9vdc RS figured as 'cool'.

[petemoore]

  Another sicke RS Story...don't read or don't buy 9vdc jacks there...
  I suppose this has been covered.
  Q: Do you have the female 9v jacks?
  A: 'What is that'? [morphed into[ "No We don't have those"
  'A': "Can I help you find something else?'> as I'm finding them anyways...lol
  ,,,so I find the 9vdc jacks and they have no literature or seeable markings as to which pole connects to _ or + ...so I buy one figureing they'd have to be negative inside...because of all the reasons that makes sense to me...but I don't really know and decide it's worth a try.
  Get home and the thing has pos connection on the outside, or that's what it is when using the new VS One Spot power adapter.
  So I use an oversized hole, perf on the outside and inside [there's thread enough for this because it's a bent sheet box and the sheet is thin enough] and electrical tape around the threads where they could touch ... hopefully ... and it works out that way ... so far ...
  I guess silly manufacturers that use _ power supply decided that should be connected to the inside jack pin ... silly to me because I'm thinking about it without knowing which way they chose [for the most part] ... maybe it's the VS one spot that;s the silly thing...seems they tout the product as useful with Boss and other effects...in which case it would make perfect sense to have the _ Gnd connect right to the case...whatever the case may be...
  I got the thing wired up and working and the VS power supply seems to be as quiet and good working as a battery so far, in every way !!! 
  "Funky looking/working [but works], and took a long time to machine the parts.
  I'll probably be ordering some isolated jacks for the rest of the units I plan on using the One Spot to power up...works great though...that's the great news.
  Yeah, I know...I should have posted questions or somehow figured all this out before hand...but you know how it is...GOtta try this thing out TODAY...it's been a few days since I got the one spot.
  Silly Mfr.'s/RS/Boss/VS...or is it just me?
  So...be warned, if you're using RS jacks for a Pos Gnd box [I can't think of other use for them than non conductive boxes] don't let the conductive boxes touch your other boxes, I leather wrapped a FF after sparks flew one night  as it temporarily caused major crackle when it touched an NPN CCt.'s box.

[MartyMart]

Pete, i have a few of those, metal cased 9v sockets, luckily only 4/5 so they are slowly getting
"used-up" on some plastic "Hammond/LMB" boxes .... which so far.... have been noiseless !!
... phew ... !
I've had a "One Spot PSU" for a year now, first one was "duff" and caused a nasty "Whine"
when used with some Boss pedals ( DS-1 for instance )
Once swopped, zero problems from it, it's used almost every day and has been toured for
three months !!
Strange, as its very "Plastic" and weighs nothing ....
quiet as a mouse though

Marty.

[R.G.]

Some random observations and history.

The 9Vdc jack as we know and accept it today was introduced by Boss, years ago. There were earlier sporadic versions using other jack/plug pairs, notably the 1/8" (3.5mm) phone jack that never really caught hold. The DC power jack predated Boss' use of it, and comes in different sizes. The one that's accepted as standard on pedals is the 5.5x2.5 mm version.

The polarity being positive on the outside is odd, and I've mentally berated whomever did that many times. It just seems wrong, and it prevents using metal body jacks because of the shorting problem. However, I believe I've doped out a possible explanation. I think Boss may have selected the polarity because the pre-existing jack has internal switching that switches the outer sleeve so it could be used to switch the battery (+) side and still use the stereo jack trick on the battery - and - power supply negative. Doing both of those is easiest if the power jack is not permanently attached to ground.

The 1 Spot adapter does seem to work well in many, many conditions, not introducing noise or hum. There are a very few bum ones, as there are with everything, but that number is truly tiny.

Here's one thing you want NEVER to do: don't ever, ever, ever hook up one of the 9V --AC-- adapters which are sold with a few pedals. Some of Line 6's come to mind, but there are others. These adapters work well with the intended pedals, but they will quickly SMOKE the very common reverse-diode polarity protection. It's reliable enough to write a "Smoke comes out of my pedal" FAQ.

The protection diode does clamp the reverse voltage to -0.7V, all right. But in doing so, the reverse currents heat up the diode, and these power supplies are able to provide enough current to heat up the diode and eventually burn it out. Being silicon, it usually shorts. That's OK as far as it goes - the pedal won't work, but is fine if you replace the diode. But if the diode shorts, then continues cooking and burns open, the 9Vac then starts frying the semiconductors on your effect board.

[no one ever]

Some random observations and history.

The 9Vdc jack as we know and accept it today was introduced by Boss, years ago. There were earlier sporadic versions using other jack/plug pairs, notably the 1/8" (3.5mm) phone jack that never really caught hold. The DC power jack predated Boss' use of it, and comes in different sizes. The one that's accepted as standard on pedals is the 5.5x2.5 mm version.

The polarity being positive on the outside is odd, and I've mentally berated whomever did that many times. It just seems wrong, and it prevents using metal body jacks because of the shorting problem. However, I believe I've doped out a possible explanation. I think Boss may have selected the polarity because the pre-existing jack has internal switching that switches the outer sleeve so it could be used to switch the battery (+) side and still use the stereo jack trick on the battery - and - power supply negative. Doing both of those is easiest if the power jack is not permanently attached to ground.

The 1 Spot adapter does seem to work well in many, many conditions, not introducing noise or hum. There are a very few bum ones, as there are with everything, but that number is truly tiny.

