MXR Distortion + Schematic questions

[o_gold]

Hello,

I'm new to guitar pedal (and electronics in general). I've got a question regarding the MXR Distortion plus schematic: http://create-electro.blogspot.com/2010/05/mxr-distortion-plus-schematic-diagram.html.

In this schematic I see there is an adapter input but also a battery sign. How does it works? when I connect the pin of the power jack to the input (AC Adapter) it disconnecting the battery from the circuit ?

I see very clearly the +v of the circuit but I cannot understand the gnd connection in this schematic. it seems that the gnd (-) of the battery is connected to the sleeve of the input jack?  how is connected to all the ground in the circuit?


What is the Earth sign you see in all three jacks (In, Out, adapter) ? should I connect it to my battery ground? (is there any difference ?)

Thanks for any help!

[GibsonGM]

Yes, in real life, plugging in a power adapter will disconnect the battery.  It is a "switching jack".     

The effect is off until you plug your guitar cable in, and then the sleeve of the plug grounds the battery (or adapter), turning the effect on.   Yes, the power is grounded the same way your AC guitar signal is     No, there is no difference in the way most effects are set up.  One ground point, essentially.

There is much info HERE  http://www.generalguitargadgets.com/how-to-build-it/technical-help/switching-and-wiring/bypass-sw-options/,  primarily under true bypass options and 3PDT, which are the norm to use today.   Look as this stuff, see if you have any questions about it, and let us know if it doesn't clear some of this up!

Hope that helps! Welcome to the forum!

[Govmnt_Lacky]

In this schematic I see there is an adapter input but also a battery sign. How does it works? when I connect the pin of the power jack to the input (AC Adapter) it disconnecting the battery from the circuit ?

By using the particular DC power jack, when you insert a wall wart (AC to DC wall power adapter) it disconnects the battery V+ (power) from the circuit and uses the power input from the wall adapter instead.

I see very clearly the +v of the circuit but I cannot understand the gnd connection in this schematic. it seems that the gnd (-) of the battery is connected to the sleeve of the input jack?  how is connected to all the ground in the circuit?

The battery GND (-) is connected to the RING of a stereo input jack. The pedal/circuit GND is connected to the SLEEVE. By doing this, it allows the battery to be "shut off" whenever you disconnect the input plug. When the input plug from your guitar is inserted, you connect the SLEEVE and RING which completes the Ground circuit and allows power from the battery to flow into the circuit.

What is the Earth sign you see in all three jacks (In, Out, adapter) ? should I connect it to my battery ground? (is there any difference ?)

Connect Your Input jack SLEEVE, Output jack SLEEVE, DC Jack center pin connection, and the circuit/PCB GND together. You battery Ground should go to the Input jack RING. (You will need a stereo input jack for all of this to work)

Here is good info to help you understand. Just look at how the Input jack, Output jack, DC power plug, and battery are wired up:

http://beavisaudio.com/techpages/pedalpower/


Hope this helps 

[antonis]

In this schematic I see there is an adapter input but also a battery sign. How does it works? when I connect the pin of the power jack to the input (AC Adapter) it disconnecting the battery from the circuit ?

Absolutely true & correct..!!

I see very clearly the +v of the circuit but I cannot understand the gnd connection in this schematic. it seems that the gnd (-) of the battery is connected to the sleeve of the input jack?  how is connected to all the ground in the circuit?

Only by plugging Input plug into Input stereo jack..
It makes connection between Input Sleeve (already grounded) & Ring (connected to -9V)..

What is the Earth sign you see in all three jacks (In, Out, adapter) ? should I connect it to my battery ground? (is there any difference ?)

Earth (brush) & GND (arrow) should be considered as one common point..
In some schematics, Earth is refered on enclosure ground and GND on Circuit ground..
Despite particular symbol, all of them should be connected together..
(but with some caution, to prevent ground loops..)

edit: Too many, faster than me, guys are hanging around..

[antonis]

Welcome to the forum!

So, your Highness only welcomes after the 3^rd post, Sir..?? 

[Mark Hammer]

What can't be conveyed in a schematic - at least not easily - is that many kinds of jacks are made of materials that have "spring" qualities.  That is, they can be bent when pressure is applied, and then return to some position when pressure is removed.  For power purposes, the "default" position is that the + lead from the battery connector is connected to the wire feeding +9V to the circuit board.  When a plug is inserted, it pushes a contact out of the way, such that this default contact is broken and the power to the bard comes from whatever the plug is providing, instead.

The general category of jacks that have such automatic defaults is referred to as "closed circuit" jacks in that a circuit/connection is closed/completed when no plug is inserted.  One doesn't HAVE to make use of the default connection.  It's just there if you want or need it.  A case in point is headphone jacks.  The default is feeding the audio output to speakers.  Insert a headphone plug and the feed to speakers is broken, and provided to the headphones instead.

[o_gold]

Yes, in real life, plugging in a power adapter will disconnect the battery.  It is a "switching jack".     

The effect is off until you plug your guitar cable in, and then the sleeve of the plug grounds the battery (or adapter), turning the effect on.   Yes, the power is grounded the same way your AC guitar signal is     No, there is no difference in the way most effects are set up.  One ground point, essentially.

There is much info HERE  http://www.generalguitargadgets.com/how-to-build-it/technical-help/switching-and-wiring/bypass-sw-options/,  primarily under true bypass options and 3PDT, which are the norm to use today.   Look as this stuff, see if you have any questions about it, and let us know if it doesn't clear some of this up!

Hope that helps! Welcome to the forum!

Thanks for your answer!

the dc jack have three connection S -  Sleeve, C - Connect, P - Pin.

So if I understand correctly, the positive(red) of the battery is connected to the common(connect) pin of the dc jack. the sleeve pin of the dc jack is connected to the +v of my circuit. The black (0v) of the battery is connected to the Pin of the dc jack and both together are connected to my gnd of the circuit?
The moment I insert my 9v wall wart adapter to the dc jack it disconnecting the positive of the battery(common) and the 9v is going from the adapter through the sleeve to the circuit ?

the 0v (gnd) of both the battery and the dc jack are connected all the time.
Did I got it right?

Or if to try in simple words: as long no adapter is insert to the dc jack, the power goes from the battery to the sleeve through the Connect pin and when a adapter is inserted the connect pin is disconnecting from the sleeve and the power goes from the adapter to the sleeve to the circuit ?

Thanks!

Edit : While I was typing this answer more posts are written that made it all very clear! so thanks everyone

[GibsonGM]

Welcome to the forum!

So, your Highness only welcomes after the 3^rd post, Sir..?? 

If I don't have an answer until their 3rd post, then third post it is! 

[o_gold]

Another small question regarding circuit with VR (virtual ground) . I want to create this ms20 9v filter : http://www.jiggawoo.eclipse.co.uk/guitarhq/Circuitsnippets/snippets.html?fbclid=IwAR3GoPDOvKmAYvjj0L_A2uniaNe-mXnSKgx14vikO0-TmAlcGGxiy5TSYEc (middle of the page)

When I'm soldering the input and output jacks, do I need to solder the sleeve of the jacks to the 0v of the battery or to the VR (virtual ground) point ?
Thanks

[willienillie]

Jack sleeves go to actual ground.

[antonis]

Just where any other AC ground should go..!!
(for not using Vref as a garbage bin - but that's another story..)