[ORDER] Erica Synths eurorack PSU

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TimoRozendal
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Post by TimoRozendal » Wed Feb 25, 2015 7:24 am

Hi there, this will be my first step towards my first eurorack setup...

quick question:
is it recommended to use 230v mains cables with a ground cable and connect that ground cable to the ground of the dc power? Or is it better to ignore the ground of the mains?

Thanks!

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latigid on
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Post by latigid on » Wed Feb 25, 2015 7:36 am

TimoRozendal wrote:Or is it better to ignore the ground of the mains?
:deadbanana:

Do some reading first, but if you are asking these kinds of questions you are not prepared to work with mains.

E.g. viewtopic.php?t=131748

TimoRozendal
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Post by TimoRozendal » Wed Feb 25, 2015 7:49 am

well, seems my hunch was right to connect it then since in that thread it is stated
this is the essence:

"The 0V of the PSU should be connected to mains Earth for both safety and common 0V reference. This is not a preference or optional. Many systems are not earthed properly, don't copy bad practise."

but both in the build manual and in the photos (Girts' and clive.grace's) I don't see any sign of that, hence my question...


EDIT: built the thing, all works well, thanks Girts!

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roglok
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Post by roglok » Sun Mar 01, 2015 3:30 pm

TimoRozendal wrote:well, seems my hunch was right to connect it then since in that thread it is stated
this is the essence:

"The 0V of the PSU should be connected to mains Earth for both safety and common 0V reference. This is not a preference or optional. Many systems are not earthed properly, don't copy bad practise."

but both in the build manual and in the photos (Girts' and clive.grace's) I don't see any sign of that, hence my question...


EDIT: built the thing, all works well, thanks Girts!
I'm with latigid on here. It's really not just a matter of making it "work", but of making it work in a safe manner.

I commented earlier in this thread on a crucial safety issue that this PSU and its distributor seems to ignore: Like in most European countries, the mains plugs in the Netherlands are F type, so live and neutral lines can be reversed. This means that the PSU has to be double fused. The PCB only features one fuse holder and the schematic in the build documentation also shows a single fuse only.

:deadbanana:

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darmklacht@gmail.com
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Post by darmklacht@gmail.com » Fri Apr 17, 2015 6:54 am

I´ve got a question.

I´ve made this PSU but had someone knowladgeable look me over just to be sure.

He told me not to connect the ground of the mains to the ground going to the rack as that would possibly create a hum in the circuit when attached to other devices with other grounds. This guy should know his shit :despair:

I feel a little confused as I´d rather have the mains attached so that when theres a short touching the panel it would go to the ground and not to me.

should I just trust the experianced guy?

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roglok
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Post by roglok » Fri Apr 17, 2015 7:03 am

darmklacht@gmail.com wrote:I´ve got a question.

I´ve made this PSU but had someone knowladgeable look me over just to be sure.

He told me not to connect the ground of the mains to the ground going to the rack as that would possibly create a hum in the circuit when attached to other devices with other grounds. This guy should know his shit :despair:

I feel a little confused as I´d rather have the mains attached so that when theres a short touching the panel it would go to the ground and not to me.

should I just trust the experianced guy?
no, he doesn't know his shit. but you do. the reason you gave is exactly why it must be done.

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darmklacht@gmail.com
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Post by darmklacht@gmail.com » Fri Apr 17, 2015 7:22 am

hmmm,
Thanks, I´ll just connect it then better be safe that sorry.
Besides that we have tested it and it worked nicely and it was an easy build...
just a bit dissapointed I didnt get the right advise safety wise. :woah:

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roglok
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Post by roglok » Fri Apr 17, 2015 7:31 am

darmklacht@gmail.com wrote:hmmm,
Thanks, I´ll just connect it then better be safe that sorry.
Besides that we have tested it and it worked nicely and it was an easy build...
just a bit dissapointed I didnt get the right advise safety wise. :woah:
on that note, may i ask where you are located and whether you double fused the mains inlet?

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darmklacht@gmail.com
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Post by darmklacht@gmail.com » Fri Apr 17, 2015 8:13 am

I live in germany, as you do.
And have it fused as it is out of the box. one single fuse.

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Egor
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Post by Egor » Fri Apr 17, 2015 9:07 am

I'm not sure if this has been asked already.... but does it make 5v as well as 12v? or will I still need a conveter like the mutable one to get a 5v rail going?

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darmklacht@gmail.com
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Post by darmklacht@gmail.com » Fri Apr 17, 2015 9:33 am

it only makes plus and minus 12 volt

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roglok
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Post by roglok » Fri Apr 17, 2015 6:59 pm

darmklacht@gmail.com wrote:I live in germany, as you do.
And have it fused as it is out of the box. one single fuse.
ok, then - let me try to explain again, since the OP doesn't seem to bother: the plugs used in germany and most other european countries are not polarised. in contrast to, for example, UK plugs, you will notice that the plug can be inserted 180 degrees flipped. this means that you never know which of the mains wires is the live wire and which is neutral. therefore there is a 50/50 chance that the fuse won't trip in case of an accident. hence it is absolutely neccessary to insert fuses for both lines.

