Mystery AMPEX video (?) processor. VR1000?

[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.

[Plumbicon]

It looks that nobody has any infos about this unit...

After a lot of g-search I finally found a pic of this item. This tend to confirm it was actually used with (or part of) the AMPEX VR-1000 first tape videorecorder. The pic is a little fuzzy but the unit is clearly identifiable in the right rack cabinet top, and this is the one and only pic which can be found of the web.

BTW, I looked inside the unit and the big linear faders are not (resistive) potentiometers but are driving a multiple tapped coil/cap assembly, very likely an adjustable delay line, or response correction filter.

[kf4rca]

It is a quadrature equalizer for the 1000. The early machines did not have MATC (Monochrome automatic timing control).
The early quad head pole tips were not always in quadrature (90 degrees) with one another. So some method of adjusting the delay of the RF coming off the pole tips was needed. The sliders are variable delay lines and added the necessary delay so all the pole tips outputs would be "together."
Each head reproduced 16 lines of the picture. With no means of correction the picture would appear segmented.

[Plumbicon]

That makes sense... then this corrector was not part of the early versions of the VR1000 and added later ? In the VR1000 user manual the recommended head poles quadrature adjustment is purely mechanical, a rather tedious and cumbersome "trial and error" process involving small adjustments of screws on the head drum to (mechanically) advance or delay the heads position until perfect quadrature was reached. Since it couldn't be done in real time many successive runs were needed and the only control was watching the (recorded) test picture on a monitor after each adjustment.

[kf4rca]

I would say that device came with the production runs of the VR1000. Manual field adjustment was not recommended for quadrature error.
If you've ever played with dihedral error on a helical machine, you know what I mean. Most likely that unit was left over when the machine was "Allenized". The Allen kits replaced sections with solid state.
Besides monochrome timing errors, there were color errors that had to be corrected too.
In RCA it was MATC and CATC which in Ampex was called Amtec and Colortec.
Attached, technician checks an Ampex Mark III headwheel panel.

[old_tv_nut]

Here's Sylvia, less faded.

[Mi40793]

circa 1958 RF channel delay frames were included in the RCA-TRT-1A/B. One for record delay, second for playback. You set the playback on a test tape for straight lines then set the record knobs to the opposite settings so recorded tapes were correct. Ampex made tgeirs later. The Ampex manual delays may have come after the TRT-1, seemed rare on VR-1000’s. I don’t know if Ampex used two like RCA, but Amtec came out about 1961 and solved the playback problem. RCA built ‘ATC’ as option for the TRT-1 same method as Amtec, a voltage variable delay line with varactors.

Early on Ampex shipped the head assy with the tape especially if there were to be additions because of head differences.