14-08-2013, 01:44 PM
By these days I've been adjusting the trace by the controls that this CRT has.
I have notice a problem in the DC mode. I set zero input and it shows a flat line as expected. Then I apply a sine wave and this sine wave is not oscillating around zero, but mostly negative, with some parts above the zero line.
I guess this is due to diferences in the gain of the two triodes used in the diferential output amplifier. What do you think?
In my opinion this can be solved by changing the twin triode which conform the diferential amplifier or simply by using only one output of the diferential amplifier to one of the CRT plates, while the other is connected to a fixed resistive divider. The second option will make me lose gain, but there is enough gain to sacrifice.
There is no problem on AC mode
I have notice a problem in the DC mode. I set zero input and it shows a flat line as expected. Then I apply a sine wave and this sine wave is not oscillating around zero, but mostly negative, with some parts above the zero line.
I guess this is due to diferences in the gain of the two triodes used in the diferential output amplifier. What do you think?
In my opinion this can be solved by changing the twin triode which conform the diferential amplifier or simply by using only one output of the diferential amplifier to one of the CRT plates, while the other is connected to a fixed resistive divider. The second option will make me lose gain, but there is enough gain to sacrifice.
There is no problem on AC mode
