Paleo-Electronics Blog » 102C84 http://www.paleoelectronics.com/blog Clueless Idiots and High Voltage Vacuum Tubes Really Do Mix! Mon, 07 Dec 2009 02:48:50 +0000 en hourly 1 http://wordpress.org/?v=3.0 102C84 http://www.paleoelectronics.com/blog/2007/09/102c84/ http://www.paleoelectronics.com/blog/2007/09/102c84/#comments Sun, 30 Sep 2007 21:57:46 +0000 Dilapidus http://www.paleoelectronics.com/blog/?p=10 It is quite possible, if you have been fooling with early Gibson or Epiphone amps, that you have run into the Sprague 102C84 network. When I did, I found precious little on the internet.

My inaugural post on this blog is dedicated to the memory of this damn thing.

What is it? It is a network of resistors and capacitors in one funky square package. It has three leads coming out the bottom and was apparently made specifically for Gibson amps. This image is from the Gibson Master Service Manual (Hawk, pg. 318) and while hard to read, it’s also hard to mistake.

The circuit inside is just below it and shows values of 500 pF , 220k (for both resistors) and 0.0047 μF (5%). I have also seen this network drawn on a 50′s GA-5T schematic but I can’t find the schematic again. The pre-crestline 5T is pretty rare apparently. You can tell it’s the 50′s version because it has four tubes, not the 5 tube Crestline.

Sprague 102C84 in a Gibson Hawk

The 5 tube GA-5T Crestline is how I got into this mess, but that is another story.

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