building your own 9v dc cables

[bartimaeus]

hi all!

you can find info on diy instrument cables everywhere, but not much on dc cables for isolated power supplies like voodoo lab and strymon. voodoo lab's longest cables are 3 feet, but i'd like to make a couple that are significantly longer (i've got a midi keyboard that runs on 9v, so i need something closer to 10').

voodoo lab recently started selling dc plugs to make your own cables. seems like they're using this jamenco part, but marking up the price a bit:
https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=138587

i figured i'd get some parts from the source and give it a go. but i haven't decided on what cable to use. does anyone have any thoughts on this? i'm hoping for something close to what truetone use on their 1spot adapter, since those seem especially sturdy.
https://www.jameco.com/z/CAR45B-100-100-Ft-Black-2-Conductor-Power-Speaker-Cable_100280.html?CID=MERCH

thanks for any input!

[ElectricDruid]

I'd say you're definitely on the right track. It doesn't make sense to spend lots of money on something as simple as a 9V DC cable. Save the cash and spend it on something that's a pain to do yourself instead. That said, sometimes it's impossible to make these things yourself for the price someone can have a robot produce 100,000 of them, so check that too.

The plugs are cheap and available in plenty of variations of quality/price. Choose how fussy you are and how much money you've got to spend.

For the cable, it needs to be reasonably flexible, but also have a low resistance, so speaker cable like you're looking at sounds like a good bet. Speaker cable comes in various grades/weights, so if you want something a bit more meaty make sure that's what you're ordering. Make sure you don't buy cable that's too big to fit through the cable strain relief of the plugs you bought (I've done that a few times with mic/instrument cable).

I can't think of any other gotchas, but maybe someone else has something?

[Rob Strand]

I can't think of any other gotchas, but maybe someone else has something?

In the past I've build a lot of these but I tended to use straight connectors.

Some of this stuff I did when I was a kid.  I'm happy to air the dumb-arse things because there were lessons to be learnt.

For the connectors.   I use straight mostly used connectors.  The connector quality here in au is pretty darn dismal.  You need to apply the absolute minimum amount of heat when soldering.   Some connectors the outer barrel becomes loose after soldering because the force holding the thing together is removed when the plastic between the barrel and the center gets remotely warm.

(not related to heat) I've found the metal on some connector is so weak that things can deform around the solder tabs and can short out.    You want the sheath on the wire to go right up to the edge of the center solder tab.    On a few occasions I put plastic tube/heat shrink around the center pin.

I never poked the wire through any wire holes, it just causes more trouble than it is worth.   

On some commercial wall-warts the cable is coax and too much heat can can melt the outer coax through to the inner sheath causing a short.  Sometimes the short won't show-up straight away.    This isn't a problem on figure 8.

Definitely don't crimp before soldering!  Let everything cool down. And don't let the crimp bite into the conductors as it can cause shorts.

I would err on smaller cable than larger since heavier cables promote most of the previous problems.   We are talking small currents so the voltage drops are small.    Wire with more strands of thinner conductors will be more reliable.

Another thing I tried was putting 15mm to 20mm of heatshrink (depending on ther connector) just past the crimp and along the cable to help stop the wires getting fatigue breaks at the crimp point.   It also stops the wires pulling out of the crimp.  You need to make sure the heatshrink size is small as possible so it tightly binds to the cable.

Lasty, I've found cheap arsed PVC cables go hard after a while and they also melt into other plastics if they sit on top of them for a while.

[vigilante397]

Back when my board was larger and more spread out I made a bunch of cables with these connectors from Tayda. Super easy to make, super cheap.

https://www.taydaelectronics.com/dc-power-plug-2-1mm-x-5-5mm-x-9-5mm-right-angle.html

[marcelomd]

I was looking for these plugs last week. Gave up and bought a premade cable.

I couldn't find the right angled ones locally and the connectors themselves were to expensive (for what they were) on ebay.

I'm not using a lot of pedals anyway so one cable once in a while was worth it.

[Mark Hammer]

I will also put in a plug (  ) for what I like to call a "power distribution box".  That is a small passive plastic box with a status LED, an additional cap for smoothing, and a bunch of paralleled 2.1mm jacks.  It serves as a kind of daisy-chain extender that you can situate at some convenient spot, and run short cables from it to the individual pedals.

