The Definitive Connecting Power Thread

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WIZARDISHUNGRY
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Post by WIZARDISHUNGRY » Wed May 27, 2015 3:59 pm

I'm currently using a Make Noise Bus Power inside a 6U case powered by a 15V 4A brick that is likely nowhere near capacity.

I have a spare HEK without power that I'd like to power off the same brick. I've noticed I'm able to power the make noise power with one of those 9V chain cables. I was wondering if there was a cheap option for power in the HEK. The uZeus receptacle is physically incompatible with the 15V brick and the cable chain. I could try and find an physical adapter but I feel pretty meh on that idea. Would a tiptop row power work? Anything else

The other stupid idea I had was running a long bus cable from spare bus board connectors through a 1.5hp gap at the end of my 6U case. The total draw from the HEK is 310 mA +12V | 140 mA -12V | 0 mA 5V which seems pretty moderate.

Has anyone run a power cable from a busboard to another case?

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Post by modezart » Mon Jun 01, 2015 5:57 am

if would do that to i would make sure that i have a fat ground cable from case to case :)

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Post by Jim Child » Sun Jun 07, 2015 10:26 am

I've tried searching for various permutations of "multiple ...this and that" but came up with nothing, so.

Guidance on Dealing With Multiple Power Supplies

What do I need to know to avoid disaster when inter-connecting modules which are powered by different power supplies?

I'm a noobie so I'll avoid asking about the more complicated scenario I forsee where the power draw of the modules installed in a case exceed the case's power unit's rating.

So, what are the guidelines when you're using two cases, each with its own power supply, to process the sound?
auld dawg learning new trix

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Post by dang_motu » Tue Jun 09, 2015 5:54 pm

Having trouble on how to connect an Analog Solutions HH88. From this picture you can see that the + or - sign is obscured by the cable mount (same with the other 12 not pictured). Anyone know what the deal is?
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Post by Studio-ES » Tue Jun 23, 2015 4:22 am

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Last edited by Studio-ES on Tue Jun 23, 2015 5:58 pm, edited 1 time in total.

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Graham Hinton
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Post by Graham Hinton » Tue Jun 23, 2015 4:57 am

Jim Child wrote: What do I need to know to avoid disaster when inter-connecting modules which are powered by different power supplies?
...

So, what are the guidelines when you're using two cases, each with its own power supply, to process the sound?
Ideally, two seperately powered pieces of audio equipment that are patched together should have balanced inputs and outputs and an Earthed screen. That is how all professional recording equipment is made.

If you connect two pieces of unbalanced audio equipment, i.e. most modular synthesizers, then you need a common 0V reference. This can be achieved by connecting the 0V of each system together and Earthing it at only one point. Often this happens invisibly through the mains Earth wiring, but that is not the best way. The important factor is the resistance of the connection which has to be much lower than the resistance of the screens of the patch cables. You can use very heavy bonding cables, but the best method is a busbar which will have a resistance of less than 100 microOhms.

There is a finite limit to how far an unbalanced system can be physically spread apart. A couple of cabinets is achievable, a whole room of wallpaper modules is not. Monster systems should be considered as separate smaller systems with only balanced connections between each. Large mixing consoles are both balanced internally and have a large busbar across the width. That is the model to follow.

More information is available here: http://www.hinton-instruments.co.uk/paprod/psu/psuinfo.htm

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+5V Power Adapters - Mutable Instruments Volts & Make No

Post by Studio-ES » Tue Jul 07, 2015 4:52 am

+5V Power Adapters - Mutable Instruments Volts & Make Noise 5V Adapter

There is a lot of valuable information in this thread, and it's greatly appreciated. I have a few questions and I'll also add several things I've observed along the way.

I was curious about the small +5V adapters which are required (for several modules) in cases with power supplies which lack +5V power, such as most Doepfer cases. The Doepfer bus boards do have a +5V LED, but the cases only supply +12V & -12V. Only a small handful of modules require +5V (in addition to +12 & -12V) but a very popular one is the Mutable Instruments Braids.

