Here's the link to Nelson's presentation at BAF 2015:

Pass Presentation BAF 2015

Slides are available in pdf. See the video description for the link.

Video Blog #1 is posted here:

https://www.youtube.com/watch?v=mWTy...KhQ2ow&index=2

Ironamp project video posted here:

https://www.youtube.com/watch?v=FZymAeaVsAg

I hope you enjoy it.

I updated the captions if you want to try Youtube's translation option - should be funny

The topic of JFET and MOSFET matching comes up often in the forums, so I thought I'd show you the jigs I use.

First up, is my trusty old JFET IDSS matcher.



There's a 9V battery inside, and the meter probes are conneted across a 10 Ohm resistor which is connected to the JFET drain. I included a polarity switch for convenience when testing P channel parts.

It's pretty easy to connect the microclips, count to five, and take a reading.



And here's what I use for the big stuff. This is my MOSFET Vgs matcher.



First, I install a sample part and let it warm up for about an hour. There's a thermistor hot-glued to the heat sink,...

This is the artwork for the PCB in the pictures. It fits into the ExpressPCB miniboard profile so it's a little cheaper to have made.

It will be necessary to check the orientation of the bias pots (I can't remember). I wouldn't want you to blow-up your $30 JFETs.

I've been mostly out of the audio hobby for a while, but I've had a few inquiries about the SemiSouth version of the Amazing FET Circlotron as of late. So, I wanted to post the performance graphs here before I lose them.