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.com power question: >800 mA PSU options for 3P case?
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Author .com power question: >800 mA PSU options for 3P case?
Sir Ruff
So I'm finally diving into the 5U world and building a system in a Model 15-style case based around Synth-werk modules. The case I am buying has 2 x QPS2s installed, but it looks like I'm going to need a QPS1 or equivalent to provide the supply that I need.

Since the case already has an AC jack on the rear panel, I'm wondering if there's any way to keep the PSU completely internal without buying the Q101/102 pair as well (and losing a front panel slot in the process)?

I'm not committed to a QPS1 if there is another option that will provide, say, 1000 mA of power and can be fitted completely internally.
bwhittington
Sure you can, but it would require rewiring the QPS-1. You would need to cut off the molex connnector and connect it to the AC input on your case. This (most likely) will require soldering the wires to the AC terminal, but if you are comfortable with that, it would be a simple job. If you aren't comfortable with doing it yourself, the job should be within the skill set of any music store repairer in your area, or any electronics repairer, etc. for that matter.

You also could purchase a like power supply from mouser, etc and save money on the Dotcom modifications you don't need. You could wire the Dotcom wiring harness directly to leads off of the DC terminals.

If you are interested in the doing it and need more info than my breezy response, be sure to ask. It is a simple job, but done incorrectly . . . Dead Banana
JohnLRice
Something to consider is that the Synth-Werk modules are deep and the QPS-1 is pretty big, are you sure it will all Fit in your case?

If it does, it should be relatively easy to install and adapt the QPS-1 to the existing AC power inlet so long as you clearly understand AC power and circuits. Have someone who is qualified to do the work if you aren't sure yourself.

I'd suggest modifying the existing AC inlet connections instead of the QPS-1, like adding a mating Molex connector to the AC inlet so you can just plug the QPS-1 into it.

If there isn't room for a big linear supply like the QPS-1 (or even if there is) contact Tony at Analog Craftsman and get clarification on his acPSU:
http://analogcraftsman.com/?product=acpsu#tab-description
It's says "1 amp +/-15v & +5v supply" but I don't know if that's per rail or all rails totaled. hmmm..... seriously, i just don't get it
Rex Coil 7
JohnLRice wrote:
Something to consider is that the Synth-Werk modules are deep and the QPS-1 is pretty big, are you sure it will all wit in your case?

If it does, it should be relatively easy to install and adapt the QPS-1 to the existing AC power inlet so long as you clearly understand AC power and circuits. Have someone who is qualified to do the work if you aren't sure yourself.

I'd suggest modifying the existing AC inlet connections instead of the QPS-1, like adding a mating Molex connector to the AC inlet so you can just plug the QPS-1 into it.

If there isn't room for a big linear supply like the QPS-1 (or even if there is) contact Tony at Analog Craftsman and get clarification on his acPSU:
http://analogcraftsman.com/?product=acpsu#tab-description
It's says "1 amp +/-15v & +5v supply" but I don't know if that's per rail or all rails totaled. hmmm..... seriously, i just don't get it
Listen to this man!! He does exemplary work, so dig around for some of his pics of the ways he's wired up input power and "take notes Pierre".

Should you elect to do away with the Q103/Q137 power control solutions, make sure to put dual line fuses in the inputs. Why "dual"? ... because you want both the "hot" and "neutral" lines fused to protect you in the event your wall outlets have been wired "goofy foot" and the hot/neutrals have been flip/flopped. You always want to set up a "dual break" so in the event of a fault both the hot/neutral will open. Place the fuses AFTER the switch so should whatever on/off switch you elect to use craps out the fuses will do their jobs and open the circuit.

It may seem like a rather obvious suggestion, but be sure to have spare fuses on hand and stored somewhere mindful so you will be able to continue playing over a long holiday weekend in the event there is a problem that you're able to fix quickly you can be back on line without having to wait for the hardware store to reopen.

d'oh!

So go hunt up some of John's images of the way he's done some of his line power inputs/switching and copy them for reference. If nothing else, you may find inspiration or have pics to send/show an electrician how you may want things done.

