Stereo Jack question

[Canucker]

Why do some places show a stereo jack for the input in a layout and some places don't? Whats the benefit of using one or drawback of not? I probably should have asked this a lot sooner since I have been building for a while.

[jimilee]

Why do some places show a stereo jack for the input in a layout and some places don't? Whats the benefit of using one or drawback of not? I probably should have asked this a lot sooner since I have been building for a while.

Stereo input if you're going to use a 9 volt battery in addition to external power. If you don't use a stereo jack your battery will run down even when nothing is plugged in.

[Canucker]

Thanks for the fast reply and making it simple! I always include a battery clip.

[Canucker]

Just to add...does it need to be the input? Can it be the output jack? I've really never come across this info before...I felt kind of silly for asking like I missed something along the way but its obviously good that I asked!

[jimilee]

Just to add...does it need to be the input? Can it be the output jack? I've really never come across this info before...I felt kind of silly for asking like I missed something along the way but its obviously good that I asked!

either is fine, it all grounds to the enclosure anyway . it's all good, this is how I learned as well, just ask questions along the way.

[Canucker]

I'm not really that shy about asking questions because people on here are really cool and knowledgeable. I figure there are always so many new people around that others will benefit from starting a dialogue. Thats my backwards way of contributing around here 

[Keppy]

Commercially built pedals use a stereo input jack almost universally. If you're building for someone else, it's expected. If it's for you, do what you want. Run the negative supply to the jack ring, so when a mono plug is inserted it will connect the ring to the sleeve, connecting the negative power supply to ground.

[GGBB]

The only reason to use the input jack and not the output is convention.  If you have battery powered pedals on a board or otherwise, you always know to disconnect the input to avoid draining the battery - no guessing.

[nocentelli]

If you have battery powered pedals on a board or otherwise, you always know to disconnect the input to avoid draining the battery - no guessing.

Unless you've got a BOSS RC-2.... 

[Mark Hammer]

I'm not really that shy about asking questions because people on here are really cool and knowledgeable. I figure there are always so many new people around that others will benefit from starting a dialogue. Thats my backwards way of contributing around here 

I like your attitude.  When I used to be a prof, that's pretty much what I'd tell my students: ASK! there will be many others, who were so confused they couldn't even put the question together, who will be glad you did.

The use of a stereo input jack has simply become a convention.  Battery switching could be done via the output jack, but it's just better if one goes through the identical action for all pedals, instead of these actions for these pedals, and a different action for that one.

If one is intent on using external power, a mono jack will happily suffice.

In past, some pedals would include a switch on a pot (often volume) to turn the power on or off.  In others - all the various licensed Mutron II clones had this - there would be a toggle switch to turn on a pair of batteries; something that was tricky to do with a single jack.  In recent years, the use and availability of charge pumps has made it possible for bipolar power to be provided  from a single-ended source, sidestepping the requirement for a toggle to turn on TWO batteries at once.

[PRR]

Battery switching with the OUTput jack can throw a big POP at the amplifier.

Batt-switch at the INput puts a big pop into the guitar, which is silent and apparently harmless.

[jimilee]

Battery switching with the OUTput jack can throw a big POP at the amplifier.

Batt-switch at the INput puts a big pop into the guitar, which is silent and apparently harmless.

You mean when you activate the effect?

[Canucker]

Tell me how much sense this makes.... I plugged a patch chord into one of the jacks I had, turned on my volt meter and started testing the tabs on the jack...with the jack in should the reading on my meter not be zero when I touch on the sleeve and the ring tabs at the same time? No matter what combination of tabs I touch the meter never displays zero.
I tested this because I had one of these jacks on an effect and after swapping things back and forth I wasn't getting a signal...unless I connected the battery ground and effect ground to the same tab.
I tried this with more then one jack and when I purchased them they were labeled stereo jack. Am I missing something?

[jimilee]

How us the + hooked up? Basic dc input, ground wire, hot wire, 9v wire?

[greaser_au]

Battery switching with the OUTput jack can throw a big POP at the amplifier.

Batt-switch at the INput puts a big pop into the guitar, which is silent and apparently harmless.

You mean when you activate the effect?

the pop will occur during plugging it in.  Consider what happens when you insert a mono plug into the jack:
1: the plug is just inserted- the plug tip touches the jack sleeve
2: the plug is halfway in -  the plug tip touches the jack ring contact,  and the plug sleeve touches the jack sleeve.
3: the plug is fully inserted - the plug tip touches the jack tip contact, and the plug sleeve is touching the ring & sleeve of the jack.

if we assume a  negative ground pedal, at 3,  the completed power circuit is  batt+...circuit+...circuit-...jacksleeve...plugsleeve...jackring...batt-
however at 2:  the completed power circuit is  batt+...circuit+...circuit-...jacksleeve...plugsleeve...guitar...plugtip...jackring...batt-

using the input jack, you won't hear the small amount of current flow caused in the guitar, but using the output jack there will be a (close to) 9V step seen by the amplifier input...

david

[Canucker]

How us the + hooked up? Basic dc input, ground wire, hot wire, 9v wire?

didn't include an adapter jack so just ground wire, hot wire and 9v wire.

[Thecomedian]

Battery switching with the OUTput jack can throw a big POP at the amplifier.

Batt-switch at the INput puts a big pop into the guitar, which is silent and apparently harmless.

You mean when you activate the effect?

the pop will occur during plugging it in.  Consider what happens when you insert a mono plug into the jack:
1: the plug is just inserted- the plug tip touches the jack sleeve
2: the plug is halfway in -  the plug tip touches the jack ring contact,  and the plug sleeve touches the jack sleeve.
3: the plug is fully inserted - the plug tip touches the jack tip contact, and the plug sleeve is touching the ring & sleeve of the jack.

if we assume a  negative ground pedal, at 3,  the completed power circuit is  batt+...circuit+...circuit-...jacksleeve...plugsleeve...jackring...batt-
however at 2:  the completed power circuit is  batt+...circuit+...circuit-...jacksleeve...plugsleeve...guitar...plugtip...jackring...batt-

using the input jack, you won't hear the small amount of current flow caused in the guitar, but using the output jack there will be a (close to) 9V step seen by the amplifier input...

david

with amp on, having cable into amp jack and then touching the exposed end of the cable on the other side will lead to noise. Plugging it into an instrument with an active 9v battery stereo jack configured will cause a pop as well. If you want no pop, turn the gain down to zero on the amp before plugging it in. I have volume knob on unit and gain on amp turned to zero when hot plugging. It's not supposedly an issue, but it does make an unpleasant sound.

[Mark Hammer]

I always understood the audible pop during plugging in to be a byproduct of those pedals that used FET-switching, like Boss pedals.  If one looks at the schematics, you routiely see a "hanging" cap that is unterminated until you plug in.

Some other effects, chiefly things like boosters, from what I can tell, can have hanging caps on the output as well, though "effects" are usually terminated.

[Canucker]

This is the jack (or collection of jacks) I'm having issues with... the center tab is tip or hot or whatever you wanna call it. I explained it above but I'll do it again. If i attach the negative lead from the battery clip to a different tab then the ground to pedal it won't work (I've tried every combination)...only when I attach the pedal ground and the battery ground to the same tab...therefore making it act like a mono jack not a stereo. I know its not the greatest quality but its whats available locally. Thanks for taking a look.

[Jdansti]

What you have there is a normally closed mono-switching jack.  When the plug is not inserted, the tip terminal is connected to the third terminal.  When you insert the plug, the connection is broken.