michaelyallop

1454010801[/url]' post='534047']

1453998798[/url]' post='534034']

They have a 4pin 3.5mm jack on them, using the screen as a common for both the left/Right channels and the Mic. I seem to have found that when plugging this into the AD903 it does not like it at all and I have had a whole host of issues, ie, cross talk between the headphones and microphone, a very quiet level from both the microphone/headphones and the return from the ring. ... In theory this should be straight forward as I am using a 4 pin XLR to 4pin jack and connecting as per the AD903 "unbalanced connector instructions". I think the problem I am having is the combined screen.

 

 

I cant find the diagram you refer to, but, the data sheet specifies that the AD903 inputs and output are transformer isolated, and "balanced and floating", so there should be no issues from a common ground from the AD903 perspective if wired correctly.

I thought this too, but something seems to be cause it to not work too well. I have tried with both, the screen from headphones and the screen from the mic connected either together or just a single screen but still no luck. I'm quite confused at the moment to be honest. I'm going to have to stop and think about it a bit more.

Thanks

1454002028[/url]' post='534036']

Yes, BlueCom works fine with both Tecpro and Stonewood (Granite) beltpacks. I had a test system using two each of all three types together and it worked perfectly. There have been several iterations of the schematic, the latest being version 1.3 (see here), which has the four-pole 3.5mm socket available on a four-pin header for your own connection. Earlier versions were connected as: Tip + Ring 1 - Headphone out, Ring 2 Mic & Sleeve - GND. Note that there is a DC offset of half the supply rail on the headphone output on that socket. It really needs a large decoupling capacitor, which is why version 1.3 was introduced.

 

As a result of the requests of Blue-Roomers, there are three unique features in BlueCom which you won't find in the other systems. Firstly, the mic gain is switchable over a considerable range to accommodate different mic types. Secondly, the low impedance headset capability is because there is bridge amplifier driving the output. It means the headset volume will go much higher. Finally, there is an offset in the volume control (R37) which if set to a higher value than the 10R on the schematic will limit the minimum headset volume so that it can't be turned down to zero.

 

Sorry, I don't have any blank PCBs available but, I know of several sets which have been built and there may be some around. Otherwise, the PCBs can be ordered from iTead in China very cheaply.

 

I hope that helps.

Thanks for this boatman. I think I'm going to build a few I think as we could do with a few more.

I just need to gather all the schematics and board files together first. It should be a good project to get sorted.

Thanks again

Hi All,

I've been watching this thread with great interest. I have limited experience in with the design of circuits but have a lot building them, hence not actually getting involved until now.

One thing we all know if that wireless comes are very VERY expensive but would be extremely handy for the likes of SM's and the crew etc.

One thing I have recently attempted is to link a cheap Bluetooth Motorcycle headset to the Tecpro AD903 2 to 4 wire unit. It apparently connects all sorts of I/O impedance's and devices to the ring with lots of adjustment.

The BT headsets themselves work over quite a distance (1200m claimed outdoors) 400m actually tested with caravans in the way in a caravan park. They are extremely clear and allow duplexing. They have a 4pin 3.5mm jack on them, using the screen as a common for both the left/Right channels and the Mic. I seem to have found that when plugging this into the AD903 it does not like it at all and I have had a whole host of issues, ie, cross talk between the headphones and microphone, a very quiet level from both the microphone/headphones and the return from the ring.

In theory this should be straight forward as I am using a 4 pin XLR to 4pin jack and connecting as per the AD903 "unbalanced connector instructions". I think the problem I am having is the combined screen. I then noticed that some people are using a mini jack on the bluecom system and wondered if a bluecom beltpack would give me the answers. First off, do the blue com work with tecpro, or would I need to replace our system? Secondly, what is it that allows the use of a low impedance headset and 4 pin jack inside of the bluecom? Thirdly, does anyone have any PCB's for the beltpack for sale? I may need to build one if it is compatible with tecpro system in some way.

Has anyone else tried something of this nature, or have any idea what my next port of call could be?

If I can get this working I will be sharing it on here just as a little blog or post of some kind.

Thanks in advance.