I had an idea to look at the little mains AC to 12v AC bricks they use for older LED lighting to see if I could replace the massive power bricks I currently use. They have a large power output but may be useless. Any thoughts anyone?
If itâs smaller than your regular 12 V brick odds are regulation isnât that great, and make sure itâs not a constant current supply before you plug it into something valuable. You really donât want your synth supply to go âI will now ramp up the output voltage until you use 300 mAââŠ
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At $2 I might have a play around and see whatâs what. (Almost said $2 a pop!)
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When it comes to power, personally I think going cheap is a bad idea. Anything that spares me from mains power is going to be of good build quality, and anything that conditions that output, like the power supply I linked to, can be negotiable. That one I linked to wasnât terribly pricy btw, if you are looking to go cheap. After everything, itâs around 42 buckazoids.
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Cheap is not my main driver (though itâs always nice). Itâs simply that these big bricks that produce 12v AC have become the norm for DIY and Iâm always looking for alternatives to defacto standard. Modern kit is produced all the time and I spotted these small units and thought a re-appliction might be possible or worth investigating. Noise, ripple, current and voltage requirements are clearly defined rules in the game we play. I just wonder if an alternative; lighter, smarter power supply is possible.
My gear is safe from everything but my curiosity and imagination 
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Hi there!
(total noob here)
Iâm planning to start to build some DIY modules. I found a crappy broken CD dj player around home and I savaged from it the power supply among other components to reuse. I found that the power supply has +12v, -12v and 5v outs. Anybody knows if it would work for powering standard modules? Would be awesome. Also, in case it works, what is the different in use between AGND and BGND as labeled in the circuit?
I attach pictures of it for reference. Thanks in advance!
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AGND usually means analog ground (which makes sense here, since thatâs shown near the ±12 V outputs). Not sure about the P in PGND but I assume itâs for the digital parts (processor? player?).
Since you donât really need +5 V for most modules, you can just stick to the ±12 V and AGND bits, and ignore the +5 V rail and PGND.
Otherwise you can probably connect AGND to PGND to make sure 0 V is the same thing everywhere, but you may want to take a closer look at the circuit before doing that to make sure theyâre both floating.
(Another issue here is that unless you can find a service manual, or some markings somewhere, you donât know how much power you can draw from this supply. CD players donât use a lot of power, but hopefully the supply will just drop the voltage or even shut off if you overload it.)
Also make sure to use a proper enclosure for the mains side of things.
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I recommend purpose built power supplies.
See link below for a good diy build.
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Thanks a lot for your answers @Caustic and @fredrik!
Will experiment with the savaged one first as Iâm in a country with hard lockdown protocol by now and I like the recycling idea.
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Even if it doesnât have the power to drive a whole synth it might make a good bench supply.
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Just about to start building some modules but I want to get my power supply done first
I was wondering if this tutorial would would work?
Iâm having a bit of trouble finding a good AC / AC Adaptor to work with the Frequencies Central Power bus (which seems to be the standard), so I thought this might be a good alternative
I wouldnât recommend that one; it relies on cheap PCBs with unknown schematics sourced from random Chinese sellers to work also if you connect them in a way they werenât designed for (see the warning section on that page).
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Where are you located? Wall warts for the FC board are generally not that hard to find. Someone may be able to point you to a vendor.
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Sydney Australia
I think Jaycar near me has some 1A 12Vac adaptors but i donât know how much i trust them
Also found a 240v to 12V transformer from an old lamp
The thing that made it difficult for me to locate a seller of 12V AC out âwall wartâ adapters is that I couldnât find a search term that wouldnât force to wade through dozens of the far more common DC out version. I finally found a company called Power Adapters UK which sold me a 2000ma version on Amazon.
I`m going to make power in rack using 2x12V 2.4A adapters and transistor for 5V line. I have question about CV and Gate lines - do I have to mount any capacitors between sockets or there should be just connections between them, creating full line for each of the CV and Gate?
I planned to use 10-15 for each of the 120HP lines, I have 2 of them. In terms of power lines do you recommend any capacitors also or I just should make lines of 16 pins sockets solid connected to the back panel of my rack?
If youâre talking about CV/Gate in the Eurorack connector, theyâre not really used by anyone (there are a few early Doepfer modules that can be configured to use those signals via jumpers, but why would you build a synth with exactly one CV and one gate signal?).
See âMeaning and usage of the bus signal CV and Gateâ here for a bit more: http://www.doepfer.de/a100_man/a100t_e.htm
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Yeah, I plan to use only DIY, so now I do not see the idea of using 16 pin stripe board, if you will carry only 4 pins at maximum (+/- 12v, +5v and ground). I bought already male and female sockets for 10 and 16 pins, so could make cables, but as I tried it is not so easy and does not seems to be such reliable as soldered connections.
As always, learn on my own mistakes : )
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