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MexicanBreed

Humming problems with a new previously-owned Godin

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tl;dr version; Just bought this guitar, humming issues, no experience in electronics, please help!

Hello everyone...it´s been quite a long time since I last visited. I hope you guys are doing well. I just got myself a beautiful, previously owned Godin A6 Ultra, just got it today in the mail!

As you can see, it was modded. I bought it on a site which I believe is owned by ebay. I´ve purchased many things there, and never had an issue. Certainly, I hope that is the case this time as well, but I would appreciate guidance. I have zero experience with electronics.

Ok, so the guitar was modded with a volume and tone pots, along with an output jack. The guitar has the original circuitry, which is a side output for the humbucker, and a  jack for acoustic or mix. I asked the seller, who has high reputation at the site, and he said he had bought the guitar from a collector in Texas. He was the original owner and had the mods made. Later, he had it put back to stock...except for the electronics on the top. He didn´t ask on what the mods where or what the configuration was.

The guitar arrived today at my dad´s house, so I went there after work to pick it up. When I got home, I immediately set up my PC (I play through amp sims) and was surprised by some hum and gainy tones, along with somewhat uneven volume. I tried both jacks just to see if I could assess both tones, but the acoustic preamp had no output. Then it hit me that it works of a 9 volt battery. I took it out, but I don´t have means to check whether it is dead. No biggie, I´ll get one tomorrow. 

So, I focused on the humbucker sounds. I didn´t open the guitar, but I read on it before buying, and remembered somebody mentioning the humbucker is wired to the preamp as well. I guess this is necessary to have either acoustic or electric, or the mix, but I don´t know for sure. I tried a few presets and the hum worsened with some, lessened with others along with some drop in volume. I fiddled with the noise gate in the VST, but that didn´t help much. When I actually tried a preset with some gain and volume, the interface input spiked, and the hum turned into screeching. I unplugged the guitar and the interface, then restarted the pc. After rebooting, I tried the same, with the same results. I was ready to blame the interface, but first I picked up another guitar with humbucking pickups...dead quiet. Well, some noise, but nowhere near what I experienced with the other guitars.

I want to try the preamp tomorrow, but my hunch is that the issue is something else. My guess is that the humbucker should work even if the preamp it´s connected to has no power...but I´m not sure on that. I have no experience with microphonic or ungrounded pickups, and that might not even be the issue. 

I´m concerned because there are no techs I know of here where I live. Maybe it is simpler than what I fear, or it might be enough to place a complaint at the site. I kind of hope for an "easy" fix and leave it alone. I would like to keep the guitar. In fact, I have a very nice pickup I would like to swap with the one it has right now, but I won´t if the design is not meant to work with another one. When trying it out acoustically, I tried the pots on the top, and they are perfectly placed and seem good quality. If possible, I would like to have the magnetic pickup swapped for the one I already have, maybe wire the guitar circuits independent of each other... 

Anyway, sorry for the humungous post...I tend to do that,

 

 

Screenshot 2017-05-19 04.46.16.png

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3 hours ago, MexicanBreed said:

Anyway, sorry for the humungous post...I tend to do that,

Not lately....good to hear from you again Joe! 

Alas, I'll be no help at all with electronics, but I'm sure @curtisa will come to the rescue once he discovers this on his side of the world. I just wanted to jump in and say hello!

Cheers!

-Scott

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Cheers Scott! It´s nice to see this website is not only well, but even growing. 

Well, after having written that wall of words, of course I forgot a crucial detail. At first, I had the Godin plugged into the interface when I immediately noticed the hum. After unplugging and plugging the guitar into all 3 jacks, lowering the volume, etc. I leaned over to adjust the noise gate. As soon as I rested my hand on the laptop, the noise reduced considerably, and the second I stopped touching the laptop´s case...hum time! It´s a metal (aluminum I guess) case. So I thought to myself, "aha! Must be a grounding issue!" I proceeded to unplug the laptop from the multi-outlet and the hum subsided as well. However, at that point I blamed the outlet, the laptop, anything but the guitar...that is, until I tried another guitar and the issue was moot.

So, I´m positive it must be the guitar...but, what is it? What do I do to fix it?

 

Thanks!!

Edited by MexicanBreed

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Beats me. Other than to agree it is likely a grounding issue of some sort, I probably know almost as much as you do on this subject. I'm confident Andrew (curtisa) can get you going. Except I think it is the middle of tomorrow night where he is (I never know for sure) so it may be a bit before he sees the problem. He usually pops in around what is mid afternoon in our part of the world.

SR

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Hey Joe,

Good to hear from you. First get us some pics of the the wiring. That may help us see what might be the obvious. It does sound like a grounding issue, but. I have heard though, that some preamps, not sure who's have had hum issues as well. ???  

MK

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Hola Mike! Nice to see friends from back in the day ;). Is Wes as humble as ever? How´s Brian? I read that Carl is now in charge, right? 

