If you connect the two channels of a plug in power input, you get half the
available input impedance, which MAY load the output of the microphone.
(depends on the mic output impedance)
Or have I misundertood the issue here?
Plug in power inputs shall not be connected, for mono. Then you also connect
the two resistors, providing the plug in power. You have to connect the two
channels with a condensor.
Klas.
At 21:33 2003-11-23 -0800, you wrote:
>Vicki Powys, you wrote:
>
>>I've just made a test using two types of adapting leads, to take a 3-pin
>>professional mic to a 3.5 mm stereo socket. For the test I'm using a Sony
>>Walkman WMD6C cassette recorder and a Sennheiser ME67 mic. The first lead
>>has a mini-plug one end and a 3-pin socket at the other. It is not wired
>>exactly as described by Rich and Dan, but it does work satisfactorily.
>>
>>The second lead uses a Tandy adapter/transformer, part no. 274-0016, cost
>>around $25 in Australia. On the adapter is written: Lo-Z Balanced to H-Z
>>Unbalanced. It isn't a pre-amp, just a transformer. Using this set-up, I
>>get 5-10 dB more gain, i.e. a stronger signal, than I do with lead 1.
>>
>>A few years I borrowed a FEL pre-amp (made in UK) which gave 20 dB better
>>gain (using lead 1 set-up) but at much greater expense. I reckoned that the
>>Tandy adapter was quite good enough to be used for a back-up system, and was
>>certainly worth the $25 for the boost in signal.
>>
>>From my test with the WMD6C, I concluded that it is better to use a
>>transformer of some sort, to connect to the pro mic. But maybe the
>>situation is different for a consumer minidisk such as MD DR7? Would the
>>minidisk have better input capacity than the WMD6C? Making an
>>adapter/transformer redundant?
>
>I think the WM-D6C's preamp is quite similar to an MD's. The "free
>gain" from a transformer is often useful; it would be especially
>valuable if you were using a low-sensitivity mike. With more
>sensitive mikes, however, you may not need the extra gain, and the
>transformer may limit the frequency response at both the low and high
>ends.
>
>>For the record, on my lead no. 1, I had shorted pins 2 & 3 which run to the
>>tip and the ring of the miniplug, while pin 1 runs to the sleeve. It seems
>>to work fine, but this isn't the same as Rich and Dan suggested, so maybe
>>I've done the wiring wrong? Would that affect the strength of signal, or
>>just be potentially more noisy?
>
>I would connect the tip and ring together at the mini-plug end, so
>the mike will feed both channels, but if you connect XLR pins 2 and 3
>at the mike end together, your signal will be very low or missing
>altogether. In a balanced circuit, the signal is the difference
>between pins 2 and 3!
>
>At the mike end connect 1 and 3 together to the cable shield, and the
>inner conductor, which feeds both tip and ring, should feed from pin
>2.
>
>If it's a 3-conductor cable wired tip, ring, and shield at the
>mini-plug end, connect the shield to XLR pins 1 and 3 together, and
>both inner conductors (tip and ring) to pin 2.
>
>-Dan
>
>
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