Replacing vintage microphone screw connector with 1/4”?

[Mr Mark]

As per the title, can I replace a vintage screw type of connector (what is it called?) with a 1/4” female chassis Jack (mono)?

Customer is requesting this and have not had to do it before. The reason being is that his old cable is kaput, the screw end is mangled but the other end is 1/4” mono - so why not?

 

[boxplayer4000]

Looks like the customer's cable is phono/screw type at one end and standard jack at the other. Both are mono so there's no problem converting both to standard mono jack at either end of the cable. I think the thinking behind the screw connection was that it would be less likely to be inadvertently pulled out during playing.

 

[jozz]

although in general it is custom to have pull protection on any SEND signal connection,
it's typical to have a simple jack female for active accordion internal pickups

 

[debra]

Should be easy. It looks like the size of the hole might even already be right for the jack socket (threaded end) to go through.

 

[Ventura]

the Amphenol screw type connector was standard on much of the pa
equipment of the era in the USA, so it was a high choice for instrument
mounting as well

also

occasionally the Mic was located inside the bellows, and the Amphenol
connector (could be) airtight
(a sprung version was also available), actually this one looks like a sprung

also

the amphenol connector is shallow, so location relative to key mechanism lift
may not have been considered for a specific accordion grille hole.. the 1/4 in jack
is a bit longer and can, in some locations, have an intermittent physical touch

after examining the pics, i would also recommend replacing ALL the wiring,
because if you don't the customer is likely to complain (later) the unit hums
(i am sure it always did) but he will blame you, and you will be making partial
repairs for the next 2 years to try and make him happy

so replace ALL the wiring now with decent shielded cable

 

[Mr Mark]

the Amphenol screw type connector was standard on much of the pa
equipment of the era in the USA, so it was a high choice for instrument
mounting as well

also

occasionally the Mic was located inside the bellows, and the Amphenol
connector (could be) airtight
(a sprung version was also available), actually this one looks like a sprung

also

the amphenol connector is shallow, so location relative to key mechanism lift
may not have been considered for a specific accordion grille hole.. the 1/4 in jack
is a bit longer and can, in some locations, have an intermittent physical touch

after examining the pics, i would also recommend replacing ALL the wiring,
because if you don't the customer is likely to complain (later) the unit hums
(i am sure it always did) but he will blame you, and you will be making partial
repairs for the next 2 years to try and make him happy

so replace ALL the wiring now with decent shielded cable

Thanks for the explanation, I do like to know what things are actually called .

This is the spring version, yes.

My immediate thought (in response to the customers any jack will do) was that the wrong one will interfere with the keys lifting.

I'm inclined to leave the rest as is with the coverage not including hum correction. For reasons because; it was not requested, additional work is out of budget, and the customer knows exactly what is going on. Very good catch though, I do appreciate the heads up...it will be interesting to hear how this sounds before and after now that I know!

 

[Ventura]

the amount of hum will vary with the sources of interference
in a room.. lots of old Fluorescent Lighting will be the worst..

original installer assumed the aluminum grille would be a good enough
shield, but it has all those square holes !

well, at least it will be working again assuming the Mics are still good

it is a reliable circuit with a treble frequency cut/drain through the
blue drop capacitor into ground via the variable resistance of the
(tone) potentiometer.. final output is high impedence

good luck with the repair/refit

 

[Caps]

A high impedance circuit is more susceptible to RF interference than a low impedance one. Nothing like having "Breaker, Breaker good buddy" come thru your speaker. If replacing wiring internal to the box I would also recommend using small shielded cable and installing a few small ferrite beads on the non shielded wires. Those non shielded wires are like little antennas.