[sdiy] Banana vs. 1/4" question

[Chris Stecker]

Time to chime in...

Reading Grant's article, I thought about the comment regarding stackable 
shielded connectors. In my last lab (a psychoacoustics lab) most of our gear 
was set up to use mini-double-banana connectors. I'd guess they correspond to 
the aforementioned 2mm bananas. They aren't perfect, but they're stackable 
vertically and horizontally, and (can) have shielded two-conductor cables. 

I also have at home a "Mac panel" system, surplus from the same lab. It was 
used to patch signal processing gear during the period experiments were 
controlled by the PDP-8. I know little about this system, but will describe 
it. The connectors are two-conductor banana-type, wider than 
mini-double-bananas but a bit narrower than regular bananas. They are also 
quite long (perhaps 3-4 cm) and [IIRC] made of two metals: a bullet-shaped 
tip (dull in appearance) and a shiny-metal shaft. Cables are shielded (though 
short). The connectors are inserted into a card frame (plastic or nylon) with 
openings arranged in a labelled grid, so for example you might patch from A-4 
to D-16. The connectors are inserted through the card, so that the tips stick 
out the back. A separate card frame contains wiping connections that contact 
these tips when a card is inserted. The frame's connections are soldered as 
appropriately to the devices of interest. The connectors themselves are not 
patchable, but regions of the grid can easily be soldered up as multiples. 
Overall, the system cards act as "patch memories" that can be placed and 
removed with altering individual patch-points. I have the frame, a number of 
cards, and many cables. One day it will serve as part of some modular 
project..."when I find the time" 

-Chris