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darmklacht@gmail.com
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Post by darmklacht@gmail.com » Sat Apr 18, 2015 2:44 pm

hmm I see,

Could It be that it was designed in such a matter that the fuse is just there in case of overloading and that in case of a short to ground the fuse of the house power would blow? :hmm:

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latigid on
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Post by latigid on » Sat Apr 18, 2015 2:49 pm

In this case: you are the fuse :ripbanana:

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darmklacht@gmail.com
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Post by darmklacht@gmail.com » Sat Apr 18, 2015 3:08 pm

I thought if there where to be a short touching the chassis, and I have the chassis grounded, the fuse of my house fusebox would blow even if there werent enough fuses or wrong fuses in the PSU.

here is another DIY PSU of very similar design http://clicksclocks.de/page/6 which seems to have no fuse at all. are these both really dangerous Faulty designs????? :despair:

some people seemed to be happy with this PSU I hope we will get to a clear concensus about how to go about this. People shouldent get hurt, but OTOH I really hope this project doesnt get a bad name if it aint that bad. Erica synths is legit and have A lot of cool projects

Thanks for all the advise.

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roglok
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Post by roglok » Mon Apr 20, 2015 5:26 pm

darmklacht@gmail.com wrote:I thought if there where to be a short touching the chassis, and I have the chassis grounded, the fuse of my house fusebox would blow even if there werent enough fuses or wrong fuses in the PSU.

here is another DIY PSU of very similar design http://clicksclocks.de/page/6 which seems to have no fuse at all. are these both really dangerous Faulty designs????? :despair:

some people seemed to be happy with this PSU I hope we will get to a clear concensus about how to go about this. People shouldent get hurt, but OTOH I really hope this project doesnt get a bad name if it aint that bad. Erica synths is legit and have A lot of cool projects

Thanks for all the advise.
the circuit breakers in your house are rated at 10-16A and entirely different beasts. they do NOT substitute fuses (schmelzsicherung).

the clicksclocks design is not faulty. just because they don't show you how to fuse it doesn't mean it can be omitted. the fuses are usually not mounted on the PCB but in a compartment that is accessible from outside the chassis, such as a combo IEC plug:

Image

makes more sense anyway. you won't have to take your case apart after blowing a fuse...

i'm not dissing Erica Synths products, just baffled that the OP publishes a DIY project that contains a potentially lethal wiring diagram and doesn't care to comment on it...

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darmklacht@gmail.com
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Post by darmklacht@gmail.com » Tue Apr 21, 2015 2:48 pm

hey a plug like that looks great, Guess I´ll source one of them and jump the fuse in the PSU.


Thanks for your help and concern.
I was kind of bummed with this project. I knew I was lacking the knowledge or at least the experiance to work with mains but thought I would have the proper help... I didnt feel so good anymore after I found the advise from the person I talked with a bit contrary to things I´ve heard and read. I´m quite happy I was able to speak my doubts here and get the support. this makes alot more sense, and makes me feel more comfortable.

Thanks alot :bananaguitar:

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Post by roglok » Tue Apr 21, 2015 5:00 pm

darmklacht@gmail.com wrote:hey a plug like that looks great, Guess I´ll source one of them and jump the fuse in the PSU.
sounds like a good idea!

i've been using this one, which includes an additional filter.

also make sure that you properly insulate all mains wiring, preferably using crimped, insulated spade connectors rather than shrink tube...

it is quite a silly idea to install the two extra mains spade connectors on the PCB without actually connecting anything to them (cf. build manual p.6 ). if you do that, you should at least cover them with some insulated dummy plugs!

i found this practical roundup of working in accordance with DIN VDE Schutzklasse quite helpful.

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Post by Grumskiz » Thu Apr 30, 2015 10:34 am

I just ordered the connector from reichelt that roglok suggested. Unfortunately it does not allow you to use 2 fuses at the same time.
It does have space for 2 fuses, but the right one is not connected to anything. Any recommendations on how to fix this? Im thinking about adding a second fuse between the filter and the switch. unfortunately i can not add one before the filter. Is this a problem?

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Post by darmklacht@gmail.com » Sun May 03, 2015 2:48 pm

thanks roglok for the info and suggestions... the dummy plugs I already used. and the pdf you sent looks interesting.

