Output levels of Sennheiser G3 receiver

[Steve House]

I don't have an iPhone so I don't know for sure one way or the other but doesn't its jack have 2 rings in it - tip, ring1, and ring2 to accomodate the left and right stereo outputs plus an extra line for input from the headset mic? For that matter, are you sure it takes a 3.5mm plug and not a 2.5mm "sub-mini" plug.

Assuming the iPhone is 1/8 wired for normal stereo, make up a custom cable. Obtain a locking 1/8 TRS plug for the transmitter end, a normal 1/8 TRS plug for the iPhone end. On the iPhone end jump the tip and ring together. On the transmitter end jump the tip and sleeve together. Wire the cable with the iPhone tip going to the transmitter ring, sleeve going to sleeve. Mark the darned thing so you don't mix it up with any other cables in your kit.

I question the validity of a "sound check" feeding the iPhone to the transmitter. Unless you're actually recording the iPhone's output, nothing you get from it in terms of level settings for the audio chain is going to be valid when you unplug the phone and plug in the real audio source to switch over to it. And if you ARE recording the iPhone output, why bother sending it wirelessly across the room? Just take the phone to the camera or audio recorder and wire its output directly to the input through a suitable adapter.

[Steve House]

Originally Posted by Tom Morrow

...
Thinking about this now, I suppose I already have what I need to put together that cable. I just take my Sescom SES-IPOD-XLRM06 cable and plug the 1/8" end into the iphone. The right (or left, I choose) male XLR of the Sescom then plugs into the female XLR on the CL2, which of course plugs into line connection on the transmitter.

...

That would work if you can get by with using only one of the stereo channels coming from the iPhone. The custom cable I mentioned above give you both channels summed to mono and would be cheap as dirt to build.

[Tom Morrow]

Originally Posted by Steve House

I don't have an iPhone so I don't know for sure one way or the other but doesn't its jack have 2 rings in it - tip, ring1, and ring2 to accomodate the left and right stereo outputs plus an extra line for input from the headset mic? For that matter, are you sure it takes a 3.5mm plug and not a 2.5mm "sub-mini" plug.

Yes the iphone does have that extra ring on the input for the mic, but the other (headphone) ring seems to be placed such that it reliably contacts a standard 1/8" stereo plug ring with 3 not 4 contacts. I also have an adapter tail that plug a 4-contact male into the iphone and expose a 3-contact female, but I have yet to feel the need for it with anything I've plugged into my iphone.

I appreciate you bringing this up as it might explain why I was getting signal out of the left (tip) but not the right (ring) when using a standard 1/8" connector in the past. If I use my kludged cable I should probably use the left (tip) channel to avoid the possibility of non-mating rings. Or add the 4->3 adapter I mentioned above.

Assuming the iPhone is 1/8 wired for normal stereo, make up a custom cable. Obtain a locking 1/8 TRS plug for the transmitter end, a normal 1/8 TRS plug for the iPhone end. On the iPhone end jump the tip and ring together. On the transmitter end jump the tip and sleeve together. Wire the cable with the iPhone tip going to the transmitter ring, sleeve going to sleeve. Mark the darned thing so you don't mix it up with any other cables in your kit.

Steve, I hear conflicting opinions from different people about whether it's kosher to sum left and right with a jumper. On some equipment this can cause signal degradation as the two amps fight with each other, and theoretically could cause one to overheat and fail. But in practice I've done it and not heard any ill effects.

I'm actually on the verge of building some summing mono headphones (which sum R+L) for a special project, and wondering if just jumpering R+L is kosher or whether I need to try and wire a transformer or resistors into the headphones. My first iteration involved a pair of 100 ohm resistors to decouple, but the signal level was too low so now I'm debating whether to just jumper instead, or perhaps just use much smaller resistors (say 10 ohms). It's wired

tip->resistor----\
Single mono driver
ring->resistor---/

I'm curious about your (and other knowledgeable posters) take on that debate, although perhaps you should open a separate thread if you have a long reply.

I question the validity of a "sound check" feeding the iPhone to the transmitter. Unless you're actually recording the iPhone's output, nothing you get from it in terms of level settings for the audio chain is going to be valid when you unplug the phone and plug in the real audio source to switch over to it. And if you ARE recording the iPhone output, why bother sending it wirelessly across the room? Just take the phone to the camera or audio recorder and wire its output directly to the input through a suitable adapter.

Yeah, I suppose that "wireless check" is a better word than "sound check" for what I'm thinking. The goal is figuring whether the range will be sufficient for a particular environment. I know it's not exactly proper, but I would place the transmitter fed by iphone test signal near the camera or sound cart area, where the receiver will end up. Then walk around listening to the signal from the receiver in various locations. I suspect that the interactivity of being able to hear the signal as I walk around the fringes would give a better understanding of the signal range than if I had to get up and move the transmitter, then walk back to the receiver each time to listen, over and over. Having an assistant walk around would be even better, but don't always have someone to serve as assistant, and it can be hard to direct them from 50+ feet away.

[Steve House]

A summing amplifier circuit would be better for your phones than simply wiring the the left and right channels in parallel. It depends on the design of the circuits feeding it how much of a problem there might be just jumpering them together.