Can y'dig it?


thumbs up thumbs up thumbs up thumbs up
JohnLRice
Rex Coil 7 wrote:
JohnLRice wrote:
Something to consider is
Listen to this man!! He does exemplary work
Or better yet look up some of the posts by Rex Coil 7, he does much better work then I! we're not worthy thumbs up

If you have questions Rex and I will be here at the Reach Around Room all week . . .. . try the veal! Mr. Green
Rex Coil 7
JohnLRice wrote:
Rex Coil 7 wrote:
JohnLRice wrote:
Something to consider is
Listen to this man!! He does exemplary work
Or better yet look up some of the posts by Rex Coil 7, he does much better work then I! we're not worthy thumbs up

If you have questions Rex and I will be here at the Reach Around Room all week . . .. . try the veal! Mr. Green
lol lol geezus ... I just woke up my wife from laughing so hard ... lol lol
Sir Ruff
hey everyone, thanks for all of your very helpful suggestions! It looks like I have a few options. I am comfortable with small part soldering, but may leave any AC/PSU cord cutting/soldering to my local tech.

For reference, should anyone care to see it, here is the case.

https://www.ebay.com/itm/MODULAR-SYNTHESIZER-MU-FORMAT-CABINET-ONLY/28 3401137778?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2748.l2649

It appears to conform to the usual Model 15 case specs (which Synth-werk also seems to use for their Model 10) so I'm guessing that the 901A/BBB modules will fit fine. Failing that, I'll just leave the back off?

It also looks like there should be enough room at the bottom for the QPS1 once QPS2s are removed. The other factor is that I will probably need two distro boards to go with the PSU hmmm.....

Rex or John, can you point me to any threads where your examples are showcased? (or hit me with some keywords to search?)

One additional question: with the back on, will overheating be an issue here?
Rex Coil 7
Sir Ruff wrote:
hey everyone, thanks for all of your very helpful suggestions! It looks like I have a few options. I am comfortable with small part soldering, but may leave any AC/PSU cord cutting/soldering to my local tech.

For reference, should anyone care to see it, here is the case.

https://www.ebay.com/itm/MODULAR-SYNTHESIZER-MU-FORMAT-CABINET-ONLY/28 3401137778?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2748.l2649

It appears to conform to the usual Model 15 case specs (which Synth-werk also seems to use for their Model 10) so I'm guessing that the 901A/BBB modules will fit fine. Failing that, I'll just leave the back off?

It also looks like there should be enough room at the bottom for the QPS1 once QPS2s are removed. The other factor is that I will probably need two distro boards to go with the PSU hmmm.....

Rex or John, can you point me to any threads where your examples are showcased? (or hit me with some keywords to search?)

One additional question: with the back on, will overheating be an issue here?
(Link sucks ... "corrupted information" notice)

HEAT: It would not hurt one bit to put convection cooling holes along the bottom of the back and along the top of the back. Hot air needs a way out (top holes) and cool air needs a way in (bottom holes). As the hot air escapes from the top row of holes, it needs to be replaced with cool air coming in through the bottom row of holes.

Either use a few large holes (perhaps two inch diameter round holes) or a greater number of smaller holes (perhaps four times as many half inch holes). If you have cats, more/smaller holes would be a better choice, which will keep curious paws from digging around in the cabinet. If you have lint/dust issues, you can staple scrub pads (aka scouring pads, Scotch Brite pads, et al) on the inside of the back panel over the holes. Air can still flow but dust/lint/cat hair cannot enter. Once every so often use a vacuum on the scrub pads to remove any stuff that has been trapped on the surface of the pads.

Hot air out through the top ..... cool air in through the bottom.

thumbs up
Sir Ruff
Rex Coil 7 wrote:

HEAT: It would not hurt one bit to put convection cooling holes along the bottom of the back and along the top of the back. Hot air needs a way out (top holes) and cool air needs a way in (bottom holes). As the hot air escapes from the top row of holes, it needs to be replaced with cool air coming in through the bottom row of holes.

Either use a few large holes (perhaps two inch diameter round holes) or a greater number of smaller holes (perhaps four times as many half inch holes). If you have cats, more/smaller holes would be a better choice, which will keep curious paws from digging around in the cabinet. If you have lint/dust issues, you can staple scrub pads (aka scouring pads, Scotch Brite pads, et al) on the inside of the back panel over the holes. Air can still flow but dust/lint/cat hair cannot enter. Once every so often use a vacuum on the scrub pads to remove any stuff that has been trapped on the surface of the pads.

Hot air out through the top ..... cool air in through the bottom.

thumbs up


good suggestions, thanks!

try this for link: Model 15 case
JohnLRice
Here's a picture of the back of your case for those that don't want to look at eBay. (I made this yesterday but I was getting ready for a show last night and . . .wasn't actually ready at all so I didn't take the time to respond Mr. Green ) Looks like he had one Synth-Werk module in the case so depth should be fine for you.


