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DIY 5U Case Questions
MUFF WIGGLER Forum Index -> 5U Format Modules Goto page Previous  1, 2, 3 [all]
Author DIY 5U Case Questions
Rex Coil 7
Dave Peck wrote:
CZ Rider wrote:

Here is a link to see the various grain and colors available. I chose the "rough black" grain.
http://www.thevintagesound.com/store/tolex-and-tweed-specialty-tolex-c -8_34.html



Well your new cabinets certainly look great, but next time you just gotta use the 'brown alligator' or 'brown ostrich' patterns! This is fun!
Snake skin.
Dave Peck
Rex Coil 7 wrote:
Dave Peck wrote:
CZ Rider wrote:

Here is a link to see the various grain and colors available. I chose the "rough black" grain.
http://www.thevintagesound.com/store/tolex-and-tweed-specialty-tolex-c -8_34.html



Well your new cabinets certainly look great, but next time you just gotta use the 'brown alligator' or 'brown ostrich' patterns! This is fun!
Snake skin.


Ah, did not see that! Even better!
tardishead
[quote="Rex Coil 7"]
CZ Rider wrote:


What Kreg needs to do is offer the small one with the large one as a kit, so you're only buying one saw trolley. While those tools are not anything as good as a table saw, for those of us that can't afford a true table saw or don't have the space for one, them Kreg units look like good solutions. In fact, the long one may be easier to use than a table saw when ripping an entire sheet of something. Watch the videos.


Yeh they look great. A cheap table saw is a waste of time and money. I bought a Makita table saw which is not worth the metal its made with. Terrible. Its only good for ripping planed pine boards. Sheets of ply and mdf - forget it. Right angle cuts no way!
hamildad
Dave Peck wrote:
CZ Rider wrote:

Well your new cabinets certainly look great, but next time you just gotta use the 'brown alligator' or 'brown ostrich' patterns! This is fun!
Snake skin.


For Tolexing my TTSH case I used Deep Space. Far more appropriate for the sounds I was making...

http://www.mojotone.com/Cabinets_x/TolexCarpetTweed_x/Mojotone-Deep-Sp ace-Tolex-55-W
Flareless
CZ Rider wrote:
My favorite DIY project was a custom Moog 1150 ribbon controller made into a synthesizer/guitar. Done in red mahogany, looks wicked badass.
]


Dunno how I missed this earlier.... WOW eek!

That's freaking awesome CZ! thumbs up applause
Rex Coil 7
hamildad wrote:
... For Tolexing my TTSH case I used Deep Space. Far more appropriate for the sounds I was making...

http://www.mojotone.com/Cabinets_x/TolexCarpetTweed_x/Mojotone-Deep-Sp ace-Tolex-55-W
Almost looks like that metal flake tuck and roll stuff Kustom used to put on so many of their offerings.

This here is the Kustom Kombo in black metal flake tuck and roll. Just looking at it makes "Green Onions" play in my head.



(Give this guy a minute or two, he starts warming up ... is it 1968 again?) ....



thumbs up
tardishead
Damn I love those old combo organs
I've got a few Farfisa
hamildad
sorry for the n00b question but what are those bars that people run along the bottom of their cases??



I guess its grounding, but it seems a lot of work....

just mocking up plans for my case, so didn't want to miss an obvious design
tardishead
Aluminium bussbars for power and ground
Very low resistance
Good power distribution reduces clicks, noise, crosstalk, cross modulation etc.
Rex Coil 7
hamildad wrote:
sorry for the n00b question but what are those bars that people run along the bottom of their cases??

I guess its grounding, but it seems a lot of work....

just mocking up plans for my case, so didn't want to miss an obvious design


tardishead wrote:
Aluminium bussbars for power and ground
Very low resistance
Good power distribution reduces clicks, noise, crosstalk, cross modulation etc.
This is very true. I'm going to hitch on to that response and expand on the concepts ... I've used some generalized explanations in an attempt to simplify the ideas a bit ... Get comfortable:

In a 5U system, the power supply has four "rails" (four different voltages) that are provided by the power supply. There is 15 volt positive - 15 volt negative - 5 volt positive - and one called Zero Volt. In the picture you referenced of my synth, there is one aluminum bar (known as a "bus bar") for each voltage. Those bus bars are part of the "power distribution system" since they are used to distribute power to all of the modules. That picture is of the bus bars in an unfinished state. They had not been drilled for the screws which are used to connect the power cables for each module. As you may guess, each power cables has four wires ... one for 15v neg - one for 15v pos - one for 5 volt pos - and lastly one for Zero volt (aka "0v").