Careful with your method of scouting out the wireless ranges. Remember that the transmitter can interact with the person wearing it so the pathways might be different when it's actually in use versus what they were when you did your walkabout. In any case, the transmission paths coming at the camera are not necessarily mirror images of the transmission paths coming from the camera.

[Michael Hamilton]

Not exactly on topic but I was wondering if somebody could help me with this.

I have 2 SENN skp 100 transmitters, and neither will fit on my AT897 mic.

The tightening ring on the transmitter just pushes the mic up. It won't fit around the mic shaft.

Does anyone else have this problem?

[John Willett]

Originally Posted by Michael Hamilton

Not exactly on topic but I was wondering if somebody could help me with this.

I have 2 SENN skp 100 transmitters, and neither will fit on my AT897 mic.

The tightening ring on the transmitter just pushes the mic up. It won't fit around the mic shaft.

Does anyone else have this problem?

First you have to unscrew the locking ring all the way.

Then you push the transmitter onto the mic. - push it hard until the lock clicks home.

THEN tighten the locking ring.

It's only pushing the mic. off because you have not pushed it on hard enough and the catch hasn't clicked home.

[Michael Hamilton]

Thanks for the reply.
I tried to do what you said to do, I unscrewed the ring all the way and pushed hard, but nothing clicked and it still won't fit right. It will seem to lock in, but the ring doesn't surround (Is it supposed to?) the mic shaft. And the assembly turns out crooked.

[Rick Reineke]

I recall having that problem with an AKG H/H. (don't remember the model #) But I found by pushing on the mic and twisting and rocking it a little whilst tightening the locking collar it would lock in. Wasn't easy though, and took a couple of tries.

[John Willett]

Originally Posted by Michael Hamilton

Thanks for the reply.
I tried to do what you said to do, I unscrewed the ring all the way and pushed hard, but nothing clicked and it still won't fit right. It will seem to lock in, but the ring doesn't surround (Is it supposed to?) the mic shaft. And the assembly turns out crooked.

The ring is nut supposed to surround the mic.

The transmitter should clip in exactly the same way as a normal XLR - all the ring does is to pull the transmitter so it holds tight and won't move.

The locking mechanism is basically the same as a Neutrik locking XLR and, I think, is actually made by Neutrik.

Originally Posted by Rick Reineke

I recall having that problem with an AKG H/H. (don't remember the model #) But I found by pushing on the mic and twisting and rocking it a little whilst tightening the locking collar it would lock in. Wasn't easy though, and took a couple of tries.

Yes, this is the way to do it - I do find that some mics with plastic ends do need this extra pushing and wriggling to get it to click in.

The problem is more with the mic. than the transmitter.

[Paul R Johnson]

I have an older AT mic and have exactly the same problem. The groove inside the mic where the locking clip drops into is just a tiny bit too far away for the edge to engage. It is exactly the same on all new Neutrik XLRs - although old, worn ones will click in ok. Switchcraft and the cheap and cheerful XLRs clip in easily - I think AT didn't use Neutrix's version of the XLR spec. When I need to use the plug on (which is rare) I just use a short XLR cable that does fit, and put the lump in my pocket!

[Rob Lombardi]

Reviving an old thread here, but is it okay to have phantom power on when the G3 receiver is plugged into my DR-100mkII?

I ask because I also want to run a shotgun and it seems to be the only way to do both at the same time.

[Rick Reineke]

Originally Posted by Rob Lombardi

Reviving an old thread here, but is it okay to have phantom power on when the G3 receiver is plugged into my
I ask because I also want to run a shotgun and it seems to be the only way to do both at the same time.

NO! ... The G2/3 has an unbalanced configuration and has been known to cause excessive noise and drain the recorder's batteries faster than you can say "how come my new batteries are dead already".
If your mic has an internal battery option, use that. If not, use an external PP supply. It may be possible to modify the G3's cable or add an iso transformer that does not pass PP, though I haven't experimented since I don't have that problem. Maybe Richard can come up with a cheap and easy remedy for that.

[Richard Crowley]

You can put a DC-blocking capacitor in the XLR connector to keep the P48 from back-feeding into the receiver output circuit. I would recommend also putting a clamp diode to prevent the turn-on/charging impulse current from getting through to the receiver output circuitry. I can draw you a diagram if you think that is what you want to do. It should not be too difficult to solder these components inside the XLR connector shell.

[Rob Lombardi]

I could solder the XLR adapter that came with the G3 kit, yes? Unfortunately, I don't know my way too well around circuitry, but I can't help but feel there is an easy solution I'm not considering.

The Tascam is a music recording device, but surely it can't the first time someone has wanted to do this? I've been scouring Google incessantly with no luck. Would there be some specialty store that sells it?

[Tom Morrow]

With phantom power, it's rarely actually damaging to engage the phantom when not needed, although it's possible that it could cause issues mentioned (noise and battery drain). Personally I would just experiment and see if it was tolerable before I started soldering custom cables to block the phantom power. But that's more of a seat of the pants approach than a "proper" solution.