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Hey!
I recently purchased a used Guild Savoy A-150 Archtop. I'm happy with pretty much everything about the guitar besides the pickup sound. There is a very loud hum (almost matching the volume of the guitar when I'm not touching the strings).
Troubleshooting steps I've taken so far:
- Purchasing an APC Line-R 1200 power conditioner/voltage regulator to plug the amp into.
- Reworking my play space to not face any outlets/dimmable lights/fluorescent fixtures.
- Testing with everything in the room unplugged/lights off.
The last step was the only thing that quieted the hum, so I think it is just being caused by EM interference rather than a ground loop. I keep reptiles and have fluorescent UV bulbs/dimmable halogen bulbs that can't be turned off (and even with them off I still get a fairly loud hum if I angle the guitar slightly up or down). My options seem to be swapping out the pickup or trading the guitar for one with humbuckers.
Are there any floating humbuckers I should consider that would fit this guitar without much modification? I'm based the UK.
Thanks!
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04-05-2022 12:05 PM
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Have you checked if tailpiece has a ground wire?
Originally Posted by Razorbill
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It is hard to tell. I can see a thin black wire going from what looks like the tailpiece to the jack. When I touch either the tailpiece, strings, or jack it slightly quiets the humming. Originally Posted by JohanAbrandt
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Hum can come from electric fields or magnetic fields. Usually with magnetic hum there is a particular orientation of the guitar that will minimise or eliminate it. The guitar probably won't be physically playable in that orientation so a humbucker would be the only solution.
Electric fields are picked up by the player or the guitar body and get into the signal path via exposed parts such as the pot wiring or, often, the unshielded output jack. This sort of hum gets louder as the volume pot is turned down, becoming maximum with it at -6dB and then diminishing as the volume is turned down further. This is because the low frequency impedance of the circuit is greatest with the pot electrically half way down.
A possible solution is thorough shielding of the electrics including the output jack. The jack can be wrapped in insulating tape and then have copper foil wrapped over that, the foil being wired to the instrument ground. If the wiring is properly shielded there seems to be no need for grounding the strings.
Another trick that I have known to work with a poorly shielded guitar is to break the ground link to the amp by using a wireless link such as the NUX B2 or similar. This lets the whole guitar float so that there is no interference current returned to the amp ground via a cable and so no voltage between the jack terminals. I found this to work extremely well with normal mains hum but haven't tried it with the more aggressive buzz from poorly shielded lamps and such.
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This pedal might help...
Hum Debugger | Hum Eliminator - Electro-Harmonix
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alligator clip from the tailpiece to the output jack ground. It serves as a temporary string ground. If it makes a difference, you have to fix the string ground.
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+ 1 on this suggestion. I have one; it zaps single-coil buzz quite effectively. Originally Posted by Gitfiddler
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Do you have sufficient access to the various components to check if a soldered connections are properly made? Apparently that can be a source of hum too.
That pedal looks interesting but expensive. A quick search turned up this much cheaper alternative - any experience with it?
Behringer HD400 – Thomann United States
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Modern buildings are incredibly noisy, from an EMF standpoint. All sorts of lights, computers, wifi routers, modems, phones, computers, and who knows what. Lots of unexpected things connect to the internet via wireless connections - doorbells, refrigerators, TVs, whatever. Then there is bluetooth. Single-coil pickups are inundated with EMF radiation every second, and much of it can produce hum, either directly or through lower harmonics. It sort of amazes me that they are at all usable.
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WiFi, BT and mobile phone networks all operate in very high frequency bands that have also been in use for a long time already (civil & military radios etc.). Lower harmonics? I know this can occur with mechanical vibrations when some high frequency signal happens to be a multiple of the Eigen frequency of the object that starts to vibrate. I'm not a physicist but I would guess this has to do with the fact that the receiving object has inertia to "store" the vibration energy. I don't that that's a thing with magnetic fields?!
