Author Topic: Building power supply for audio mixer  (Read 963 times)

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Offline FrankentronicsTopic starter

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Building power supply for audio mixer
« on: February 12, 2020, 02:19:33 am »
Greetings,

I bought a used Alesis Multimix8 audio mixer without a power supply.

There is a 3 pin (I guess DIN) connector in the back with the following specs labeled next to it.

18VAC x 2
320mA x 2

The replacement power supply is about $50 and it says that there is a torodial transformer inside. I think the original "power supply" is in fact just a transformer (the PCB with rectifiers and voltage regulators is in fact inside the mixer).

Will the following transformer do the job, or will it overheat?

https://www.alliedelec.com/product/rs-pro/6719081/70647091/

But I'm guessing the following would be a better choice, right?

https://www.alliedelec.com/product/rs-pro/6719126/70647102/

Or can someone recommend an entirely different one?

Thank you, all, in advance.
"If you obey all the rules you miss all the fun."
- Katharine Hepburn
 

Offline MarkF

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Re: Building power supply for audio mixer
« Reply #1 on: February 12, 2020, 02:33:04 am »
Either one would be okay.  Even the small one is twice your requirement.
  The small one is 0.8A per secondary
  The large one is 2.0A per secondary
 
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Offline FrankentronicsTopic starter

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Re: Building power supply for audio mixer
« Reply #2 on: February 12, 2020, 03:08:00 am »
Oh, I see...

Thank you very much.
"If you obey all the rules you miss all the fun."
- Katharine Hepburn
 

Offline Jwillis

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Re: Building power supply for audio mixer
« Reply #3 on: February 12, 2020, 04:46:39 am »
Oh, I see...

Thank you very much.

Another place you could look at is https://www.antekinc.com/transformers/
They have really well built products as well.
 
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Offline FrankentronicsTopic starter

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Re: Building power supply for audio mixer
« Reply #4 on: February 14, 2020, 03:39:27 am »
I rigged up a salvaged transformer and it seems to work.

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The salvaged transformer is not toroidal. Is there any reason why it should be toroidal?

Also, the salvaged transformer is rated at 17V - 0 - 17V. But I actually get 19V - 0 - 19V at full load.

Thanks...
"If you obey all the rules you miss all the fun."
- Katharine Hepburn
 

Offline Jwillis

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Re: Building power supply for audio mixer
« Reply #5 on: February 14, 2020, 04:46:08 am »

The salvaged transformer is not toroidal. Is there any reason why it should be toroidal?

Thanks...

Not really . Toroidal are more efficient but you be fine with E core transformers. Your measurements are about right . The transformer is rated for 110V AC but your house Mains is 120V so the secondary will be about 19V . No worries about the extra voltage on the primary.
« Last Edit: February 14, 2020, 04:50:41 am by Jwillis »
 


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