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Atchley's "Hum Buster" mod...


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6/11/1999 3:17 PM
Dave James
Atchley's "Hum Buster" mod...
Well, with the reduced forums, I have a semi-captive audience! So...  
 
 
 
Has anybody out there (besides Mr. Aloha of whom I appreciated his resposne) modified a Strat as per Mr. Atchely's suggested method? I've done this to my '95 MIJ model and received some reduction in hum, but not to the level as I anticipated.  
 
 
 
Any input would be great...constructive that is!  
 
 
 
Later,  
 
 
 
Dave James  
 
JMP  
 
 
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6/12/1999 12:42 PM
MJ Harnnish Re: Atchley's
Single coils are going to hum no matter how well you shield though the shielding does help quite a bit at times. If the hum is still bothersome you can switch to new pickups (humbucking; the new DiMarzio Virtuals are supposed to retain the SC sound which being very resistant to noise)or try to get even more extensive with the shielding (diminishing returns here). You might also want to make sure that you don't have major environmental noise generators nearby (i.e. TVs, computer monitors, and flour. lights) since even a humbucker's going to have problems with major sources.  
 
 
 
You can also wire in dummy coils (I hear some pros have this done) though I've never seen exactly how you do it  
 
 
 
MJ
 
6/12/1999 10:11 PM
Hi

I have in the past advocated body shielding, and there is usually some advantage to it, although in some instances it can cause further problems (like acting as an antenna for radio signals, turning the body cavity into a noisy dielectric, etc.). Usually it does help, but I don't think anyone I know of who's done this got the results they had hoped for. Frankly, I think the infamous "single-coil hum" isn't usually that bad, most strats I've played don't have much (or any) more hum than most humbucker-equipped guitars. Of course, I have seen unfortunate exceptions... I'm sure the DiMarzio VVs are pretty good, it's a great company, but from what I've heard from people I'd be more tempted to try Kinmans, although I think all the the aftermarket pickups (particularly "noiseless") seem kind of high-priced (but what doesn't?). I just put a set of Fender Custom Shop Fat '50s on one of my strats, and with the middle pickup RWRP there are noiseless positions, but even with any single coil it has much less noise than the '68 Les Paul I've been using. They are extremely quiet, and sound like the classic '50s strat pickups with just a little more output (since they're modeled after the "average" 1958 strat pickup, which was hotter wound than any other "vintage" year). Got 'em for under $150, no other modification to the guitar; lots cheaper than Kinmans, DiMarzios etc. Usual price is still under $200 U.S.  
 
Hi
 
6/12/1999 11:42 PM
anonymous
With body shielding you have to make sure you've got it connected to ground or it's worthless. I agree, it usually helps, sometimes it doesn't. It's improved my guitars but not HUGELY. My single coils always hum but it's only an issue when you're silent...  
 
 
 
I don't know what the status of the Kinmans are here in the US but as of a few months ago they stopped selling them in the US b/c of a threat of a lawsuit from DiMarzio. Supposedly Kinmans was going to make a slight mod and start selling again but I haven't heard anything since.  
 
 
 
On some LPs, the wire running to the toggle switch isn't shielded and it acts as a major antenna.  
 
 
 
MJ
 
6/13/1999 0:20 AM
tracy

Have you tried shielding the individual pickups.  
 
I did this to a friends guitar and he claims 90% reduction in hum. I used 3/8" inch electrical tape around the pickup winds if there isn't already a tape covering. Be careful , you only have one shot at it because if you take it off you'll tear a wire for sure. Thats all it takes to ruin a pick up is one little broken strand. Then I cover the tape with 3/8" copper foil stickey backed tape. This is the shield and is almost as good as a metal cover. This tape can be found in stained glass art supplies and is used to wrap glass pieces to be soldered together. The last instruction is to tie this tape to ground. On a strat type single coil, solder a small 1/2" long piece of small solid gague wire to the copper foil tape. solder the other end to the negative pickup wire at the eyelet soldered connection.  
 
