Three Channel Jones Colorizer

Three Channel Jones Colorizer

Though I always intended to build a colorizer, boards were in short supply, and I managed fine colorizing by patching subcarrier into video rate VC inputs of various modules - mostly my keyers. This was a lean approach. On a recent trip to Owego Dave Jones revealed he had 3 channel boards on a shelf along with the last RGB board. He generously gave them to me, as long as I actually built the colorizer. Considering Dave's designing a new and improved Eurorack version of the colorizer, the value for these older boards is limited, especially considering the large form factor.

With help and prodding from my intern - Eli Coplan, we started loading the boards. The small push was all that was needed. This was completed the summer of 2018. It might still need some trimming though it's looking pretty good.

Deciding on the box and panel design slowed me down. Even though I had the old sloped Hammond box, like the one installed at the Experimental TV Center, it seemed too big and table top space is a premium. The old card racks I have are also bigger than needed and it's hard to debug the boards with ribbon cables in a card rack. I bought this 3U black Hammond box that seems just fine.

One of the motivations is to document the last ('80s version) colorizer as I go. My last trip to Signal Culture I spent time photographing in minute detail one of the old colorizers Dave has. There were a great deal of modifications, which also changed over time as improvements were added. 

Three channels? In a way I am very content that's all David had on the shelf. Four channels is more typical, but three will work just fine and takes less space. Unlike every other Jones colorizer, this will not have single end composite video inputs and outputs. Notice the single BNC for subcarrier. All patching is on the front panel, differential video and +-5 cv, in true modular fashion. Since I am using standard mini jacks, what is usually ground is isolated from the panel using plastic bushings and washers.