That's what I was hoping you wouldn't say... can't afford a set of new valves at the moment unless there's a cheaper alternative to the Marshall ones that's recommended to use (£30 each = £120 for the lot
). Is there any way of testing them individually eg by measuring resistance between certain pins or something, to see which one's broken, if that's the problem? The EL34s were all replaced by Marshall in September 2006, I've checked the work ticket and the part numbers match. Why would switching the mode make it go wrong, I've changed it before, or is that just co-incidental?
All help is very much appreciated.