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DIY Modular Synth Power Supply (sorta)
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page Previous  1, 2, 3 ... 11, 12, 13, 14  Next [all]
Author DIY Modular Synth Power Supply (sorta)
Joe.
megaohm wrote:
Was this a find or can it be bought somewhere specific?


I had "Metal Instrument Enclosure" on my eBay watch list for a while, and picked it up for $50 (with free shipping) on sale. I think they're around 80-90 usually with S&H.

Only annoying thing is stickers won't stick to it. so I can't make a sticker faceplate for it.
PowerShower
I built an MFOS linear and it really turned this old Serge into a smooth sounding machine. Power really does affect the tones. I had always just thought that the VCO's were cheap and the sine wave was always a little rough and unstable. The sequencer was very random but I got used to it. Built the MFOS power supply and connected 6 full sized panels to it. I don't know exactly how many amps its pulling but I have it fused at 1.0 A. I will tell you that you need some monster heat sinks on the regulators. With the little ones I had It would get so hot that the system would peeter out. Also I used a toroidal transformer for the input like the doepfer uses. Oh and dont buy a bunch of parts. go to yardsales and scoop up everything thats junk. I use knobs, power plugs, switches, fuse holders, etc from anything I can get my hands on. Frankensynth that shit!
lvn
I'm completely new to eurorack stuff, but I've been looking into building a cost-effective eurorack and I found this power supply on ebay. Would this be a good starting point to power three bus boards?

http://www.ebay.com/itm/271887905587
dadacore
I bought a brand new Power One Hbb15 1.5 from Mouser, the sensing terminals seem to be already factory connected as they show continuity between outputs and respective terminals and the center ones to GND.
The only issue is that the transformer is humming like hell. Checking the output of my MI Elements on a fft it's showing 50 and 150Hz spikes on at -78dbFs and an higher noise floor than usual.
It's the first time I buy a commercial PSU thinking it would be better than a diy one.Am I the only person with a shitty transformer or it's normal?
Grumskiz
I am also using a PowerOne supply in my modular. In my case it's an HAA-15-3 I think. It's set up to +12V/-12V and delivers up to 3.4A. I don't notice any hum on the signals, but the transformer produces an annoying accoustic hum....I had to mount my spring reverb tank about a meter away from it or it would pick up the sound.

I took care to get a low resistance 0V path by running many wires in parallel between the supply and the bus cards. I am only at about 50-60% of the recommended maximum load and the transformer continues to drone even when nothing is connected, so in my case I don't think load is an issue. I have a feeling it's just the way the transformer is mounted and I tried to tighten the screws that hold it in place, but nothing changed.

Regarding your issue dadacore:
I don't think I am qualified to suggest fixes. But maybe some professionals around here can.
You could try to just power one module though and monitor the output of it and run an fft again and see whether it's better or not.
DJMaytag
dadacore wrote:
I bought a brand new Power One Hbb15 1.5 from Mouser

An HBB-15-1.5 can be configured to output anywhere from 12 to 15 V on the positive side, but -5 to -15 V out on the negative side. Double check to see what the voltage output is. Based on your symptoms, I have to wonder if you don't have one or both voltages set incorrectly. There may be a jumper setting to allow for the -5 V output on the negative side.

Quote:
the sensing terminals seem to be already factory connected as they show continuity between outputs and respective terminals and the center ones to GND.

I believe there should be some continuity, via an internal resistor, based on some previous responses.
DJMaytag
I saw a few things in this thread, which I just discovered, and thought I'd put my 2 cents in. I'm a former electrician, but I was never fully licensed by the state, so take this with a grain of salt. I used to work mostly with 3-phase 277/480Y and 120/208Y systems in commercial & industrial settings, so I know a little bit about high voltage wiring. I am no expert, however, so keep that in mind when reading the following.

numbertalk wrote:
Another question - what gauge wire did you use to connect the AC inlet/mains power to the primary side of the power supply transformer? Would it be ok for me to use stranded hook up 24 AWG wire, for example? Should I use something heavier on this side of the power supply?

I would use either stranded or solid 12 gauge wire designated as "THHN" wire, the kind you’ll find at Home Depot for wiring the electrical in your house and most commercial installations. It should be rated for 600 V, as well. The thicker the wire, the less resistance. Less resistance equals less likelihood of the wire burning up.