As far as I know, these +5V Adapters will take the required +5V from the +12V power rail for modules on the bus board which require +5V. Please correct me if I'm wrong.

Here's my question: How much power will a 5V adapter actually take from the +12V power rail? It's been mentioned recently that for the Mutable Instruments Volts 5V adapter, the rule is "remove from the +12V rail half of what the modules will draw on the +5V rail. " I also recall reading another old post from another veteran that mentioned something similar. I've searched with no luck.

Okay, for example, Braids requires 15mA +12V, 15mA -12V, & 85mA +5V.
So in a Doepfer case, with a Mutable Volts adapter plugged into one header on the bus board, & Braids plugged into another, will Braids draw 57.5mA from the +12V rail, 15mA from -12V, & 0mA from +5V? (57.5mA=15mA+half of 85). Is that correct? And are those numbers at max draw or is it average? I guess power specifications also depend on how the manufacturer tested? But that's another topic. Sorry.

Since we have to keep a close eye on power consumption, and be careful not to exceed the power supply's limit (1200mA with the Doepfer A-100P9 for example), it may be helpful to know what these +5V Adapters are actually doing.

One observation:
I've noticed that the header for the Make Noise 5V Adapter is too short to attach to shrouded headers on several bus boards in a skiff I have. The tiny circuit boards are in the way. It fits perfectly on a Doepfer bus board header since those aren't shrouded.

Thanks again. Below is a photo of the Make Noise & Mutable Instruments +5V Adapters.

Image

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Post by Studio-ES » Tue Jul 21, 2015 3:09 am

^ Any experienced wigglers have any advice/insight?

How much power will a 5V adapter actually take from the +12V power rail? It's been mentioned recently that for the Mutable Instruments Volts 5V adapter, the rule is "remove from the +12V rail half of what the modules will draw on the +5V rail. "

Since we have to keep a close eye on power consumption, and be careful not to exceed the power supply's limit (1200mA with the Doepfer A-100P9 for example), it may be helpful to know what these +5V Adapters are actually doing.

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Post by pichenettes » Tue Jul 21, 2015 4:21 am

So in a Doepfer case, with a Mutable Volts adapter plugged into one header on the bus board, & Braids plugged into another, will Braids draw 57.5mA from the +12V rail, 15mA from -12V
Correct so far.
& 0mA from +5V?
The adapter will supply 85mA to the +5V rail.

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Post by Studio-ES » Wed Jul 22, 2015 10:47 pm

Thank you, I appreciate the clarification.

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cannonball swandive
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Studio bus

Post by cannonball swandive » Tue Aug 18, 2015 5:32 pm

I connected a module backwards to my tiptop audio studio bus and now the light for my -12 rail isn't lighting up. Any suggestions? :help:

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Post by touchfuzzygetdizzy » Fri Aug 21, 2015 6:59 pm

Hoping someone can help me with this - I bought a used Doepfer module and the power connector is incorrectly built. The red stripe doesn't align with either triangle on the plastic pin connectors. So my first question -

a) Is there anything special about the plastic-triangle marked female pins? Or is that just a convenient marking for -12v? In other words, as long as -12v on the module and -12v on the power are connected by the same wire, does the triangle indicator matter?

More to the point, the key headers are misaligned between the power connector and my board. I've never had this issue, but even with -12v pointing the same way as the power -12v the pins don't align (and it can't be "flipped" because of the way the connectors are keyed). If that's confusing, refer to the attached picture (also note I DID NOT plug this in like this or any other way, the picture is merely for reference). Now I'm assuming this is a no-go, but my question is -

b) Is there any fix for this? Do I need a new power cable? Is this somehow ok as long as the first connected pin is -12v?

I appreciate your guys' help!
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Post by Studio-ES » Sat Aug 29, 2015 10:32 pm

When people talk about Eurorack having no power standard, yours is just one good example.

You just need to make sure the -12V from the back of the module is connected to the -12V side on your bus board's header. Which side is -12V on your bus board?

