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In need of a Power Supply for a Alesis Multimix 8 USB (18V) (Will pay)

Discussion in 'Recording' started by bass_and_art, Apr 4, 2013.

  1. bass_and_art

    bass_and_art Member

    I was just given the Alesis Multimix 8 USB but my friend had accidentally thrown out the power supply with some other old electronics. As it would turn out, this is very hard to find. There are no after-market power supplies made, as far as I can tell. The specs are 18V 500 mA and here is a picture of what I need:
    Snapshot_20130404.jpg

    If anyone out there has this kind of power supply I will gladly pay what I can. I don't have a lot of money, but just let me know what sounds good to you. or if you know where I can get one that will work I would greatly appreciate being pointed in the right direction.

    quickest way to get a response for anyone who has one they can sell is to e-mail me at thomaspatton2010@yahoo.com

    Thank you for anyone who can help.
     
  2. Kurt Foster

    Kurt Foster Distinguished Member

    did you try a search of Google? it took me less than 1 minute to find THIS.


    yhst-15436568105612_2256_4254169.gif

    POWER ADAPTER, 18*2VAC @ 1000mA, 110V
    Regular price: $45.00
    Sale price: $45.00
     
  3. McMurphy

    McMurphy Guest

    Well there you go... exactly what you need.

    On the other hand, it's no big deal to make your own power supply. All you need is a 110-24 V transformer, rated for 1.5/2 amps. In-line fuse and power switch. A bridge rectifier. A couple of large filter capacitors and an National Semiconductor, Texas Instrument, etc., 18 V regulator rated at least at 1 amp or more. And then you have a power supply costing about $25. You build it into an aluminum project box. Everything available at RadioShack.

    Frequently it's hard to find specialized connectors for these power supplies to your mixer. Sometimes it requires a modification to a 4 or 5 pin, XLR connector which are much easier to find in comparison to some of those bizarre Taiwanese connectors. 4 pin XLR's were regularly used for 12 V power supply connectors for video cameras. Pin 1, is ground and Pin 4, was 12 V of positive DC. 2 & 3 were not utilized. Sometimes you find these on other mixers with ground, +48, +15, -15.

    The only thing you have to find out is whether it required 18 V of DC or 18 V of AC? One will be the lucky and the other will take it out forever LOL. And I'm wondering how they obtained +48 for the Phantom power? So they are likely using a DC to DC up converter? So I really question that rating of 18 V? Maybe you should pick up a manual that includes a schematic? They can be helpful.

    McMurphy
     
  4. Boswell

    Boswell Moderator Distinguished Member

    The Multimix 8 USB only needs a.c. power (at 18.5V 700mA), as the rectifiers, regulators and smoothing capacitors are built into the unit.

    If you design your mixer to take low-voltage a.c. power rather than d.c., it's easy to use voltage-multiplying techniques to get the 48V phantom power rail. The required current is only a few mA.

    The mixer unit would probably work on 18V d.c. input, but there would be no phantom power.

    PS I would snap up that power unit from Instrumental Parts while it's still in the sale and before it goes back to its normal price.
     
  5. McMurphy

    McMurphy Guest

    Yeah Boswell, I checked the specs on that mixer power supply.

    So it only requires a simple power transformer to convert 110 V AC to 18 V AC and you'll be up and running. No worry about polarity of the 18 V supply side because it's AC.

    Assuming that the power supply has plenty of current to deliver, the internal power supply circuitry may also include DC to DC up-converters to create 48 V DC, low current, for the Phantom power needed for condenser microphones. These DC to DC up-converters have come into play and become quite popular in recent years more so than in the past. It's now all on a microscopic chip. I would be surprised if that mixer does not offer Phantom power. Even if it only works off of an 18 V supply.

    Of course it's always desirable to have the company supplied unit. Thankfully, this kind of simple AC supply, only requires a simple transformer and the connectors you need. These transformers are available from companies like Newark Electronics, Digi-Key and others. This is a typical off-the-shelf readily available power supply transformer. You're going to pay a heftier fee for the factory supply. You don't need to. This is as simple as screwing in a lightbulb. No kidding.

    McMurphy
     
  6. Kurt Foster

    Kurt Foster Distinguished Member

    your correct if you are all set up with a workbench and tools but not everyone is.

    ok so i get in the car drive 10 miles round trip to the radio shack (cause it's 5 miles up the road and 5 miles back)... i dick around finding a parking spot, buy the parts and ohh don't forget a soldering pencil, flux and solder because i don't have that stuff already ...

    then i go home and i go to put the parts together but i have to drill holes in the box so i get back in the car and i drive 10 miles round trip to home depot (cause it's 5 miles up the road and 5 miles back) and buy a drill and bits ..get back home and spend 2 or 3 hours putting it all together then i have to mickey mouse the connector on the mixer ... oops another drill bit ... back to home depot (another 10 miles) ... finally i get it all done and it works (maybe) or it fries the mixer (perhaps, because i really don't know what f i'm doing) but if it works it still looks like crud and is kludgy ... yeha i saved what? 20 bucks ... ohh but i drove 30 miles, spent 10 bucks on gas and and 25 bucks on parts and it took me 10 hours ....but wow i saved 10 dollars! ohhh i forgot ... the drill and bits cost me another 40 bucks and the soldering supplies were another $20... duh

    i know you mean well but sometimes you diy guys crack me up. for me, to not have to go through all that 45 bucks is cheap .. like the man said it's on sale .. get one while it's still 45 bucks the price is going to go up to 45 bucks soon!
     

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