{Collins} Bias Current 30L-1



Hello again people…Once again I need the assistance from some of you Pro’s in the group…..This question pertains to the Idleing current or should I say the Bias current on my Collins 30L-1 Amplifier…Recently I deceided to upgrade the power supply for the second time ….last time was about 18 years ago…the power supply was upgraded with the Young Kim board this time…i noticed when the mic is keyed with no modulation…audio gain turned to zero…it appears the plate current meter seems to indicate 100 Ma…If I remember correctly it was 110 Ma…in the past…although i should mention I did originally use 811A’s but now have 572B’s in there !  My question…if I run at the 100 ma..Bias…would there be any problem ? I do remember that the very early models ran 130 Ma…and then they came out with the bulletin to modify it for 110 Ma…to reduce heat and get longer tube life…I have two questions…1 ) What would cause that slight change in Bias Current ? 2 ) Would there be any problem running the amp with 100 Ma…. It seems to work quite nicely…from what I see and hear so far…Personally I think it might have something to do with the bias cap used…but its new and its the one supplied with the Young Kim Upgrade Power Supply board…

Any and all comments and input will be greatly appreciated

Thanks People
Carl
WB2PVY


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