[ADD]

Well as some might have read, I got my Move today and although I am quite happy with it, it isn't quite the mind-blowing experience I had anticipated. Nevertheless, it has a lot of very strong qualities and does indeed sound pretty darned good to me. Apart from it's very decent sound, I like the external power jack and I'm looking forward to using the 16-48 capabilities of the DAC once I start building up my collection of lossless 16-48 (and higher resolution) downloads.

Anyway, I've read a lot here about powering the Move - both internally and externally via the DC jack. Having read the manual, the external requirements are a regulated supply of between 6 and 12 volts with a minimum current delivery of 50mA. The manual also goes on to state that (in my words), the more power the merrier, so long as one does not exceed 12 volts.

Well, I wasn't thrilled with my rather cheap 12 volt regulated supply. I was getting about -75 dB of mains hum through the amp - something I of course did not get with batteries. A better 9 volt regulated supply (dedicated to something else) eliminated the very low level hum, but it got me thinking about using some decent battery power externally.

Having gone to Coles and missed out on their crazy 9 volt block battery sale, I was gobsmacked today when I went to Coles and saw they were selling those big fat 6 volt lantern batteries for a mere $3.39 each

That's about $9 off or something! So I bought two thinking....let's connect them in series and stick 12 volts of pure DC power through the Move's DC jack.

I was a little worried, though, that although the amp was getting 12 volts, since the user manual suggests 10 volts as the optimum. So I also purchased some resistors today to test (I needed the 1 watt variety, not the 1/4 watt ones, as going by Jan's power requirements, there is close to 1/2 watt disipated in the power input - say 9 volts at 50 milliamps).

I then inserted a 160 ohm resistor in-line from the two lantern batteries connected in series. This gave me approximately 9.8 volts at load (measured at the amps DC input) from the two new lantern batteries. I should add that I run the amp in high current mode and high gain mode. I'm not sure what values would work optimally in the other modes.

Firstly, I was quite surprised at how the sound of the amp improved when it got more than 9 volts of clean DC power. I tried a lot of different resistor values which changed the voltage at load from between 6 volts and 12 volots.

There did seem to be a sweet spot at around 10 volts, with no real improvements that were obvious to me at higher voltages. The sound presentation did seem to become progressively flaccid as the voltage was reduced below 9 volts. Admittedly, perhaps some of this was the placebo effect.

Nevertheless, a couple of big lantern batteries connected with a suitable dropping resistor seems to me like a nice way to power this amp externally via the CD input jack, since you get perfectly regulated, clean power and can set the voltage at whatever you wish. I don't know how long these batteries will last, but I imagine quite some time compared to the little block 9 volt!

 

[Citizen Kan]

I guess that's ok if you want to use the Move as a home amp., but it would make it decidedly less moveable.

 

[Negatron]

Good thinking, good solid battery current is what a regulated power supply is trying to emulate. One small problem however. By inserting a 160 ohm resistor in series you have just unregulated your voltage effectively having a voltage regulator with a 160 ohm output impedance which is beyond terrible for a regulator. 12 volts by itself won't hurt anything, you are within spec.

Remember when in doubt: MORE POWER! Excuse me I gotta' go, something is smoking on my bench.

 

[ADD]

Hi Negatron,

Thanks a lot for pointing this out.

The LED on the front of the Move seemed to glow (almost worringly) brightly when the two 6 volt batteries were brand new (without the 160 ohm resistor). I sort of took that as a visual warning that maybe I was right on the very limit of things. I've just taken the resistor out now as per your comments above, and now (after 24 hours continuous use), the input voltage is 11 volts. At 11 volts the LED seems to glow about the same as it does with lower voltages. I know the LED doesn't mean anything as such - but it sort of made me stand up and pay attention.

But I'll definitely leave the resistor out then. I can see what you mean now. With the resistor the voltage changes according to load, which is exactly what a regulated supply isn't. I guess (hope) that Jan engineered headroom into the thing so that indeed 12 volts will never do any harm to it (since it does seem to sound better with 10 volts or more to my ears).

Of course there are other batteries to try - I was also thinking of a pack of 8 rechargeable AA batteries - very cheap and easy to recharge, since I think this rediculous price on these 6 volt lantern batteries is a mistake - normally they are normally about $12 each just for the for the standard zinc ones.