Hi,

I am trying to find a solution that will enable me to power my synth module from rechargeable batteries. I could do with some help please, if any one would be as so kind to do so.

Whilst I play with circuit bending on synths, and more than capable with soldering, etc, I am not electrically qualified and I am worried about damaging the £600 synth module.

It is a DSI Tetra. Rating 13-15VDC 450 mA.

I need to power it from a rechargeable source that is small as possible and readily available. I have thinking about either a laptop battery, or preferably domestic batteries.

Would it be best to wire in series, 2 x 9v batteries and some kind of voltage inverter (a resistor inbetween the batteries and the connection onto the PCB maybe?) or 12 x AA batteries? -Which would give the longest life out of the two options?

-I suppose the 9v option would be smaller and I could link further cells in parallel in order to get battery life? -

Also I am a bit confused with the mA, is it as simple as putting the correct resistor inline somewhere along the chain?

Any ideas, drawings, web links - if I can buy a solution off the shelf, would be very gratefully received. I know it probably pretty basic to you guys, but my knowledge of synthesis far outweighs my basic electronics understanding. I cant afford to blow this thing up! You can email me if you wish.

Thanks,

Andy

 

9v "PP3" type rechargeable batteries would be dead within minutes.

If you used a 12v 8AH SLA (sealed lead-acid) or VRLA (valve-regulated lead acid) battery with an efficient DC-DC boost converter, you might get about 6 hours' use until the battery was 50% discharged, and you'd have to charge it up again. This would probably be one of your least expensive routes, but the battery would be somewhat heavy at around 2.2kg/4.4lbs

You might use a Li-Po battery pack with a DC-DC boost converter; these batteries are much lighter in weight, but have an annoying habit of catching on fire occasionally - and they are considerably more expensive than VRLA/SLA batteries.

You didn't put your general location in your profile (like country and state or province) so it's pretty difficult to suggest an off-the-shelf solution, as availability varies greatly around the globe.

 

It is a DSI Tetra. Rating 13-15VDC 450 mA.

Also I am a bit confused with the mA, is it as simple as putting the correct resistor inline somewhere along the chain?

No, that wouldn't be a good move. Using a resistor to control voltage works only for a constant load, like a light bulb, and even for that it wastes power. Your device probably has a varying need for current (maybe even much less than the quoted requirement, which would help battery life a LOT), and therefore the voltage would vary all over depending what the load at the moment was. Not good.

A string of 10-12 AAs in series MIGHT work, but if your thing truly needs 450mA, the AAs won't last real long. And having that many in series makes bad connections and bad cells an increasing problem. Putting 2 banks in parallel, of 10 in series each, would work in principle but again, I think it would become prohibitively kludgy. Something like a motorcycle battery would look better.

 

See this is why i'm here, I'd probably jumped in with the 9V solution, and then watched it die as soon as I play with it for 10 mins.

OK thanks for your inputs. I am in the UK, but I plan to take this to USA, hence the need for a commonly found source.

With regard to the motorcycle battery, this is far to big and heavy. It has to fit inside a small place.

Any other help appreciated.

 

Hello,

Is this the one you are talking about?
http://www.davesmithinstruments.com/products/tetra/

On the front it says 13-15 VDC @ 450 mA.
See also the attached manual.

Bertus

 

Yep Thats the correct synth