Ground

[rippa32]

I am having troubles trying to work out how a schematic translates into a circuit. I understand that the ground symbol (the triangular one) just means that all those points are connected and not an acual earth ground (I was very confused before I realised this). But my question is, how are they connected?

http://www.geocities.com/CollegePark/Library/1355/rmclassicfuzz.gif

I understand that all those ground points are connected to the battery (I think) despite it not being obvious in the way that's drawn but how does that work when there is only one wire coming from the battery that they could be connected to?

Also what do those large zig-zag lines at the input and output jacks mean?

 

[Dean Huster]

The large "zig-zag" lines represent the internal spring contacts of the phone jack that connect to the tip, ring and/or sleeve of a typical phone plug that's been inserted.

The emitter of the transistor and the end of each of the pots are connected to a common point or "ground" in this circuit. There are several symbols used for "ground" and these symbols vary according to the industrial discipline or country of origin. Some indicate true earth ground (the term called "earthing" in the U.K. vs. "grounding"). Some indicate chassis ground (the pitchfork-shaped symbol typically). Some that are true hollow equilateral triangles may indicate floating grounds, grounds that are a common connection within a circuit but never connected or later connected by a single wire to another ground, such as chassis ground or earth ground. For instance, the signal acquisition section of a bench-style, mains-powered DMM has a "floating" ground that's usually connected to the COMMON jack, but for safety purposes, is never connected to the chassis. Audio preamplifiers may have several "floating" grounds that are eventually connected to chassis ground or the supply return to reduce hum-inducing ground loops.

Dean

 

[rippa32]

Hey thanks, that answered my question perfectly. But just to clarify does the grounding go through the jack and into the amplifier which then gets grounded on the chassis of the amp?

 

[Hero999]

Yes but grounds do not actually have to go to earth ground.

Ground is just a reference point, your amplifier might not have its chassis connected to ground at all.

 

[mhar]

Looking at that circuit, it appears the sleeve is missing on the output and input jacks. All jacks have ring, tip and sleeve. usually tip is hot audio, ring is cold return and sleeve is ground. So audio cables are wired tip=red, ring=black, sleeve=screen of cable - if that's your cable.
XLR connectors (large 3 pin plugs) stand for X=screen, L=live(hot), R=return.
So when we plug everything in we hope we don't get HUM.
I would not use the battery switch on input jack connector - use a separate on/off switch - likely to get great splats plugging in jack.
On that circuit the sleeves(long bit) goes to common ground(earth like symbol) also the other three points Q1, 47k resistor and 2k pot. If you use a switch for battery then the + battery goes to one side of switch, the ground the other.
On the subject of earths, in a TV studio for instance, it may have a power earth - all the lighting and 3 phase supply. Technical earth would be the racks and equipment, domestic earth all kettles, microwave, watermachines, air-cons etc. So when someone plugs the kettle in it dosn't take out the Studio.
I just forgot on thing you may have to connect ring bit to ground this depends how guitar wired.
Happy fuzz sound!

 

[rippa32]

I would not use the battery switch on input jack connector - use a separate on/off switch - likely to get great splats plugging in jack.

That's fine, all my other pedals that are made by big companies do the same actually. And I generally just plug all my stuff in before turning the amp on anyway.

But thanks for the tip.