Ex USA manufactured audio broadcast services equipment, 1990’s era
BACKGROUND:
I like to know what the pedigree is surrounding the electronic components I use or extract from equipment, these jack sockets are bit of a mystery to me …
Very nice construction, these jack sockets looks VERY similar to Switchcraft NL114 series enclosed jack sockets but I cannot positively identify these as being from Switchcraft because the only indication of the manufacturer is stamped into the rear (solder tags area) and it appears to be a logo SC within a diamond shape. I have hunted around and cannot find any references to Switchcraft using an SC monogram as their “mark” although it does seem that there is mention of Switchcraft using SC in their early days but a stylised version. The SC imprinted into the plastic on this socket is “plain text” within this diamond shape. Take a look at this closeup photograph of the logo …

Because of this I cannot declare categorically that these are Switchcraft product but geez, they certainly look very similar to the NL114’s in particular …
UNIDENTIFIED MANUFACTURER – Jack Socket
Country of origin is most likely USA – it would be extremely unlikely for a professional audio equipment designer and manufacturer to use anything other than USA made components (or European possibly but certainly not Chinese)
Series: Unknown and not stated on the body but extremely similar to the Switchcraft NL114 series
TRS (Stereo) Jack Socket
Fully enclosed
This is a completely sealed package and it is not intended for the user to “get inside” so I cannot visually examine the contact points but I did DC resistance test them.
2x completely isolated switches (normally closed)
Panel mount
Solder tags to the rear
1/4″ (6.35mm)
Fully Insulated Black moulded plastic body with two sides being metal, these are connected to the signal ground/Earth pin on the socket
Contact material is not known but suspected to be Ni-Ag (DC resistance tests indicate extremely low contact resistance)
Chrome metal threaded nut with a chrome metal washer
The front thread of the socket is plastic, not metal, meaning that when mounted on a metal panel the socket is electrically completely isolated from the metal mounting panel.
TESTING:
I have sat down and checked the contact resistances and also the switching operation. The two switches are independent of each other and have no direct connection with the Tip, Ring or Sleeve connections. Both are normally closed switches.
See the photograph of the rear with pin numbers (imprinted into the body) and the function of each solder tag contact point.
COSMETIC CONDITION
USED
Clean
NO damage to the body, the solder tags nor the nut-thread and metal washer
The solder tags (only some were in use) have been de-soldered reasonably cleanly (no dags nor wiring left behind and an open tag hole)
I have a few of these sockets and they have now been individually placed into sealed clear plastic packets to maintain the current condition while awaiting a new ‘purpose in life’