Buzz and Hum in Gibson SG

[jellyfish]

Hey everyone. I just posted a YouTube video of a problem I am having with my Gibson SG. Here is the link:

To sum up the problem/video:

Buzzing
Let's say we're only in the bridge pickup. Tone knob all the way down = no buzz. As tone knob increases, buzz increases.
Let's say we're only in the neck pickup. Same exact thing.
Let's say we're in both (pickup switch in the middle position). It only takes an increase of one tone knob to create buzz. Obviously if I turn up both tone knobs, buzz will be present.

Humming - forget about the buzz. I'll just roll the tone knob all the way down.
Let's say we're only in the bridge pickup. Volume at 0 = no hum. As I increase volume all the way up to 9, the hum gets louder and louder. Then when I finally turn the volume up the last little bit to 10 (all the way up), hum goes away.
Let's say we're only in the neck pickup. Same exact thing.
Let's say we're in both (pickup switch in the middle position). Let's also say we have both volume knobs all the way up. If I drop one volume knob to 9 or anything below, no hum. Doesn't matter which volume knob. If I drop both volume knobs to 9, the hum comes in.

I then compare the results with a Squier stratocaster. No humming or buzzing with the strat. So something is obviously wrong with my Gibson SG. I think it's odd because usually single coil pickups are buzzier/"more hummy" than humbuckers... hence the name humbucker. But in this case, my SG is the problem and the strat is just fine. I would really appreciate any help with this! Any ideas?

Ryan

[acheld]

Didn't listen all the way through, but:  Shielding/grounding within the instrument.

My experience with this is that is a pain to track down.   I'm an amateur guitar builder, and in my builds now I shield the cavities, use shielded cable in long runs and pay a lot of attention to grounding.   That strategy will normally yield an acceptable result -- but not always (to my frustration).

Now, why your SG is noisier than your Strat -- I don't know.   New problem?

[pdf64]

Check for 0ohms resistance between everything that’s supposed to be connected to the jack sleeve. Including strings, pickup metalwork, pickup switch bushing.

[jellyfish]

Now, why your SG is noisier than your Strat -- I don't know.   New problem?

Honestly I think this has been going on for a while but it recently started to get on my nerves for whatever reason.

[jellyfish]

Check for 0ohms resistance between everything that’s supposed to be connected to the jack sleeve. Including strings, pickup metalwork, pickup switch bushing.

Thanks for the advice. I will try it right now.

[Willabe]

Now, why your SG is noisier than your Strat -- I don't know.   New problem?

Honestly I think this has been going on for a while but it recently started to get on my nerves for whatever reason.

Your ear is growing, opening up. Happens the more we spend time with music. As this happens you'll hear more things you never noticed before.

I started hearing the kick/bass drum or hi-hat pedal squeaking on some songs on albums.   

[jellyfish]

Check for 0ohms resistance between everything that’s supposed to be connected to the jack sleeve. Including strings, pickup metalwork, pickup switch bushing.

So I tried doing that and everything is essentially 0Ω. The only things that were very slightly off were the tuning pegs:
High E tuning peg = 7.4Ω
B tuning peg = 4.7Ω
G tuning peg = 3.5Ω
D tuning peg = 3.0Ω
A tuning peg = 2.0Ω
Low E tuning peg = 1.8Ω

I'm guessing that the reason that it goes from highest resistance to lowest resistance is just because the strings are what bind the pegs to the guitar's ground, and the gauge of string decreases (gets thicker) from high E to low E (higher resistance to lower resistance). I'm sure all this is negligible.

So I took off the backplate to see what can be done. Honestly this was my first time trying to see how it works but it looks friendly enough to draw out the connections by using continuity mode on a multimeter. From what I gather, this is the basic... "schematic" of a single guitar pickup.



Then the switch just chooses which pickup. Or if you want both pickups, the switch just combines the outputs (middle lug of bridge volume and middle lug of neck volume) together.

