Tube Heaters in DC

Started by sjaltenb, October 27, 2010, 02:27:16 PM

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sjaltenb

Hi,

Trying to rebuild my tube drivers. I had removed the transformer from the pedal (12VAC secondaries @ 200ma). Can't I simply add a DC jack and run 12VDC into the pedal and allow it to be rectified again onboard, or will this mess with the tube heaters, which I'm guessing run off the incoming AC before it gets rectified for the rest of the circuit.

Please let me know. I also have a 2nd unit that runs off of a 24V CT AC... I am not sure how I could do the same. I believe it gets half wave rectified in the circuit.

Thanks a bunch. I'm going back to a normal pedalboard so as soon as I get these few kinks worked out...there won't be all these questions anymore!

defaced

Depends on the particulars of the circuits.  Do you have schematics?  There are alot of way to skin the tube circuit cat and alot of them depend on AC inputs to power internal transformers that supply high voltage to the tubes. 
-Mike

slacker

#2
I don't think you can run it off DC. According to this schematic it uses positive and negative DC voltages, so you need AC to get those. If you changed the rectification to something like Aron's Shaka Tube you could run it off an AC wallwart. The heaters already run off DC so no worries there.

http://analogguru.an.ohost.de/193/schematics/Chandler_TubeDriver.gif

MetalGuy

Yes, you can run your Tube driver from a DC source BUT with some mods. You'll need to modify the power supply section and add a charge pump like TC1044S or LT1054 in order to get the negative voltage. Just make sute the charge pump can handle 12V or more. I would recommend a 12VDC regulated power supply.

sjaltenb

ahh. Sounds like more trouble than it is worth  :icon_rolleyes:

I may just reinstall those transformers. Why did I have to remove those power cords ahhhhh