That said, 14 gauge should be the absolute minimum you'll want to use for wiring on the mains side. While you're only drawing a few amps on the output side of your PSU, remember that the breaker in your panel is usually going to be a 15 A or a 20 A breaker. In case your electrical system actually delivers that much current to your PSU on the mains side, you'll want to size your wire high enough to accommodate that inrush of current an not fail (i.e. melt the insulation). This is why I would use 12 gauge, which is rated up to 30 A.

If you shop at a place like Home Depot, you should be able to buy it by the foot, which should only set you back a couple bucks. I work part time at a True Value, and we sell 12-14 gauge wire for 25 cents/foot. It’s not terribly expensive. It's only when you buy 500+ ft spools of 10-12 gauge wire that it can get up there in price.

LetterBeacon wrote:
The wire I'm going to use to go from the AC inlet to the power supply is this stuff from Maplin. Its max. current is 6A and its nom. conductor area is 0.75mm2. According to a chart, 0.75mm2 equates to halfway between 18 AWG and 19 AWG - do you think this is thick enough?

I’d recommend 14 gauge as a minimum. I am going to wire my PSU up with 12 gauge if not 10, which I happen to have a ton of around the house from rewiring my house (mostly the kitchen) a couple years ago. If anyone is ever passing thru Madison and happens to need a bit for your DIY project, hit me up. I have a couple 500 foot spools of 12 gauge left over. LOL

bf wrote:
Odd note, but when I wired the studio I did so with the receptacles having the ground up (I know this is contrary the the typical practice). If a power cable was ever partially pulled out and something were to fall and make contact with the plug, I'd rather it hit the ground prong than the hot one. I don't understand why the common practice is the other way around.

It's more common than you might realize. National Electric Code has no opinion on how outlets are installed, so you can feel free to install them however you wish. However, some builders have spec'ed installing a certain way, like when building a new office building, a hotel, etc. The electricians have to follow what's in the spec book, per the designer or customer.

Kopter wrote:
Another pretty noobish question: I'm about to start wiring up my Power-One supply, and I'm wondering which kind of wire to use. I mean, would using 18 gauge be OK for both my mains

No, use 14 gauge as a minimum. 18 will probably work, but should there be a fault in the line, you'll want some overkill by having thicker wire. Go with 12 gauge if you can, and you shouldn’t ever have to worry about the wire heating up/melting.

BBlack wrote:
Can you tell me how necessary 600V wire is? The wire I'm using doesn't have a voltage rating...

EDIT: Nevermind, found some. But one thing - is it the wire that connects to the transformer's terminals that needs to be 600v, or all the wire involved?

It's probably a really good idea to use 600 V wire for the mains wiring, yes, and it's best to use the thickest wire you can use. For the low voltage outputs to your distribution points, you certainly can use the same 600 V wire. You'll have a substantial amount of voltage & ampacity "headroom" in that wire.

ndkent wrote:
Not an expert but can probably help. U.S. voltage should be 110 to 120v.

120 V +/- 10 V (110-130 V) isn't unheard of for a range of voltages you'll see in typical single phase residential wiring. There are differences in 3-phase systems, when looking at 208 V vs 230 V, but those are mostly power issues that will be found in commercial settings, and won't really matter to most users.

NOTE ON GROUNDING: Use as big of a ground wire as you can, which will help reduce resistance to earth. The less resistance you have on the ground, the less likelihood of having noise problems. Graham Hinton can definitely school all of us on this topic, and his advice should definitely be heeded.

Also, it's part of the NEC (National Electric Code) that ground wiring and terminal screws should be colored green, and should have appropriate insulation. I know few will adhere to this, but for insurance purposes (should anything ever blow up), adjusters can and will look for anything they can to deny a claim. Not having your system wired & grounded to code can be quite costly, so splurge for the green wire and green grounding screws in the electrical department.
TripJ
Thanks for your advice, DJ.
I'm just about ready to put my PSU in a case and you bring up some good points.

But a question....

My PSU has a fuse on one side of the AC(110V) after the terminal connections.
Should I put another fuse(an inline) between my AC line and my case switch (my switch is unfused)?

I did not know a green screw for the ground was part of the NEC.
So when my 3 wire 110VAC lead enters my case, I take it that the green line should be bolted (with a green machine screw) to the metal bottom of my case, preferably near the PSU. Correct?

