Sonar FS2340 and FS3023 Power

[hifiman]

I have found the schematics on both but does anyone own these and can tall me how to cut the dead key back to 1-3 watts? Thanks

[Night Crawler]

Increase the value of the screen grid resistor on the final amplifier.

[hifiman]

Increase the value of the screen grid resistor on the final amplifier.

Thanks. Would that mean just replacing the resister or are some adjustable?

[51]

screen grid resistors are a fixed value.

[Night Crawler]

Would that mean just replacing the resister or are some adjustable?

It's a fixed value in the FS2340 I don't have a schematic for the FS3023 but I'm sure it's a fixed value also the only time a variable is used that I've seen is in a ham transmitter and it's used on the screen grid of the driver tube to control the drive level to the final amplifier stage.

To lower the output on the FS2340 find pin 9 on the 6BQ5 final amplifier one end of a resistor will be connected to it along with a bypass capacitor.

Disconnect the end of the resistor going to pin 9 leave the bypass capacitor connected.

For the following the value will have to be determined by trial and error to get the output wattage you need start with a 10k.

Install the experimental resistor make sure it's a 1 watt or greater in series between the end of the resistor that was disconnected from pin 9 with the other end of the resistor going to pin 9.

Your option if you want the swing use a 100uf 350wv or 100uf 450wv capacitor in parallel with the resistor with the negative side going to pin 9of the 6BQ5.


If you can post a schematic for the FS3023 I'll give you the connection points.

[hifiman]

Would that mean just replacing the resister or are some adjustable?

It's a fixed value in the FS2340 I don't have a schematic for the FS3023 but I'm sure it's a fixed value also the only time a variable is used that I've seen is in a ham transmitter and it's used on the screen grid of the driver tube to control the drive level to the final amplifier stage.

To lower the output on the FS2340 find pin 9 on the 6BQ5 final amplifier one end of a resistor will be connected to it along with a bypass capacitor.

Disconnect the end of the resistor going to pin 9 leave the bypass capacitor connected.

For the following the value will have to be determined by trial and error to get the output wattage you need start with a 10k.

Install the experimental resistor make sure it's a 1 watt or greater in series between the end of the resistor that was disconnected from pin 9 with the other end of the resistor going to pin 9.

Thanks for your help. I do appreciate it.

Your option if you want the swing use a 100uf 350wv or 100uf 450wv capacitor in parallel with the resistor with the negative side going to pin 9of the 6BQ5.


If you can post a schematic for the FS3023 I'll give you the connection points.

[hifiman]

Would that mean just replacing the resister or are some adjustable?

It's a fixed value in the FS2340 I don't have a schematic for the FS3023 but I'm sure it's a fixed value also the only time a variable is used that I've seen is in a ham transmitter and it's used on the screen grid of the driver tube to control the drive level to the final amplifier stage.

To lower the output on the FS2340 find pin 9 on the 6BQ5 final amplifier one end of a resistor will be connected to it along with a bypass capacitor.

Disconnect the end of the resistor going to pin 9 leave the bypass capacitor connected.

For the following the value will have to be determined by trial and error to get the output wattage you need start with a 10k.

Install the experimental resistor make sure it's a 1 watt or greater in series between the end of the resistor that was disconnected from pin 9 with the other end of the resistor going to pin 9.



Your option if you want the swing use a 100uf 350wv or 100uf 450wv capacitor in parallel with the resistor with the negative side going to pin 9of the 6BQ5.


If you can post a schematic for the FS3023 I'll give you the connection points.

Thanks for your help. I do appreciate it.