The case ventilation isn't done very well at all , typically you'd want vent holes below the heat producing elements and then vent holes at the very top of the case for the best convective air flow. That said, I've never found modular synths or their power supplies to get very hot (with the exception of some small eurorack switching supply modules) and the panels are full of (jack) holes and there are often spaces between panels so heat will escape. I'd even argue (out of my ass since I have no evidence to prove or disprove this hihi ) that a mostly sealed analog modular might operate with more stability then a well ventilated one since the sealed one wont be as affected by sudden room temperature changes? hmmm.....

The existing power system is a bit on the funky side but I've certainly done similar things in the past and it worked fine. hihi


At the very least I would do one of two things with the AC inlet so that it's less of a pain to have the back off when connecting modules etc:
1) I would remount the AC inlet to the inside of the case and cut a hole in the back that lines up with it so that the back can be removed without anything attached to it. Preferably using an AC inlet with an on/off switch.
2) if you don't want to buy a new AC inlet, wood back, etc you could just make a horizontal cut all the way across the back a few inches up so that the small piece with the AC inlet can stay permanently attached and the large upper piece can be more easily removed when needed.

So, yeah, I've built a few supplies for modulars . . . over 15 I think at this point.


Here's a couple related threads:
https://www.muffwiggler.com/forum/viewtopic.php?t=2628
https://www.muffwiggler.com/forum/viewtopic.php?t=8935
https://www.muffwiggler.com/forum/viewtopic.php?t=19389

Initially I was mounting the distro boards to the tops of the supply, which was quite tedious since the supply needed to be completely disassembled to do it and also a somewhat bad idea since if the power supply happens to fail and needs to be replaced, it would be (will be d'oh! ) a lot of work!



In my most recent builds I've started mounting the distro boards to the panel instead which is a lot less work and more easily repaired in the future if needed.



Thinking about it today, I'd do things differently still . . . . for instance having the AC Inlet + power supply AND the distro board on the same panel isn't the most efficient time and material wise if the power supply goes bad. My initial thought way back on power supply #1 is that I wanted the power supply to be modular as well, so if it goes bad I could just disconnect it and put in a new 'spare' or take one from a less critical case, which of course I can do, but with my designs I'd need to disconnect ALL of the modules from the distro board. Not a big deal if in the studio and I can take my time but in a live situation where a supply might die at sound check and I'd need to do a supply swap before show time, it would be a lot less stressful with less potential for screwing things up if the distro board was attached to a separate panel of to the inside of the case with a single connector from the power supply to the distro to deal with.

Also, one thing I don't care for is the orientation of the power supply on the panel since the voltage output trimmers are impossible to access when in use, and that's made doubly hard with the distro board attached. It would be nice if I had designed it so the power supply was rotated with the trimmers facing the back of the case and there were holes or an access door to get to the trimmers, or maybe the supply could hang below the panel enough to get to the trimmers and then mount it up higher and a separate vent panel below it could be removed to access the trimmers? hmmm.....

But all that said, power supplies rarely go bad and distro boards are even less likely to fail so . . . . . spinning
hsosdrum
JohnLRice wrote:
Here's a picture of the back of your case for those that don't want to look at eBay. (I made this yesterday but I was getting ready for a show last night and . . .wasn't actually ready at all so I didn't take the time to respond Mr. Green ) Looks like he had one Synth-Werk module in the case so depth should be fine for you.


The case ventilation isn't done very well at all , typically you'd want vent holes below the heat producing elements and then vent holes at the very top of the case for the best convective air flow. That said, I've never found modular synths or their power supplies to get very hot (with the exception of some small eurorack switching supply modules) and the panels are full of (jack) holes and there are often spaces between panels so heat will escape. I'd even argue (out of my ass since I have no evidence to prove or disprove this hihi ) that a mostly sealed analog modular might operate with more stability then a well ventilated one since the sealed one wont be as affected by sudden room temperature changes? hmmm.....

The existing power system is a bit on the funky side but I've certainly done similar things in the past and it worked fine. hihi


At the very least I would do one of two things with the AC inlet so that it's less of a pain to have the back off when connecting modules etc:
1) I would remount the AC inlet to the inside of the case and cut a hole in the back that lines up with it so that the back can be removed without anything attached to it. Preferably using an AC inlet with an on/off switch.
2) if you don't want to buy a new AC inlet, wood back, etc you could just make a horizontal cut all the way across the back a few inches up so that the small piece with the AC inlet can stay permanently attached and the large upper piece can be more easily removed when needed.

