Soldering under a microscope

Been doing a little audio hacking on the Taranis…

Tonight I had an opportunity to do some hacking on the Taranis. I am working on a video on how to perform a few of the audio mods that folks have been doing with the Taranis. This is a Rev A audio daughterboard, and I just added a 1000uF capacitor on the VCC and GND pads.   This is expected to stop some of the audio buzzing that is plaguing the Taranis. Lots of smart folks have been working on a fix, so I thought I would do some testing once things settled down.

Here is my work station.  I can’t believe how small this little circuit board is! It’s tiny!  It’s about the size of my thumb!  The microscope is helpful to get a good look at things, during and after. Of course, I am also capturing video from it so I can do a how-to video.

Soldering under a microscope

Here’s the cap I installed.

1000uF Modification

I did some testing, and the results were a little surprising to me. As you can tell in this first photo, the audio from the speaker was much improved. It was a huge success.

Taranis Audio Signatures Speaker

However, the test results from the headphone jack were not quite what I expected. The audio, in my opinion, was actually worse.

Taranis Audio Signatures Headphone

So, I am not sure if the guys who are coming up with the mods are checking the headphone output as well. It’s possible they haven’t.  Not many people desire to use the headphone jack. I have asked them for some feedback on this.  I want to make sure this isn’t a behavior that is just isolated to my radio. I expect that it’s not. I don’t understand anything about the audio circuit in these radios. I have to rely on folks smarter than me to come up with solutions…and then I just do what they say works. : )

That’s it for now.  If you have any info on this sort of thing, I would appreciate the feedback. In the meantime, I’ll be trying to figure out what the deal is.

EDIT:  Well, someone on the forums pretty much nailed it. The issue with the increased audio in the headphone cable, turns out to be from the cable itself: In the form of RFI. I ran another recording, and this time moved the cable around, up and down and to and from the radio.  The result pretty much speaks for itself!  Clearly there is some interference generated from the cable.  This could be a problem for people that prefer to use headphones with the Taranis. It seems that it needs to be addressed separately from the speaker noise reduction. I still have some other mods to do, so we’ll see if any of them fix this part.

Screenshot 2014-02-23 23.08.40