As I'm sure you will find out, or perhaps have already found out, making cables of a length that reaches where they need to go without being so long as to have sloppy slack hanging around that needs to be tucked away, can be a bit of a problem.  Almost as bad as making/having power cables too short to go from the main supply to the pedal in question.  Having a sort of "satellite campus" that can turn one output of a supply into 4 or 5, much closer to the pedals, can provide a convenience.

As always, all cautions about feeding/daisy-chaining pedals from a single supply should be observed.  But if you have a handful of analog pedals whose proper functioning can be maintained from a daisy-chained common source, such a small  secondary box can provide a convenience.

[FUZZZZzzzz]

I used to work for a company that distributed these guys: http://www.stageninja.com/stage-ninja-products/professional-retractable-cable-reels/

maybe a little bit off topic, but retractable cables are pretty cool imho thus a little harder to diy.

they make cool clamps as well

[duck_arse]

a couple of years ago, I ordered some of these female in-line jacks, for to make some 9V batter clip-to-ext power adaptor cables ......
https://www.taydaelectronics.com/hardware/dc-power/dc-power-female-plug-connector-2-1mm.html

one small problem - when I grabbed the handle to unscrew it, the plastic crumbled. literally crumbled into a pile of plastic rubbish on the desk. so I threw them into a box, forgot about them until this week, got them out again as a current-build solution. gave a slight squeeze on the plastic of the 3 remaining, they all just went to bits. gah!

[PRR]

> a company that distributed these guys:

I have a drop-light in my garage which is EXACTLY their 50' power reel, except red, with a lamp. Mine must be 40 years old and I paid 1/10 of what the Ninja folks want for new.

I am flummoxed why I would want the same reel loaded with CAT6 Network cable?? Yes I move PCs and net-gear around a lot, but ? ? ? ?

[Rob Strand]

the plastic crumbled. literally crumbled into a pile of plastic rubbish on the desk

You see some crazy shit these days.   In the 70's the thought of dodgy parts never entered your head.  It's like the plastics were made using a rapid prototyping machine to use up old metal parts.   That stuff disintegrates after a while.

[bartimaeus]

thank you all for the replies, that's more info than i expected! for normal use this probably isn't worth it, even for those experienced building patch cables, but every once in a while there's one unit that's a little to far away...

For the cable, it needs to be reasonably flexible, but also have a low resistance, so speaker cable like you're looking at sounds like a good bet. Speaker cable comes in various grades/weights, so if you want something a bit more meaty make sure that's what you're ordering. Make sure you don't buy cable that's too big to fit through the cable strain relief of the plugs you bought (I've done that a few times with mic/instrument cable).

i've made that mistake with large speaker cable too, i thought something bulkier would be more reliable , but it ended being impossible to work with. seems like the insulation for this wire is a bit thicker (3.6mm) than the 24AWG listed for the internal wire, but i'm hoping it's still small enough. i guess i can always trim off extra insulation and cover the ends with heat shrink if need be. at least the wires shouldn't be too bad to solder with.

For the connectors.   I use straight mostly used connectors.  The connector quality here in au is pretty darn dismal.  You need to apply the absolute minimum amount of heat when soldering.   Some connectors the outer barrel becomes loose after soldering because the force holding the thing together is removed when the plastic between the barrel and the center gets remotely warm.

(not related to heat) I've found the metal on some connector is so weak that things can deform around the solder tabs and can short out.    You want the sheath on the wire to go right up to the edge of the center solder tab.    On a few occasions I put plastic tube/heat shrink around the center pin.

I never poked the wire through any wire holes, it just causes more trouble than it is worth.   

On some commercial wall-warts the cable is coax and too much heat can can melt the outer coax through to the inner sheath causing a short.  Sometimes the short won't show-up straight away.    This isn't a problem on figure 8.

Definitely don't crimp before soldering!  Let everything cool down. And don't let the crimp bite into the conductors as it can cause shorts.

I would err on smaller cable than larger since heavier cables promote most of the previous problems.   We are talking small currents so the voltage drops are small.    Wire with more strands of thinner conductors will be more reliable.

Another thing I tried was putting 15mm to 20mm of heatshrink (depending on ther connector) just past the crimp and along the cable to help stop the wires getting fatigue breaks at the crimp point.   It also stops the wires pulling out of the crimp.  You need to make sure the heatshrink size is small as possible so it tightly binds to the cable.

Lasty, I've found cheap arsed PVC cables go hard after a while and they also melt into other plastics if they sit on top of them for a while.

i've faced a lot of those heat-related issues with miniature 2.1mm jacks in the past, it's crazy how quickly they give up the ghost! good to know i'll need the same cautions with these...

i'll definitely use that advice about heat shrink! i expect these longer cables might be tripped on, so extra security is a must. i just hope this plastic isn't the melty kind...