So, yeah, I've built a few supplies for modulars . . . over 15 I think at this point.


Here's a couple related threads:
https://www.muffwiggler.com/forum/viewtopic.php?t=2628
https://www.muffwiggler.com/forum/viewtopic.php?t=8935
https://www.muffwiggler.com/forum/viewtopic.php?t=19389

Initially I was mounting the distro boards to the tops of the supply, which was quite tedious since the supply needed to be completely disassembled to do it and also a somewhat bad idea since if the power supply happens to fail and needs to be replaced, it would be (will be d'oh! ) a lot of work!



In my most recent builds I've started mounting the distro boards to the panel instead which is a lot less work and more easily repaired in the future if needed.



Thinking about it today, I'd do things differently still . . . . for instance having the AC Inlet + power supply AND the distro board on the same panel isn't the most efficient time and material wise if the power supply goes bad. My initial thought way back on power supply #1 is that I wanted the power supply to be modular as well, so if it goes bad I could just disconnect it and put in a new 'spare' or take one from a less critical case, which of course I can do, but with my designs I'd need to disconnect ALL of the modules from the distro board. Not a big deal if in the studio and I can take my time but in a live situation where a supply might die at sound check and I'd need to do a supply swap before show time, it would be a lot less stressful with less potential for screwing things up if the distro board was attached to a separate panel of to the inside of the case with a single connector from the power supply to the distro to deal with.

Also, one thing I don't care for is the orientation of the power supply on the panel since the voltage output trimmers are impossible to access when in use, and that's made doubly hard with the distro board attached. It would be nice if I had designed it so the power supply was rotated with the trimmers facing the back of the case and there were holes or an access door to get to the trimmers, or maybe the supply could hang below the panel enough to get to the trimmers and then mount it up higher and a separate vent panel below it could be removed to access the trimmers? hmmm.....

But all that said, power supplies rarely go bad and distro boards are even less likely to fail so . . . . . spinning

You, sir, are a madman. OUTSTANDING work!!! we're not worthy we're not worthy we're not worthy we're not worthy we're not worthy
JohnLRice
hsosdrum wrote:
You, sir, are a madman. OUTSTANDING work!!! we're not worthy we're not worthy we're not worthy we're not worthy we're not worthy
Thank you kind sir! Hug
Rex Coil 7
hsosdrum wrote:
...You, sir, are a madman. OUTSTANDING work!!! we're not worthy we're not worthy we're not worthy we're not worthy we're not worthy
See? Told ya!! thumbs up
Rex Coil 7
This 'n here is the shizknuckle! ......







Hey John ... are the plastic standoffs for the distro boards threaded or do those blue anodized socket head screws go all the way through with nuts/flats/locks on the other side of the panel?

hmmm.....
JohnLRice
Rex Coil 7 wrote:
This 'n here is the shizknuckle! ......
Hey John ... are the plastic standoffs for the distro boards threaded or do those blue anodized socket head screws go all the way through with nuts/flats/locks on the other side of the panel?
Thank you, master builder sir! Hug

They are threaded nylon standoffs so separate screws are one each end. I really prefer threaded stand offs to the non threaded type, makes assembly much nicer/easier IMHO.

I can't see them in the pictures but I'm "pretty sure" I put a small lock washer between the panel and the stand off and I don't think I put a lock washer between the distro PCB and standoff. (those nylon standoffs hold pretty snug) On my older designs where I mounted the distro on top of the power supply chassis I always used a nut and lock washer (or a Keps nut etc) to attach the bolt to the chassis as a little over kill because I wanted to avoid the slight chance that the screw might come loose over time and drop down to contact the underside of the power supply's PCB! MY ASS IS BLEEDING BOOM! hihi
Sir Ruff
JohnLRice thanks for the suggestions and photos. Great looking supply! Not being of the DIY persuasion (and not knowing to what extent I could rely on my tech to go beyond just re-wiring of a pre-bought supply) it would be great to have something that I could just drop in like this (that's assuming the case width is actually correct!). Are you making these for sale, or just for your own purposes?
JohnLRice
Sir Ruff wrote:
JohnLRice thanks for the suggestions and photos. Great looking supply! Not being of the DIY persuasion (and not knowing to what extent I could rely on my tech to go beyond just re-wiring of a pre-bought supply) it would be great to have something that I could just drop in like this (that's assuming the case width is actually correct!). Are you making these for sale, or just for your own purposes?
Thanks for the kind words and interest but I only make these for myself because it's too risky to sell them without having them UL/CE approved etc. (hides)