Will do on the pics as soon as I get home. Last night I went to bed late and it didn´t even cross my mind. I must remember to pick up a 9v battery to test the acoustic preamp...I just hope that works and that the other issue is a relatively simple one. There´s a friend of mine, guitar player as well, who told me a few weeks back he had put together a small transistor amp... Maybe he can help me if/when there´s stuff like soldering involved.

Edited by MexicanBreed

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I have no experience with the Godins, so I can only speculate what might be the issue. It sounds like a grounding problem, but I note that some people on the internet mention that the mag pickup passes through the preamp first, so unless the 9V battery is installed you may get strange results. Other people mention that the strings are infact ungrounded, and the pickup needs to have special shielding in order to be hum-free. If the pickup in your guitar isn't the original GAHN1 unit this could also be an issue.

@ScottR - We Australians have mastered the art of time travel and are now 17 hours into your future. You can thank me yesterday ;)

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More food for thought. This thread seems to be from someone who modded their Godin A6 to allow the mag pickup to work without the aid of the 9V battery and preamp, but ended up with hum and buzz because of the ungrounded strings.

As the strings appear to be normally ungrounded in the Godin (acoustic guitar-type bridge has no way of providing a conductive path from each string to ground), the preamp must have some onboard smarts to reduce the inherent noise from the mag pickup, so plugging in to the regular mag output without a 9V battery will give odd results.

In addition, installing a direct feed from the mag pickup to a third output to try and bypass the preamp will result in hum and buzz, as there is still no ground on the strings.

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3 hours ago, curtisa said:

I have no experience with the Godins, so I can only speculate what might be the issue. It sounds like a grounding problem, but I note that some people on the internet mention that the mag pickup passes through the preamp first, so unless the 9V battery is installed you may get strange results. Other people mention that the strings are infact ungrounded, and the pickup needs to have special shielding in order to be hum-free. If the pickup in your guitar isn't the original GAHN1 unit this could also be an issue.

@ScottR - We Australians have mastered the art of time travel and are now 17 hours into your future. You can thank me yesterday ;)

Hi Andrew, thanks for weighing in. I had all the intention of taking pics of the wiring and testing the thing with the 9v battery in, but I´m up to eyeballs in work. I may not even get home tonight. 

I remember reading about the mag pickup as going through the preamp as well...that gives me hope this issue is actually a non-issue (fingers crossed). However, I was considering the fact that this guitar is already modded and may ask for help on this. I guess the previous owner meant to isolate the mag pickup from the preamp...although why he had a top-mounted jack I cannot guess, given there are two working outputs already. So, I own a guitar with the Seymour Duncan P-Rails (with the Triple Shot mounts), and love the neck pickup sound. I was thinking I could make use of the top pots and jack with the P-Rail. The Godin is, in my opinion, closer to being a thin electric-acoustic with an added mag for further tone shaping, rather than each tone reaching its full potential...but the idea of having both is enticing! However, I don´t know if the humbucker in the guitar now is designed to be used with the preamp and that if swapping the pickups is realistic, even. Oh well...I love the guitar´s feel, and having it work would be enough.

This is the P-Rail, along with the Triple Shot. Description

Thanks beforehand.

seymour-duncan-shpr-1n-p-rails-neck-7595

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20 hours ago, curtisa said:

More food for thought. This thread seems to be from someone who modded their Godin A6 to allow the mag pickup to work without the aid of the 9V battery and preamp, but ended up with hum and buzz because of the ungrounded strings.

As the strings appear to be normally ungrounded in the Godin (acoustic guitar-type bridge has no way of providing a conductive path from each string to ground), the preamp must have some onboard smarts to reduce the inherent noise from the mag pickup, so plugging in to the regular mag output without a 9V battery will give odd results.

In addition, installing a direct feed from the mag pickup to a third output to try and bypass the preamp will result in hum and buzz, as there is still no ground on the strings.

I just realized I hadn´t fully understood what you said in this post. So, modding the guitar (as the previous owner did) and isolate both paths would indeed not work. That´s kind of a pity... If it´s not too much trouble -and this is only out of curiosity-, how do other preamps work then? How do regular acoustic electrics deal with hum?

2) So it seems that isolating the mag from the preamp is inherently impossible due to the bridge, right? When I get home and have a few minutes, I´m gonna pop open those covers and take the pics. Maybe no modding is poosible/necessary/desirable...Wish the luthier had told that to the previous owner (the pots look cool though, but it´d be cooler if they worked!). Maybe the P-Rail can replace the current pickup?

Edited by MexicanBreed

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3 hours ago, MexicanBreed said:

how do other preamps work then? How do regular acoustic electrics deal with hum?

Piezo pickups do not rely on the conversion of an electromagnetic field to generate something that can be amplified. They rely on physical vibration to generate sound, and hence are inherently immune to electromagnetic signals.

Mag pickups rely solely on sensing variations in electromagnetic fields, which makes them ideal for sensing the changes in the proximity of a steel string as it vibrates...and unfortnately ideal for picking up external noise from motors, radio stations, computers, light dimmers, switchmode power supplies, transformers etc...and us.

