I've continued my experiments with power supplies for the volt+.
I have used the following.
1. 12 volt lithium ion battery extender (Anker Pro 2)
2. 12 volt laptop power supply 5 amp.
3. 19 volt laptop power supply 2.5 amp Lenovo
4. 19 Volt laptop power supply 4.9 amp Asus
5. 13.6 (12 volt listed) linear regulated power supply Astron 12BB. `12 AMP peak, but probably more like 7 continuous (found it on Craigslist and wound up with 3 of them if anyone wants to buy one)
6. 24 volt 12 amp linear regulated power supply Power One. (also Craigslist but more expensive $50)
first, the 19 volt 4.9 amp supply from Asus sounds very good to my ear. I found mine on E-bay for $6 shipped. It's clearly the best value and the least obtrusive.
The 12 volt laptop supply works fine, but it's not as dynamic. The 19 volt Lenovo supply with lower amperage was also fine, but maybe wasn't quite as full sounding.
the battery has this very beguiling creamy sound. There's lots of bass. fwiw, it actually seems louder than the 19 volt laptop supplies. It's fun, but it's like there's sort of a soft curtain around the music, maybe because the
highs seemed to roll off a little. Obviously, it has the advantage of being very portable.
I would disagree with the one reviewer here who said that a laptop supply sounds better than the Astron on the Volt +. With the Astron, there's more detail, the bass is much more solid, etc. especially at higher volumes.
You do have to turn the volume up a ways though.
For me, the winner was the power one, but it's not an immediately noticeable difference. It's cleaner and quieter at low volume. I can pick up touch on instruments a bit better, especially percussion. I especially noticed that harmony between voices and instruments is better defined. Interestingly, there's really very little difference volume wise between 24 volts and 19. It may be that I listen in a 12X12 foot room. In fact, there's not much difference between 12, 19, and 24. Actually, that makes sense, since if you double power, you only get a 3 db increase in volume. What I do get is a greater sense of control. A Ford Focus and a Mercedes can both go 90 miles an hour, but that speed feels very different inside each vehicle (stopping, handling, changing gears, etc.) I did find that I had to adjust the voltage dropout on the Volt+'s capacitance multiplier for the Power One.
Here's the downside. The Power One is huge, probably double the length of the Astron. It's not in a box; it's just a heavy duty rack mount frame with a very large transformer and a circuit board that's easily 4 times the size of the volt+ board. They originally retailed for close to $300 while the Astrons are around $120. There's a law of diminishing returns with this stuff. I do prefer it to the other power supplies I've tried, but I'd say the 19 volt laptop power is more than satisfactory.