This diagram I sketched up (below) depicts a basic power transformer used in the power supply for synthesizers. On the left side is the power coming in from the wall socket. On the right side is the power output side. Left = input (called "primary" side or "primary voltage"), right = output (called "secondary" side or "secondary voltage"). Let's look at the right side, just beneath where it says "Dual Secondary Windings". Note the little "+" sign next to where it says "15 volt". That's the 15 volt positive power rail. Think about how electricity powers something .... electricity must flow both TO the device, and the it must flow back FROM the device ... this is called a "complete circuit". Voltage has flown both to, and from the device being powered up (like a light bulb, or a synth module). So if the 15 v+ is flowing TO the module, how does it return back to the power supply? It uses the Zero Volt wire (the word "wire" can also be expressed as "rail" or "tap") to return back to the transformer to create the complete circuit.

The same exact process happens for the 15 volt negative output ("rail" or "tap"). 15 volts negative flows from the transformer, out to the synth module, then back to the transformer using the Zero Volt wire (or "rail" or "tap") to return to the transformer creating that completed circuit again. As you may be able to tell by now, the Zero Volt "rail" (or "tap") has a lot of burden placed on it because it is responsible for carrying both the negative and positive voltage "returns" to the transformer secondary windings.

(Note that in 5U/MU systems there is that extra 5 volt "rail" coming out from another "tap" in the secondary windings, it too must use the Zero Volt wire to complete it's roundabout circuit ... however Euro systems do not generally have a 5 volt "tap" ... just to get that said).



So as the power is sent out of the transformer to the modules, the aluminum bars act as conductors, each one carrying a different voltage TO the modules, with one of the bars being responsible for carrying voltage BACK to the transformer. That is the Zero Volt Bar.

Below is a picture of a completed bus bar system built by Graham Hinton of Hinton Instruments in the U.K. (look at the lower right side of the image). When completed with all of the modules' power cables attached, a bus bar system looks more like this (I used a Euro power system as an example for no other reason than it was all I had on hand when I posted this ... don't let the fact that you only see three bus bars throw you ... as I had said above, Euro systems are configured differently than 5U/MU systems having only THREE bars instead of FOUR.)



Why use these big ass bars? The bus bar distribution system is what I call the "apex predator" of power distribution systems. You can just use a bunch of wires all soldered together at one end (tying all of them together in bundles, each bundle representing one of the separate voltages). Like so (below is a Synthesizers.Com "QDH" power distribution "Squid" ... called a "squid" due to it's squid-like appearance).

Note how there is one ~thicker~ wire attached to one "bundle", and there are four bundles. Each single bundle feeds a number of modules. One single "thicker" wire comes directly from the transformer's voltage taps (one wire for 15 pos, one for 15 neg, and so on).



(below) you can better see how this system is set up. One thick wire that comes from one transformer "rail", then a number of thinner wires soldered directly to the thick wire. One soldered up "wad" is the same as one bus bar. It's where all of the modules' power cables receive "power distribution" from.



Why is the bus bar system better? Let's think of electricity as people. Let's think of (let's say) 100 people. Now, think of the bus bar as a hallway in an apartment building. And think of each individual apartment as a synth module. As you might imagine, the WIDER the hallway, the more efficiently those 100 people can traverse through it. The more narrow the halllway, the less efficiently those 100 people can all walk through it. The WIDE hallway is like the bus bar. The NARROW hall way is like the soldered-up wire wads.

Since each apartment door only needs to deal with one person to go through it, it can be much more narrow than the hallway. Said another way ... the power distribution system (the hallway) needs to be as wide and unrestrictive as possible .... but the individual module power cables (the door to each apartment) can be much less "wide" (or more restrictive) since it's only dealing with a single person (module).