I have no idea what's inside the Godin, but I would have to assume that it is something similar to the Graphtec Ghost preamp, where the piezo and mag signals are both run through the preamp where blending/volume/tone takes place, before being passed on to the two individual output jacks.

 

3 hours ago, MexicanBreed said:

So it seems that isolating the mag from the preamp is inherently impossible due to the bridge, right?

Quite likely. A simple test to confirm this would be to plug in your guitar as before and check you have lots of noise, and then touch the metal outer case of your guitar lead while it is plugged in. If the buzzing goes away, the strings are ungrounded.

 

3 hours ago, MexicanBreed said:

Maybe the P-Rail can replace the current pickup?

Not sure. It's probable that the P90 would have to pass through the onboard preamp as the existing mag pickup does. However if the P90 is a true single coil you may end up with worse issues with hum and noise (I suspect that the use of a humbucker on this guitar is a deliberate design choice). Have you spoken to Godin to see if they have any advice on replacing the stock humbucker with a P90?

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I have worked on the Godin Piezo & Electromagnetic combo in the past and they're pretty straightforward. 

You will need to get in touch with Godin and ask them for the A6 Ultra wiring diagram. That should help is determining how its supposed to be wired in the 1st place. The A6 has treble/bass controls for the humbucker, which I believe are active.

My guess is that the pickup was not installed properly with the tone/volume pot. Really, why do that when there's already an EQ on-board? 

Do the vol/tone only affect the humbucker? If yes, you could add a brass underplate under the bridge and ground that to the vol/tone pots.

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PHEW!!

Cheers everybody! After a long, tiring weekend, I got back home a couple of hours ago. First thing I did after having something for dinner was put the damn battery in...yep, that was all it needed! 

I tried both sounds and, well...some tones are really nice, others need work -on my part, most likely- with EQ and stuff. I am really glad that it was nothing else than that...I feel like I could really bond with this guitar. Still, I wish the humbucker had more personality on its own. I just found this on a metal forum (of all places!), where the guy contacted Godin and they said he could put in any passive humbucker, but they advised against modifying the outputs. Godin Ultra A6 mod - Godin customer service response

@Guitar2005: thanks for chiming in! I will try to get in contact with them in regard to the wiring. I can only guess the previous owner meant to isolate the humbucker from the preamp... the guitar is back to stock, except for the pots and the jack. It looks cool, but it´d be cooler if it had worked! To be honest, it´s not that the on-board EQ doesn´t work, but maybe he just wanted to control it as a more regular electric...I know that I´d have liked that as well. The pots and third jack are not wired to anything anymore, Would that brass underplate aid in grounding the humbucker then? Is it possible to have the humbucker separate from the acoustic preamp? Is it desirable to do so?

@curtisa: When I get in contact with Godin, I will ask specifically about the P-Rail...I´d really like to use it. 

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6 hours ago, MexicanBreed said:

 Would that brass underplate aid in grounding the humbucker then? Is it possible to have the humbucker separate from the acoustic preamp? Is it desirable to do so?

Yes, the brass underplate will help you to get a proper ground. You will run a wire from the plate to the ground on the tone/vol circuit of the humbucker.

http://www.stewmac.com/Luthier_Tools/Tools_by_Job/Tools_for_Bridges/Plate_Mate.html

They are easy enough to make yourself. Also, keep in mind that you'll need a small cutout or hole on one side for the piezo wire to come out.

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Welll...uh...this is embarrassing...

I had a lot of work during the weekend and just had the time to make sure that the battery was all that was missing. The guitar now works fine. And yet...(famous last words!)

Well, as I was saying, this is embarrassing. I wrote to Godin customer service on Monday, and was driving home from work thinking that it was silly to mod a perfectly good guitar unless you had the knowledge to make that mod work...Then it dawned on me. It WAS silly indeed!

Now, if I may draw your attention to the attached pic...yep, that´s brass plate, mate! Also, Godin got back and sent me the wiring. Am I right in assuming that taking the humbucker out of the preamp would not result in sound degradation? As it is right now, the humbucker blends in with the piezo. What I find this does in terms of tone is that, when the humbucker´s volume is all the way down, the acoustic suffers. When I bring it back up, there´s a  considerable boost in terms of volume and clarity, plus the humbucker sound itself. I would prefer to have both routes separate, but hoping this does not affect the preamp; it does need the bit of humbucker right now to achieve a nice tone.

Godin´s service mentioned they have never tried a P Rail, but that it should be doable; however, the rep didn´t address the single coil issue (I made sure to explain this in my email). Anyway, if it´s possible, the plan is to put that P-Rail in and route it out to the pots and jack. Yesterday, after the battery thing and a bad cable, I could appreciate having two distinct sounds processed separately...never had so much fun with my clothes on!

Could anyone confirm based on the wiring that removing the humbucker won´t affect the preamp? Thank you so much for your interest so far.

2017-05-22 22.22.31.jpg

A6 Ultra 1.pdf

A6 Ultra 2.pdf

Edited by MexicanBreed

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Not sure I follow.... Before getting into the other issues, let's just focus on one, fix that and move on.

Does the humbucker still hum/buzz?

Did you add that brass plate?

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