How to explain Hum-cancelling

[4real]

Welcome to GN2...and too late, you just got a +1 from Oz for keeping it real...4real!

You are quite right, it is the nature of such things to get further into the mire of 'detail' but the essentials are the essentials and well put...hoe to see you contribute more and share a few more ideas...

[jerry]

Thanks all for your kind words!

I was trying to be cautious with my suggested explanation because I know that forums are communities. Over time, the members come to know one another and look forward to interacting. Then, along comes some jamoka expressing his own ideas of how things could be better and he can upset the existing tranquility. So, I just wanted to avoid that, if possible, while still sharing my thoughts.

Thanks again for your welcoming comments!

Jerry

[sumgai]

Jerry,


Jerry, Jerry, Jerry..... I buy you books and send you to school, and whaddya do?

This here is The NutzHouse, eh? Do you really expect that there's such a thing as

Dec 3, 2012 9:04:10 GMT -5 jerry said:

existing tranquility

in here?   I can see right now, bringing you up to speed is gonna be our Number One priority! ;D


I mean, after all, if we can deal with Kyle Is In My Head, then you're gonna have very difficult time knocking us back for a loop, trust me on this one.






sumgai

[newey]

Since that post is Jerry's second, he's also now entered in the Year-End Raffle!

Others have already welcomed you, Jerry, but I'll "second that emotion" . . .

Hello and Welcome to G-Nutz2!

[jerry]

Thanks again! I'll be posting.

[angelodp]

Thank for a very concise discussion on hum canceling. I wonder if the subject of pickup to pickup effects has been discussed. What I mean is, when we have two hum buckers on a guitar their screw poles are not oriented in the same way. The screws are closer to the neck on the neck pickup and the screws on the bridge pickup are closer to the bridge, all good and obvious right. Now on some guitars the humbuckers are spun 180 degrees, both with the screws inward. In some guitars the neck pickup is spun 180 so that the screws are towards the middle of the guitar. My question is regarding the various properties of the pickups as we do this sort of dance with the pickups. I understand that the screws are the area that pickup reads the vibrations and that when we change the orientation we are favoring a certain frequency response. Is there more to this? Whats happening to the intra-pickup magnetism?

Ange

[newey]

I understand that the screws are the area that pickup reads the vibrations and that when we change the orientation we are favoring a certain frequency response.

The screws are not "the area that reads the vibrations". In a HB, we ordinarily have two coils which sense string vibration (unless we're talking about a "stacked HB"), and only one of the two has screws. The screws are used to adjust output from one string to the next, just like raising or lowering the pickup as a whole. Single coils with staggered pole pieces are a (non-adjustable) way of achieving the same thing. For example, if you switched to a different type of string, you might need to adjust the relative outputs, particularly in the case of going from a wound G to an unwound G string (not done much anymore, but common back "in the day").

Now, in HBs where the coils are identical and where the coils are not being split, rotating one HB 180 degrees won't really change much, and won't affect the degree of hum-cancellation. However, where the coils are dissimilar, or where the coils are being split, we may get different sounds by selecting the screw coils as inner versus outer coils, and we may also want to rotate a HB so as to maximize hum-cancelling when splitting coils, if we want both inner coils to be hum-cancelling, for example.

Is there more to this? Whats happening to the intra-pickup magnetism?

Nothing changes with the magnetism, as the magnet hasn't moved relative to the coils.

[mongoose]

 new here... self taught SmrtAsh... so hold your knockdowns... I built a few in my younger years and the thing I found created the most hum, was the grounding of the pot cases to the amp line.  Well I built this shield from foil that completely surrounded the control box from the pickups magnetics, then I grounded all the cases together and hooked them to the farthest point from the amp line(see path of least resistance) then I made a loop of the + and - in the amp line that included all my guitar controls--in the negative side of the circuit in the guitar... like halfway through everything is the +/- connection... The change from line to load--- the last thing in my line back to the negative side - of the amp jack, was the volume control.  The pickups were isolated on the 5 way with the grounds of each feeding the Positives of the next pickup, and the tone was quite impressive with 2 caps of different sizes on each side of the tone pot (isolated as they were with eaches own output to the line out jack.

You should try this... seriously!!!  A true bypass isn['t reallly possible in a serial circuit so I tried to do the next best thing.... just a guess!

I didn't have a guitar to test it on, just a small homemade amp and some parts ... so, if it works you have to share the profits with me!!!

Remember that in electronics, the center tap must always be connected.  There is no power or ground available to the center tap ifits not connected to  its respective location... To be specific, always tap the center to the line if you can, but if the center is past the line, it must be grounded respectively to the circuits requirements... hint hint!!