stereo jacks for pedals

[FLchuckles]

hows comes you use a stereo jack for input and mono for output?  whats the diff?

[davent]

Power switching, the stereo jack is wired to connect/disconnect the battery's negative terminal from the circuit, when the mono plug is inserted the ring terminal (battery) shorts to the sleeve which is connected to circuit ground.. Stereo jack could be used in the output position but usually see it as the input jack.

[Ice-9]

A stereo jack socket on the input allows for the battery to be switched on/off when a jack is inserted into it or removed from it. It switches the battery negative by connecting the gnd and ring terminals together by using the barrel of the jack to make a connection between the two.

Edit-----Ha you just beat me to it Davent

[Kipper4]

the stereo jack on the input is used to switch on the power to the pedal.
theres no need to do it on the output too.
Check this out.

http://www.beavisaudio.com/techpages/StompboxWiring/

notice the ground wire from the power supply jack goes to the ring of input jack
and the ground from the pcb goes to the shield of the input jack
well when you plug your mono guitar jack cable plug into the input the ring is joined to the shield and pressto the ground now has continuaty.
theres your input jack power switching

I hope this helps
Rich

[digi2t]

the stereo jack on the input is used to switch on the power to the pedal.
theres no need to do it on the output too.
Check this out.

http://www.beavisaudio.com/techpages/StompboxWiring/

notice the ground wire from the power supply jack goes to the ring of input jack
and the ground from the pcb goes to the shield of the input jack
well when you plug your mono guitar jack cable plug into the input the ring is joined to the shield and pressto the ground now has continuaty.
theres your input jack power switching

I hope this helps
Rich

Geez, since we're on the subject, can someone look at my TC Electronics Integrated Preamp thread, and tell me why a Stereo jack is used on the input. The battery on/off is done on the output side, rather than the input. The input is handling some sort of other power switching chore, which quite frankly, I'm not getting.

Could someone explain that one to me? Thanks.

[FLchuckles]

cool! thank you for taking the time to respond!   gunna look at schematics and try to grasp that part of the circuit.

[Ice-9]

Geez, since we're on the subject, can someone look at my TC Electronics Integrated Preamp thread, and tell me why a Stereo jack is used on the input. The battery on/off is done on the output side, rather than the input. The input is handling some sort of other power switching chore, which quite frankly, I'm not getting.

Could someone explain that one to me? Thanks.

Can't find that thread Digi2t, can you post a link

[digi2t]

Better yet, here's the schematic from which I worked from. Check out the input side. Battery switching chores are handled on he output side.



What is Q1, the diodes, and resistors ? Current control?

[duck_arse]

with nothing plugged in the input, but the power on cause of the output jack, the q1 is on, shorting the opamp input to ground. plug in, transistor open, and you never even knew it was there.

and probably dethumps, too.

[digi2t]

with nothing plugged in the input, but the power on cause of the output jack, the q1 is on, shorting the opamp input to ground. plug in, transistor open, and you never even knew it was there.

and probably dethumps, too.

Thanks duck. Makes sense.

[Ice-9]

with nothing plugged in the input, but the power on cause of the output jack, the q1 is on, shorting the opamp input to ground. plug in, transistor open, and you never even knew it was there.

and probably dethumps, too.

Yes, the base of Q1 through resistors R1-R5 makes C-E conduct when when no input jack is inserted effectively grounding the input. when a jack shorts out the junction of R1-R5 to ground and the diode network D2-D3 stop Q1 conducting making an input signal pass through to C1. it seems a strange way to address power and popping. I'm guessing that it could stop all that naughty popping when inserting a jack into the input while the amp is powered up.

[digi2t]

Maybe considering that this sucker can boost up to 20db, maybe a depop circuit is a good idea, especially if the amp is cranked.