31-10-2012, 01:05 PM
Yes I agree, a PA design primarily, I think that standby arrangement was used to avoid various cathode emission/degridation issues. I found a reference to a similar Geloso amp and the manufactures recomended proceedure at intiall switch on was to go standby 'till the valves heaters/cathoder had warmed up to the correct temperature. Historically it seams to stem from the days when directly heated cathode rectifiers were used when the full HT was availble to the O/P valves before those valves cathodes had attained their working temperature, this situation can arise in the circuit posted in this thread as it uses solid state rectifiers, all interesting stuff, and gives an insight to circuit techniques used in vintage stuff we come across.
Lawrence.
Lawrence.
