out of phase

[jerry8jb]

Hi to all, I posted this in the wrong forum and was advise to repost here:


Hi all,
I've made some search in teh FAQ, but I guess my questions are too basic.
I have a very hard head for electric, (Teacher's fault) but want to learn.
Here I'm sure, a few basic question for you:

- What is the difference between ground and shield (I told you I was hard headed on electric issue)?
- Can I correct out of phase on a 2 conductor hum by reversing ground and output connections?
- Bare or shield wire, (on a 4 conductors hum)does it always go to ground ?(vol pot casing) Meaning when we reverse green and black wires to correct an out of phase, does the bare follow the green?
- Is there a measure we can take to confirm an out of phase condition?

- Any good starter book for a hard headded like me on electric?
PS I will read all the FAQ...
Thanks


...I finally reposition the bare wire to the ground and it has remove the zapping sound. I seems to have problem with the new switch I put on. It "switch: ok for at start but when playing and switching a lot to test my installation, I end up with one position that stops working...I redo all the wiring to check for cold solder joint and even replaced the 2 potentiometer with WD parts. The switch is a ym-30 (Japan) can it be that the new switch is defective?

Thanks again for your time

Jerry

 

[BlueGuitar]

Re: out of phase

#1 - What is the difference between ground and shield (I told you I was hard headed on electric issue)?
#2 - Can I correct out of phase on a 2 conductor hum by reversing ground and output connections?
#3 - Bare or shield wire, (on a 4 conductors hum)does it always go to ground ?(vol pot casing) Meaning when we reverse green and black wires to correct an out of phase, does the bare follow the green?
#4 - Is there a measure we can take to confirm an out of phase condition?
#5 - Any good starter book for a hard headded like me on electric?

#1. Ground and shield are basically the same... "shield" is the outer conductive part of a cable.

#2. If you have a shielded cable with two center conductors you can probably reverse phase by reversing the two leads. However if you have a shielded cable with a single center conductor then you need to partially dissemble the pickup to:
A. reverse the two coils wires that are not soldered together
-or-
B. flip the magnet like a pancake.

#3. The bare wire always goes to ground.

#4. There are instructions for checking phase using an analog ohmmeter in the Donald Brosnac book.

#5. Donald Brosnac's Guitar Electronics.

 

[BlueGuitar]

Re: out of phase

...
#4. There are instructions for checking phase using an analog ohmmeter in the Donald Brosnac book...

"Phase Test"

"Using an oscilloscope is the professional way of determining phase, but this tool is very expensive. A more economical method to determine pickup phase is to use only a magnet, a screwdriver, resistor, and analog ohmmeter: switch the ohmmeter to d.c. ohms and hook up the pickup. Make sure the needle is in a centered position on the scale so you can see its motion clearly. If the needle is off center, it can be centered by using a resistor in series with the pickup. For example, if you have a 10,000 ohm pickup, and 20,000 ohms would be the center of the scale, use an 10,000 ohm resistor. Now the needle should be standing straight up (or nearly so). Wave the magnet (preferably a bar magnet) in one direction closely over the pickup. You will notice that the needle of the ohmmeter will be deflected either right or left. Your only concern will be the first, or major deflection. Tapping the pickup with a screwdriver can be used in place of waving a magnet. This is an easier method for some people to use."

"If all pickups deflect the needle in the same direction (always right or always left) the pickups are in phase. If the deflections are in opposite directions, the pickups are out-of-phase."

from Donald Brosnac's Guitar Electronics 1980 edition- page 95