Battery powered amps?

[madmax]

Hmmm...
Never even thought of this as a possibility.

http://cls.audiogon.com/cgi-bin/cls.pl?ddampstran&1108308615&demo&3&4&

madmax

[RobXant]

Looks like Jeff has some competition:D

The "other" battery powered amp (http://www.thinkgeek.com/electronics/audio/6cd8/)

[Danny Tse]

How about the Tripath battery-powered digital amp (http://www.audiocircle.com/circles/viewtopic.php?t=14587)?

Before it dropped its separates line here in the US, Technics had a battery-powered pre-amp.

[madmax]

Anyone try it yet? Any of the class t amps? I may order one.
madmax

[mhardy6647]

http://www.welbornelabs.com/images/ultra1b.jpg

Ron Welborne's Ultrapath preamps:
http://www.welbornelabs.com/ultra.htm

All things being equal, battery power makes more sense for low-level amps (line-level preamps, phono preamps, headphone amps), IMO.

That being said, if current draw requirements are reasonable, then battery power makes A LOT of sense for any electronic equipment (even vacuum tube equipment), as it eliminates the need for AC filtering in the power supply. It DOES make it a bit harder to generate HV, though (since transformers won't work with DC)... although one can always put batteries in parallel to get some high voltages (kids, don't try this at home!).

There is a whole family of low-voltage vacuum tubes that do not require high plate voltages... these were designed at the tail end of the tube car-radio era, when transistor AF sections had become practical but tubes were still better for RF and IF applications.
More info on low-voltage "space charge" tubes: http://www.duntemann.com/12vtubes/12vtubesindex.htm

A neat low-voltage tube project (hybrid tube/SS headphone amp/line-level preamp):
http://pmillett.addr.com/hybrid_head.htm



http://pmillett.addr.com/images/hybrid_head.JPG

[madmax]

Cool kits! I might try to build the headphone amp at some point.

I ordered one of the Sonic Impact amps to see what it is. Under $30 you can't go too wrong. I'm sure I will be modding it to see what I can get it to do. May need to find some highly efficient speakers too.

madmax

[B3Nut]

Originally posted by mhardy6647
although one can always put batteries in parallel to get some high voltages (kids, don't try this at home!).





Actually, you'd want to put the batteries in series. :) Wiring batteries in parallel increases the current delivery ability. 10 9V batteries in series will give you 90 volts, perfect for old portable tube radio sets that took 90V "B" batteries for their tube plates.

TP

[mhardy6647]

... umm... duh. Whoops.

Brain and hands are disconnected, as usual. Thanks for correcting my gaffe.

[madmax]

I read right over it as well... :)
madmax