I had already built a box using the Silicon Chip Multi Function Active Filters so I decided if Jaycar still had some of these kits I would fit one in this cabinet. This meant I had to also build a circuit board for an LM386 power amplifier and a 12 volt regulator. I did not want to run the filter/amplifier from the Powermate supply because this would not be used very often. I managed to find a small 10K Log pot fitted with a switch so I removed one of the push button switches and modified the bracket that held the switches to mount the pot. This switch turns on and off a 15-0-15 volt 150 mA transformer and the rectifier and regulator are on the circuit board with the LM386 amplifier. NERC club member Eric turned me up an adaptor from the short splined shaft to a quarter inch shaft so I could use the knob in the photos.
I am looking for a photo of the inside of an unmodified SP-820, I have lost the early photos I took of the box. I think the SD card went through the washing machine and was hung on the cloths line. If you have an SP-820 I would appreciate a photo to add to this page. I make my photos 900 pixels wide but any size will do, I will adjust it to my fit.
Back to the Shack page
Back to the Ham Radio pages
Back to the Domestic Radio pages
Back to opening page
Written by and Copyright, Phil. Storr © Last updated 20th April 2014