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I figured there might be some skepticism about the voltage inversion so here are pictures showing the values when keyed. As you can see there is a negative voltage inversion through the 6.8k resistor and then a positive inversion through the RF choke. The Sam's shows that there should be a negative value at the tube pin which isn't occurring. The only thing I can think of is that they created a negative impedance converter that isn't working properly. The reason I suspect this is test point #1 is positive and the expected value per Sam's at V12 pin 6 is expected to be positive, which it is. The only thing between test point 1 and V12 pin 2 is the 6.8k resistor and the RF choke however they're expecting that value to suddenly be negative, which it is at test point 2, before becoming positive again. The curve ball is that pin 2 is tied into the A20 adjustment. Disregard the values themselves. The values are affected by the location of the loading knob and it was in a different position.

<blockquote data-quote="Champo" data-source="post: 774786" data-attributes="member: 60887"><p>I figured there might be some skepticism about the voltage inversion so here are pictures showing the values when keyed. As you can see there is a negative voltage inversion through the 6.8k resistor and then a positive inversion through the RF choke. The Sam&#039;s shows that there should be a negative value at the tube pin which isn&#039;t occurring. The only thing I can think of is that they created a negative impedance converter that isn&#039;t working properly. The reason I suspect this is test point #1 is positive and the expected value per Sam&#039;s at V12 pin 6 is expected to be positive, which it is. The only thing between test point 1 and V12 pin 2 is the 6.8k resistor and the RF choke however they&#039;re expecting that value to suddenly be negative, which it is at test point 2, before becoming positive again. The curve ball is that pin 2 is tied into the A20 adjustment. Disregard the values themselves. The values are affected by the location of the loading knob and it was in a different position.</p></blockquote><p></p>

[QUOTE="Champo, post: 774786, member: 60887"] I figured there might be some skepticism about the voltage inversion so here are pictures showing the values when keyed. As you can see there is a negative voltage inversion through the 6.8k resistor and then a positive inversion through the RF choke. The Sam's shows that there should be a negative value at the tube pin which isn't occurring. The only thing I can think of is that they created a negative impedance converter that isn't working properly. The reason I suspect this is test point #1 is positive and the expected value per Sam's at V12 pin 6 is expected to be positive, which it is. The only thing between test point 1 and V12 pin 2 is the 6.8k resistor and the RF choke however they're expecting that value to suddenly be negative, which it is at test point 2, before becoming positive again. The curve ball is that pin 2 is tied into the A20 adjustment. Disregard the values themselves. The values are affected by the location of the loading knob and it was in a different position. [/QUOTE]

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