I do remember listening to radio stations via a record player pickup, long ago
Meanwhile I figured out that the Behringer device I linked to above is for line-level applications (could be used in the effects loop?), but they have the NR300 pedal (a Boss clone apparently) for about the same price which actually gets a higher eval score than the Hum Debugger.
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Thank you for all of the suggestions everyone!
I ordered a HumDebugger and will see if that helps. It should arrive tomorrow. If it minimises the hum without destroying the tone I'll be happy. If that fails I will give a wireless link a shot.
I have an above-average amount of electrical devices plugged in (including many IoT connected devices) which could definitely be contributing to the noise.
Sadly I don't have the skills or tools to check the soldering. I have the updated A-150 that has all of the electronics nestled under the pickguard. If I was to try and shield the electronics I'm not sure how to go about it. There isn't a cavity to line with copper shielding tape. Without unscrewing the pickguard, here are some photos of the connections.
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This is your only hope! Originally Posted by Gitfiddler
I have this pedal and it works.
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From what I understood shielding this wouldn't help (much) anyway because the noise is picked up by the pick-up itself. Originally Posted by Razorbill
Exactly what does that hum debugger do, something different from other noise gates (which filter out mains hum if the input is under some configurable level)?
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The hum debugger seems to be a comb filter or stack of very narrow band filters precisely aligned with the mains frequency and its harmonics. It has to work off its own AC adaptor which presumably gives it access to the correct frequency. It is fairly transparent but has a slight echo on its strongest setting.
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It reads the frequency of the line voltage in real time and filters that frequency and its harmonics out of the signal. A noise gate does not filter out anything. Rather, it shuts down the entire signal at its input below a dB threshold set by the user, irrespective of frequency. If the hum is in the signal path (as it is with pickups picking up EMI), noise gates really only help with quieting it down during silences. Once you start playing, the hum returns along side the playing. If buzz is quiet enough to just be an annoyance during long silences but to not really be noticeable while you're playing, noise gates are useful, But if the buzz is bad enough to be heard while you're playing they don't really help. The hum debugger addresses that problem. It's not perfect (it can add some artifacts to the tone under some conditions), but it can make single coil pickups usable in environments where they otherwise would not be. Noise gates can't do that. Originally Posted by RJVB
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In addition to the Hum Debugger pedal, I have my amps plugged into a high quality power strip/surge protector. Every link in the electrical signal chain can add to noise.
Good luck!
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So it does get AC power (the device says 7.5VAC but the product page says 7.5V DC...). Originally Posted by John A.
The principle is clever but I see relatively many dissatisfied user evaluations (on EU retail sites; maybe it works less well with our 50Hz?!)
Are you suggesting it can also detect and filter out other frequencies (IIRC certain kinds of pump can introduce a low frequency noise on the mains)?
I expected them to apply a rumble filter when activated but maybe that's a bit pointlessA noise gate does not filter out anything. Rather, it shuts down the entire signal at its input below a dB threshold set by the user, irrespective of frequency.
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Bluetooth and wifi both operate in the 2.4GHz band, different but not hugely different frequencies. All I meant by mentioning bluetooth separately is that there are lots of bluetooth transmitters around - phones, speakers, all sorts of things, which add to the already high noise levels. In my practice room I have a couple of computers, two (!) wifi routers (ATT makes things difficult), LED lights, speakers, and probably more I'm not remembering. It's sometimes difficult to find a position for single coils which doesn't have some hum. With one of the guitar wireless systems I have (Xvive) the signal gets cut out frequently, and I found that hiding the receiver from the router, behind a speaker cabinet and a tube amp helps. Most other rooms in the house have even more wireless devices, including TVs, streaming boxes, digital photo frames, all sorts of things. Plus all the EMF emitted by cell towers, TV and radio stations, powerlines, cosmic and solar radiation, etc etc. Modern households are very, very EMF noisy, and it all can affect pickups.WiFi, BT and mobile phone networks all operate in very high frequency bands that have also been in use for a long time already (civil & military radios etc.).
