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Using Sennheiser wireless with Shure splitters

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Using Sennheiser wireless with Shure splitters

Postby railteacher » Sun Jan 17, 2021 2:58 am

Hi everyone -

I’m slowly upgrading a Shure SLX14 system to Sennheiser EW 500 G4 units.

I presently have several Shure UA844 signal distribution units, which have both 12v and RF outputs for up to 4 receivers.

The Sennheiser has some nice features that the Shure doesn’t have, such as supplying power to the receivers via the BNC RF cables. The Sennheiser units also have 12v present at the BNC connectors for active antennas, which is something not found on the SLX series (UA844 and 844+ does have the 12v DC bias on the RF connectors).

I know the DC component is blocked when not needed, but I’m wondering if I can connect these Sennheiser units to the UA844’s and use the DC power coming from the Shure power pigtails? The Shure voltages and polarity are the same, but the Shure power supplies are able to provide more current than the Sennheisers require. Something in the range of 500ma drain for the Senns versus about 1500ma for the SLX’s.

I know several churches which have migrated from the SLX to Sennheiser via the RF Venue RF distros with no issues, so I’m guessing the UA844’s would also work.

Anyone able to confirm this?
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Re: Using Sennheiser wireless with Shure splitters

Postby Mike Stranks » Sun Jan 17, 2021 9:34 am

Welcome! :thumbup:

I don't know either of those units, but am used to the principles involved.

If the voltage and polarity are the same AND the unit is happy to receive DC (or it can be switched-off) then there should be no cause for concern.

The key thing with these sort of calculations is always voltage. Too much of that and 'pphht' the blue smoke and funny smell follows...

A device will draw the current it needs. As long as there is more than enough for its requirements then all will be well. As an example, the sockets in my house are capable of supplying 13 amps; I regularly connect things that need, perhaps, 0.25 amps.
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Re: Using Sennheiser wireless with Shure splitters

Postby captainmicrophone » Thu Jan 21, 2021 8:54 pm

Railteacher,
Don't do it. Why try this experiment?
Doesn't the Sennheiser come with a power plug?
I have never set up this type of receiver configuration, with the antenna distro supplying power to the Rx.
The DC (receiver power) from the Shure antenna splitter is not switchable.
The Shure has a RF bandpass specification.
Some Sennheiser receivers are made to be powered by the BNC plug.

Look carefully at the two manuals:
Shure
https://pubs.shure.com/guide/UA844SWBplus/en-US

Sennheiser
https://www.manualslib.com/manual/70332 ... e=6#manual

The Shure UA44 does the job of distributing the antennas plus the DC supply.
It is possible to mix and match antenna distros you just have to make sure some things.
The specifications of both Shure and Sennheiser SEEM to be the same

Best practice is to stay in name brand.

Also the antenna distro is made for a particular receiver and it is suited to the RF sensitivity and frequency range of that receiver.

I have used Sennheisers mixed with Shure systems, generic distros, home brewed antennas and distros... you have to be careful.

In the long run, when you sell off your old Shures you can sell the old antenna distro too.
If your receivers are close to the stage action, you may be able to slowly add the new Sennheisers on whips antennas until you get a new antenna distro.

If your receivers are far away from the performers...
WHY?

A smart RF design puts the receivers near the performers with long sound cable to the board, if there is a digital board (console) the inputs from the receivers belong in the stage rack.
A unity gain antenna system is a good idea especially if you are running lots of them.

Antenna distros with booster amps work ok sometimes but they can multiply the interference from broadcast TV, other stages, In ear monitors... guest RFs.

Post a picture of your RF design or write a greater detail of the space and the RF systems in play. I will check the forum.

Do you have wireless intercoms?
I have made good money telling sound departments to separate the wireless intercom antenna situation from the wireless mic antennas.

ANYWAY be careful, it can be trouble to mix and match. You can't put gas in a diesel engine. Like the Mike Stranks says the result could be a pfft and bye bye new receiver.

Also a data connection is another ground to think about. I have had added data connections put a buzz all over my wireless. (the computer should be on the same power)

And when adding new gear use software to select the new frequency.
Turning on one new thing can mess up other wireless that you would not expect would have issues.

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