A most unusual triode circuit

[martin manning]

I had thought of using a 1.5K instead of the 8.2K as rightly or wrongly to my ear the 1.5K value sounds fatter.

8k2 is pretty cold bias, even with the 270k plate load. I would consider 220k plate and 3k3 cathode.

So I figure the cap has to be wired in with the wrong polarity. I have this strange feeling that I won’t hear any difference but the cap will fail in the fullness of time.
So the 22uF cap in series with the 100 ohm resistor has the wrong polarity?

Yes it has about 3 VDC on it, which you can easily verify.

[Mark]

I had thought of using a 1.5K instead of the 8.2K as rightly or wrongly to my ear the 1.5K value sounds fatter.

8k2 is pretty cold bias, even with the 270k plate load. I would consider 220k plate and 3k3 cathode.

So I figure the cap has to be wired in with the wrong polarity. I have this strange feeling that I won’t hear any difference but the cap will fail in the fullness of time.
So the 22uF cap in series with the 100 ohm resistor has the wrong polarity?

Yes it has about 3 VDC on it, which you can easily verify.

I had 3.2V on the cathode, and I thought that indicated the triode was running pretty cold. Given the losses through a tone stack are significant, I thought this wasn’t a good place to be running the triode cold.

I will try the 220K and 3.3K combination that you suggested.

IMG_2144.png

IMG_2145.png

IMG_2146.png

Thanks again for all your assistance Martin.