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-   -   Plugging Senn 100 series into sound board (https://www.dvinfo.net/forum/all-things-audio/24010-plugging-senn-100-series-into-sound-board.html)

Steve Keller April 3rd, 2004 10:05 AM

Plugging Senn 100 series into sound board
Hi all,

Thanks for all the information that I've learned through your questions and answers here, now I've got one that I couldn't find a direct answer:

Can I plug a 1/4" headphone output into my Sennheiser EW100 series transmitters without causing smoke (from the transmitter), stink (from the smoke), and sweat (from me)? My understanding from other posts here is that the EW100's can take a line level input, but is the output from a headphone jack anywhere near line level?

I have the usual problem for new people trying to plug into the varied sound boards at receptions and am looking for good ways to do it without dubbing the music. So far on this site I have found XLR outputs to wireless seems to be common, any other common outputs besides 1/4" headphone and XLR? I guess I've seen dual RCA line outs that I assume a trip to RadShack would remedy with proper coverters also...

I guess I'm nervous about attenuators because I'm not real sure when they're needed. I assume they would be needed to take down line level to mic, but I'm not sure how much is needed and I'm not sure how much the EW100's will take. Would this attenuating cord be a magic bullet for recording a headphone signal or is it unnecessary for the Senns?


Thanks for any insights you may have on any or all the questions here!

Mike Rehmus April 4th, 2004 12:23 AM

Look in the Senn manual. You will find that the bodypack transmitter has a stereo input socket. The sleeve is ground and the tip and ring connect to different inputs. One is for microphone levels, the other for electric guitar input. I don't remember which.

Marty Atias April 4th, 2004 07:27 AM

Well yes, with care and the proper cable. Though it would be better to use the mixer's RCA outputs if there are any free.

The ring and sleeve connections for the SK100 transmitter are for line levels up to 2.4V. It is not a stereo input (the tip is for a microphone).

The headphone output of a mixer is essentially a stereo power amp output for small speakers (headphones), so you would have to keep the volume down to avoid overdriving the transmitter's input.

You would also have to combine the tip and ring (left & right) of the headphone output to make it mono.

Using a spare set of RCA outputs would be a t the proper level, and a simply RCA Y cord would make it mono. You would still have to make the input connection.

Steve Keller April 4th, 2004 11:09 AM

Thanks for the heads up about the tip vs. ring and sleeve. I would like to be able to connect the following ways to be able to adapt to the varying sound systems out there...any comments on the following methods?

1. headphone 1/4 jack - stereo 1/4 to mono 1/4 adapter to something like a Rolls DB25 matchbox with some attenuation (I think it's either 0, 20 or 40 dB selectable). From the DB 25 using the XLR as an output to the XLR adapter supplied with the EW100 system. (I guess I don't know if the XLR adapter functions as a transmitter input, I've only used it as a receiver output to the camera.)

2. dual RCA line out to RCA Y cable - if the Y cable ends in a mono 1/8 miniplug would that go directly into the EW100 transmitter?

3. 1/4 line out - 1/4 mono to 1/4 mono cable to Rolls DB25, again some attenuation, then the EW100 XLR adapter (see my question about that adapter in #1)

Any suggestions or comments would be welcome as I haven't ventured into this area yet.


Mike Rehmus April 4th, 2004 12:52 PM

Do not plug a mono plug with line-level signals into the transmitter.

Make or have cables made that directly connect an output with the input of your attenuator and then from there to the transmitter. They aren't very expensive to make or buy; adapters are just trouble waiting to happen, especially the Radio Shack versions.

You have to sit down with the schematics or at least the pin-outs for the gear and decide what you require.

I would not use the headphone outputs from a sound board as they can be misadjusted during the performance to your great disadvantage.

Get a line output from the mixer and attenuate it with an in-line switchable attenuator like the Shure. Go from the RCA or 1/4" output of the mixer to the attenuator to your transmitter. Use a wye connection cable to pick up both L&R channels and deliver them to the attenuator.

The only other consideration is that some transmitters actually leak RF back to their inputs and this will cause some mixers, my Shure FP32 used with the Senn plug-on transmitter, for example, to oscillate. The solution is to put a capacitor in the signal path from mixer to transmitter. I think Jay Rose mentions this along with details on the cure.

Marty Atias April 4th, 2004 03:45 PM


What's wrong with plugging a line level signal (an RCA output would typically be at -10dBV or 1.0 Volt) into the line level input of the transmitter (which is rated at 2.4V max or +7.6dBV)?

I don't see the need to add the complication of an attenuator. That would even take the headphone output at low to moderate level. However I do agree that that it should be avoided.


The XLR on the cable that came with the unit is is a male, it will not work with the transmitter. If it is female, it could be wired for either the mic or line input. Check the manual.

Mike Rehmus April 4th, 2004 06:38 PM

I have yet to find a mixer output that is nominal line level. And some, you will find, will only put out something halfway in-between line and microphone level. So you end up using the microphone input but having to attenuate.

Better to have the tools and not need them than the other way around.

Peter Jefferson April 7th, 2004 04:04 AM

some mixers have a record out as rca.. you might be able to get a cable made to accomodate this.

Recording outputs will not utilise the mixing consoles master EQ (if it has one) so it would offer a rawer mixwhich gievs you teh scope to adjsut EQ according to whatever you need for Video, NOT the venues PA...

As for teh connection, as theyre mono connecitons, i usually run 2 transmitters and 2 receivers out of the record out with an adapted RCA

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