Loud Bypass cleaners?
I'm afraid I don't know what you're talking about, My '68 Fairfax is nice and minty, with plenty of the original attachments, manuals, packaging, Etc. only tool I do not think I have for it is the optional buffer/polisher.
Anyhow, the thing's barely above a whisper, how is this considered loud?
By "Bypass" I'm assuming you mean non-direct-air, As dumb as that sounds. Did such a thing as a direct air fairfax exist?
I'm confused and puzzled by your posting.