Nothing seems to be wrong... everything looks good inside the guitar - no loose solder joints etc. When I plug the guitar into the amp and touch strings or grounds (such as potentiometers) the buzz is ever so slightly reduced but not by much. I took out the little board and switch for you guys to look at. Any advice would be greatly appreciated!

Ryan

[acheld]

Let it be.

I don't have any better advice at this point.   The resistance for strings to jack is what I see in my builds.

[Blueboozer]

Leave the bridge ground wire (the one that goes in the green connector) out and see if your buzz goes away.

You can also plug in the pickup connectors one at a time and narrow it down to a pickup, but my guess is the PCB and the ground.

Emerson Custom sells an excellent prewired SG harness.

[jellyfish]

Leave the bridge ground wire (the one that goes in the green connector) out and see if your buzz goes away.

You can also plug in the pickup connectors one at a time and narrow it down to a pickup, but my guess is the PCB and the ground

I just tried removing the ground wire that goes in the green connector and buzz got worse. I then plugged in one pickup at a time and the buzz does not change. Hmmmm

[jellyfish]

Let it be.

I don't have any better advice at this point.   The resistance for strings to jack is what I see in my builds.

I would normally just leave it alone, but that buzz in the video is only with a 15 watt amp. When I plug the SG into my 50 watt or 100 watt, the buzz is horrible. And in those amps, the strat is still fine. It especially irks me because the SG (Gibson) was hundreds of dollars more than the strat (Squier). I think I'm going to try shielding the cavity. The problem is the underside of the PCB lays directly on the wood like you see in this photo.



This means I'm going to need to line the whole wooden inside with aluminum, then add a thin layer of some sort of non-conductive material so the solder joints under the board aren't all shorted to each other. Now what kind of material would that be? Not sure yet, I'll think of something.

Any other tips?

[jjasilli]

Not sufficient proof it's the guitar.  Does the same thing happen with other amps?  Your amp looks old - maybe a vintage Silvertone?  3-prong plug?  I love my Silervertone 1482, but these type amps have incoherent grounding circuits.



Have you tried other guitar cables?


Ambient factors:  fluorescent lighting? El motors (fans, other appliances)?  Dimmer or fan control switches?  House grounding?


Single coil Strat noise is heavily dependent on the proximity of the guitar to the amp, and which way the guitar is facing. 

[jellyfish]

Not sufficient proof it's the guitar.  Does the same thing happen with other amps?  Your amp looks old - maybe a vintage Silvertone?  3-prong plug?  I love my Silervertone 1482, but these type amps have incoherent grounding circuits.



Have you tried other guitar cables?


Ambient factors:  fluorescent lighting? El motors (fans, other appliances)?  Dimmer or fan control switches?  House grounding?


Single coil Strat noise is heavily dependent on the proximity of the guitar to the amp, and which way the guitar is facing.

I really think it's the guitar. I tried three different amplifiers with both the Gibson and the strat. All the same - Gibson buzzes/hums, strat is silent with all amps. I tried in another room and plugged into a different wall - same thing. Silvertone has a 3-prong plug. I might do aluminum tape for shielding the cavity then do a layer of electrical tape over that to prevent shorting out the board. I will post an update after I do this.

[jellyfish]

Hey everyone! So I shielded the control cavity and the pickup cavity in the Gibson SG. Problem solved! No more buzzing and no more humming! I'm honestly kind of blown away by how much of a difference it made. Here is a video I made of the new and improved Gibson SG:

So if any of you have noisy humbuckers, give this a shot! It may not help or change your guitar like night/day like it did for me but it doesn't hurt to try it! Thank you everyone and thank you acheld for recommending shielding! I really appreciate it, buddy.

Now does anyone have any idea as to why this worked so well? Any possible theoretical explanations for what is happening? I can't help but be really curious about this. Like I said I did not think it would work this well hahaha.