On the back of the Doepfer's PCB near the power pins, there should be one side that has a white stripe, which indicates -12V. Not all Doepfer modules have it though. That Doepfer cable pictured looks like a stock Doepfer cable too. Can't be 100% certain though.

Now find the -12V side on you bus board's headers, and make sure -12V goes to -12V.

Typically, the power cables' red stripe corresponds to -12V, but due to some manufacturers using those shrouded headers (like you have), the keyed notches don't line up so occasionally the wire needs to be reversed, the notches need to be ground down, or the header's shroud trimmed.

I know this post is a bit late, but please let us know how you made out. And who makes that flying bus cable that's pictured.

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Keso
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Post by Keso » Sat Sep 05, 2015 2:31 pm

Hello, Im still comfused abouth this triangle. Bulding my first rack right now and got a cable with the triangle on diffrent sides of the ribbon cable. Have tried to understand the meaning of this frome the first post but english isnt my first language.... is there any danger if the red stripe still is right?

plaese explane to this noob : )

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Post by Graham Hinton » Thu Sep 17, 2015 5:13 am

The red stripe on a grey ribbon cable and the moulded triangle on IDC connectors both indicate Pin 1 and should match. If you have a cable where the triangle does not match the stripe it has been made by somebody who does not know what they are doing and should be repaired or discarded.

It is unfortunate that Doepfer defined the cable orientation without reference to the proper pin numbers. Pin 1 = -12V would define how everything should go.
Not all ribbon cables have a red stripe, some have a blue stripe and if you used multicoloured ribbon cable pin 1 would be brown.

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Post by templar » Tue Oct 13, 2015 2:16 pm

EDIT: nevermind

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Post by JoakimB » Fri Oct 16, 2015 8:59 am

Hey! I'm really new to eurorack and super scared of making mistakes with the power. Need some help connecting my 4ms Spectral Multiband Resonator. :)

Below i have copy pasted from the manual. Do I need to flip the jumper thing or am i good to just plugin it in? I have a doepfer low cost case. It has both a +5v and +12v pin on the busboard. If i am good to go i would need someone to confirm that the red stripe is -12V. Couldnt find info on that in the manual. Thanks in advance! :)
Power consumption:

+12V rail:

86mA max (jumper set to 5V)

110mA max (jumper set to 12V)

-12V rail: 28mA max

+5V rail:

25mA (jumper set to 5V)

0mA (not used when jumper set to 12V)
and
Most modern modular power supplies provide power on the +5V rail. It's recommended to use the +5V rail when available. If
your system does not provide +5V, or if your +5V rail is noisy, the SMR can be set to generate its own +5V from the +12V rail
by moving the jumper to +12V as shown above.

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Post by doubtfulsalmon » Sun Oct 18, 2015 5:12 am

Ok, this might be a bit of stupid question but I figured this is the best place: I've got the version doepfer a100 diy psu with the barrel socket mounted directly to the board, what is the best way to go about connecting to a socket mounted in the wall of my case?

My first thought is to just desolder the onboard socket and replace with spade terminals or solder wires straight to it, but maybe there's an easier solution? All of doepfer's installation/technical information I can find is of the version without barrel connectors connecting board and transformer.

Thanks to anyone who can shed light on this.

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Post by Axelerator » Fri Oct 23, 2015 10:22 am

First post !
Graham, your explanation of the grounding Problem was the best i did came over in some years of DIY now ! Short and nice !
I plan to build myself two or three suitcase Systems for
different Tasks.
as all my gear is balanced , i will put balanced i/o on each case,
which should help earthing.
now my big question : should i provide some balanced Multipliers
and patch Point in each case, so i could cross patch balanced between the cases ?
..that would mean a serious number of balanced patch Points..

or would that be to much for fm/mod cv Tasks ?
-but i think i have to do it this way, or i will have the eart messed up either
and again..
Thanks in advance !
ax

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Post by Graham Hinton » Fri Oct 23, 2015 11:34 am

Hello Ax
Axelerator wrote: I plan to build myself two or three suitcase Systems for
different Tasks.
as all my gear is balanced , i will put balanced i/o on each case,
which should help earthing.
The thing that helps with earthing is to have a proper mains Earth connection to each case and not to mix the system 0Vs with the Chassis Ground. Both are connected to Earth, but should not otherwise connect, especially at jack bushings on panels.

