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Atanas

"Soundcraft Signature 12" - 12 volt DC modification

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Hello all

This is my first topic. Today I left my Soundcraft Signature 12 to the local audio engineer to be modified to 12volt DC power.

I plan to run it through my MeON cart power with 12volt DC on 13Amps.

I wrote to Soundcraft and ask them for some schematics about board's power rails. They give me just a simple answer like this one -

Yes, as an analogue mixer with USB functionality, it does indeed require +/-17V (approx), 5V (USB) and 48V (phantom power).

 

regards"

 

So a  week later  I will have some more info and can tell you more about this.

Really hope all this will be safe and wan't have any problems.

The good thing is that the board will have both - 220v AC option *(I'm in Europe, Bulgaria) and also 12v DC option.

This is for now

Best

Atanas

 

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Did you get a price for this mod?  I did a similar mod to a Mackie 1202, and the mod cost as much as the price of the mixer.  However it was very worth it to have the mixer be able to run on DC, as you know--way easier than having have an invertor.   I'll be interested to hear how your mixer works after the mod--my Mackie (modded by Forrest of Trew Audio) was quieter on DC than it was on its internal AC supply.  It's really too bad that Soundcraft wouldn't help you more.  Over the years I've either modded or had modded many analog mixers, and the good companies used to be willing to give or sell you circuit diagrams, parts lists etc..  I've noticed that many companies are not so cooperative anymore, this is a problem for professional use.   

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So now after more than a week I finally understood that the modification won't happen. It's really hard to be made. My guy told me its too hard to make DC to DC convertor +17v and -17v ( 4.5 amps ) form 12 volt power supply.He tried but too much electrical noise is getting to the channels. He offer me a Pure SineWave inverter but it too noisy for me and I don't want to use it. Now he finally told me he can make an special UPS that can run ot 12 volts and also on 220 volts so I can have power for the mixer. The most important thing for me is NO noise at all. He promise won't have any transformation noise or any fans at all. Lets see what he can do and I will share it with you.

I'm really impressed by the quality of the mixer. The pre-amps are really really quiet. 

The bad thing is that my show starts at Friday so I don't have that much time. Hope at the end everything will work fine.

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This is the cart with the mixer. I used the UPS as inverter and it works perfect. Really happy with the sound of this mixer. I used only line inputs and they sounds fantastic. Working with faders really helps me for the scenes with many lav mics. The problem with my MeOn is that is too old and the cells are gone. So I can't use it becouse there are no enough AMPS for this mixer. Maybe if I fixed somehow I can try modify to 12v from the MeOn.

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you can buy some good LiFe battery packs from Aliexpress.com - and plug into the Meon. They are cheap - about 200$ for 40A (may not be 40A as advertised, but hey, it's better than not having ANY battery power from the Meon!)... 

 

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The MeON Its actually working . I can use it for the the Sound Devices, Lectro, Comtek and etc. This way uses like 3.0 Amps from the Meon and its ok. Works fine for at least 1 hour without any AC. Its like 10 years old Meon :) If I plug the mixer's inverter to it then goes like 5-6 Amps and starts producing some mechanical/electrical noise.  Can you please help me and tell me a bit more ? What kind of Nickle Metal hydride batteries I need to buy ? I open the MeOn once and I saw its like a pack of some small batteries parallel connected to each other. I was wondering what kind are those batteries so I can order some similar. Thanks

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The Meon on your cart is probably from 2006.

I'm afraid it is not as simple as replacing the NMH cells. The cells in the battery packs are carefully matched, and the pack includes a DSP that controls the individual charging and discharging of the cells, which is partly responsible for it lasting 10 years. I wonder if half of the pack "went to sleep". This could happen with the early models when left unattended and self discharged below 5V. One side would wake up and charge, but the other side would not. If this is the case, the sleeping side can be woken up, which can restore its capacity somewhat. It is probably possible to replace the individual cells, but this is unknown territory and probably not safe, so I can't recommend it.

To "wake up" a sleeping battery pack, electrically separate the two battery packs by disconnecting the wires going to the terminals. Then remove the battery top and locate the terminals after the controller circuit board. Measure the voltage of the two packs separately. If one of them reads between 5V and 0V, then it is asleep. If so, apply about 14 volts to the sleeping battery terminals (directly to the battery, not the controller). There will initially be very little current drawn, but after a time (hour or so), the current will increase and the charging status will start to work. When the battery gets up to about 12V, put the batteries back together and the system should then charge normally with its internal charger. I've done this several times before. Of course, it's possible that the batteries are both working and just suffering old age, but I bet one of them is asleep, and much of the capacity can be restored.

Just remember that when applying power to the raw battery packs, connect the power supply leads carefully, stand back about 5-meters, wear eye protection and a leather jacket, clear the house, and turn on the switch with a long wooden stick. (half joking)

 

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