Cable question regarding Linkwitz mod to WM61a

Archived from groups: rec.audio.pro (More info?)

Brad <bradp@blarg.net> wrote:
>
>My question is regarding the cable I should use. I would like to use
>some very small gauge balanced audio cable. Considering that there
>are 3 connections though, is it advisable to run it on 2 conductor
>cable with a braided copper shield as the 3rd conductor, or does it
>make more sense to try to find a 3 conductor cable?

Well, one of those 3 lines is ground anyway, so there is no reason not
to use it as the shield. You might get marginally better RF rejection
with a three-wire line and the shield telescoped.

Belden makes a lavalier mike cable that is a star-quad if you are really
set on splitting the ground return and the shield.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Archived from groups: rec.audio.pro (More info?)

Brad wrote:
> Hello,
> I am going to build a pair of mini binaural microphones using the 3
> wire Linkwitz mod to the Panasonic WM-61a capsule.

FWIW, there is no performance advantage with three wire.
The two and three wire are identical from an AC circuit
point of view and perform identically.

In the three wire, the gate sees ground through the varying
diaphragm capacitance and in the two wire it sees the supply
rail. Both are at AC ground. Between the two there is a
reversal of the static charge on the diaphragm/backplate
capacitor but this has no effect on operation.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

Archived from groups: rec.audio.pro (More info?)

Len Moskowitz wrote:
> Brad <bradp@blarg.net> wrote:
>
>
>>Hello,
>>I am going to build a pair of mini binaural microphones using the 3
>>wire Linkwitz mod to the Panasonic WM-61a capsule.
>
> This modification should rightly be called the "Miller Mod" after Lyman
> Miller, the fellow who developed it. Linkwitz has popularized it in the
> DIY mic community, but Lyman should get the credit.

Actually, it is the 2-wire mod that Siegfried attributes to
Miller. It was his clever insight that the diaphragm could
be connected to either ground or to Vcc to yield the
identical source follower operation and that a simple
reconnection at the capsule would effect that while leaving
only 2 wires going back.

When Siegfried realized it was being given his name he
updated his site to give the correct attribution but I fear
it is too late to correct the widespread usage of "Linkwitz
mod." :-(


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein