Diode Matching Unit
- Media:DMU.pdf I found this article on the Bitx forum.
I bought 500 1N4148 diodes. I found I could match them so close the meter wouldn't move at all. A bad match is anything more than about 2 or 3 ua. I bought a matched set for comparison and they were about 3ua apart. It didn't take long to find almost perfect matches and it was well worth it in the mixers performance. I used a ziff socket for holding the diodes because it was easy to clamp them into it.
Many multimeters have a Diode test on them. You can simply use this to find diodes with matching tests that will provide you with a matching pair of diodes. Also, the Minima schematic has a very simple circuit that you can use in the bottom left to use any multimeter to test diodes. From everything I've read, this is a very worthwhile step. -Source