Tubes run on 9v?

[Alpha579]

Hey all,
is there any reason a tube circuit cant be run on a 9v battery? Or does it need to be 12v. If so, can i use a 9v batt and 3v pack in series? Or does it need to be AC. Sorry for the newb question, but i dont have any experience with tubes.

[Peter Snowberg]

The most common tubes you see in guitar use are the 12A_7 series. The heaters of these want either 12.6 volts at 150mA or 6.3 volts at 300mA just to heat the thing up. That's more than a 9V battery is willing to supply so that's half of why such effects don't run on 9V batteries. The other half has to do with the plate a.k.a. B+ voltage. To get a good clean signal you need a couple of hundred volts and the conversion of 9V to 250V is only so efficient. When you add those needs together you end up with something that's hopelessly outside the territory of a nine volt battery.

You can absolutely run tubes from batteries, in fact all the first tube circuits were all battery supplied and the B+ name is derrived from the "B battery" which supplied the high voltage. The "A battery" was a BIG dry cell that supplied the fillament power.

There are a whole line of tubes that were made for battery power, but the 12A_7 series is not from them. Sadly these tubes are mostly in the past at this point.

Take care,
-Peter

[zachary vex]

just like Peter said... and sure, it might be possible to come up with a circuit that would efficiently extract all of the energy from a 9 volt batter to fire up a tube circuit but it would drain a rectangular 9 volt battery in a matter of seconds.

[Ansil]

there are some nice little christmas tree like bulbs that have super low requirements but alas still not 9v transistor battery capabliites

[Alpha579]

oh well...any way, where can i find the shaka tube schem? I cant find it under aron nelson...i think it was his design...

[Alpha579]

Am i right in saying the shaka tube runs on 12v?

[aron]

It's in schematics 2. There are multiple drawings of the schematic. Yes, it runs on 12V

[Alpha579]

thanx, didnt think to look in that one...

[Alpha579]

Whats the shaka tube like? Has anyone built it?

[aron]

Here's the demo:

http://www.diystompboxes.com/pedals/sounds/shakaTubeDemo.mp3