Post by giantlaser on Jan 17, 2017 17:59:43 GMT -5
Stuck in newbie level where severe hum keeps happening after many attempts of trying to fix the connections. The kind of hum that stops when you touch a metal component so it must be bad ground hum.
It's about a stratocaster that I want to rewire. I went from trying to get the entire deal working after one rewiring session to now just hoping to succeed wiring my Seymour Duncan SH-4 directly to the jack output. I've been hearing the fierce hum the whole time after having pluggin in the guitar cable
Now, please keep in mind that I'm very very thick when it comes to trying to understand electronics, I kindof understand what's being said in the Discerning thread, yet when it comes to the details that are needed to put the knowledge into practice I have no idea what is being talked about. I do understand the basic idea behind testing the connection with the ohm setting on a multimeter though. What I would do is hold one pin of the meter on the ground sleeve of the output jack and the other one on the bridge. The value actually does drop to 0 eventually and the the beep occurs. And yes, even with the humbucker just wired directly to the output jack. So i did that and also just really trying to check every ground connection. Most would beep instantly, somtimes it takes a little before the Ohm value drops to zero entirely but it would always do so eventually. Could that also mean bad connection?
I also check that the green wire from the SH-4 is ground and black is hot. Red & Wire is twisted together.
Last Edit: Jan 17, 2017 18:03:03 GMT -5 by giantlaser
OK, we're going to need some more information to be able to troubleshoot this. If the problem is hum, does the pickup work when connected directly to the output jack? IOW, do you hear the strings through the amp, together with hum, or just hum, with no music?
The "brain scanning" technique is not going to help much to track down a hum issue. How, exactly, is the guitar wired at present? And, have you tried swapping cables, using a different amp, and so forth to eliminate other variables?
One quick check you can do, if the guitar has the standard Strat "football" style jack plate, is to unscrew the jack plate to see if the hum stops. If it does, the output jack is touching the end or side of the cavity when it's screwed into place.
does the pickup work when connected directly to the output jack? IOW, do you hear the strings through the amp, together with hum, or just hum, with no music? How, exactly, is the guitar wired at present?
Yep it does. And it is currently wired straight to the output jack.
OK, so if the pickup is connected directly to the jack, then the hum has to be coming from either the pickup or the jack- unlikely that the wire would be the source of the problem.
First thing to check is basic- is it possible that you have the output jack wired backwards? It can sometimes be hard to tell which lug is for the tip and which is for the sleeve, often you have to have the jack in your hand to be able to tell which lug is which.
If the jack is wired correctly, then the pickup is a more likely source of the problem than the jack, so start there with a close visual inspection, focusing on the wires coming off the coil. Are they intact? Any loose threads of wire that might be shorting out somewhere? You can also disconnect the pickup and use your meter to test the DC resistance. This might not tell you much, if anything, but if there was a significant difference in the measured DC resistance from what SD says it ought to be, this might indicate that the coil was broken or shorted internally.
If you have a spare jack lying around, you can try swapping that in to check if your jack is the problem. Again, the pickup is more likely the problem.
The fact that the hum disappears when you touch the strings is an indication that your bridge ground is functioning OK, but you can also test that with your meter to be sure- check between the bridge and the output jack negative, it should show 0Ω or very close to zero.
Last Edit: Jan 18, 2017 12:53:42 GMT -5 by ashcatlt: lowercase omega: ω
If the jack was wired backwards, the hum should get worse when you touch anything on the "ground side" because you're basically touching the tip of the cable.
I'm a little confused how the bridge connects to the jack. When you said the pickup was straight to the jack, I assumed everything else in the circuit had been disconnected. I'm not sure how much difference this will really make anyway.
Definitely measure resistance between green and black and also between the red/white connection and each of the others.
If it's just the pickup or the jack, then it's either the pickup or the jack. I feel like in this case it has to be the pickup.
Last Edit: Jan 18, 2017 13:04:54 GMT -5 by ashcatlt
Yeah, I was going to say something about that. When we're talking about this kind of noise, it's all about relative levels - signal to noise ratio - and that's really hard to evaluate when it's just the pickup connected to the amp. You're hearing all noise and no signal, so have no reference for comparison.
I once spent several days crawling around my studio with headphones on and everything cranked trying to track down and eliminate (or at least reduce) every source of hum and buzz in every piece of equipment. Ended up going around in circles and just about drove me over the edge. In the end, it had no real impact on my recordings.