But to get things more confusing, I had an electric engeneer look at it (someone different than the person I mentioned earlier in the thread) and he advised not to connect the ground of the mains to the ground after the transformer because it was isolated anyway, and any potential difference between grounds could lead to dangerous voltages.

so I think I´m going to step away from this project... I knew I was a noob, and therefore wanted to first connect it after getting a green light from someone who checked it. I feel pretty comfortable with the information I was supplied with here in this topic. but as long as other people keep saying no I feel a little uncomfortable... I just want to be sure and have someone confirm it has been done right that held it in his or her hands.

Thanks to anyone who helped anyway, I still feel the info here made most sense of what I´ve heard.

Whoever is interested in this PSU, drop me a PM. I might trade it off for something nice.

I´m pretty sure its a nice projekt for people who know what theyre doing.

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darmklacht@gmail.com
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Post by darmklacht@gmail.com » Sun May 03, 2015 2:49 pm

I´m goinna stick with a power switcher with voltage regulators instead. had better experience with that. :mad:

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Post by TripJ » Mon Nov 30, 2015 8:30 pm

Hey Folks,

Working my way through my first SDIY. I chose to go with Erica because they seem to have a nice, concise line of bare PCBs available, including this PSU. Ordering parts has been an education and I wouldn't recommend that route unless you have free time and patience to spare, or you just like being educated.

My toroidial transformer arrived in my second order of parts from Mouser,
VPT24-2080 as indicated on the BOM(for about 10bucks less, check Gopher Electronics). At first I thought I'd received the wrong part, but double checking, looks like it checks out. It is a close fit at 80mm OD, but the coil pictured in the manual looks like a tight fit also, so I suppose it's OK.

The Mouser tech sheet indicates it will accept 230 or 115VAC depending on how it's wired. What surprised me was it's 4.16A rating wired with 115VAC input. Seems beefier than what is normally spec-ed in a eurorack case.

http://www.mouser.com/catalog/catalogusd/648/2171.pdf

Has anyone used any other transformers, say the VPT24-1040 , a 2.08A version?
It has a 71mm coil OD with a little more breathing room -also cheaper and lighter, perhaps more appropriate for a small case.



As part of my education....
This link is a short paper on AC-DC conversion including Bridge Rectification used in this design.

http://www.dummies.com/how-to/content/h ... nic-c.html

The bridge rectifier spec-ed in this design, KBL04, is now listed as obsolete and out-of-stock at Mouser. I bought a few from them just 6 weeks ago. If you are in a bind for it, send a PM.

j

PS
I will be adding a board for 5V in my next series of builds. Any recommends for a PCB?

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Post by TripJ » Fri Dec 04, 2015 10:36 pm

It works!

Image

The secondary side took some head scratching since I'm so new to this, but my deductions were correct and no fire flew.
Each of one of a jumpered pair through-holes into the ground plane (black and orange in this case). Each of the remaining two secondary leads (red and yellow in this case) go to the traces each leading to an inner pin of the bridge rectifier.

The primary side, I followed the parallel instructions and jumpered for 115VAC input by tinning together the appropriate leads(gray with brown; blue with violet) and shaped them with pliers to get them to fit in the holes. Seems like there would be a better way but it felt solid.


It measures a little off on voltage, but I'm going to get the wiring cleaned up and mount it, cap the open terminals before I start messing with it much.

Today I built the transistor shields for my first two VCOs (Erica's)

Image

and discovered I'm a few caps shy of an oscillator.

:doh:

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Post by andrewF » Tue Dec 08, 2015 5:09 am

TripJ wrote:It works!

Image

That exposed fuse looks plain fkn dangerous :deadbanana:
and electrical tape on mains wiring is never a good idea, at least get some heatshrink.

Normally I'd say 'great job' for anyone that does a bit of DIY. But there are problems with your build that can easily kill you, or kill someone else, seeing your build just makes me feel very uncomfortable.

Erica Synth is being very irresponsible selling these PCBs.

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Post by livefreela » Tue Dec 08, 2015 8:29 am

trip, i don't mean to be an alarmist - but that thing scares me. the crimps on the mains terminals look wildly oversized (if they're the same as the the empty ones you have fitted on the other size of the board) for that gauge wire and a bit of tape isn't going to solve the problem. also, barbering the primaries freaks me out too. stressed wire invariably fractures (especially with that kind of slack flopping around on the leads), and while i'm not the fussy sort and am usually down for a kludge of any kind, fussy is the only way to handle mains. most of the linear psus a strap or jumper of some kind to more safely accommodate the various primary wirings.

i hate to rain on your parade man, that's not my intention - but a loosed primary, exposed fuse, etc. can easily start a fire or stop your heart.

blowing the odd polarized cap, incorrectly placed ic or whatever on 12v rails is something we've all done (and continue to do) but working with mains is an entirely different beast altogether with tremendously consequences.

we're all in this sdiy thing to learn - and we've all had our face palm moments - just please don't get yourself or someone else hurt.

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