Is it known whether these exist as discrete quad masters? I think they were single-inventory matrix releases with no dedicated stereo mix, so it's possible they were only laid down that way, but I'd love to hear them in discrete digital quad (PCM or DSD).
There's a case for both outcomes: in the 'yes' column is that there was a
Billboard article about Ed Michel, who ran Impulse! back (and was the one behind the label going single-inventory quad) and he said he did discrete and matrixed mixes simultaneously at the Village Recorder by connecting two studios together using tie lines, and using one for the discrete mix and one for the QS mix, and he'd walk between the two control rooms to make sure both sounded good. Also in the 'yes' column is that the Sun Ra quad master tapes that sold on ebay (like
this one for example) were both 4-channel discrete and 2-channel QS encoded, which backs up this assertion. So you'd figure if Michel did discrete tapes for the albums he produced, that he'd probably insist on other mixes done for the label by other producers and/or at other studios deliver both discrete and matrix tapes too.
In the 'no' column, the fact that the two Isley Bros. quad mixes done at Kendun (
Live It Up and
The Heat is On), the latter done by Heenan, both don't have discrete quad masters - and we know that
Live It Up never did because the vintage Q8 has the same matrix-decoded mix found on the D-V SACD - so it's possible that Heenan's SOP was to just mix direct to matrix-encoded stereo and not do a discrete master at all. I'm still not sure why this was the case for the Isley Bros. because every single other mix done for CBS has a discrete master tape, and even just from an efficiency standpoint, you can make a matrix master from a discrete master, but you can't make a discrete master from a matrix master. Unfortunately Heenan
passed away a decade ago after a battle with cancer so these are questions that can never be answered.
Unfortunately I think the whole thing is moot because as far as I can discern, if there were discrete Impulse! quad masters, they all went up in smoke with all the other ABC tapes (and all their subsidiaries like Bluesway, Cadet, Chess, Command, Dot, Dunhill, Paramount, Ranwood etc.) in the 2008 UMG vault fire.