has anyone built a 12v or 30v tube amp?

[Capacitordeath]

I've stumbled across Sopht's amp site, where the builder has used "space tubes" ??? to build a fully functioning valve amp @ 12v across the board, AKA wall wart power supply. If you have built one, got any pics/vids/suggestions?

[Enzo]

Call me silly, but perhaps a link to the site you mention would let the rest of us find out what you are referring to.

[Capacitordeath]

la link.

http://www.sophtamps.ca/mambo/index....tpage&Itemid=1

I'm hoping that more people have built something like this successfully.

[tubeswell]

Well the 12V version just ain't my cuppa T (cheap OT?, or having the stages biased badly? something is wrong because the distortion sounds like a buzzing mozzie);

http://www.sophtamps.ca/sounds/sopht_12al8.mp3

The 30V one sounds a bit more promising

http://www.sophtamps.ca/sounds/sopht_30v_clip1.mp3

The one with the KT88 sounds good (but that ain't a 30V amp)

http://www.sophtamps.ca/sounds/good_...lean_strat.mp3

[tedmich]

Hoffman amps has a tiny 12VAC->240VDC tranny for $22 which can be used to make your typical tube preamp pedal, you'd still need the wallwart though...

The old PAIA stack in a box is still available (B+ ~40V ??!!) and has been tweaked a bit here:
http://www.guitar-pedals-effects.com/DualTubeSIAB.html

found this small PS designed to use tube audio in your car:http://www.audiohobbyist.com/diypart...kit/carpsu.htm

[unparalleled]

Space charge tubes

I've stumbled across Sopht's amp site, where the builder has used "space tubes" ??? to build a fully functioning valve amp @ 12v across the board, AKA wall wart power supply. If you have built one, got any pics/vids/suggestions?

Early car radios used these. The audio Output was often a 12K5 (Link). they used them so that a transformer/vibrator power supply was not needed.
http://www.google.com/search?hl=en&q...=Google+Search
"Radiomuseum" is a great reference for tube type info.
When repairing such radios it is easier to replace the O/p tube with a FET to drive the speaker.

Any tube can be used at low voltage like a space charge type but obviously you ain't going to get great results because of the low peak to peak output.

I plan to build a 12Volt tube stereo amp for automotive use and my HT will be derived from a modified 12/ 240 V inverter, just take away the output square wave chopper circuit and you have a power supply 2- 300 VDC and heaps of current available.
Such a power supply could be incorporated into a large Guitar amp to make it function on 12 volts, but you would want to have something charging the battery! (alternator)

[Capacitordeath]

I was hoping someone HAD built one of these little guys, and had knocked out some of the bugs in it. If the space charge tubes are affordable (since nobody uses them, I imagine), a little 12v guitar amp would be a neat gift to friends who play. I can envision a tiny combo with a 5in speaker.

I'd call it "The Smokey Yunick Champ". There's an odd car reference for ya.

[tbryanh]

http://www.sophtamps.ca/mambo/index....d=25&Itemid=37

[sportster4eva]

I was hoping someone HAD built one of these little guys, and had knocked out some of the bugs in it. If the space charge tubes are affordable (since nobody uses them, I imagine), a little 12v guitar amp would be a neat gift to friends who play. I can envision a tiny combo with a 5in speaker.

I'd call it "The Smokey Yunick Champ". There's an odd car reference for ya.

Chevrolet Power God!! I actually have this book. It's the smallblock bible.