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Bypass cap on feedback resistor

Posted by Johnny K on April 1, 2005 at 14:54:59:
I have an Eico ST70. I'm thinking of a separate power transformer for the screens of the 7951 tubes. I'm still in the process of deciding whether to rebuild it as a power amp or pretty much as is.
One of the things I notice on vintage schematics is a cap on the feedback resistor. This rolls off the bass to the feedback. Why did they do that? That goes against everything I would think you would want to do to a pentode stage. Why would you *not* want to put bass into the feedback loop?
So what's the advice for rebuilding? Replace with better component or leave it off? If left off, do you play with the value of the feedback resistor? Any insight and/or advice appreciated.
Thanks.