RS components sell tubes! Please ignore this if you know, but I just noticed myself, and I've been cruising around their site for a while.
They seem to be Chinese, judging from the datasheets, but not completely sure of branding. Very cheap. Don't know how they rate in terms of micro-phonics and other measurables, but maybe worth a try?
http://za.rs-online.com/web/search/searchBrowseAction.html?method=retrieveTfg&Ne=4294958012&N=4294921824+4294201950
They seem to be Chinese, judging from the datasheets, but not completely sure of branding. Very cheap. Don't know how they rate in terms of micro-phonics and other measurables, but maybe worth a try?
http://za.rs-online.com/web/search/searchBrowseAction.html?method=retrieveTfg&Ne=4294958012&N=4294921824+4294201950