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Re: Batteries vs. Mains Power Supplies

* Batteries are excellent power supplies for ss source components - viz. the Ron Sutherland "PHD" battery powered Phono Stage. Batteries will provide low noise (no noise??) voltage rails which are hard to obtain using a mains power supply.

Batteries aren't exactly noise free. They do have some amount of electrochemicla noise. However they don't have the ripple voltages which plague unregulated AC supplies.

* However, it is impractical to use them for tubed source components??

That would depend on what one considers impractical. Tubes were originally powered by batteries (hence the "B+" designation). Just have to string enough cells together.

Also, some tubes can work well at much lower voltages than usual, down to around 24 volts or so.

* Incidentally, if you have a mains charger connected to the battery then this must be switched off when using the source component, otherwise noise will get through to the power rails and the "benefit" of using batteries is lost.

Yeah, kind of pointless to use batteries only to have what amounts to an AC power supply tied across them. :)

* However, batteries are no good for power amps because they do not "keep up with" the power demands imposed by the amplifier. IE. a mains power supply, with its considerable amount of microFarads, can better deliver the fast current pulses which a power amp requires.

How "fast" they are depends on their internal impedance. I've heard tell that batteries can have rather high impedances at high frequencies but I've yet to see any solid evidence of it.

Besides, there's nothing preventing the use of the same reservoir capacitors you'd use with an AC supply.

That said...

:)

se






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