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Feedback question, Philco 6017 PA amp

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  • Feedback question, Philco 6017 PA amp

    Hi all,

    I got this cool little Philco PA amp, recapped and it plays very well. Clean, clean sound even at volume. Since I have no use for the phono input, I removed the phono circuit and am using the phono level pot for an across the line master volume control, to help get some decent breakup at lower volumes.

    I'd also like to experiment with the negative feedback loop in this set. Apart from a switch to disconnect the negative feedback which I will try this afternoon, anyone have any suggestions on how to alter this loop to provide a little more versatility? Thanks!

    Click image for larger version

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  • #2
    You could create a mid boost, as it were, by cutting mids and designing up some filters to just let bass and/or treble pass.


    • #3
      The schematic you posted isn’t complete. You might get more out of it by using a SS rectifier. It would raise your B+. (Make sure the filter caps can take the increase) Not a lot of tubes there so it limits what you can do. If you want dirt you also might consider putting a 100 watt Lpad (they are $12 from Parts Express) on the output if it’s too loud for you and driving it with a TS type pedal.