2 Single Output Bench Power Supplies vs One Dual Output Supply

Just getting into DIY module building and am trying to save a few bucks. I’m located in the US and would like to get a bench supply for my shop for testing my modules and gizmos. I realize there are some cheap alternatives for using a case supply for KOSMO/Eurorack for testing, but would like a generalized bench supply for other electronic work outside of synth building too. When my builds are case ready, I’ll setup a case supply for them then.

Since I have to supply both +12v and -12v is it better to use a single dual-output supply, or can I get away with 2 single output supplies to do the job? Besides the pain of having 2 boxes, are there any electrical drawbacks that could bite me down the road? I realize it’s a noob/dummy question, but would rather be safe than sorry.

Dual and triple output supplies I’m finding on the web are expensive. I can buy 2 decent, budget DC supplies for cheaper than one dual. I just don’t want to shoot myself in the foot buying 2 supplies and it not give me what I need for synth and guitar effect building…

Either is fine as long as you wire them up right. That said, a MeanWell RT65B should run you about $35 and is a simple solution.

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Provided you only need ±12 V and +5 V, and no adjustable current limit.


Thank you for the replies guys. I sincerely appreciate it. So it sounds like I can pull off 2 independent bench supplies. For about $120 I can get 2 economy supplies vs. $200++ for a single dual output. It would be nice for a single box, but I can live with a little extra bench space eaten up by a second box…leaves more money for other parts and goodies for builds.

I’m going to have a look at the MeanWell RT65B you mention also. I do like the sound of $35 :grinning:


Some rip-tie or hotglue (or, oh my dear, duct-tape…) will make a single box out of two :stuck_out_tongue:


I would advise you to use 2 adjustable power supplies with current limiting. Especially if you are new to electronics and are a mere human, you are likely to make mistakes which when powered with full voltages will cause things to blow up. However, if you have adjustable supplies this offers you the possibility to turn up the voltage from 0 to the target value while keeping an eye on the current drawn. If there is an immediate short or one at a low voltage or the current drawn is higher than expected you will be able to spot that before blowing up parts of the circuit. This can prevent a lot of frustration. I have 2 of this type: MCH-K305D. You can get them cheap at aliexpress and similar sellers. But there are others. A regulated power supply is a thing you buy for life, so it does not hurt that much if it costs a bit of money.

B.t.w. do not focus too much on +12 and -12 Volts. There are a lot of 9 Volt circuits around (especially effect pedals) that can be interesting additions to your musical instruments.


:rofl: Sounds about right to me

That’s kind of what I was thinking myself. Seems I can get 2 lower cost single output adjustable bench supplies for a little less than one dual or triple. I did see one triple with good reviews on Amazon for about $200 though. It will hurt a little to spend that but you make a solid point about future use. Whatever I buy I want to be flexible for development. It will be used for my synth and effect adventures plus other electronics projects too. Happened to do some quick math and it seemed like 2 single outputs would save a little scratch up front.

When I’m ready to case up I’m going to get a purpose specific supply at that time.

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As mentioned elsewhere I bought myself a triple bench supply recently.

It’s a Chinese made unit with two variable supplies up to 30 V, 3 A and a fixed 5 V supply. The two variable supplies can be used independently, in series, or in parallel. Obviously this is way beyond what you need for testing synth modules, which is all I’ve used it for so far.

I’ve seen this (HY3003F-3 under various brand names) listed for $170 to $200 new. I bought mine used from ValueTronics International (located in Elgin, IL, USA) for $60, plus $20 shipping to my US address. It was shipped quickly and well (in a box full of packing peanuts, though, which I hate having to deal with).

It has some scuffing on one side but otherwise looks pretty much like new. So far as I have been able to tell it works perfectly. The variable supplies can be set up for fixed voltage or current. The + and - outputs float, so either can be tied to ground — one of each to make a ±12 V (or ± whatever up to 30 V) supply.

The displays are bright and easy to read. Red for current and green for voltage helps readability, at least if you’re not colorblind. Resolution is limited to 100 mV and 10 mA, but that’s good enough for my immediate needs. (Certainly the current readout is good enough to distinguish “ok looks good so far” from “oh shit turn it off!!”)

I haven’t checked the accuracy of the current displays but my multimeter says the voltage displays are dead on.

I’m happy with my purchase and would definitely recommend looking into getting one from ValueTronics if it’s the sort of thing you’re feeling the need for.