I had an AGI 511 preamp for years. It used a ribbon cable that went from the board to another board of the rca connectors. A popular upgrade for this was to remove the ribbon cable and use good quality shielded cable to each connector. A very large increase in dynamic range and overall better sq. Photos can be seen on line of the internals of this ribbon cable. A poor design when used within the audio signal path, ime. Many other upgrades were available as well, as mine was an all out assault. Thinking about it, I should have kept it, but I was offered a nice amount of $ for it, so it went.
