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How small can they make tubes?


Lanefair

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Cause if you could make really small ones, well, that would be great for pedals wouldn't it?

 

 

They used to make some tubes only slightly thicker than a pencil, though still a couple of inches long. These were designed for battery operated equipment. They were used in a lot of WWII era portable radios. They still required a fairly large battery to supply the heater current, though. It's been a while since I looked at the specs for any of these, but I recall the plate voltages were in the 24 to 30 volt range. You wouldn't be able to run these on a 9V battery. Not enough voltage OR current.

 

There's a problem with making tubes too small. The interelement capacitance goes way up because the electrodes are so close together. You also can't run higher plate voltages because, in a vacuum, there would be arcing (little lightning bolts of current) between the cathode and plate.

 

I don't think anyone still makes these tubes, and I don't think there would be much NOS stock floating around. There just wasn't that much demand for them. Tubes like the venerable 12AX7 were used in a lot of consumer products, like television and radio sets, so the manufacturers made boatloads of them. That's why there is still a good supply of NOS stock.

 

Since you'd probably have to plug the thing into the wall anyway, might as well use the more commonly available tubes and go with a slightly bigger box. In fact, why not just make rackmount unit with a remote footswitch?

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Cause if you could make really small ones, well, that would be great for pedals wouldn't it?

 

 

 

it'd be stupendous, cuz then every single pedal maker could be selling valve pedals that did absolutely nothing better than their SS counterparts, but the makers would make more $, and the buyers could strut around just like that naked emperor.

 

 

toobs =/= great

 

great design = great

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