Help with Sennheiser 421

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

Eli Crews wrote:

> I'm looking for help with a vintage MD-421 N, serial number
> 139696. The three-pin (mini-XLR?)

DIN (Deutche Industrie Norm), what fits as a screw on is a female plug
called a minitüchel, Sennheiser has them, they are preferable to use on
the mic end of the cable.

> connector has come loose, and the 5-posititon
> selector switch has been stripped (spins freely,
> but still operates).

This might, might mind ya, mean that the locking screw - under the
serial number badge - is loose or missing.

> The three wires have come undone from their pins. I can solder them
> myself if I know the pinout.

On my recollection of this, it may be erroneus

1) hot 3) return


2) ground

> One wire is red,

Probably hot

> one is blue,

Probably return

> and one is black.

Probably ground.

> Any help would be appreciated.

Call or email Sennheiser North America for exact info and to get the mic
end plug for the cable. Be aware that the connection numbering and
number-allocation differs from the XLR defaults, and from all variation
thereof.

Sennheiser may also be able to supply a rear end that allows you to skip
the frequency response altering thingie and to use XLR's on it, it is
"only" about fitting the mic with the large tüchel rear end and then fit
an xlr-adapter to that one, if it is avaiable. Kinovox here in Denmark
modded my 421's like that back in the late 1970'ties, but it may have
been with non-standard parts of their own manufacturing.

Do not expect it to sound like a version 2 .... and the frequency
response got a lot smoother during the manufacturing life of version 1.

Some old 421's end up suffering from membrane rigidity syndrome and
loose all bass - perfect if you need to emulate a telephone, but useless
for anything else, verify that this has not happened prior to using too
much money on it.

> Eli Crews


Kind regards

Peter Larsen

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