Thanks
DJMaytag
Thanks for creating this thread. I wish this would have been easily accessible from the various 5U/Euro/Frac forums regarding powering your system, but I'm glad I eventually found it.

While I wasn't particularly daunted by the idea of wiring up my own system, I'm feeling a bit better about selecting Power One type supplies for my first system that I'll be starting soon. I was leaning towards getting two "unsigned" supplies (i.e. HC12-3.4-AG), and wiring them together to form a bipolar supply, like this (from the MFOS website):



I'm fairly certain I don't want to do this now, as wiring up two separate supplies sounds like a bit of a nightmare (not to mention adding a 3rd for +5 V power down the road). I think I'll keep an eye on ebay for an HCC15-3-AG type power supply. smile

Anyway, thanks again for all who have contributed to this thread!
DJMaytag
TripJ wrote:
My PSU has a fuse on one side of the AC(110V) after the terminal connections.

Is it "mains wiring --> terminal strip --> fuse --> transformer"? Without seeing how your supply is configured, it's hard to give advice.

Most of the PSU's that have been discussed in this thread DO NOT have any sort of fused protection (at least not that I've seen). Muffwiggler was pretty clear about that in the first post of this thread.

TripJ wrote:
Should I put another fuse(an inline) between my AC line and my case switch (my switch is unfused)?

My understanding is that the best route is to get a fused mains socket, or even a fused socket with an integrated switch (maybe like THIS).

From there, I believe that very short wiring should go to the switch, and then an inline fuse. This way you can flip the switch off an be sure that there's no exposed 110 V connections when you're changing a blown fuse (of course, unplugging the mains is always the safest choice). While it might be redundant to have two fuses, the point of the fuse near the mains socket/switch is to protect the wire from there to the equipment from failing. Any wire downstream from the fuse should be protected from failure, which is why you want it as far upstream as possible.

TripJ wrote:
I did not know a green screw for the ground was part of the NEC.
So when my 3 wire 110VAC lead enters my case, I take it that the green line should be bolted (with a green machine screw) to the metal bottom of my case, preferably near the PSU. Correct?

Close. Where mains wiring and low voltage mix is something I would defer to Graham Hinton on, as he has written some excellent points about this, notably this one:

Quote:
If you have one PSU the correct way of grounding it is to tie the 0V output(s) to Mains Earth. If you have several PSUs it is better to float the outputs, tie all the 0Vs together and connect to Mains Earth at one point only. Mains Earth should still be connected to Chassis Earth on all equipment, but most modular synthesizers do not have a proper distinction between the two.
(LINK)

I'm building a wooden case (as many of us have), so that means having to bring that mains earth lead from your power cord to something like a terminal block/strip. From there, a wire should be attached to your PSU chassis and also to your 0 V distribution point - if I'm understanding Hinton correctly. If everything is connected to this one point, it minimizes the potential for noise on the ground lines.
DJMaytag
$30 for a good looking used HCC15-3-AG on eBay! Step 1 complete towards building my first modular. smile
yoctoflop
Got it all hooked up, yay!


BOOOOO very frustrating

Reading 0v on all outputs. I measures 120v at the input so I'm not sure what it could be. Can feel a faint 60hz vibration. Power transistors are cool.
DJMaytag
TripJ wrote:
I did not know a green screw for the ground was part of the NEC.

I wanted to follow up on this to clarify this rule. The code book is written in a very odd way, and it's easy to get this confused.

If a green screw is used, it can ONLY be used for the purposes of grounding. If you use a normal screw, you could tie the neutral and ground together on that screw. If you use a green screw instead, you could not do that.

Sorry for any confusion or extra work this may have caused.
DJMaytag
So once you get this all set up, does anyone else feel like there's a need for a nice active bus board, or is the power from some of these Power One type supplies clean/regulated well enough to go to a passive distribution board?
DJMaytag
This "sales pitch" from a brochure in particular made me question the need for active boards:

Quote:
When you look at the [insert board name here], it is easy to see the many components mounted on the board; all this circuitry is there to give quality power second to none.


