DIY Modular Synth Power Supply (sorta)

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Rex Coil 7
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Post by Rex Coil 7 » Tue Nov 14, 2017 2:28 am

fuzzbass wrote:Something like this, pictured on page one of this thread:

https://www.mouser.com/ProductDetail/Mo ... qfA%2fE%3d
We're just not communicating here.

How am I supposed to push a spade connector on to a solder post? That seems like nonsense. One can also use nothing but pliers to remove fasteners, but that doesn't make it the optimal way of doing things. Nor is turning your underwear inside out when it becomes soiled.

I've seen the picture you mentioned, it's not how I wish to do things.

I got lucky, located a picture that better explains my question (and really pretty much answers it as well).

Look here.....
miminashi wrote:Image
I don't know how else to explain this to you. You're just totally missing my question.

But thanks anyhow, I honestly appreciate your well intended responses.
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Post by keninverse » Tue Nov 14, 2017 9:18 am

Wrap and solder around the post...that's how it's designed. And don't use the center hole. It'll be harder to extract solder later if there are problems. Strip the wire so you have enough for a good mechanical connection around the post for at least 1.5 full turns around the post. You may want to preheat the post so it's just melting solder before you strip and place the wire. 60watt iron should be fine but you may need to push the temp up a little. Work fast if you're using off the shelf pvc wire or consider ptfe.

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Post by omorange » Sun Feb 04, 2018 4:44 pm

hey guys, new around here but not new to DIY electronics. I'm moving over to a linear supply because my 'beefy' switching supply is having trouble with all the digital modules I've been making.

I just snagged a tested Power One HDCC-150W-A (unsure of age, boards look clean and are black) that I'm hoping to stuff into an 50cal ammo can for an external PSU. I know the frame wont fit so I'm planning on, at the very least, cutting the backing frame/heat sink into pieces (if not removing it completely and relocating the mosfet/transistors to a separate heat sink). I was planning on going the dual OVP route to protect both +/-12 rails independently. I have a 80mm computer fan that I'm planning on cooling the case with as well as some cheap ammeter/voltmeters for monitoring the 3 rails that I'll stick into a removable cover just inside the lid with maybe a couple USB jacks just in case I have a few devices looking for power if I'm playing out. I'm mostly worried about heat/adequate airflow despite it originally being aircooled stock, it wasn't designed to be locked up into a metal box.

Instead of reinventing the wheel I was planning on using a 4 conductor 14awg speakon cable for connecting my euro case to power output. Any reason that wouldn't work? contacts of the jacks I selected are rated for 40A and the 14awg should be good for in the realm of 15A (though being a multi-conductor canare speaker cable specifically i cant find ampacity ratings for the conductors)

Am I missing anything? I've built power supplies before, some for audio applications but tbh they were kit-style builds. I'm an electrician by trade and confident in my abilities but after reading a few threads around here I know some people know a lot more about this stuff than I do. Thanks!

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Post by omorange » Sun Feb 04, 2018 5:42 pm

omorange wrote:I was planning on going the dual OVP route to protect both +/-12 rails independently.
on second thought, can you regulate -12v with one of these? without a bunch of modifications? Unsure if reversing the polarity/connecting +out to 0V is the correct method here.

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Post by Mochi_Stryper » Sun Feb 04, 2018 10:05 pm

Hey all,

I scooped an HCC15-3-A for the low on eBay. I'm measuring continuity to ground on the terminals on the transformer's secondary side. This immediately told me to not proceed and ask for help.

Is this common behavior for the secondary side of a transformer? My gut's telling me this is bad news. I'm measuring resistances to ground in the ohm and subohm range.

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Post by omorange » Sun Feb 04, 2018 10:11 pm

Mochi_Stryper wrote:Hey all,

I scooped an HCC15-3-A for the low on eBay. I'm measuring continuity to ground on the terminals on the transformer's secondary side. This immediately told me to not proceed and ask for help.

Is this common behavior for the secondary side of a transformer? My gut's telling me this is bad news. I'm measuring resistances to ground in the ohm and subohm range.
is the supply board still connected? I'm thinking you'd know if the transformer was smoked. it has a distinct smell that rarely goes away. I could be dead wrong because without having one in front of me (about 4 days from getting mine), I'd say it may have a center tap on the secondary of sorts and that is common to 0v on the board which is typically tied to ground. since the windings are just lengths of wire or metal, its a typically low resistance from one end to the other, if one end is tied to ground... well you see where i'm going with this. it may even be internally tied to ground via the frame so disconnecting the board may not change the outcome.
Last edited by omorange on Sun Feb 04, 2018 10:25 pm, edited 1 time in total.

