Bump.
I came across a post on diyAudio from Doc B. in 2007 suggesting that Bottlehead put the C4S in the public domain some time ago, so I'm assuming there's no intellectual property protection issue.
I already have the schematic (from the the SII kits I have), but I'd love to read the handbook or whatever documentation used to be supplied with the old BH C4S kits. Is there a digital copy kicking around somewhere? Or, with BH's permission, would someone with a hard copy be willing to scan it and post/email it? @Doc B or @PJ: would that be ok?
I know Morgan Jones has a version of a cascode constant current source in his book (of which I have a copy), but I'd like to read what John Camille/BH had to say about the BH version, if at at all possible.
According to Doc B's 2007 posts on diyAudio, John Camille also published a bunch of info about the C4S in Sound Practices in the 90s, but I have no idea how I'd go about locating a copy of that.
Edit: just discovered that hificollective in the UK sells all issues of SP on CD for $25 (plus almost that much for Fedex, unless one wishes to risk UK Royal Mail). I've ordered a copy. But still hoping a copy of the BH C4S material can be made available.
Many thanks,
Derek