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Adapting Equipment for 12 volt Dc Usage


stitch

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I am part of a small arts & recycling company not-for-profit-ect.

We use solar panels & batteries for power.

All workshops/events use recycled materials where poss.

 

We are keen to explore the possibility of adapting our dj rig to run 12 volt DC.

We have technical support from amongst our friends & supporters to sort out everything except the cd players & dj mixer unit.

 

Any advice on makes & models that could be adapted to run 12 volt dc would be gratefully received.

 

At the moment we are using Pioneer CDJ 100s(Pioneer appear very coy about stating directly that running them on 12 v is possible-they won't say no its not possible, but won't dismiss the notion that if we by-passed the step-down transformer that the motor could run happily) & DJM 300 Mixer.

 

Why bother with 12 volt? Because its there! Pure sine wave inerters are expensive, H&S rather like 12 volt outdoors (most of our events are under canvas), a 12 volt rig would open some doors for us.

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I would also be interested in that, I was laughing loudly when a 6th form band was playing at the leavers party, and they were running cabs inside (filling) cars like a clio etc. and running an inverter to power them O.o quite a good idea, until I had to get out the jump leads from my dads car. I would love to find a way to do this, rather than using an inverter, even if I bunged a few more batteries in or the like
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Seems a bit crazy to take a perfectly good piece of kit and bodge it to work on 12V when you can buy a 300W inverter for less than £40? I suppose the idea is feasible if the psu is a simple transformer/bridge circuit. If so I'd guess a couple of regulators would give you the 5V rail you need (guess) and whatever rail voltage they use for the other circuitry like motors etc.

 

I was a bit unclear on the purpose - the djs run off 12V and then what? Loads of 12V car amps that each drive a cab?

 

Assuming that you can do this - what do you charge the batteries from? (please don't say the mains!)

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There are several mixers that run at 12 volts:

 

I think I have a couple at work, and :( found these very quickly:

12 Volt mixer

And another

 

With the CD player, you need to find out if the transformer in the unit steps down to 12 volts or if it is some other voltage or even several voltages.

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I'd still say that inverters are the best route simply most of the products you will be using are mains based anyway, and it makes life a lot simpler if power comes from one source.

 

Also if a fault develops in any piece of equipment, it can replaced easily when running at 240v

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Stitch,

 

I can see your reasoning, but I can also see many arguments for not using 12V....

 

1) Inverters are inefficient and many produce a poor quality sine wave.

 

2) Running devcies at 12V limits the output voltage swing, so headroom and power output can be limited. Attempts to bridge or try other fancy tricks to improve output are either an additional expense or can degrade quality.

 

3) Adapting devices to run on 12V carries the usual caveat of forfeited warranties, non compliance etc.

 

I'm not saying "don't do it" per se, just querying whether the benefits are really that tangible?

 

Simon

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If you find a mixer that runs on 12V make sure that it is 12V DC and not AC. Using a 12V AC supply is very attractive for audio equipment designers as it makes it easy to obtain reasonable internal +/- voltage levels. I noticed that the Maplin mixer that Mark mentioned requires AC and possibly wouldn't work on DC.

 

Using multiples of 12volts is also attractive as higher voltages often allow you to run at lower currents which translates to thinner, less expensive cables. For legal purposes I believe that anything up to 60V is considered low voltage although don't quote me on that.

 

Cheers

 

James.

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For legal purposes I believe that anything up to 60V is considered low voltage although don't quote me on that.

BS7671, the wiring 'regs', call anything up to 120 volts dc between conductors extra-low voltage.

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Many thanks for all the reponses.

We had intended to use car amp/speakers. Two cabs with mid/tweeters (stereo) one sub (mono)

We currently use 110 amp hour leisure batteries (via an inverter) topped up with solar panels.

The desire for 12 volt relates to the following:

The cost of pure sine wave inverters. (Although a negative earth reduces hum & crackle to negligable proportionson the current set up.)

12 volt rig would allow us to get by some health & safety concerns-it would also open the door to a number of events for whom the 12 volt idea is appealing. We have now been offered a dj mixer that functions on 12 volt DC-waiting to see what its like-no details as yet. Had been impressed by the sound quality, battery efficency(three wheel chair batteries ran the rig for upwards of six hours over 3 days), & volume of two 12 volt rigs I saw out & about in the summer-but unfortunately lost the details I was offered on both occassions-####!! One was using an all-in-one mixer/cd players unit the make & model of which was.......no it gawn. Will post as things develop-all ongoing advice gratefully received.

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You dont need to invert to mains sine wave, you can invert to anything you like. A pair of 60V rails would make for a decent power amp.

A pair of 60v rails could also be acheived very easily with 10 batteries.

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A pair of 60v rails could also be acheived very easily with 10 batteries.

Indeedy. The thing that was in my mind was that solar electric systems tend to be 12V, 24V or 48V, as size goes up. The numbers are really dictated by the off-grid market, these are the supply voltages that the inverters for that marketplace (eg Trace) operate off.

 

Also I seem to recall that the old (ok, ancient) Seck mixers have in their handbook how to run it off car batteries, and the same PSU was used by the Spirit Live amongst others, so clearly running mixers of big batteries is an intended possibility.

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