EEVblog #571 - Sennheiser EW100 G3 Wireless Microphone Teardown

[Axles]

Notice the unusually large 4MHz crystals or oscillator hybrids on both devices. These most likely generate the frequencies that are later used to synthesize the RF, so they are high quality and most likely temperature compensated.

There is a pretty good view of a "can" at 17:40 in the video.  A snapshot is below.  Am I right in assuming this is a 4 MHz oscillator?  What is the brand?  Matsushita?

Mike in California

I would probably say that's a smd filter from Mini Circuits

[calzap]

Notice the unusually large 4MHz crystals or oscillator hybrids on both devices. These most likely generate the frequencies that are later used to synthesize the RF, so they are high quality and most likely temperature compensated.

There is a pretty good view of a "can" at 17:40 in the video.  A snapshot is below.  Am I right in assuming this is a 4 MHz oscillator?  What is the brand?  Matsushita?

Mike in California

I would probably say that's a smd filter from Mini Circuits

You could be right, but their small devices in all the pics that I have seen use a simple MCL logo.  Crystek Microwave also came to mind, but I can't find any pics of their devices that use the logo seen on the device in the video.

Mike in California

[beaker353]

Don't count analog RF mics out yet.  I would venture to guess that 90% if not more of the transmitters you will find in large scale productions will be analog. Digital still still has a lot of hurdles to overcome before you find the big boys trusting their reputation on digital. Latency is a factor for sure, but people forget about how truly robust analog transmissions are to interference especially when wireless mics are sharing the same spectrum as broadcast TV here in the US. Analog RF mics will start to give a seasoned engineer (the console operating kind) subtle warning signs that there is something nasty afoot usually long before all hell breaks out. Digital RF mics have this bad habit of going from perfectly fine to nothing when the spectrum gets bumpy. (There are few things worse to a mix engineer to have your lead mic start cutting in and out while the talent is on stage and you are powerless to do anything about it from behind the console.) You can add error correction and a host of other technologies to help out the digital signal , but this adds even more latency to a system. Speaking of latency, you have to keep in mind that there is a finite window you have to stay in before you start effecting the performance on stage. Many on-stage performers wear in-ear monitors instead of traditional wedge stage monitors. They hear themselves through a combination of the in-ears they are wearing, and the acoustic conduction up their jaw to their ear. You start adding too much latency to the in-ear signal with digital RF transmissions, digital console, and other digital processing gear and you start creating a crazy comb filter problem for the poor performer. From some experimentation I'm done on stage with female vocalists, 6ms seems to be about the point in which they start to have a hard time maintaining pitch. This is one reason that even though an analog console now can cost 4 times as much as its digital brother, you will still find plenty of analog desks in use for monitors just to keep this  latency down.  We are in the process of a 250k upgrade to our show wireless systems, and you will not find any digital transmission gear on our list...

-EM

[atw60444]

Beaker, that was an interesting insight thank you. And some singers can sing in pitch? That's good to know too

[beaker353]

Beaker, that was an interesting insight thank you. And some singers can sing in pitch? That's good to know too

It has been known to happen from time to time...

-EM

[SeanB]

With Autotune even I can sing properly. Without the cats leave the vicinity and windows are in danger.

[CJWarlock]

I was using this Sennheiser transmitter with lapel mic for a few times in the past so I had an ocassion to test it. It really is a hell of a wireless mic and works good even in the environment filled with diffrent RF signals that may cause problems on other wireless mic systems. I was using it together with the stationary receiver (EW500 if I remember correctly). Pretty reliable in my opinion. And the construction quality and overall feeling of the lapel mic transmitter really is impressive.

On the other hand, I had some problems with the handheld transmitter (EW100 G2 IIRC) when PA-ing a small event in the center of the city. Battery level (in the handheld mic) and RF signal level were 100% OK and it still would weaken or break transmission for a few tens of ms every few seconds. Tried different channels. I guess it there could be some strong interferences from the railway station (100 m away) or the transmitter could be somehow damaged. I was doing only a few PA-ings with that set and it wasn't mine so I didn't checked that case deeper. However I'd be happy if someone would just by the way share some knowledge about such behavior of EW100 G2 handheld transmitter.

[sq6rdy]

Small LT chip marked LTPG, near charging connector is step-up 1A 3MHz DC/DC converter (LTC3401).

There is a pretty good view of a "can" at 17:40 in the video.  A snapshot is below.  Am I right in assuming this is a 4 MHz oscillator?  What is the brand?  Matsushita?

Mike in California

This component is made by Murata. It's not oscillator, probably some kind of SAW filter or similar device.

[NiHaoMike]

Many on-stage performers wear in-ear monitors instead of traditional wedge stage monitors. They hear themselves through a combination of the in-ears they are wearing, and the acoustic conduction up their jaw to their ear. You start adding too much latency to the in-ear signal with digital RF transmissions, digital console, and other digital processing gear and you start creating a crazy comb filter problem for the poor performer. From some experimentation I'm done on stage with female vocalists, 6ms seems to be about the point in which they start to have a hard time maintaining pitch. This is one reason that even though an analog console now can cost 4 times as much as its digital brother, you will still find plenty of analog desks in use for monitors just to keep this  latency down.  We are in the process of a 250k upgrade to our show wireless systems, and you will not find any digital transmission gear on our list...

Wouldn't it make more sense to do the feedback locally instead of sending it out to the console and back? Also, FPGAs can do mixing, effects, and more with very low latency, down to a few samples. Main problem is that it's not trivial to deal with clock skew, but that can be prevented with a master clock.

[komet]

Wouldn't it make more sense to do the feedback locally instead of sending it out to the console and back?

The monitor signal contains other channels as well as your own in order to be able to keep in tune and time with the rest of the band. Also I think it is post-EQ. Digital is definitely not better. A low latency is far mor iportant for monitoring than low noise.

[eceforge]

So here's my question -- where do you find small little LCD modules like that...I've looked in the likes of mouser and digikey and the few options that there are seem to almost always be out of stock. Anybody have a good source? I tried searching for a few of the numbers that were shown in the video on the back of the LCD, but I didn't turn anything up. Obviously doesn't have to be an exact match for that LCD just something in the same size range. The standard 16x2 character LCDs are always too big and clunky with their associated backpacks for small projects.

[bdumaguina]

Hello,

I understand this is an old thread. But this is one of the best teardowns of the Sennheiser EW 100 G3 series Tx and Rx.

I've handled these things for a while now and had my fair share of DIY repairs from replacing antennas, cleaning out corrosion that sometimes build up from talents' sweat seeping into the circuit board (I work in the film industry), swapping out a good RF board from a defunct unit to a unit with a problematic RF board, etc.

This time around I'm getting an unusual problem on the Rx. Tx is good - I'm getting audio in with a lav mic - and if I paired the Tx with a different Rx I can get audio to pass through.

On the problematic Rx - I'm getting good RF activity - it's rock solid. I can also "see" AF activity - BUT - when I connect the Rx to a mixer or recorder via the 3.5mm jack - I'm not getting any signal/audio.

I don't think the physical connection (the 3.5mm jack) has any problem - anywhere else I can look? Which of the mentioned chips in the video could be responsible for the audio output on the 3.5mm jack?

Thanks,
Bryan D.