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Hello All,
A little while ago I posted a thread about a Marshall Major that was blowing fuses. With everyone's help I was able to track down the problem and fix it. In the thread someone brought up the idea of modding the grounding points for the bias and PT CT. Since I notice that the major has a fair amount of hum at idle, I though I might as well try this mod to see if it will reduce the hum. I'm posting a picture of the mod that was submitted to the thread to see what everyone thinks. The idea is to move the bias ground point to the filter cap ground and move the PT CT ground to where the diodes ground. Since I have the Major on the bench I would appreciate any other suggestions anyone might have on Mods or tweaks to reduce noise/hum in this beast. No MV on this beast. I run it at about 110 VAC to keep it within the factory specs for which it was designed. Thanks..
A little while ago I posted a thread about a Marshall Major that was blowing fuses. With everyone's help I was able to track down the problem and fix it. In the thread someone brought up the idea of modding the grounding points for the bias and PT CT. Since I notice that the major has a fair amount of hum at idle, I though I might as well try this mod to see if it will reduce the hum. I'm posting a picture of the mod that was submitted to the thread to see what everyone thinks. The idea is to move the bias ground point to the filter cap ground and move the PT CT ground to where the diodes ground. Since I have the Major on the bench I would appreciate any other suggestions anyone might have on Mods or tweaks to reduce noise/hum in this beast. No MV on this beast. I run it at about 110 VAC to keep it within the factory specs for which it was designed. Thanks..