Why not convert?
You may remember the old vibrator power supplies, used in old car radios. These were used specifically for B+. The more modern equivalent is to use a 555 timer to drive a MOSFET. I don't understand your desire to run a [non 12V] tube at this low voltages.
DC-DC conversion allows you to have the optimum B+ for whatever design you choose...Of course if your wish is to see if it can be done, you sound like you are already well on your way!
Good Luck!!
You may remember the old vibrator power supplies, used in old car radios. These were used specifically for B+. The more modern equivalent is to use a 555 timer to drive a MOSFET. I don't understand your desire to run a [non 12V] tube at this low voltages.
DC-DC conversion allows you to have the optimum B+ for whatever design you choose...Of course if your wish is to see if it can be done, you sound like you are already well on your way!Good Luck!!
Alastair E said:I was experimenting at 12V as I didnt want inverters etc or voltage-doublers as its to be used in the car., direct off the usual 12-14V supply
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I quite like the challenge of restricting myself below 15V just to see what can be done with the common audio valve types like above, rather than the special Car-Radio tubes made specially for 12V.....(I havent actually got any of those 'specials' 12V valves at the moment either!)
Yeah, I guess he likes the challenge.
I have built his posted schematic and it works with a 6SN7.
6SL7 is not so good though. The 6SL7 seems to struggle a little on 24V.
I have to say that this low B+ concept has opened my eyes to the possibility of diy tube circuits.
Just wish I'd known more before spending £80 on a 'Tubalizer'.
Cheers,
Martin.
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Alastair E said:shameless bump...Sorry!
Are you bumping about the battery life? The typical 9v is made up of six AAAA 1.5v cells, which have a 625mAh lifespan for alkaline... twice that for lithium. NiMH rechargables are actually 1.2v cells, so you get 7.3-8.4v at 250mAh. if you are going rechargable, you may want to consider a Li-ion flat pack like in a cell phone or MP3 player. They are 3.6v cells, so you can get them in 10.8-11.1v for around $20. A lot of them will shut off below a certain voltage though.
AA batteries are probably a better choice if you have the room... or even AAA. AA Alkalines are 2800mAh, and AAA are 1,200mAh, which is 2-4 times better than a 9v.
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