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Hum in cathodyne PI

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Im on my phone and fer some reason it wont let me search...but appearantly Im allowed to start a thread...
My cathodyne phase splitter hums. Usually this goes away when I elevate the heater. But not this time. I have tried:
-Elevated heater above, below, and at same potential as the cathode. Also tried heater to gnd. When elevated I use 22uF to gnd from cntr of heater tap (resistor divider no cnt tap on heater secondary).
-Double and triple checked heater wiring.

If I disconnect the plate side output of the cathodyne the amp is dead silent. And sounds very good with only the one phase coming from the cathode of the cathodyne. So I know the hum comes from the cathodyne PI.

The entire amp shares one heater secondary. Its a single channel with 2x 6V6, driver is 6922 preceded by a single 12AX7 as first gain stage and PI.
Edit: the cathodyne is ac coupled both in and out.
Any suggestions? Thnx.
 
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I can see the risk of HF oscillations when cheap skating like this and using same b+ but since the PI has gain <1 I didnt expect low frequency or hum from heater leakeage problems. Still have problem understanding how the heater leaks into only the PI in this config.
Anyways lesson learned. Always use separate bypass for all active devices gain or no gain.
I see ure from Seattle Audiowize. I was there maybe ten years ago and found a really neat local guitar amplifier brand. Cant remember name but seems the product was combos built in uncovered plywood, just stained. Very handmade like. You know what Im talking about?
 
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