If you want a top notch power supply built for your system consider talking to Graham Hinton! thumbs up He can customize his designs to perfectly fit your needs and they are similar to what I build for myself, only better and CE approved! hihi His prices are quite reasonable for the quality you get as well and if you are going to load up your case full of those nice Synth-Werk modules, you owe it to yourself to get the best! SlayerBadger!
http://www.hinton-instruments.co.uk/paprod/psu/fullpower.htm
http://www.hinton-instruments.co.uk/paprod/psu/distribution.htm
Rex Coil 7
JohnLRice wrote:
....If you want a top notch power supply built for your system consider talking to Graham Hinton!
Ain't that the truth!!!!!

Here's a couple of pics of his stuff I have stuffed away in my album .....








Sir Ruff
Thanks for the Hinton suggestion! Nice looking stuff. Even if it's a bit more than doing myself, I think it would be well worth having something bespoke and ready to go as opposed to sourcing and cobbling together myself.
Sir Ruff
Ok, so I heard back from Graham and it seems like his stuff won't be compatible with the case cos it's not the 19" standard.

So I'm having a few additional thoughts and wonder what people think here:

1) I just buy another QPS2? simplest solution and easiest to install, BUT this risk is here that I will running up against max mA on 1 or 2 of them and it's my understanding that PSUs should run at about 60% capacity. (The Synth-Werk 901A/BBB run 120 mA alone, for example.)

2) I ditch this case (as much as I like the aesthetic) and go for Moon Modular M500-RP, which rackmount and powered version of the same Model 15/3P case design. Price is reasonable and I would have a nice 2A PSU neatly mounted inside. The downside of this is that I won't actually be rackmounting it and so it's not going to look great. Sadly I can't afford the very nice 3P case they make.

Being one for the most parsimonious option, I'm leaning toward option #2, but it definitely loses a lot of the vintage vibe!
JohnLRice
Sir Ruff wrote:
1) I just buy another QPS2? simplest solution and easiest to install, BUT this risk is here that I will running up against max mA on 1 or 2 of them and it's my understanding that PSUs should run at about 60% capacity. (The Synth-Werk 901A/BBB run 120 mA alone, for example.)
Using more then one power supply in a system can be problematic, especially with little ones like the QPS2 where there isn't an easy way to tie the 0v rails together. Also no need to go as low as 60% capacity, 75% to 85% is good enough and depending on the supply type and design even running at 100% of stated capacity is fine. (and it also depends on what sort of "in-rush" current demand your collection of modules cause. Some modules may cause next to nothing and others may cause a lot)

I think you'd be better off removing the existing QPS2 supplies and get something like a single QPS1, a Q137 AC inlet panel, and a QDH20 power harness. Then you'd just need to bolt the QPS1 to the bottom of your case, cut a larger module sized hole in the back panel where the existing AC inlet is to mount the Q137, plug the QPS1 into the Q137 and connect the QDH to the QPS1 and modules.

Sir Ruff wrote:
2) I ditch this case (as much as I like the aesthetic) and go for Moon Modular M500-RP, which rackmount and powered version of the same Model 15/3P case design. Price is reasonable and I would have a nice 2A PSU neatly mounted inside. The downside of this is that I won't actually be rackmounting it and so it's not going to look great. Sadly I can't afford the very nice 3P case they make.
I'm "pretty sure" that the Synth-Werk modules won't fit in the Moon M500-RP? It's a somewhat shallow case but double check with Moon or a reseller like Noisebug to be sure. If you want to get a new case and keep the same ascetic Moon makes the M500-P but it's quite expensive. I "think" it's deep enough for Synth-Werk modules but please verify this before purchasing!:
https://www.noisebug.net/products/500-p-tolex-case
Sir Ruff
JohnLRice wrote:
I think you'd be better off removing the existing QPS2 supplies and get something like a single QPS1, a Q137 AC inlet panel, and a QDH20 power harness. Then you'd just need to bolt the QPS1 to the bottom of your case, cut a larger module sized hole in the back panel where the existing AC inlet is to mount the Q137, plug the QPS1 into the Q137 and connect the QDH to the QPS1 and modules.


Thanks, yes, this does seem like this most logical route if I want to keep the case design.

EDIT: removed Q101/102 comment as I saw you mentioned the Q137, which I had been ignoring. Looks like the best option!
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