[AMRadio] push pull output XFMRs and neg feedback


John Coleman jc at pctechref.com
Mon May 18 10:42:01 EDT 2009


Thanks Jim
        I'll give that a try before switching the XFMRs out.  I guess what your saying is that the slight tolerance differences of components and layouts me be enough to cause this and that the XFMR wires are color coded different doesn't mean they or all wrong.  In his schematic the resistor is 3300 ohms and the capacitor is .001 uf.  The plate resistance of the 6SN7 is supposed to be about 7000 ohms.  With this data, how does one calculate the roll off and how does the un-bypassed cathode resistor and feedback to that cathode effect the response.  I have always done this sort of thing experimentally but I figure that someone with a degree may know the actual methods to calculate all of this.  BTW the cathode resistor is 1000 ohms and the plate resistor is 47K.

Thanks for the tip.
John, WA5BXO


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