Your shield has been created. Do this to all single coil pickups in the guitar. Don't be too suprised if this does work very well.
 
6/13/1999 2:15 AM
nic
I've shielded indiviual SRV pick ups, didn't like it and sucussefully unshielded them. I guess the wax was thick enough or the electrical tape not sticky enough to ruin the coils. I now have the cavities shielded which works okay... The best mod I have tried is tunning out the hum in my head. ;) Hey heres a crazy idea, what about making a thing that cancels out 60Hz sound rather than cutting them? Notch filters cut other useful frequencies. I don't know alot about cancelization but my dad and I were discussing a sucure telphone both were some voice still excaped the booth. He said they talked about putting a speaker on the outside of the booth that aired the same frequecies that bled through... I sorta laughed but it was a cool thought. Remember those high school physics experiments that involved the two tunning forks no sound was supposed to be audiable? Is this plausable?
 
6/13/1999 3:08 AM
Steve Ahola

To nic and all:  
 
 
 
    The Boss SE70 multi-fx processor has one algorithm that just removes the 60hz hum from a stereo signal, and it seems to do that rather well. However, I've never tried it to remove the hum from a guitar. (I'll have to try it out in an FX loop to see how it works.)  
 
 
 
    Lindy Fralin recommends that his pickups not be shielded because of the capacitive effect (which removes some of the high freqs). On the other hand, some strat pu's would be improved if you shaved some of the highs off. (I've shielded my Fralins and find that they still have plenty of highs.)  
 
 
 
    As for wrapping the coils with electrical tape, I believe that it was Mark Hammer here who suggested wrapping the coils with plumber's teflon tape instead. (In fact he wraps them tightly w/ the teflon tape instead of dipping them in wax to pot them. I've done the wax treatment to most of my pickups but I really doubt that the wax has ever penetrated to inner coils. The mfg's often use a vacuum process to draw the wax all of the way to the middle.)  
 
 
 
    BTW the difference with the John Atcheley method is definitely noticeable if you play your strat in front of your tv or computer monitor. What would normally be "buzz saw city" is a noise that I can live with (given the circumstances: I hate wasting my time watching TV so I'll kill two birds with one stone...)  
 
 
 
    IMHO vintage single coil pickups will always be susceptible to noise and static floating around the immediate RF environment; rotating your guitar to a "nulled" position can usually eliminate most of that noise. Shielding the cavities, coils, and pickguards can help even more and if you approach the ground paths and signal returns as you might do designing a guitar amp you can reduce the noise even more. At this point we are reaching (or have already passed, depending on your perspective) the point of diminishing returns and it may not be worth the added time and expense to go the full John Atcheley route.  
 
 
 
    In any case, browsing through John's site really turned my head around concerning the wiring of my guitar harnesses; I had previously gone on the assumption that the less wire used, the less chance to pickup up stray noises. So I would run cable shields and signal returns indiscriminately, and the end result was a guitar that was usually noisier than I had hoped for (and I never knew why!). So I view the "John Atcheley method" more as an attitude or perspective than just a punch list of instructions to follow: basically just be aware of the RF hash out there and try to design your wiring harnesses to keep that crap away from the audio signal as much as possible.  
 
 
 
    Although I haven't tried any of the new pickups from DiM and Kinman mentioned in this thread I believe that one of them will (or already has!) designed a hum-free pickup that captures the sound and response of a vintage single coil strat pickup. Vintage Guitar magazine A/B'd a set of Kinmans against a set of Lindy Fralins and the Kinmans came pretty damn close to capturing the same sound. I believe that they used the exact same strat and just swapped out the loaded pickguards for their test...  
 
 
 
    Thanks for letting me pontificate a bit!  
 
 
 
Steve Ahola  
 
 
 
P.S. I liked the tip about getting self-adhesive copper foil from a stained-glass supply house! I've been buying packages of ~3" x 10" sheets used for circuit board repairs and modifications, but I have to drive 50 miles to restock my cupboard.
 

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