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>> NOTE >>
The following information is intended solely for the purpose of better understanding the configuration and operation of the EAD10 microphones. Absolutely no recommendation or encouragement is being made (implied or otherwise) to use the main or sensor units outside the configuration specified in Yamaha’s manuals. Any use of this information for any other purposes is done so at an individual’s own risk and responsibility.
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TLDR SUMMARY
Based on testing below, the key findings are:
— The MAIN UNIT outputs a continual 12VDC on mic input jack “B“. 12V is provided across both audio high & ground as well as audio low & ground. Given these alone, the powering is -likely- compliant with the P12 Phantom Power specification.
— The MAIN UNIT does not output any voltage on trigger input jack “A”.
— The SENSOR UNIT must receive 12VDC on output jack “B” in order for the mics to operate.
So if the above are true, how was the OP able get audio from an acoustic kit with only the sensor unit “A” output connected to a PA and without 12V phantom power to the sensor unit “B” output? (i.e. two things that disagree with above).
Answer: The piezo trigger. Piezo transducers can pickup sound (pressure level differences) and serve as mics. Usually the audio quality is mediocre, but this one is decent.
Need more proof? See additional details below...
MAIN UNIT
Powered on with A & B input cables connected, but disconnected from sensor unit...
Jack A input (trigger):
— 0V output on T-S (Tip to Sleeve; hot to gnd)
— 0V output on R-S (Ring-Sleeve; cold-gnd)
— 0V output on T-R (Tip to Ring; hot to cold)
Jack B input (mics):
— 12V output on T-S
— 12V output on R-S
— 0V output on T-R
Given the above, the main unit is -likely- providing P12 compliant Phantom Power (as defined by IEC 61938) to the sensor unit mics. (Note: IEC 61938 also includes the P24 and P48 variants, the latter being the 48V standard most widely in use at the present time.)
To confirm it is -definitely- Phantom Power compliant would require a schematic of the main unit interface. The level of integration is too high for visual inspection. For certain, it is definitely NOT an alternative powering scheme (e.g. T-Powering) that puts voltage across the audio lines instead of to ground.
SENSOR UNIT (with cover removed)
Physical inspection...
— Jack A output is connected to one side of a connector interface board; removable cable behind jack is connected to piezo BD trigger on back of sensor unit.
— Jack B output is connected to other side of interface board; removable cable behind jack is connected to a microphone driver board on front of sensor unit.
— Above microphone board, two thin wafer mics are mounted 90 deg from each other and each 45 deg from vertical center. Each is encased in rubber grommets that slide into a metal Y frame. No part numbers are visible on mic capsules, but appear to be electret condensers.
When connected to MAIN UNIT which is connected to a powered speaker...
— 5V is present at each mic input.
— Speaking into mics and “tapping” on back of piezo are both audible through speaker.
When disconnected from MAIN UNIT and only B output connected to powered speaker...
— 0V is present at each mic input.
— No audible output from either mics or piezo.
When disconnected from MAIN UNIT and only A output connected to powered speaker...
— 0V is present at each mic input.
— No audible output from mics.
— Tapping (more so) on and speaking (less so) to piezo are both audible.
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fl.tom,
If you don't mind, I'd like to revive your commentary on this topic. Here is the quick backstory: I have been putting together various rigs for hybrid drumming that combines signal processing of acoustic drums with triggering of samples. Someone on a discussion thread mentioned this was similar in concept to the EAD10 and I agreed, but then made the following excuses as to why I wasn't using the EAD10, which I do own, for that purpose:
"I'll describe my two grievances with the EAD10: First, the BD trigger only senses the hoop, not the BD batter head like most conventional BD triggers. This makes getting any sensitivity out of the trigger nearly impossible. A related issue for me is that I like to mount a cowbell on the top of my BD hoop. A conventional BD trigger can be mounted elsewhere on the hoop (though there are still problems with that, the solution to which I will include below) but not the Sensor Unit of the EAD10... You can, of course, bypass the BD trigger on the Sensor Unit by plugging a separate trigger unit into the BD jack, but that complicates the setup and defeats half the point of having the bulky Sensor Unit. The second major issue is that because the Sensor Unit houses two wide radius omni mics to capture the entire drum set from a central point, you can't get a monitor or main speaker anywhere near it without it feeding back. It's all good if you and your bandmates use IEMs and have the mains a fair distance away, but in a small club it can get difficult. For my part, I bring my own drum monitor to fill out my sound for the audience and the feedback has caused me to turn down the EAD10 to unsatisfying levels... As mentioned earlier, I have a hard time with hoop mounted BD triggers in general because I like to mount cowbells and such on the hoop and its hard to isolate them from the trigger unless I move the cowbell off of the hoop..."
However, this did get me thinking that the EAD10 is a nifty unit and I should try some workarounds to get it to satisfy what I want. The first and easiest is to simply trigger the BD with a separate trigger as I describe above. My preference in an On Trigger, but there are other possibilities. The second solution is where I need your advice: I was thinking of not using the Sensor Unit at all and plugging in a microphone into the "B" jack, but the specs of the microphone and how the EAD10 deals with the signal are still a little unclear to me. I have to say that I don't need the mic for full coverage of the kit but really only the snare drum. It's possible I might want to try two overheads, but that would be for later experimentation after I figure out how the mic input works.
So here are what I see as the options and you can advance or deprecate them as you will: 1) a stereo condenser (Rode, A-T) terminating in 1/4" TRS adapter. Not sure is these can be powered by 12V phantom, but some of these are battery powered; 2) a mono condenser terminating in with a mono to TRS stereo adapter. Same issue with phantom power; 3) a dynamic mic terminating in a mono to stereo adapter. I don't know if there would be any issues with EAD10 preamp given it is designed to work with a condenser (?)... Thanks in advance for any advice.