[Plumbicon]

I'm looking for informations about the unidentified AMPEX unit pictured below. No model # nor any identification tag can be found, only the AMPEX logo engraved in the 19" faceplate. It's clearly a factory made unit, not prototype or home made. There are only four large linear controls and a "IN/OUT" switch. It's all tube based which dates it from the late 50ies/early 60ies. From the connectors and tubes used it doesn't look like an audio unit but very likely some video corrector/processor. Since it has 4 identical channels I'd guess it was a part of a quad(ruplex) broadcast tape videorecorder, maybe the VR1000 ? Someone told me it was an adjustable delay line to compensate for (geometrical) quadrature errors in the video headwheel but I know AMPEX was opposed to electronic correction of head quadrature errors and never used such devices. I have the original VR1000 factory manuals and promotional papers and no mention or pictures of this unit can be found anywhere, It's not a part of the two 19" big rack cabinets associated with the VR1000 either.
Hopefully someone here could identify it and tell me more about this strange unit, and its purpose. Click on the pictures below for more details.