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,...

Haven't had a chance to update last two months.. the a10 preamp was completed with a little help from my dad and is now integral part of my setup. I even put my Linn magik up for sale.. it's that good.

Last month I started to gather the parts for the objective2 headphone amp. I got about 50-100 units worth of PCB and parts. I will start to package them as kits and sell some assembled. It will be my first try at selling here.

Last two weeks I finish building and rebuilding my Ck2iii headphone amp. The initial build was with an outboard power supply and headphone amp. The cost was running a little high since I build it using momentary switch, etc..

Then I rebuild it two days back into a single enclosure with a switch at the IEC instead. Cut cost down a lot since I no longer have to deal with umbilical cord, etc

-joe

Re-purposed my HiVi M6A into these ZX Spectrums designed by Paul Carmody. They're a groovy little speaker with this crossover and the B&G Neo3 PDR which I am absolutely in love with now.

I hate facebook but I'm willing to give Google+ a go. Now they have "product" pages as well as "people" pages, I have made a little port to RJM Audio.

RJM Audio Google+ page

https://garysmitheda.com/paper/ARM-Techon-note.pdf

Its a single page review of ARM Techcon. At the end I think he means 'PC design' not 'PCB design' as he's written.

He says:

If Intel doesn’t do something soon this might not be much of a war.

He knows some guys at Intel read his analysis so I think he's sugaring the pill. Intel is rather like the hare in the old fable of the tortoise and the hare. The hare woke up and tried to catch up with the tortoise but it was too late. That's exactly where Intel is right now - they've become awake to the issue but they've missed the boat.

https://www.diyaudio.com/forums/wild-...eld-coils.html

I had hoped that this might happen some day.
I will be watching this

...

OK so I've been a bit slack getting to the second instalment. I actually finished the last coil about three weeks ago and have made the crossovers.

Tip number 1. Wear Gloves!! After the first coil my fingers were killing me. I'd pulled back the skin on my fingertips so hard that it was coming away from under the fingernails. Ouch!!! The gloves I subsequently wore were just normal rubber dish washing gloves. These worked quite well because they allowed me to put tension on the wire (holding the spool) and I no longer got sore fingers

Tip number 2. If you can make the same value with different size formers, choose the one with the lesser turns per layer. My pancake coils were much easier to make than the taller ones.

I think that the reason for tip 2 is that the more turns per layer, the more chance that small kinks in the winding wire will add up to enough to make it hard to get the last turn on for any particular layer. The coils...