THE GREAT MULLARD MAGIC BLOG — MHOS

I have an e-mail today from Peter in Australia who was asking why my results for a given valve were 1000 times smaller than some he had bought elsewhere - I was concerned as to the uninitiated, my results could suggest that I may be peddling devices which were low emission rubbish! I smiled wryly as the decadic factor indicated that Peter had bought valves with their Mutual Conductance (gm) expressed in micro-mhos, so, how best to explain this........ OK, let's start with the basics, mutual conductance is the measure of the 'goodness' of a valve  with some people colloquially...