This is why it's ok to have skinny little module power cable wires, but not as ok to have a restrictive power distribution system.

Let's extend this analogy a bit farther. Think of each hallway as the "to my apartment" hallway (same as the 15 volt power rail), and think of each voltage (positive, negative) as a single floor (one floor for positive, one floor for negative, and so on). So there is one hallway on each "floor" (one wire for each voltage). 3 separate floors, each with it's own "go to my apartment hallway". But, there is only ONE "return to the street hallway" for all of the floors! That one single "escape" hallway is like the Zero Volt rail. It has to deal with ALL of the people coming out of each floor of the building at once. 3 separate hallways to get IN TO EACH apartment on each floor, but only ONE hallway to get out of all of the apartments FROM ALL of the floors. Which is why the Zero volt conductor (the escape hallway for all of the floors) has to be well though out.

So .... the hallway is like the distribution method (bus bars = wide hallway, or soldered bunch = narrow hallway) and the apartment door is like a power cable for one single synth module.

You can also think of the power system like a tree. With the power supply being the trunk, the bus bars being the branches, and the modules being each leaf. As you get closer to each leaf, the trunk turns into branches, the branches turn into twigs, and each twig feeds each leaf. Big heavy conductors close to the power supply, and they can become smaller as they approach each module (leaf).

With all of that said, the bus bar system is the "apex" of distribution systems. It provides nice heavy branches (hallways) that feed each little twig (door or module power cables) that feed each module (apartment or leaf).

However, many people "get away with" having less efficient systems. That can create some problems such as cross talk, and leakage (LFO signals reaching modules even though there is no patch cable connecting the module to the LFO), grounding problems (which can create audible noise), and some modules that use human fingers as conductors (aka "capacitive controllers" like the Rene, or like the Lightstrip modules where your finger is actually conducting electricity ... sortof ... so just touching the panel makes the module change it's activity which is how the module is actually designed to operate). Some of these "capacitance" type modules don't work right at all if there are power leaking issues and grounding issues.

Why have I gone to all of this trouble if I can get away with a less involved setup? Because I wanted to build an "apex distribution system". Same reason anyone climbs a mountain or enters a foot race. To do it the best way possible. Yes, it takes time. A lot of time. Yes, it takes patience. Yes, it takes a lot of attention to detail.

All of those "yes" answers are precisely why synthesizer case manufacturers don't go to all of that trouble. It takes a lot of labor, which drives the price of the power distribution systems up.

New customers just getting started with modular synths find the power system to be the biggest "drag" ... it doesn't make any sounds, it doesn't look cool, and it's all hidden inside of the cabinet. So it's a big old drag. It deters people from getting started with modular synth systems. So to draw in new customers, manufacturers tend to sell "narrow hallways" (if you will) to attract new customers. They ~work~ ... but they're not the optimum.

There are very few manufacturers that offer high spec power systems, but the idea of "solid power" is gaining traction in the modular synth community, so we're seeing better efforts being offered as time goes by.

Hinton Instruments makes top end "apex" bus bar systems, which are far less costly than most people think. When you think of the total cost put into the collection of modules most people end up with, investing less than 10% (that's ten percent) of the amount spent on modules is really "nothing" compared to what is invested in modules. It is money well spent, that's certain.

But starting out, a less efficient system is acceptable. But be aware that, that "tree" is going to grow like the proverbial WEED. So be prepared.

If you are designing your own cabinet, it is most wise to design the power system FIRST, then design the cabinet around the power system. Most people install the power system nearly as an after thought, long after the cabinet has been designed and built. This is the least wise method of doing things. Going back to the apartment building analogy, it's like designing the entire building first, then putting in the fire escape system as an after thought. When the most people are going to be flooding those "hallways" all at once attempting to flee to safety.

Apologies for the extended length of this post. I wanted to address the question of "what are those bars for?" not just for the person that asked it in this thread, but to provide some answers for all of the lurkers and searchers that may come across this thread/question from afar.

