- two 9 volt batteries
- a suitable wall wart
- a generic laptop PSU
- a DIY solution
Two nine volt batteries can easily power the B1 for a long time since the current drawn by the B1 is very low. According to Nelson Pass it draws less than 0.02 Amps (that's 20 mA). Batteries provide a clean DC but tend to be empty when you need them most... Furthermore batteries are expensive.
A wall wart is a cheap option. Suitable wall warts usually cost only a few euro's, look in the sale bins at your local electronics shop. Wall warts however can suffer from ripple on the DC since cheap wall warts generally aren't regulated.
A generic laptop PSU is an option but they're not exactly cheap. Besides that they're also overkill, since they must be capable of supplying several amps of current. All those amps cost a lot of money.
So that leaves a DIY solution. This is what I'm gonna do. I've bought a Velleman K1823 kit. It's a regulated power supply that uses a LM317 voltage regulator. With the included trim-pot I can dial-in any supply voltage between 1.5 and 35 volts. Maximum current is 1 Amp, plenty for my application. I'm not gonna use all the parts in the kit though... Why not? Because this is DIY, that's why! The capacitors are Jamicon brand and these will be ditched in favour of Panasonics (1µF and 10µF) and a 2200µF Vishay. The whole PCB is very small and combined with a suitable and small toroid transformer I'll have a nice DIY PSU. And since current draw is so low I might even get away with not using a heatsink for the LM317. The LM317 is supposed to be way better than the 78xx range of regulators. Hopefully this regulated PSU and the RC filter on the B1 itself and a ferrite bead on the supply wiring will result in a clean DC supply for the B1. Other B1 users have succesfully used this kit too BTW.