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Shawn D

Wiring Shure WL184 lavs for Lectrosonics TA5F

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Hey all you brilliant electrical minds. I just purchased some Shure WL 184 hypercardioid lavs to use with my Lectrosonics SMQV transmitters. I replaced the connectors with TA5F and tried wiring them up based on Lectro's "Simple 3-wire 5V" diagram using a jumper across pins 2 and 4. It worked but it had some noticeable hiss and required a lot of gain (about 35 and up on the SMQV) and was pretty nasal and lacking in bass. Then I found a wiring method on the Shure website that said to try just wiring up pins 1, 2, and 3 to ground, bias V, and mic in respectively. This provides the mic with only 2 volts and not the 5V that the Lavs prefer. This also worked and sounded better with less hiss and a fuller sound than the Other wiring but it still requires similarly high gain. I'm wondering, does anyone have a better way to wire up these mics to Lectro TA5F's that maybe supplies them the full 5V and might require less transmitter gain? Thanks!

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1 hour ago, Shawn D said:

Hey all you brilliant electrical minds. I just purchased some Shure WL 184 hypercardioid lavs to use with my Lectrosonics SMQV transmitters. I replaced the connectors with TA5F and tried wiring them up based on Lectro's "Simple 3-wire 5V" diagram using a jumper across pins 2 and 4. It worked but it had some noticeable hiss and required a lot of gain (about 35 and up on the SMQV) and was pretty nasal and lacking in bass. Then I found a wiring method on the Shure website that said to try just wiring up pins 1, 2, and 3 to ground, bias V, and mic in respectively. This provides the mic with only 2 volts and not the 5V that the Lavs prefer. This also worked and sounded better with less hiss and a fuller sound than the Other wiring but it still requires similarly high gain. I'm wondering, does anyone have a better way to wire up these mics to Lectro TA5F's that maybe supplies them the full 5V and might require less transmitter gain? Thanks!

Hi Shawn,
1. Shield to pin 1 of the TA5. Also use lower fingers of the TA5 strain relief to grip the shield for RF grounding. Upper fingers grab insulation.
2. Red wire (Fet drain) to pin 3 of the TA5.
3. Black wire (Fet source) to pin 5. This puts a 2.7k source load to the mic.
4. Jump pin 2 (5 Volt) to pin 4 (bias set) to get the 4+ Volts setting of the Servo Bias.

This all assumes the Shure schematic on their website is correct. Sometimes the manufacturers get cute and don't show a true schematic.

If you need more gain, run the black wire to one end of a tiny 1k resistor. The other end of the resistor goes to pin 1 ground. As a test, you can try running the black wire to pin 1 for maximum gain.

You can do all this testing without crimping the strain relief and without the black cover on the TA5F. You don't even need the metal locking section. All you really need is the plastic pin carrier with the wires attached and it goes on and off the pins in the SM very easily. It makes it easier to reconfigure the connections. Once it all sounds right, do a full assembly of the TA5F with the locking section, crimps and plastic strain relief.

Best Regards,
Larry F

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Larry,

The wiring prescribed by you seems to be the same as the fig11 on the Lectro website "simple 5v 3-wire mic" which I tested first.  That configuration gave me about 3-6dB less signal that the wiring on the Shure customer help forum (pins 1, 2, and 3 to ground, bias V, and mic in respectively).  However I just tried what you recommended and to achieve max gain combined the black wire and shield at pin 1 and that gave me 6dB more gain than the Shure wiring.  I'm quite happy with this, thanks Larry!

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Hi Shawn,
The Shure mic may have an internal resistor not shown on the schematic. Jumping pin2 to pin4 gives a full 4+ Volts on the mic rather than 2 Volts as in the Shure recommended wiring. Glad we were able to fumble our way to a solution.

Best Regards,
Larry Fisher

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Hey Larry,

I just did a job where we used these Shure directional lavs again and I rented an SRb and LMb combo for an extra channel.  I ran into a very quiet signal from the lav even when the gain was cranked to it's max gain, 44 I believe.  It was very noisy and such a low output that I even turned to using "mic" preamp settings on my Nomad to give it even more preamp gain so it would be usable in the show.  I tried all 6 of my Shure 184 lavs on this TX and while some were a bit louder than others, all were basically unusably quiet.  It appears that perhaps the input stage on the LMb is different to the SMQV's that I was using without issue.  

My questions are:

1. Is the input stage wired or setup differently on the LMb than on the SMQV?  Is this like the servo/simple wiring incompatibilities?

2. Are any of the other Lectrosonics TX's (LT, SSM, UM400) also wired in a way that would be incompatible with my current wiring for my Shure 184's that currently works with my SMQV's?  I'm considering getting an SSM but that would require a lemo-ta5m adapter and this seems like it could also pose a problem.

 

Thanks!

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On 9/13/2016 at 3:43 PM, LarryF said:

Hi Shawn,
1. Shield to pin 1 of the TA5. Also use lower fingers of the TA5 strain relief to grip the shield for RF grounding. Upper fingers grab insulation.
2. Red wire (Fet drain) to pin 3 of the TA5.
3. Black wire (Fet source) to pin 5. This puts a 2.7k source load to the mic.
4. Jump pin 2 (5 Volt) to pin 4 (bias set) to get the 4+ Volts setting of the Servo Bias.

This all assumes the Shure schematic on their website is correct. Sometimes the manufacturers get cute and don't show a true schematic.

If you need more gain, run the black wire to one end of a tiny 1k resistor. The other end of the resistor goes to pin 1 ground. As a test, you can try running the black wire to pin 1 for maximum gain.

You can do all this testing without crimping the strain relief and without the black cover on the TA5F. You don't even need the metal locking section. All you really need is the plastic pin carrier with the wires attached and it goes on and off the pins in the SM very easily. It makes it easier to reconfigure the connections. Once it all sounds right, do a full assembly of the TA5F with the locking section, crimps and plastic strain relief.

Best Regards,
Larry F

 

Hi Larry,

 

I have found myself wiring some Shure 184's for Lectrosonics TA5. Can you clarify if when you suggested running the black AUDIO wire to pin 1/Ground without the resistor, you mean **instead** of going to Pin 5 at all? Or... Black wire to Pin 5 + Ground?

 

Thanks!

-Jim

 

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