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It runs off an AC power supply, not DC. I am 100% certain of this. A friend of mine in Switzerland has one, and he has told me it works fine. There are older versions that don't work as well, and I think a lot of the bad reviews are of those. Originally Posted by RJVB
No, I am not suggesting anything. I'm directly stating what the Hum Debugger does (i.e., filter out the frequency of mains hum and harmonics (i.e., integer multiples) of that. The manual says that's what it does. My experience confirms that's what it does. Originally Posted by RJVB
I can't account for your expectations. All I can do on this subject is say what I have learned from experience and reading about how this device works. Originally Posted by RJVB
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Exactly 2 in my house, because I like my Magic Trackpad well enough to put up with its BT requirement. The radios are off in all other devices that support it in to avoid unnecessary power consumption. Sadly support for the 5Ghz WiFi band has been slow to come to lower-end devices; I can't help but think that frequency band should cause (even) less problems with pick-ups. The problems with your wireless links are of course related to WiFi conflicts itself; routers aren't always good at finding the most appropriate channels (instead of just the 1st available channel). Originally Posted by sgosnell
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Bluetooth radios use an almost immeasurable amount of power. I have two keyboard/mouse combos which use battery power, and a standard AA battery lasts for months, very close to a year, and they're always on. The computer itself uses many times more, and adding the bluetooth radio doesn't cost me more than a few pennies per year. I'm not penurious enough to worry about it. You might be.
The conflict with the guitar wireless and wifi router are of course just a symptom of many sources of 2.4GHz radiation present. It all adds up, and the harmonics from the interference add up. Some gets picked up by the Rhythm Chief pickups, in some orientations. I don't really think my house is so very different from the average home here. RF radiation is strong everywhere, from LF through SHF.
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Both my current house and prior house have old tube and post wiring. That is the cause of a lot of interference problems. I also have a high power radio transmitter nearby currently.
At my prior place, I got a Godin Kingpin and was very disappointed to find the amount of hum, to the point the guitar was virtually unplayable plugged in. I got a HumDebugger, and like magic the hum was gone.
Currently I don't have too much trouble from my current lot of guitars and amps, including a guitar with a RC1000 RI and a Tele. I had a prior Ibanez acoustic amp that was poorly shielded/grounded, and the hum from that was intolerable. I could hear the local NPR station almost as loud as my own guitar with that one. I sold it to a friend who hasn't had any problems with it (guess he has more modern wiring in his place).
I would highly recommend A) checking the grounding of the guitar jack, and B) (if no issues there) getting a HDB before doing any more intensive investigations. You may find that the problem is easily solved without much effort.
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And I thought I was living in a museum Originally Posted by Doctor Jeff
My Magic Trackpad holds maybe a month or two at most on 2 AA NiMh rechargeables (and I turn it off overnight). My iPhone's battery won't last the day if I activate the BT radio (maybe because it gets used by the France "anticovid" app which doesn't use Apple's more efficient framework developed for this kind of application).
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Correction: knob and tube wiring. My house was built in the late 20's, so not surprising. It's a pain and expensive to update. So if you live in an older house chances are at least some of the house has this wiring.
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The house I'm living in is much older than that (but some parts are much younger). I've never seen a place that had been occupied at some point after WW2 or so that had this kind of wiring (which I in fact know only from American horror movies though I *may* have seen 1 or 2 left behind porcelain knobs). This one even didn't have the "prehistoric" fuses where you replaced the wire. Either way, we had an electrician go over the installation as the 1st thing before we even started the other modifications; they replaced a lot but apparently most of the cables were already to current spec. There are just 2 wall outlets left that don't have ground, and they're in my office (I'm halfway to adding an earth cable to one of them). Originally Posted by Doctor Jeff
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