24-04-2012, 02:23 PM
Hi Lawrence, its the same for me all ktw, exept the other set it has 3 could be EF89,s, fitted by a previous owner, l know there are other octal valves but they are lower gain eg 6K7 near Equivalent i suspect lower gain. The KTW61 is a variable μ amplifier pentode for use in RF or IF stages within an AGC controlled superhet receiver. So a valve having the same or above would be ok. I would leave all alone if the set disd not need a big overhaul, but iuts looming, even the output stage could be changed for an EL84, this sounds horrid to do toi a set like this, but if its hard or very expensive to get replacement valves, its the only option, i did substitute some valves as they were so low on emission the set was geting less and less selective...regards....Alan