Here's one thing you want NEVER to do: don't ever, ever, ever hook up one of the 9V --AC-- adapters which are sold with a few pedals. Some of Line 6's come to mind, but there are others. These adapters work well with the intended pedals, but they will quickly SMOKE the very common reverse-diode polarity protection. It's reliable enough to write a "Smoke comes out of my pedal" FAQ.

The protection diode does clamp the reverse voltage to -0.7V, all right. But in doing so, the reverse currents heat up the diode, and these power supplies are able to provide enough current to heat up the diode and eventually burn it out. Being silicon, it usually shorts. That's OK as far as it goes - the pedal won't work, but is fine if you replace the diode. But if the diode shorts, then continues cooking and burns open, the 9Vac then starts frying the semiconductors on your effect board.

very informative, thanks! now i know what to do in the ds-1 my buddy smoked a few months back...

[vanhansen]

Good points, R.G.  Question though, does it matter if you use the + or - side of the battery with the input jack trick?  I use the negative side and have had no problems.  In fact, the switching jacks that I have, which are also from RS, have 2 lugs off the center pin, 1 which is disconnected from the circuit when a DC jack is inserted.

Pete, the polarity of the jack has nothing to do with the jack itself but how it is wired up (your post came across like that to me anyway).  I've used one of these too and fried a 386 when I hooked it up with center positive rather than center negative.  Had my adapter been center positive, it would have been fine.  Instead, I saw a little puff of smoke and then a nasty smell.  Oops.  Good thing I had extra's.  New chip, swap the wires around on the jack, insulate it and she fired right up.

[Garrett]

Instead, I saw a little puff of smoke and then a nasty smell.  Oops.  

Smoke is for cigarettes and solder joints.   Always use the ol Volt/Ohm meter before applying power to your circuit.  It may save a self inflicted kick to the head. 

                             

[R.G.]

does it matter if you use the + or - side of the battery with the input jack trick?

You have to use the grounded side, whether that's positive or negative on the battery. The guitar plug you insert shorts the ring conductor lug to the (grounded) sleeve on the input jack. The switched side of the power supply has to be the grounded side. So for negative ground pedals, you switch the negative battery wire. For positive ground pedals, you switch the positive battery wire.

We could easily confuse beginners here.

We're discussing different types of jacks. The input jack for the effect is a 1/4" phone jack, and it must be a stereo jack for the power switching to work. It is possible to find 1/4" phone jacks with isolated switches that can also be used for switching power, but they are rare.

The power jacks we're discussing are the coaxial barrel type. They accept a barrel type plug with a metal sleeve on the outside and a hole in the middle of the plug. These jacks have a third lug that is shorted to the outer sleeve contact when there is no plug inserted.

[vanhansen]

does it matter if you use the + or - side of the battery with the input jack trick?

You have to use the grounded side, whether that's positive or negative on the battery. The guitar plug you insert shorts the ring conductor lug to the (grounded) sleeve on the input jack. The switched side of the power supply has to be the grounded side. So for negative ground pedals, you switch the negative battery wire. For positive ground pedals, you switch the positive battery wire.

Cool, thanks.  I've been using the negative battery wire as the switch for my negative ground builds.  I totally wasn't thinking about the ring lug of the stereo input jack being tied to the sleeve with a mono plug when I asked that question, and I knew that.  Silly me.

...MORE COFFEE PLEASE!!   

[Eric H]

However, I believe I've doped out a possible explanation. I think Boss may have selected the polarity because the pre-existing jack has internal switching that switches the outer sleeve so it could be used to switch the battery (+) side and still use the stereo jack trick on the battery - and - power supply negative. Doing both of those is easiest if the power jack is not permanently attached to ground.

Yes.
Also the pin connects first (as you insert the plug), grounding the supply before the positive is connected. If you yank out the plug, the ground is the last thing to go. Probably a good thing.

-Eric

[The Tone God]

http://www.diystompboxes.com/smfforum/index.php?topic=33606.0

I will furthur add to my post in the above linked thread that most barrel power jack cases are plastic and insulated from the mounting surface reducing the problems of ground/power isolation.

The only problem for us is that it is hard to make the appropriate holes for those jacks. We end up using the bulky round isolated jacks which can be drilled with ease.

Andrew

[petemoore]

Pete, the polarity of the jack has nothing to do with the jack itself but how it is wired up (*your post came across like that to me anyway).
   Yes, that is what Was meant, another thread contains an 'addendum' including more recent thinking [on my part] that the jack itself could have the text 'assigned polarity' or something...
  The RS 9vdc jacks I bought have but two lugs...no switch...which is ok for me, I prefer to either let them run, or switch the wall power supply before the wart to keep the WW from running when not in use. I Most often leave all the signal connecting cables in place anyway.
  Yupp, when using non insulated jacks like these, it is simple but a little messy to just invert the polarity before the jack [ie cut the adaptor wire, invert it, solder it, iso-insulate...wrap them with tape, which is the next thing I'll do].
  While I'm cutting and inverting the WW's wire, I'll add some plugs at that point, maybe even 1 battery clip.

[Paul Marossy]

I have a bunch of pedals with those RS jacks. I just used some electrical tape and o-rings to isolate the jack from the enclosure. 

[petemoore]

I just used some electrical tape and o-rings to isolate the jack from the enclosure. 
  Thas what I've got going on for the 1 pedal I've installed a jack in, but I'm reversing the polarity of that jack and the PS so all the jacks holes can be simply drilled...and that's all. Neeter, sweeter, less messy looking, Super EZ/sure fire. Plus I won't have to worry about the hole eating it's way through the electrical tape somehow...probably wouldn't [I have three wraps thick on it].