So, throwing a bunch of stuff on a bus board proves that it's good? What about any of the components on an active board make it necessary, minus any circuitry to convert +12 V to +5 V, when compared to a passive board?
NV
DJMaytag wrote:
So once you get this all set up, does anyone else feel like there's a need for a nice active bus board, or is the power from some of these Power One type supplies clean/regulated well enough to go to a passive distribution board?


Assuming you have the correct PSU and have wired/calibrated it correctly, the output of a Power One +/-12V PSU can go directly to a passive board. There should be no need for additional circuitry in between unless you are trying to regulate +5V out of it or set up some LEDs for monitoring the connections.

If you are sending the power to multiple busboards try not to daisy chain the boards and instead use a terminal to distribute the power from a central point to each board. Use as thick of wire gauge as you can for these connections - I'd recommend no thinner than 16AWG personally, but a lot of people use 18AWG.

Quote:
So, throwing a bunch of stuff on a bus board proves that it's good? What about any of the components on an active board make it necessary, minus any circuitry to convert +12 V to +5 V, when compared to a passive board?


The components you see on an active busboard are for handling the output of the transformer into eurorack-friendly power, similar to the components you see on the circuit board beside the transformer in a Power One PSU. An active board is just a passive busboard with a PSU strapped to it and generally with the transformer handled as a wall or line wart. If you already have a Power One wired up an active busboard would only be necessary if you needed the additional power in your system.

If you do throw in an additional active busboard definitely do not attach your Power One to it. You'd be running a PSU into a PSU in that case.
agitprop
Could you expand on how to connect the Sense lines at the point of load? I am wiring up a 5A HDD-15-5-a, and I'm not sure I grasp how to wire both sense wires in this context.

daverj wrote:
You should also connect the appropriate sense lines when doing the adjustment since these can cause the output voltages to be slightly off.

JohnLRice
agitprop wrote:
Could you expand on how to connect the Sense lines at the point of load? I am wiring up a 5A HDD-15-5-a, and I'm not sure I grasp how to wire both sense wires in this context.

daverj wrote:
You should also connect the appropriate sense lines when doing the adjustment since these can cause the output voltages to be slightly off.

Pretty much like the diagram shows and explains.

For modular use most people just connect the posts together with the shortest piece of wire possible. This is because in a modular synth there are multiple "loads" (load = device using the power) so you can't connect the sense lines as intended. You could connect them at your distribution board but, I'm not sure it would really gain you any positive benefit?

Imagine you had an installation where you had a single device that had to be 10 feet away from the power supply like . . .not sure what, a precision motor or super accurate weather monitoring device or?? In that case you'd want to run the sense lines all the way out to the device that is 10 feet away.
DJMaytag

I've got a 5V PSU on order off eBay ($20 for an HB-5-3/OVP) and am interested in doing something like the above image with my PSU's (the HB-5-3 and my HCC-15-3 for +/- 12V).

Could I take out the board from the HB-5-3 and connect it's power connections to the transformer power outputs on the HCC-15-3? I don't see why the beefier transformer from the HCC-15-3 wouldn't be sufficient to use with the HB-5-3? It'd be nice to make a dedicated power box that's separate from my actual IKEA Rast cases, and ditch the extra weight from the HB-5-3's transformer.

Thoughts?
JohnLRice
DJMaytag wrote:
Could I take out the board from the HB-5-3 and connect it's power connections to the transformer power outputs on the HCC-15-3? I don't see why the beefier transformer from the HCC-15-3 wouldn't be sufficient to use with the HB-5-3
No, don't even consider attempting this!

The secondary of the transformer is the wrong voltage and even just asking this question indicates to me you don't understand enough about electronics to safely experiment with power supply modifications. I'm not being rude for the sake of being a dick, it's just that your health, safety, property and the health, safety and property of those around you could be at risk. thumbs up
DJMaytag

The above is an all in one package triple output PSU, a HDCC-105W power supply, which has essentially what I'd like to do. It's got one transformer and two boards connected to it, the +/- 12v output board that's in the HCC-15-3 and (based on the PSU naming) the 5v output board from the HD-5-3.

What if the part number was identical in the above triple output PSU and my dual output HCC-15-3? If it was, there shouldn't be any issue connecting both boards to the appropriate secondary taps, right?

FWIW, when I posted the question about this, I hadn't considered that the secondary taps for one transformer might be stepping the voltage down to closer to the target output voltages for each board (15v for the HCC-15-3 and near 5v for the HB-5-3).

