It appears that the "tech" that modded my Marshall (when it was previously owned by someone else, did a half-vast job. With a good set of new tubes, it will not bias any hotter than 27 mA - way too cold. I'm getting mixed information on doing the conversion the right way: 1. A "pro tech" source online indicates that only the bias range resistor (47K) needs to be cut to half that value (parallel it with another 47K), and move the negative feedback loop wire from the 4 to 8 ohm tap. 2. Marshall clearly states that the bias feed resistors need to be bumped up from 150K to 220K, the bias range resistor needs to go up to 56K, and the bias supply resistor needs to go from 120K up to 220K. They make no mention of doing anything with the feedback wire. These 2 simply do not agree with each other. The only "mod" that was done to mine was to knock the 47K bias range resistor to 38K. I can't imagine dropping it to approximately 23K! So what is the tried and true method?