Hey Charles, the Halcyon BC's (11 I think) and the Entr'acte recording Society (5) were were the ones with a different label, but they were still duplicated by BC. Aside from the labels you mentioned, they also duplicated Mercury, Phillips, Spectrum, Telefunken, and Deutsche Grammophon. There are a few that were recorded from digital masters and are marked as such on the covers. I've got a couple and one is good and one is just OK. The sound aside, the performances are almost always wonderful (since that is how say, one Mahler's 1st was chosen over another one) as long as you agree with Barclay's taste. There's also a few DBX encoded tapes (which I have none of and I've never stopped to figure out how many there were) but some are definitely available as Dolby encoded tapes too ( Ozawa's reading of " The Rite of Spring"). There are also a few ( the Ozawa just mentioned included) that, even though recorded in the 4 track format, are only recorded in one direction. These are recordings with particularly high dynamic peaks and were duplicated this way to avoid crosstalk.
So, to answer your question,.. they were all duplicated at a much lower speed than typical factory tapes (I understand that the ratio was changed somewhere along the line) and all were recorded onto good tape stock. What really sets one apart from the others seems to be the master used and the engineering of that master. I've never really gone back and counted the ones I've labeled as "Demo" quality but out of the 180 or so that I have, I'd guess that it's somewhere around 25. There are tons of "9s and 10s" and very few outright "dogs". Needless to say, I need the Costco size bottle of Last.