I will also put in a plug (  ) for what I like to call a "power distribution box".  That is a small passive plastic box with a status LED, an additional cap for smoothing, and a bunch of paralleled 2.1mm jacks.  It serves as a kind of daisy-chain extender that you can situate at some convenient spot, and run short cables from it to the individual pedals.

a "satellite campus" is a pretty cool idea, i hadn't thought of that! i'm sure it's fairly flexible, but any thoughts on the cap value for smoothing? 10uf perhaps?

Back when my board was larger and more spread out I made a bunch of cables with these connectors from Tayda. Super easy to make, super cheap.

https://www.taydaelectronics.com/dc-power-plug-2-1mm-x-5-5mm-x-9-5mm-right-angle.html

a couple of years ago, I ordered some of these female in-line jacks, for to make some 9V batter clip-to-ext power adaptor cables ......
https://www.taydaelectronics.com/hardware/dc-power/dc-power-female-plug-connector-2-1mm.html


one small problem - when I grabbed the handle to unscrew it, the plastic crumbled. literally crumbled into a pile of plastic rubbish on the desk. so I threw them into a box, forgot about them until this week, got them out again as a current-build solution. gave a slight squeeze on the plastic of the 3 remaining, they all just went to bits. gah!

tayda is great for some stuff, but their plastics can be pretty terrible. their miniature dc jacks are also some of the worst i've found, and consistently bread on me. i'm hoping they start making them better soon, like they did with their resistors. but for now i'm pretty reticent to order either of the plastic dc jacks listed.

[Mark Hammer]

I use 100uf, but that's me.  I include a status LED (+ current-limiting resistor) to confirm that power is reaching the box.  Note that all jacks are paralleled, which means that any of them can be used as the "input" and the rest as outputs, providing some flexibility in where you can stick it on your board.

[willienillie]

^ Mine is the same, except no LED, and I used a big electro along with a 100n ceramic.  FWIW I've never noticed any noise reduction from my noisy wall wart (I have a quiet one too), I guess due to lack of series resistance before the caps.

[amz-fx]

I will also put in a plug (  ) for what I like to call a "power distribution box".  That is a small passive plastic box with a status LED, an additional cap for smoothing, and a bunch of paralleled 2.1mm jacks.  It serves as a kind of daisy-chain extender that you can situate at some convenient spot, and run short cables from it to the individual pedals.

There is one important difference between a power distribution box and a daisy chain cable. which also makes them perform quite differently in practice.

The daisy chain cable has all of the jacks on one pair of wires that extends back to the power source. This means all of the current draw from every pedal on the chain is passing through those wires, and if there is a modest amount of resistance, there can be a voltage drop on the chain that is significant enough to cause problems with noise. With the power distribution box, each output fans out from the main power source and the pedals each have a separate path for the current flow so there is less current in each power wire pair, and less voltage drop. This alone eliminates many problems, especially with high current digital pedals that may be polluting the power rail. Also, I have found most daisy chains to be of minimum quality (to keep the cost down), but you can chose the quality of wire in the distribution cables from the power box since each plugs in separately.

Best regards, Jack

[amazingalf]

I built a set of cables this weekend. They fit together very nicely and were easy to solder.

I used this cable from Redco: https://www.redco.com/Mogami-W2314-Miniature-Instrument-Cable.html

These right angle connectors from Mouser: https://www.mouser.com/ProductDetail/kobiconn/mp-136l/?qs=Lwc5PRdFGhTv4mt6A%252bSkmg%3D%3D&countrycode=US&currencycode=USD

[CodeMonk]

I used the same connectors, but different cable from here https://www.performanceaudio.com/shop/mogami Mogami 2319

[bartimaeus]

interesting! i use 2319 for all my audio cables, but thought the impedance wouldn't be right for power. i guess 9V is so small that it still works fine?

[CodeMonk]

interesting! i use 2319 for all my audio cables, but thought the impedance wouldn't be right for power. i guess 9V is so small that it still works fine?

Running up to 18 pedals, with a Power Pedal 2 Plus, some daisy chained, my pedals all work fine and the board is dead quite.
Well, 16 pedals, I have 2 pedals (MXR 10 band EQ and Fulltone Fulldrive 2 MOSFET), sharing a separate 18 volt supply.
I use 2524 for audio.
Also, audio cables are on the top of the pedalboard, with all power cables underneath.