SteveH wrote:Gents,
What I may do is use a rotary switch to select UL/Pentode/Triode mode in the place of the cap. I believe I would need a 2P3T rotary switch ?
When I tried something similar, I ended up with one pole for each tube. With two KT88's, I used a DPDT switch to switch the resistor and OPT tap for each tube in and out.
Not sure a cheapo rotary switch is suitable for handling high voltage...others would know more about than me. Allied Electronics has a good rotary that might work: http://www.alliedelec.com/Search/SearchResults.aspx?N=0&Ntk=Primary&Ntt=747-6685, but you'd need 3 positions with 4 poles. They're sealed and rated at 0.3A @ 125VAC. These get kinda 'spensive, though. I'd put some ceramic caps across the contacts also.
Chris