COS-11D 3.5mm for Sennheiser Not Locking on SK-500 G4

[mtski13]

Hi Everyone,

I am new to this forum, and I mostly do small crew documentary work, so plenty of experience with sound, but by no means anywhere close to an expert.

I just bought a brand new Sanken COS-11D with a HICON 3.5mm locking Sennheiser termination. For the life of me, I can’t get the connector to lock onto a SK-500 G4 body pack. Tried it with a SK-100 G3 and it works, but no luck on the G4. The provided MKE2 that came with my G4 locks onto the G3 and G4 no problem. The retailer I bought from has sent me two different COS-11Ds now, and they both have this problem with the HICON connectors. Also,  the Sanken COS-11Ds both work and sound great, they just won't lock.

I found one post with this exact issue on reddit (r/LocationSound), but otherwise not too much online. 

Has anyone else run into this problem with the COS-11D, SK-500 G4, and a HICON termination? Can I ask the retailer to terminate with another manufacturer, if so what would you recommend?

Thanks!

[The Documentary Sound Guy]

Switchcraft makes a better one.

Lots of people complaining about HICON in this thread, I'm not surprised you have issues: 

 

[SDsmixer]

The Hicon does stink. I've had my COS11's repaired 3 times and repair station only offered that brand unfortunately. Just do it myself now and Switchcraft is definitely(as above) the correct suggestion!

 

 

https://www.bhphotovideo.com/c/product/1155476-REG/switchcraft_35hd_series_35hdlbaus_3_5mm.html

[mtski13]

Awesome, thanks for the insight!

[Conor]

The Hicons are terrible and unreliable. The Switchcraft are decent and the best are the ones that Sennheiser themselves sell.

[PMC]

Years ago when I was using G3 units as body packs the performers frequently broke the connectors when the units were not concealed in belts because they stuck out so much. I replaced the switchcraft locking connectors with the switchcraft right-angle non locking 3.5mm connector and stop having problems. Sometimes I would put a piece of tape across the connector to secure it in place.

 

I have never experienced a broken TA3 or TA5 connector.

[Rick Reineke]

Alternately  Markertek.com has the Switchcraft, Sennheiser and TecNec  M-3.5 S locking plugs in stock. I have been using the lower priced (all metal) 'TecNec' for years w/o problems on numerous lav mics, Trams, MKE-2, B6, COS11.   The TecNec's locking ring also retracts enough to use the plug on conventional non-locking input jacks as well

[mtski13]

Thanks for the recommendations! These are affordable, so I might purchase a few and test with my transmitter before asking the retailer to re-terminate it. They have pushed back on the HICONs and said that it must be a problem with my specific transmitter. I find this odd considering I have tested 3 different lavs (admittedly, all Sennheiser because that is all I can access) and all of them lock nice and tight.

[Kambor]

Maybe it's a dumb suggestion, but have you checked the nut on your transmitter is tight? I had locking problems once in a show but didn't notice the female jack nut wasn tight all the way until I checked home. Long shot, but worth trying...

[mtski13]

I will check, but I believe the nut on the transmitter is tight. 

 

Interesting development today. I was able to get ahold of some calipers and a SK 100 G3, SK 100 G4, and then I have the SK 500 G4. Here are the diameters of the threads on each of the input jacks:

 

SK 100 G3 – 5.83mm

SK 100 G4 – 5.86mm

SK 500 G4 – 5.71mm

 

So, the HICON connector is likely just a tad too big (as it fits both the above G3 and 100-G4) and that is why it doesn't catch the threads on the 500-G4. Interesting that the standard Sennheiser terminations have no problem locking to all three transmitters, so the 0.15mm difference doesn't seem to affect them. I am going to test the AF out on my receiver tomorrow to see if the smaller threads are consistent on the 500-G4s or my transmitter just got a one-off smaller jack.