Dan Dugan wrote:
>> > Open the male xlr plug and make sure the shield is going to both pins
>>
>>> 1 and 3, and the hot to pin 2.
>>>
>>
>>This should not be necessary. I, in fact, don't tie signal cold to
>>shield on purpose. So if you forget and leave the phantom power on you
>>won't short it out. And I never have these problems. I did not even when
>>I was still using the Telinga with the Stereo miniplug cable.
>
>
> We're talking about an unbalanced microphone circuit coming in that
> has just hot and shield, and how to connect it to a 3-pin XLR input.
>
> If the input is transformer isolated, as the best equipment is, the
> result of leaving one signal pin (2 or 3) unconnected will be low
> gain, increased noise, and a scratchy, treble-emphasized sound.
>
> If the input is electronically balanced, as in mid-priced gear, the
> result will be increased noise from the unterminated leg.
>
> Of course it's necessary to keep phantom power off when using an
> unbalanced mike. That's why it has a switch.
>
> Walt, if you've been able to get away with wiring your mike inputs
> wrong, you are either 1) not getting the best performance from your
> gear, or 2) very lucky.
I have not had anyone complain about the quality of my recordings from
the Telinga. There has been no difference either way.
I did the same thing when I was using a adapter box with ministereo jack
at the Portadisc. And, I've also tried it the other way, with shield and
cold tied together. That makes no difference. Except, in the case of
adapting into the 5 pin stereo system to tie the shield into signal cold
on the ministereo jack means that I'll have shorted phantom power for
the MKH 5 pin configured systems I use. They don't run well with one leg
of the phantom shorted.
The Telinga is the only unbalanced mic I use. I use the system the way I
do to keep from having to maintain a separate set of Y cables for it.
Note the following, I connect both signal pins. Signal hot and Signal
cold are connected. But there is a third pin, the shield (pin 1). That I
do not tie to Signal cold. I think you misunderstood and thought I did
not run both legs of signal through or that the shield was tied in at
the Telinga end. I agree, that would not work very well at all, both
legs of the signal must go through.
In my current system with the Telinga, Signal hot and Signal cold are
connected through to the appropriate points on the Telinga circuit
board. Signal cold is a common point between both channels on the board,
though I run separate conductors from there on for the two cold sides.
Shield is connected through to the cable shield, but I don't tie that to
the circuit board Signal Cold. So there are no floating things in the
cables. The shield runs as far as it does any good.
Note I also break off the shield before the mic in a similar way for the
SASS/MKH-110. There because running the shield to both mic housings will
cause the RF oscillators of the two mics to interact and produce a nasty
whine in the output. So, the shield ends there in the same manner as in
the Telinga, at the mic end of the cable, not connected at that end,
but, of course, connected all the way through to the portadisc's Pin 1
shield ground.
The Telinga itself has no shield around the circuit board to tie to,
it's unshielded inside a plastic handle that's non-conducting.
Connecting to Signal minus won't shield anything, that's just a circuit
trace running the length of the board.
Note that phantom power is between the shield and both legs of the
signal. By not tying the shield to signal, I really don't have to worry
if I forget to turn it off. The Portadisc can operate perfectly well
with one leg of phantom power shorted, though you are using more
battery. But I'm not to eager to experiment with 48 volts running
through the Telinga. I, of course, turn it off when not needed, unless I
forget, which has been known to happen.
We are talking about two unbalanced channels that come in on 4 internal
conductors in the Telinga's cable. Counting the braided shield there are
5 independent conduction paths. The two signal minus are tied together
in the Telinga's handle, but not after that on their way to the
Portadisc. These 5 conductors are attached to a 5 pin XLR. Pin 1 is the
cable's shield connection and ties through to the Pin 1 shield of the
portadisc. Pin 2 and 3 are one channel, Pins 4 and 5 the other. The 5
pin system then get's broken out using a 5 pin to 2-3pin Y cable, that's
wired in the standard balanced configuration at the Portadisc end. This
short Y is also used with all my MS and SASS mics. Where it supplies
phantom power.
When I first looked into how to handle balanced conversion to
unbalanced, I found there seemed to be two camps, those that connect
signal cold to shield and those that don't. Both seemed to get theirs to
work. And I tested both configurations and found it did not matter, at
least in nature recording.
My alternate connector "Y" is the plugbox I made when I first got the
Portadisc:
http://frogrecordist.home.mindspring.com/naturerecordists/plug.jpg
This adapter has both a ministereo jack which was my connection to the
Telinga until I modified it, and a balanced 5 pin stereo jack. In order
to work with phantom powered mics it must have the shield not connected
to signal cold.
Before I used that one, I used this one:
http://frogrecordist.home.mindspring.com/naturerecordists/adapter.jpg
Made from one of the radio shack gold cables, this one does connect
shield and signal cold. I abandoned it primarily as the dangling
connection was too easy to snag.
I'm not using the plugbox as much now as 1) I don't need a ministereo
jack, and 2) I keep the Portadisc in one of the Porta Brace cases
designed for it. The connector end of the Portadisc is protected by a
velcro sealed Cordura tube. The plugbox fits entirely within that tube,
so a connection to it is well protected, but a little harder to get at.
The Y connector I'm using now has the 5 pin XLR long enough to just
stick out through the velcro seal, making mic cable changing a little
more convenient. A XLR connection is a little less worry about snagging
than the ministereo one was.
Walt
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