Many so-called balanced I/O modules incorrectly connect 0V to the cable shield. This is known as "the pin 1 problem" (referring to XLRs). If so, this might upset the rest of your studio and cable shields only connected the other end. This is a pain to keep track of and I dislike having cables that are not wired 1:1.
now my big question : should i provide some balanced Multipliers
and patch Point in each case, so i could cross patch balanced between the cases ?
If think you mean balanced multiples (a balanced multiplier is a linear four quadrant multiplier used for ring modulation). Yes, any system needs multiples and a balanced one needs balanced multiples and also phase changers. It is common to use up spare sections of a jackfield for this.
or would that be to much for fm/mod cv Tasks ?
-but i think i have to do it this way, or i will have the eart messed up either
and again..
You have to decide how to organise your three systems. Either you treat each case as a separate system with a couple of balanced outputs to connect to a mixer or you want to freely crosspatch between the cases. If the latter then you need a good (i.e. low resistance) common 0V connection between the cases to patch unbalanced. My preferred approach is to have totally balanced modules so that I can freely crosspatch anywhere to outboard devices and all the modules I offer have this option when fitted with bantam jacks, but you won't find many others that do.

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Post by Axelerator » Sat Oct 24, 2015 8:00 am

Graham, thanks for your fast answer !
yes the pin 1 Problem .. i did diy all my Studio Equipment, so for this part i know i followed the same route everywhere.

I would have to diy some bufferd bal/unbal patchpoints for each case then.
this way i have control to do it right and maybe save a buck !
Do not need too much, as every system should give me enough stand alone power.
But having some Connections will open another universe..;)

so, thank you again !
ax

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Post by Graham Hinton » Sat Oct 24, 2015 8:37 am

Axelerator wrote: yes the pin 1 Problem .. i did diy all my Studio Equipment, so for this part i know i followed the same route everywhere.
I hope that is (XLR) pin 1 to chassis and NOT 0V.

Be careful if you mount bantams or TRS on the same panel as 3.5mm jacks. Ideally the panel, jack bushing and cable screen should be Chassis Ground and unbalanced signal returns should be via the 0V power rail rather than the cable screens, but that isn't the way Eurorack and other modulars are built, it doesn't have an enclosing Chassis Ground and 0V is randomly connected to panels.
I would have to diy some bufferd bal/unbal patchpoints for each case then.
this way i have control to do it right and maybe save a buck !
One way to solve this problem is to have a rear panel that is Chassis Ground and separated from the front panels frame and take the balanced connections from there to other cases or to a balanced jackfield. DB25s in AES59 format may be used on panels with 0V as long as the cable does not have an overall screen connected to the shell. Normally it is individual screens connected to pins and these should not connect to local 0Vs.

Our Octal Trimmer modules have correct 0V and Chassis Ground wiring and are often used for bal/unbal conversion in either direction.

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Post by abmusic » Tue Oct 27, 2015 11:16 pm

Hi!

So I have a Korgasmatron II coming in the mail via Ebay and had a question. Someone told me that Intellijel flips their ribbon connectors around. Is this true?

If so, does this mean the red cable will be ON TOP leaving the module and ON BOTTOM going into my bus board? Power is a Doepfer P9 case.

Thanks so much! Don't want to blow anything up.

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Post by weirdo » Wed Oct 28, 2015 3:46 am

I connected my old Cwejman Modules + Synth Tech e350 after reading in this forum.. but followed the instructions from Wowas PDF in the end. All modules are working fine. :yay:
NEVER TRUST A RIBBON CABLE! NEVER TRUST THE RED STRIPE
Thanks for this tipp!

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Post by confusedmachine » Mon Nov 09, 2015 10:13 pm

Does anyone know if you can get by with a regulated 12VDC supply into an Elby ED126? Or does it have to be 15V?

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