Replacement PSU Help

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reliableman

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I have a mixer made by Allen & Heath (System 8 1616) that is lacking a power supply and the only info i have on the specs of the original psu for the mixer are:

+/- 15v DC at 1 amp per rail

The original PSU provided phantom power as well, but I'm not too worried about that as I can use other sources for that.
I am looking for a suitable alternative to replacing the original PSU because bascially, they don't exist anymore. I have found some people that have the same mixer and have found a good alternative PSU that works (one guy for $45). Tried to contact them for help, but never got responses. I tried contacting several companies for advice regarding the original PSU, and all they have had to say is "we have nothing like that in stock now" which was pretty much no help at all. I have tried doing research on PSUs, but I haven't found much of it be straight and to the point. Because of my limited knowledge I struggle to find meaning in a lot of things that I have read.
PLEASE HELP! I apologize for my ignorance. If anybody can provide any insight into what my options are that would be great.
Thank you for any alternatives or advice that you can offer.
 
Here is a Good quality PSU Kit ....

http://fivefishstudios.com/index.php/PSU-2448mk2-Kit.html


It will Run you about $75 and you will have to put it together and Find a Box to put it in and it will also supply +48v DC for Phantom ....


if you were electronics oriented and had more time than money you could put one together yourself for Less ......
 
Did A&H really not respond? In the past they have been very good about supplying tech info and schematics :confused:

The FF power supply is good, but might not supply enough current for your board. LM317 is limited to 1.5A, which should be OK, but you have to consider thermal dissipation too, *especially* if you use the FF-supplied transformer. He is designing for higher voltage with relatively low draw. The PSU is trimmable, but the extra voltage from the transformer must be dissipated by the regulators. So a 25-0-25 transformer will need to drop (very roughly) 10V to get down to +/-15V, that's 10W at 1A. I don't think those heatsinks are up to 10W dissipation; they'd need thermal resistance of less than 10C/W (ideally like 4C/W).

Problem #2, phantom. I'm guessing FF uses a voltage doubler on the +25V for phantom; if you select a 15-0-15 transformer to avoid the power dissipation problem, now you need a tripler instead of a doubler.

Problem #3, backlights for all of those VU meters. Probably a separate power rail I would guess, maybe just 12VAC.

All that said, I think you need to start poking around inside the A&H and see where the PSU pins go. The FF schematic is a good starting point, select an appropriate transformer(s) and beef it up for the higher draw, and you might be good to go.
 
Minion: thanks for that recommendation. I actually bought the mixer with building a power supply in mind, so that idea plays well with me. I have taken some classes and I'm excited to learn more about building electronics from scratch. I just haven't gotten there yet...embarrassing to admit.

mshilarious: thanks for the advice. I had this recommended to me as a solution. I know I would still have to work out getting an AC cable wired up w/ a connector and some other stuff, but for $30 including shipping it seems like a great replacement.
Would it be relatively cheap and easy to get somebody (or DIY) to set that up?
 
If you decide to build something, you might go with switching regulators. It takes a few more parts, but they waste less power and thus dissipate much, much less heat.

For the +15V side, there's a 15V version of the LM2576 (LM2576-15) and a -15V version of the LM2990 (LM2990-15).
 
All I can really tell from that is it will put out +/-15V at the required current. But I don't know if it's quiet because I don't know what it was designed for. Being eBay, I also don't know if it works ;) I also don't know what else your mixer needs to run.

Re: switchers, they are great, but if you are not familiar with proper ground design and component selection for them, I wouldn't recommend them for first-timers.
 
hey! have you tried JLMaudio?

google their shop,,,they carry units that will do +-15v and phantom. They also sell transformers and the customer service is great.
 
i'm buying something similar to that Power One unit, and i'm getting a local(houston,tx) tech to put all together for me after i buy all the parts. thanks the help.
 
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