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MC-40 bias current?
MC-40 bias current?
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Old 16th March 2013, 04:08 AM   #1
Richard Wright is offline Richard Wright  United States
diyAudio Member
Join Date: Aug 2011
Location: Michigan
Default MC-40 bias current?


This is my first thread on here so bear with me. I have a pair of MC-40's that I have been using for about 15 years now. I am generally pleased with the sound. When I first got them, I changed out the caps and put in the schottky diodes in the power supply. However, until recently while scanning ebay I noticed re-cap kits which include a pot to set the bias current, as changing the original selenium diodes to silicon will change the bias current, and it will need to be adjusted. I never considered this aspect until I read the listing. I have not seen any information anywhere as to where or what I am supposed to be looking for as far as voltage/current values, other than the power supply voltages along the voltage divider resistors. Does anyone have any info as to what I should be looking for? Also, at the time, I replaced all the Bumblebee caps with Sprague Orange Drop 751 series caps. Was this a bad idea? Are there any other caps that won't break the bank that would be recommended? Should I replace the old resistors? Any info would be greatly appreciated.
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