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wiring adaptors for BOTH +/-bias

Zach R

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Is it possible to wire an adaptor (ta5 to waterproof MM) to work for both positive and negative bias trams?

I feel like the stock mm adaptors are wired to handle both but I'm not sure how that would be wired - Is there an extra jumper somewhere on the ta5M side of the adaptor?


Specifically I'm trying to figure out what the wiring should be for that lectro cable that works with both  +/-bias trams and a redband cos-11..

The current cable I have doesn't work at all with the -bias tram and creates some grounding issues with the cos-11 when you touch the metal casing of the MM



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thanks for the tip Eric! I checked the site and found some wiring guides but they all are microphone specific for positive OR negative bias mics on the TA5F side.

..so, I'm still trying to figure out the adaptor's ta5M end and how I'd go about wiring it to work happily with both +/-bias tram and this redband cos-11.

..it seems it's definitely possible since, if I'm not mistaken, most um/sm transmitters can handle either wiring these days. (I've never had a problem with newer transmitters and interchanging my mics.

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hmm I get that the mic itself would only be able to take + or - and that's all dependant on the wiring as you'd ground what you don't want going to the mic?* ... But the adaptor /transmitter it connects to can be wired to allow either option, right? 


isnt that one of the additions lectro made to all (most?) Of its transmitters around 2007?

The only reason I bring this question up is because I had a cable that works with both my positive and negatively wired trams as well as that pesky cos11 I spoke of.


*I admit I am no master on the topic of wiring but have been trying to do my research.

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lectrosonics has a user forum/group, and also excellent email response (or telephone,toll free) if you can't find what you need on their web site, which has lots of useful technical FAQ's...

maybe I don't understand your question, but a + bias requires different wiring from a - bias mic, so you will need separate adapters...

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" I'm just looking for the wiring diagram for that. I guess. "

I would expect that wiring to be available on the Lectro site...(you can do your own homework and search for it)...

as I noted:  toll-free telephone and email work very well...

BTW: two wire and three wire is not the same as + or - biasing...

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 I'm still on the search around their forums and documentation as well as waiting on an e-mail about the topic - I'm trying all my resources for this one and appreciate your input immensely.

- so far no luck on the specs I'm looking for though.


I thought about it being a 2/3wire issue - I speculate my issue with the sanken is actually a 2vs3 wire issue where the cable maker didn't take 2/3 wire compatibility into account (even though It was requested) but the tram issues are definitely bias related since the function is split right down the center with my -bias mics not working and my + working fine. .


Hopefully I'll find something over on the lectro forums/documentation resources!


Thanks again for the thoughts.

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so apparently the wiring for that adaptor was never published on the site by lectrosonics!

I received an e-mail back that as a response to my questions they have now created one and posted it on their site - so that's pretty great.


Homework is done.


If anyone else is interested in this it can now be found here:



Or more conveniently here's the wiring:

TA5 Pin 1 to Sleeve
TA5 Pin 2 not used
TA5 Pin 3 thru 2.74K to TA5 Pin 5
TA5 Pin 3 to Tip
TA5 Pin 4 not used
TA5 Pin 5 thru 10K to TA5 Pin 1

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