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Nelson Pass Presentation

Posted 26th October 2015 at 04:50 PM by Michael Rothacher (Audiohobby.com)
Updated 26th October 2015 at 04:53 PM by Michael Rothacher

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.
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Video Blog#1 Posted

Posted 7th May 2014 at 10:16 PM by Michael Rothacher (Audiohobby.com)

Video Blog #1 is posted here:

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

Posted 1st November 2013 at 12:56 AM by Michael Rothacher (Audiohobby.com)
Updated 2nd November 2013 at 05:52 PM by Michael Rothacher

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
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Matching Stuff

Posted 27th November 2011 at 12:24 AM by Michael Rothacher (Audiohobby.com)

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.

Click the image to open in full size.

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.

Click the image to open in full size.

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

Click the image to open in full size.

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,...
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Compact PCB For All JFET Circlotron

Posted 25th January 2011 at 12:59 AM by Michael Rothacher (Audiohobby.com)
Updated 2nd October 2011 at 11:59 AM by Michael Rothacher

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.
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All JFET Circlotron

Posted 22nd January 2011 at 11:29 PM by Michael Rothacher (Audiohobby.com)

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.
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