Adjustable B+ and Cathode Current linestage

Brit01 · 29th July 2009, 05:53 PM

Just built a linestage (actually a CF buffer), and have been trying with different 9 pin tubes.

Now it occurred to me that I could incorporate a variable resistor in the power supply to vary the B+ and also a variable resistor for the cathode.
Put in 2 meters, one to measure the current in mA and another to measure the B+.

So when I swap tubes or simply tune the current to find sweet spots, I can increase or decrease the B+ to balance with the cathode resistor.

Of course all within limits of the rectifier and tranny current.

Has anyone done this before? Don't see why it wouldn't work well.

Wavebourn · 29th July 2009, 06:01 PM

This thread may help you a lot:

http://www.diyaudio.com/forums/showt...02#post1833902

Loading on gyrator you can forget about anode voltage adjustments. Also, you get the best possible linearity from your tube, compared to a plain resistive load.

Brit01 · 30th July 2009, 12:12 PM

Thks Wavebourn. Have to have a read of that when I get a bit of time. Looks interesting.

29th July 2009, 05:53 PM	#1
Brit01 diyAudio Member Join Date: Jul 2008	Adjustable B+ and Cathode Current linestage Just built a linestage (actually a CF buffer), and have been trying with different 9 pin tubes. Now it occurred to me that I could incorporate a variable resistor in the power supply to vary the B+ and also a variable resistor for the cathode. Put in 2 meters, one to measure the current in mA and another to measure the B+. So when I swap tubes or simply tune the current to find sweet spots, I can increase or decrease the B+ to balance with the cathode resistor. Of course all within limits of the rectifier and tranny current. Has anyone done this before? Don't see why it wouldn't work well.

29th July 2009, 06:01 PM	#2
Wavebourn diyAudio Member Join Date: Sep 2006 Location: Pleasant Hill, CA	This thread may help you a lot: http://www.diyaudio.com/forums/showt...02#post1833902 Loading on gyrator you can forget about anode voltage adjustments. Also, you get the best possible linearity from your tube, compared to a plain resistive load. __________________ If I disappear suddenly, that means I finally created a time machine and pushed wrong button that brought me to Stalin's Russia. In any experiment any result is the result. Even if it is negative.

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30th July 2009, 12:12 PM	#3
Brit01 diyAudio Member Join Date: Jul 2008	Thks Wavebourn. Have to have a read of that when I get a bit of time. Looks interesting.