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Post by Mochi_Stryper » Sun Feb 04, 2018 10:21 pm

omorange wrote:is the supply board still connected?
I received the supply with primary side jumpered for 120V. I received the supply with the terminals on the secondary side running from terminals C, BT, B, & B to their respective silkscreens on the supply PCB. The supply's outputs are currently disconnected. The supply's sense lines are jumpered to their respective output terminals.

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Post by omorange » Sun Feb 04, 2018 10:27 pm

Mochi_Stryper wrote:
omorange wrote:is the supply board still connected?
I received the supply with primary side jumpered for 120V. I received the supply with the terminals on the secondary side running from terminals C, BT, B, & B to their respective silkscreens on the supply PCB. The supply's outputs are currently disconnected. The supply's sense lines are jumpered to their respective output terminals.
I edited my last post, check that out. Also I was asking if the supply board was still wired to the secondary of the transformer, not whether or not the outputs were connected to anything. ALSO, to clarify. YES secondaries are very commonly tied to ground in some fashion. that power pole outside your house with the transformer on it is an example of this.

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Post by Mochi_Stryper » Sun Feb 04, 2018 10:59 pm

omorange wrote:Also I was asking if the supply board was still wired to the secondary of the transformer, not whether or not the outputs were connected to anything.
Just trying my best to clarify that the supply isn't currently spaghetti junction. Difficult to say what these secondary outputs are given that Bel Power hasn't provided me with any documentation on the transformer, but if I were to venture a guess:
C=Common
B, B= Voltagea, and Voltageb
BT=Center Tap

So you're saying it's entirely possible and very likely that resistance between the secondary terminals will be relatively miniscule because the sole resistance between each terminal is a winding of conductive wire?

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Post by omorange » Sun Feb 04, 2018 11:38 pm

Mochi_Stryper wrote:
omorange wrote:Also I was asking if the supply board was still wired to the secondary of the transformer, not whether or not the outputs were connected to anything.
Just trying my best to clarify that the supply isn't currently spaghetti junction. Difficult to say what these secondary outputs are given that Bel Power hasn't provided me with any documentation on the transformer, but if I were to venture a guess:
C=Common
B, B= Voltagea, and Voltageb
BT=Center Tap

So you're saying it's entirely possible and very likely that resistance between the secondary terminals will be relatively miniscule because the sole resistance between each terminal is a winding of conductive wire?
correct. a center tap/bond to earth is how the secondary side of a transformer basically creates a reference point for all other voltages generated to then be utilized or measured in multi-phase/multi-voltage AC applications. Yes this is a DC power supply, but transformers dont work with DC and a transformer is more or less the most efficient and clean way to step voltage up or down, which is what its doing before it rectifies and regulates the voltage from AC to DC.

That said, there is little to no documentation on these things so I'm not even going to try and guess what their labels on the secondary mean. once powered you could measure them for yourself! I say get your fused mains connection ready and plug it in. maybe somewhere a fire extinguisher wouldnt make a big mess 8-)

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Post by Rex Coil 7 » Mon Feb 05, 2018 8:07 am

omorange wrote:
Mochi_Stryper wrote:.... So you're saying it's entirely possible and very likely that resistance between the secondary terminals will be relatively miniscule because the sole resistance between each terminal is a winding of conductive wire?
correct. a center tap/bond to earth is how the secondary side of a transformer basically creates a reference point for all other voltages.....
This may help those that are reading to understand things a bit more clearly (I drew this up myself, there's most likely more detailed drawings elsewhere on the internet).

Image

Even though I've labeled the outputs as negative and positive, those are actually AC voltages that get rectified to negative and positive in the regulation boards.
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Post by omorange » Mon Feb 12, 2018 1:21 am

So I got my HDCC-150W-A from ebay, it seems to test out fine. I hooked up 2 OVPs, from common to +/-12V instead of doing one from the positive rail to the negative rail. Then, with the rails calibrated to +/-13.5V I slowly dialed CCW from full CW. I was monitoring the rail voltage which would immediately drop to ~0V when I heard the OVP trip. It never tripped the mains 4A fuse during this, however. Anything I need to consider changing about this setup? obviously I want to minimize exposure to the short, but I've heard these PSUs can handle it. The fact it isn't tripping the mains I guess is my biggest concern. I'm still planning on shoehorning voltmeters/ammeters to monitor every rail but i'm quickly running out of space in this enclosure. :eek:
Last edited by omorange on Mon Feb 12, 2018 6:08 pm, edited 1 time in total.

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Post by flts » Mon Feb 12, 2018 9:35 am

Edit: on second thought, let's leave this to experts.
Warm thank you to everyone for the past 10 years. I'm not active here anymore for personal reasons, so for those I've had the pleasure of dealing with please send an e-mail instead of PM if you wish to get in touch.

