In-line Mute Switch for Sennheiser SK2000 Wireless Belt Pack w/ Shure PG30 Headset

Greetings all. Long time reader, new member and first time poster.

I've got quite a cluster-you-know-what on my hands. I'm the newly appointed technical director of Montana State University sports facilities and football season is fast approaching. With the job I've inherited a good deal of gear and its associated issues that have been band-aided over the years. There's good, and there's bad, and it's my job to make it all work together--you know the drill.

In our football stadium we use a Sennheiser 2000 series wireless system. Fantastic system, but there's more. Our referee uses an SK2000 wireless body pack with a Shure PG30 headset. Apparently they used to have a Countryman E6, but had lots of issues with feedback when the ref was in the end zone of our scoreboard, where a cluster of Danley boxes are housed to provide coverage to the entire stadium of 17,000. At the end of last season, they scrapped the E6 and went with a cheap Shure PG30 that places a capsule directly in front of the ref's mouth and used a TA4 to Lemo 3-pin adapter to interface with the Sennheiser transmitter.

Fast forward 10 months and I take over as TD and start testing all this gear. Low and behold the TA4 to Lemo 3 adapter already has issues with with cutting in and out due to some intermittent connection in the cable (it's about 2 inches of wire with TA4 on one end and Lemo on the other, with the issue falling somewhere in the line between the two).

Add to that our athletics conference is mandating that all teams incorporate an in-line (between the headset and transmitter) mute switch for the refs to wear on their belts for easy access--and they've even gone as far as to mandate a specific model, the Telex RSB-2, which, no surprise, doesn't appear to be made in a Sennheiser-friendly form.

RSB-2: Electro-Voice RSB-2 Referee Mute Switch

The RSB-2 features TA4 connectivity, which is fine for our headset, the input side of the switch, but no so fine for the output side--especially considering I've already got an adapter that is failing.

Long story short, I would like to convert the output side of this Telex switch to Lemo 3-pin to work with our Sennheiser SK2000 and eliminate that extra adapter and potential points of failure.

In summation, I need the setup on the ref to work like this:

Shure PG30 headset > TA4 in on Telex RSB-2 switch > Lemo 3 in on Sennheiser SK2000

This switch must work silently, meaning I may need to modify the switch itself. Upon opening it up it appears it does nothing but lift pin 2. My gut tells me this will not switch silently once I get the right connectors. Obviously my first step is removing the TA4 output from the Telex and replacing it with Lemo 3-pin, but while I'm in there doing this I want to go ahead and do whatever needs to be done to make this thing work well.

Sorry for the short novel you just had to read, but I need some reassurance what I'm trying to accomplish isn't outright stupid. Any advice, insight or tips that you can provide are greatly appreciated.
 
Re: In-line Mute Switch for Sennheiser SK2000 Wireless Belt Pack w/ Shure PG30 Headse

Talked with Mike Tucker, a very helpful service technician at Sennheiser.

Mike confirmed my thoughts that the switch would need a circuit mod to mute silently, as all the switch does now is lift pin 2. He explained that in its current state, the switch allows a rush of DC current to flow in whatever direction the switch is being thrown, causing the dreaded "pop."

Sennheiser service is willing to have me ship my Telex RSB-2 to them for modification and subsequent operational testing. I will also have them take care of re-terminating the TA4 output to Lemo 3-pin, as I don't have the required Lemo termination tools--which are way to expensive for me to justify.
 

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