Cathode follower

[sbirkenstock]

Hi Everybody,

I put a cathode follower channel in my BF Vibroverb project.
Pretty much copied from the Bassman 5f6a.
It distorts very early, so I went into detail and it created some questions for me.....

I tried to follow the flow with an USB Oscilloscope (PicoScope).
My Strat put´s out about 120mV on an E chord.
So I feed the amp with a sinus wave of 120mV (swing from -120 to +120 mV)
The first stage output swings from -3V to +3V.
So amplification factor is about 25. Can this be correct? Plate resistor is 100k, cathode 1k5.
I adjust the vol pot after the first stage that it delivers -1,5 to + 1,5 volt to the grid of the second stage.
This will make the wave go -30V to +30 volt going around the 218 volts
of the plate. (Just lower than the 218 volts in idle, looks like the middle is 200v rather than 218)
So far so good.
The grid of the 3rd stage of the cathode follower is directly connected to the plate of the 2nd at pretty high voltages.
But still, should the input signal only fluctuate like 1,5 or 2 volts from the idle point of the grid?
But the cathode of stage 3 (going to the tone stack) then again delivers a wave that is -30 to +30 volts.

Any info on this?

Best regards,

Stephan

[matt h]

(deleted)