Lastly, here's a more representative image of my bus bar system as it is now (nevermind the terminal strips mounted on the angle aluminum railing suspended above the bus bars, those are for distributing CV signals into the rear of each module as part of a CV signal normalizing project I am doing in my synthesizer ... which is a completely separate topic) .....





The heavy aluminum "blocks" are where the heavy cables that come directly from the power supply connect to each bus bar. In the picture below, you see the heavy cable (Class K 1/0 welding cable) compared to 16 gauge wire, and 24 gauge wire. The 16 gauge is the "big wire" that was soldered to the bundles of the soldered bunch system .... the 24 gauge is what the individual module power cables are made of ... just to provide a visual comparison.



As power distribution systems go (in their order of preference) .. best being first:

** Bus Bars. (really wide hallways)
** Bus Boards. (not as wide hallways).
** Soldered bunches. (narrow hallways).

I'd best sign off here. This post has become ridiculously long, and I have not even addressed chassis grounding yet!

Hope I helped!!

(unsubscribed - not mad or having a hissy fit - just trying to keep my number of subscribed threads under better control - if you wish to correspond please feel totally free to send me a PM - thanks!)

cool
hamildad
this is brilliant, thanks,

I'll spend a bit of time digesting all this, but its really great to have this knowledge in one place.
tardishead
Rex Coil 7 wrote:

I'd best sign off here. This post has become ridiculously long, and I have not even addressed chassis grounding yet!
Hope I helped!! cool


Great post. Really helps when everybody can visualise every aspect of this.
Lets spread the word.
tardishead
CZ Rider wrote:

The Moog P cabinet dimensions are 8" deep, 24 3/8" high and 18" wide. Moog used 1/2" plywood. I did simple butt joints and glued them together. So my top and bottom pieces were 18" X 8" and sides 23 3/8" X 8". I think that was I cut them to. Just purchased a 4' X 8' X 1/2" sheet of plywood and ripped it with a table saw.
I did a few walnut cabinets, but those were the first tolex type. Wanted to expand the original Moog.
Here is an almost 5U Aries modular I did in walnut.
Can see the general construction, with walnut sides, top, cross pieces and a valance panel. Used a 3/4" plywood base.


Hey there
Couple of questions
How far back from the front of the cabinet are the modules set back? 1/2"?
And the case lids on Moog cabinets how deep are they. I presume they are made with a large flat piece of 1/2" ply with 1" ply strips?
CZ Rider
tardishead wrote:


Hey there
Couple of questions
How far back from the front of the cabinet are the modules set back? 1/2"?
And the case lids on Moog cabinets how deep are they. I presume they are made with a large flat piece of 1/2" ply with 1" ply strips?

The original Moog modules are almost flush with the sides. Might be 1/64" or 1/128" recessed. The lids are all the same construction, all 1/2" plywood. I will have to measure the depth. Don't use those much and they are stored away.
tardishead
CZ Rider wrote:

The original Moog modules are almost flush with the sides. Might be 1/64" or 1/128" recessed. The lids are all the same construction, all 1/2" plywood. I will have to measure the depth. Don't use those much and they are stored away.


Thanks thats great.
So one more question. Where did you get the corners from?
And what American size screws are used to secure the modules 8-32??
hamildad
Quick question as I need to get his straight in my head.

if I am running wires from PSU to 3x distribution blocks, I need a mult but for power, so PSU goes to mult and then I can safely distribute the 15V/-15V/Com to each dizzy block without wiring 3x cables to each powerone post.

something like a Wago 222 terminal block would work for this?

whats the safe and secure method of doing this?
hamildad
Have come up stumped, almost finishing the electrics in my case.

I am distributing the +15V & -15V via Wago 222 terminals.

I send a healthy 15V into the Wago only to get a measly .8V out the other end.

I thought Wago's were straight bus terminals, so cant work out whats going wrong??