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Post by omorange » Mon Feb 12, 2018 6:28 pm

I caught your post in email notification. just using recommended fuse setting for my mains voltage from the table printed to the frame. I think everything is fine. I'll know straight away that there is a problem when an OVP trips as modules will lose a rail and hopefully just stop working/working correctly.

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Post by omorange » Tue Feb 20, 2018 9:22 am

As I havent powered my rack with the PSU yet (since its all cut up waiting parts and reassembly into the ammo can enclosure, does anyone know if the TO-3 packages generate a ton of heat and could stand to be air cooled under load? I was looking at putting them into some of those keystone insulators for some peace of mind after shoehorning everything together, but dont want to run into excess heat problems. There is a 80mm fan cooling the enclosure though for adequate air cooling.

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Post by slumberjack » Fri Aug 17, 2018 4:41 pm

now after wiggling with switching supplies i think i gonna try out a linear one.
maybe only to find out that this very little noise i can hear sometimes is gone.
really wierd is that sometime i don't even hear it, sometimes i hea it and i doesn't bother me at all. but sometimes it's anoying as f*.

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Post by paterursus » Fri Aug 17, 2018 5:00 pm

slumberjack wrote:now after wiggling with switching supplies i think i gonna try out a linear one.
maybe only to find out that this very little noise i can hear sometimes is gone.
really wierd is that sometime i don't even hear it, sometimes i hea it and i doesn't bother me at all. but sometimes it's anoying as f*.
L-1's linear PSU is available either as a kit or as a built unit. I have two, and I've filled up the headers with modules (including tube modules) and had no issues. They're great supplies - well built and good performers.
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Post by deadAMps » Sun Sep 02, 2018 6:38 pm

This guide was a big help, thanks! I have an HCC15-3-A all wired up in a case, calibrated and working, except...Picked up a couple volt/current meters and I'm not exactly sure how to wire them in. Could someone give me some direction on this?

It's the DSN-VC288. Here's a link to the wiring diagram...

http://hamguyparts.com/files/Download/Chinese%20DVA.pdf

Sorry, not enough posts to upload pics yet!
[/img]

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Post by dhaillant » Mon Sep 03, 2018 2:50 am

deadAMps wrote:This guide was a big help, thanks! I have an HCC15-3-A all wired up in a case, calibrated and working, except...Picked up a couple volt/current meters and I'm not exactly sure how to wire them in. Could someone give me some direction on this?

It's the DSN-VC288. Here's a link to the wiring diagram...

http://hamguyparts.com/files/Download/Chinese%20DVA.pdf

Sorry, not enough posts to upload pics yet!
[/img]
The current measurement in DMMs needs a shunt resistor to read a voltage drop caused by the current going through.
The diagram shows that these modules require the current to be read on the *low side* I.e. the ground for the module monitoring the positive rail.
As the shunt resistor will add a non negligible resistance in your ground path, just be aware about the potential problems it might create.

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Post by deadAMps » Mon Sep 03, 2018 11:34 am

These have a shunt in the circuit.

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Post by deadAMps » Mon Sep 03, 2018 11:57 am

The OVP-12G, is there any info on how to calibrate that or how to wire it in?

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Post by nickajeglin » Fri Mar 22, 2019 2:50 am

Can anyone with an older "power-one" branded HCC15-3-A (with the two big 10000 uF caps) give me a closeup picture of the board? Specifically the rectifier diode CR8. I just got a well used one off ebay, and there's resistor piggybacked in parallel to that diode. It looks like either a factory rework situation, or a field retrofit, so I'd like to know if anyone else with a working supply has it on there before I go messing around with the thing.

Edit: Sorry for the thread necro! I googled into here and didn't even notice the post dates.

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Post by JohnLRice » Fri Mar 22, 2019 11:45 am

nickajeglin wrote:Can anyone with an older "power-one" branded HCC15-3-A (with the two big 10000 uF caps) give me a closeup picture of the board? Specifically the rectifier diode CR8. I just got a well used one off ebay, and there's resistor piggybacked in parallel to that diode. It looks like either a factory rework situation, or a field retrofit, so I'd like to know if anyone else with a working supply has it on there before I go messing around with the thing.
I don't have one but I Googled up this reasonable clear image of one (build date 1998):
Image

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Post by nickajeglin » Sun Mar 24, 2019 4:51 pm

Thanks John, I suppose I could have googled it myself :doh:

That's very helpful, it looks like the resistor is definitely a later addition. Once I get it fired up, I'll test both with and without the resistor. I'm curious why the former user would have added it. Especially considering that I bought it from a medical equipment liquidator, I assume that it would have been in service somewhere with people who know what they were doing.

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Post by CLee » Sun Mar 24, 2019 5:48 pm

Mine doesn’t have it either
Image

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