Originally Posted by: pogoheadI'm about to attempt to make my own effects unit (fancy a challenge plus it's got to be cheaper). [/QUOTE]
[font=trebuchet ms]Good luck! Hobbyists pay a lot more for components than equipment manufacturers do, simply because individual parts cost more when bought in small quantities. The skills and experience you will acquire is well worth it.[/font]
Originally Posted by: pogoheadI've got a load of circuit diagrams but where the pots are, theres the resistor symbol with 2 lines either side, then an arrow pointing at the middle of the resistor that seems to come from where one of the lines goes to.
I can't tell which of the 3 pins is supposed to be which, and if it's displaying the component from from the top or the base.[/QUOTE]
[font=trebuchet ms]The resistor symbol depicts the fixed resistive element of the pot. The ends of this part are attached to the two outer terminals of the pot. For the most common types, anyway.
The arrow represents the 'wiper' that moves along the surface of the resistive element when the shaft is turned. If the designer was being really nice, the schematic will have CW (ClockWise) or CCW (Counter-ClockWise) written at one end of the symbol to show which end the wiper moves toward in that direction of shaft rotation, as viewed from the knob.[/font]
[QUOTE=pogohead]Also, why do you put wiring to the base of a pot? I've done it when rewiring Strats but can't figure out why.
[font=trebuchet ms]You find a lot of this because most guitar-builders are cheapskate lazy gits that want to save a few pennies, and most guitar buyers don't know any better than to let them get away with it. The back of a pot is used as a quick way to ground part of the circuit. It also causes something called a 'ground loop' because there are several different 'ground' points created with this technique. This makes a guitar noisy because it has no protection against interference from external sources. Go to >GuitarNuts< and check out their wiring diagrams and instructions called "Quieting The Beast".[/font]
[QUOTE=pogohead]On the I.C's front, someone once told me that the legs on an IC aren't actually in numerical order. Is there a standard layout for all IC's, are they different for all of them or is this just a load of rubbish? :confused:
[font=trebuchet ms]There is usually a mark at one end of a DIP (Dual Inline Package) IC. If you look at the IC from above, with the marked end at the top, Pin #1 is at the top left corner, with the rest of the pins numbered from there in counter-clockwise order. For example, a 14-pin DIP with Pin #1 at the top left corner, will have Pin #1 through #7 down the left side, with Pin #8 through #14 up the right side. The data sheet for each IC should show this.
Transistor pin-outs vary a lot, so you will have to be very sure that you get the correct data sheet for the particular transistor you have. Bipolar transistors will have terminals marked E B and C for Emitter, Base, and Collector. FET's (Field Effect Transistors) will have terminals marked D G and S for Drain, Gate, and Source. The body of a transistor is often too small to allow the pins to be marked directly, do there is usually a tab, a mark, or a flat spot used as a way to locate the pins. The data sheet will usually have a picture to show which pin is which.
FET's, and most IC's can be damaged by even a small amount of static electricity, so read up on handling techniques that help to prevent this from happening.[/font]
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