If the HB-5-3 does indeed expect around 5v on its power inputs AND the transformer in the HCC-15-3 does NOT have taps to step down to close to 5v, then I do understand that my idea won't work. This is why I asked the question, to see if there was something I hadn't considered.
JohnLRice
It's typical to use transformers that bring the AC voltage down to just about the desired final DC voltage output so that the regulation circuitry doesn't have to work so hard.

If you look at the two supplies you have, there is one set of 3 contacts for the transformer's secondary output but on the triple output supply you pictured notice there are two sets of three secondary output wires.

You'd be much better off using both of the ones you have as-is at the same time or getting something like a HDCC-150W-AG and selling the other two etc.

Best of luck!
DJMaytag
Ok, thanks for the response. I had assumed from a manufacturing standpoint, that it would make sense to use as many of the same parts as possible, rather than have a different part/design for seemingly identical products. It might be the case that the boards are the same in different supplies, but it doesn't look like the transformers are necessarily the same.

In my HCC15 PSU, the +/- 15v outputs are tapped off the 3 contacts labelled as "B BT B" outputs (the only contacts available) and there are no contacts provided where it's labelled as "A AT A." In images I'm seeing on the HB5, the taps are labelled as "A AT A," the opposite of the HCC15. A triple output PSU like the HDCC150 has all taps available, though they look to be labelled differently.

For now, I don't really have any need for 5v in my system, so it's not a huge deal. I was just trying to avoid buying the HDCC150, as its 5v output is rated for a whopping 12 amps!
abelovesfun
Hello,

Just trying to be safe here.
I have a HAA15-0 Condor Supply that I hope to wire up for +/-15 V in the US.

Per the panel, I jumpered 2 and 4, and 1 and 3.


Now posts 1-5 are all reporting continuity, which alarmed me, but looking at the datasheet, this seems to be correct:


The data sheet says to remove jumpers VW1 and VW2, but I can't find these anywhere on the board. From the other posts in this (great) thread, it appears I'll just have to use the trimmers - is that correct?


I found a power inlet with a fuse holder, but it didn't come with any documentation. I'm assuming I'll wire it up like so, is that correct?

Note, in the above, -S is connected to -Out; -S RTN is connected to COM and +S RTN; and +S and +OUT are connected.

Let me know if there are any corrections to be made to the wiring.

Thanks so much!
JohnLRice
abelovesfun wrote:
Now posts 1-5 are all reporting continuity, which alarmed me, but looking at the datasheet, this seems to be correct
That should be OK. Read up on how transformers work! thumbs up https://en.wikipedia.org/wiki/Transformer

abelovesfun wrote:
The data sheet says to remove jumpers VW1 and VW2, but I can't find these anywhere on the board. From the other posts in this (great) thread, it appears I'll just have to use the trimmers - is that correct?
Not all models and versions have the "cut jumper for +15v" feature. Your data sheet might be out of date or you have an earlier model PSU? If your PSU states on the outside it can provide +-15v you should be fine, just adjust the trimmers.

abelovesfun wrote:
I found a power inlet with a fuse holder, but it didn't come with any documentation. I'm assuming I'll wire it up like so, is that correct?
Looks OK at a glance but it would be best to find some documentation on the inlet. Having the hot and neutral wires reversed could work just fine or cause problems (minor to serious). Note: one change - connect the power inlet ground terminal to the metal PSU chassis (use a crimp eyelet or spade connector with a bolt+nut+washer+lockwasher or similar) and then optionally (depending on the country you live in and what the standard practice is and who you choose to listen to on the subject ;-) connect a separate wire between that chassis ground bolt and the COM post. (also use the COM post for your 0v reference line)

abelovesfun wrote:
Note, in the above, -S is connected to -Out; -S RTN is connected to COM and +S RTN; and +S and +OUT are connected.
Looks fine. The -S and +S are the "Sense" connections and help keep the voltage at the desired value. They are mainly needed for running some voltage sensitive equipment like 10 feet away from the PSU. The Sense lines detect the voltage at the load and adjust to compensate. Pretty much everyone that uses these supplies for modulars just connect the Sense lines at the PCB, like you already have them.

Since this is a power supply thing, get two more confirmations that what I said is correct and if something bad happens, remember I just told you to NOT TRY THIS! hihi
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