bigdnfay Posted February 3, 2002 Share Posted February 3, 2002 ha guys, I have a vintage Mac 2100 power amp.When the system is turned on, there is a thump thru my khorns.This is with the preamp gain all the way down and the mac gains set half way. Someone told me I have a problem with DC leakage. Is this the case or is this person blowing smoke . If this is a serious problem, what's causing it? Should I take the amp out of my system? I am not an electrical engineer,so any comments would be helpful. Big D Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted February 3, 2002 Share Posted February 3, 2002 Big D. I think the question is: how heavy is the thump! I got an MC250, which is a smaller version of the 2100 and an MC50. They both thump a bit, but it is just noticable. My MC50 would start up with a God-awfull screatch if it was turned off and then right on again. That required all now output and driver transistors to fix. AL K. Quote Link to comment Share on other sites More sharing options...
djk Posted February 3, 2002 Share Posted February 3, 2002 Thumps and squeals with old McIntosh SS equipment are bad capacitors.They cannot 'leak' DC to the speakers because of the autoformer on the output.Considering that the caps are 25~35 years old, I'd say you got your money's worth.Second generation SS from McIntosh (2120,2200) added speaker turn on delay relays to eliminate these noises.You could add the relay circuit, fix the caps, or do both. Quote Link to comment Share on other sites More sharing options...
bigdnfay Posted February 3, 2002 Author Share Posted February 3, 2002 Al, The thump from my 2100 is fairly noticable.Lately I have been turning the gain down on the amp at start up and no thump. Will continuing to use the amp(using this proceedure) cause any longterm damage to my khorns? Or is this something that should be addressed right away?(having transistors replaced) The amp still sounds great. Thanks for the input. Big D p.s. Been using your network design now for awhile.Put the old AA's back in...one song later...had to change them back...ALK's RULE! djk, Is replacing the caps an expensive proceedure? I love the amp and would hate to put it out to pasture. Given me many hours of pleasure. thanks , Big D This message has been edited by bigdnfay on 02-03-2002 at 11:43 AM Quote Link to comment Share on other sites More sharing options...
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