Portable PA

Post by jb » Sun Sep 10, 2006 3:45 pm

Anybody ever ran a PA off a battery?

I'm going to be in a parade on saturday, and the goal is to sing songs from the back of a cart. I don't want to use a generator because a) I don't have one and b) they're noisy.

I've looked at some cheap portable PA type things (like from DAK), and I've looked at an inverter to run my guitar amp off a car battery.

Has anybody done this before? Any advice? Fidelity isn't important, it's just got to be loud enough to be heard over a parade crowd, and live long enough to finish the parade route, and cheap enough that I don't feel like I'm wasting a lot of money.

Advice appreciated.

J

Plat · Post by **Plat** » Sun Sep 10, 2006 8:07 pm

The only thing that comes to mind is the Roland Micro Cube. It has a clean "Mic" mode, but that's probably way underpowered for your purposes. I could barely hear it over larger guitar/bass amps when practicing at Bolio's house a year ago.

jack · Post by **jack** » Sun Sep 10, 2006 9:27 pm

or what about the Pignose Hog 20. rechargeable battery operated, has 2 ins so you could run both a guitar and a 1/4 " mic cable into it, and its only about $120.

fluffy · Post by **fluffy** » Sun Sep 10, 2006 10:52 pm

An inverter should be more than capable of powering a decent-sized guitar amp. Just make sure you have enough wattage. Higher-wattage ones cost a lot more though, but I believe they carry some decent ones at CompUSA and maybe at Radio Shack.

Post by jb » Sun Sep 10, 2006 11:04 pm

I guess the variables are going to be how much the inverter + battery will cost vs. the Pignose Hog 20, which appears to be basically the same result as an inverter/battery/guitar amp. My guitar amp (a Fender Princeton 112 65 watter) will be louder than the Pignose, but probably not sound any better.

I'm having a hard time getting the Internet to give me a price on a 12v/car battery. Stupid recalcitrant Internet.

200w inverters are $30 at Target. 400w jumps to $50.

I do have this 85w Acoustasonic, which would sound GREAT. But it's so fucking heavy, I think it would break the thing I'll be riding in.

<a href="http://www.flickr.com/photos/johnorama/122492847/" title="Photo Sharing"><img src="http://static.flickr.com/41/122492847_107fb13ce7_b.jpg" width="1024" height="803" alt="DSC00854.JPG"></a>

fluffy · Post by **fluffy** » Sun Sep 10, 2006 11:37 pm

200W should be way more than enough. As far as how long it'll last, IANAEE<sup>*</sup> but IIRC V*A=W so look at your power consumption (W) and your voltage (V) and the amps of current necessary to drive it for any given time period is wattage/voltage (in this case, 120). Then just divide the number of amp-hours the battery is rated for by the amperage and you'll get the number of hours you can expect it to last (approximately, though the inverter itself also incurs a power drain of its own and it's hard to tell whether an inverter will always drain its peak wattage or if it'll only drain what's necessary since really an inverter is just a really loud 60Hz tone generator).

But anyway, a 200-watt inverter running at peak at 120V will take around 1.7 amps (though just to be safe let's call it an even 2 amps), so to run it for an hour you'll need a battery with a capacity of around 2Ah.

<sup>*</sup> I am not an Electrical Engineer