Huba-Swift
Have you checked for shorts between your voltage rails? It's hard to tell from your picture, but I'm guessing the red wires are being used for both -15v and +15v? I could see it being pretty easy to mix them up. If there aren't any shorts between any voltage rails I'd also check the continuity of the Wago bus terminals. I'm not familiar at all with Wago terminals so I have no idea if they're straight up bus terminals, but seeing as you have a little meter it shouldn't be hard to track down the culprit.
hamildad
Went back to it and it was crossed wires. All giving a thorough 15v where needed and the PSUs been trimmed to 15.00v.

IEC socket keeps blowing the fuses but i’ll Just have to search for any stray wires and make sure I have the right fuses.

Might even have sound out of it by the end of the weekend!
hamildad
Managed to get the main case all sorted, some seriously, i just don't get it with regards to a STG EG that liked one power cable and didn't like another, and I have a STG switch that might have got confused in transit...

Now got a wiring issue with the upstairs cab..... not difficult to fault find, but I tested it yesterday and was looking good....

got a Q960 and Q170 being brought over from the US by colleagues next week, so thats a good incentive to get it all working...
Synthbuilder
hamildad wrote:



I'd put the Wago blocks much closer physically to the output pins of the power supply. Use the thickest and shortest leads possible to connect the blocks to the power supply pins.

Then use the thickest and shortest wires to connect the Wagos to the distribution PCBs. The wire lengths look a little longer than they should be at the moment.

Or...

Replace the Wago blocks with a Faston block like this one:

https://www.rapidonline.com/Catalogue/Product?Id=21-0716

I think it'll probably allow for much thicker wire. You'll need a crimper and a suitable number of 1/4" blade female sockets.

Also, what's the black and white wires going to each of the distribution boards? Is it mains earth? I'd be tempted to connect mains earth to the 0V connection on the Wago/Faston block - again a nice thick wire is needed here. There is no need to earth the 0V outputs at the power supply if the distribution is earthed - although the metal frame of the PSU should be bonded securely to earth for safety reasons. Any earth wiring that goes to 0V should be kept a reasonable distance away from the transformer without adding excessive length to the wire. Wiring taken too close to mains transformers can create hum problems.

Tony
hamildad
thanks for the comments Tony,

I've trimmed the leads to the Dist blocks since phot was taken, but will think about moving the Wago blocks. I'm always worried about too tight cables getting strained in movement. but I can easily trim this lot down.

Quote:
what's the black and white wires going to each of the distribution boards?


the Krisp1 boards I used have a GND fixing hole, so this is Mains earth going to the boards. (using shamefully thin wire though)

Quote:
There is no need to earth the 0V outputs at the power supply if the distribution is earthed


If I can upgrade the wire on the above Earthed connection to Dizzy board, I might do away with the Earth to 0V.

Quote:
although the metal frame of the PSU should be bonded securely to earth for safety reasons.


yep, all done.
cornutt
Nice work! Where did those distro boards come from? (Or did I miss that in the thread?)

hamildad wrote:


If I can upgrade the wire on the above Earthed connection to Dizzy board, I might do away with the Earth to 0V.


Mine is not earthed at all. Avoids ground loops this way. I plug it into a GFCI for safety (I think you guys call it an RCD).
Synthbuilder
cornutt wrote:
Nice work! Where did those distro boards come from?

They're Oakley Dizzy MU boards available from Krisp1.

Quote:
Mine is not earthed at all. Avoids ground loops this way. I plug it into a GFCI for safety (I think you guys call it an RCD).

Unless you are using a double insulated external transformer specifically designed to work with no earth then missing the earth off is a really bad idea. Apart from the safety issue there is also a problem with excessive leakage currents from the mains side to the low voltage side. If they aren't shunted to earth properly you can get excessive noise on your audio outputs.

Tony
hamildad
2x Oakley Boards as the man says.

then I have Corsynth board for the Cabinet above.

the reason for this is I can drive the top cabinet off the main PowerOne PSU when in joined up mode, but then I can use a dotcom PSU to drive the top Cabinet separately if I just want to roll with a 13MU set up.

the Oakleys dont need a 5V, but I needed 5V separately on the top board to use the dotcom PSU.

re: missing out earth, you wont get me missing it out on anything. not in this country....our houses have proper earth,so its a vital safety measure.
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