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

Discussion in 'Tech Talk - Electronic Repair Modifications DIY' started by bass_and_art, Apr 4, 2013.

  1. bass_and_art

    bass_and_art Member

    Apr 4, 2013
    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:

    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

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

    Kurt Foster Distinguished Member

    Jul 2, 2002
    77 Sunset Lane.
    did you try a search of Google? it took me less than 1 minute to find THIS.


    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.

  4. Boswell

    Boswell Moderator Distinguished Member

    Apr 19, 2006
    Home Page:
    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.

  6. Kurt Foster

    Kurt Foster Distinguished Member

    Jul 2, 2002
    77 Sunset Lane.
    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!
  7. redcondurango

    redcondurango Active Member

    Jun 7, 2019
    Alesis multimix 8 usb FX psu.jpg
    Better late than never. There are still plenty of these kicking around and they offer some nice bang for your buck. Should you find one without its power supply unit never fear - here is the solution. The ebay reference for the three pin adapter was - 1Set M16 2/3/5/6/8Pins Screw Type Electrical Aviation Plug Socket Connector 400V. It will more likely than not come from the far east. Choose the 3 pin - obviously. See the image below for how to wire it up. There is a jumper between the two live positions, which is where the cable with the grey stripe is soldered. See the grey jumper . One position powers the phantom and the other the unit o coz there's only one power line you need to jump it round to the x 2 position for phantom power to microphones. Phantom on/off is on the front of the unit. The wall wart is also available on ebay - ALTO PRO ZMX52 MIXER 18V AC POWER ADAPTOR/SUPPLY/TRANSFORMER (KC AC-1800500) from poweradaptorsuk. Just search up the specs. I cut the end off the wall wart and soldered it up as per the image. It works fine. Watch out for surges to your speakers when switching on and off. Fortunately my monitors have a power up delay feature. Not sure if that surge is anything to do with the mod or the unit, which isn't earthed, seeing as there are only two wires. Go figure? The unit works though which is better than the dead unit which arrived on ebay minus its original psu which are nowhere available. Don't let anyone tell you this takes power via USB. Its old school 18V x 2 not 5V DC. Alesis multimix 8 usb FX psu.jpg

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