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strat re-wiring question


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8/2/1999 8:03 PM
charlie
strat re-wiring question
Anyone done John Atchley's "Hum-busting Guitar Shielding and Wiring" mod to their strat? (See link from Steve Aloha's site).  
 
 
 
I performed these mods and generally like the results - quiet even near the monitor of my PC! - but there is a popping sound now when I switch quickly from the neck to bridge positions. (Note: I also split the tone controls to separate capacitors.) Never heard this with stock wiring. I can minimize this pop by changing switch positions slowly.  
 
 
 
I think this may be from the large cap shunted between the circuit ground and the shield. Any takers?
 
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8/3/1999 3:32 AM
Steve A.

Charlie:  
 
 
 
    I do get a small pop or click when switching to and from the series linkages on my Sup'rStrat wiring harness, both before and after the John Atcheley mods. I suppose that a small pF cap could be added between the contacts of the switch to reduce that noise but it really isn't loud enough to bother me that much. (I did hear from someone who had tried the Sup'rStrat harness with a set of active EMG pu's and the pop was loud enough to shatter a speaker cone... He did like the Sup'rStrat harness more than the EMG's and decided to reinstall the stock passive pickups.)  
 
 
 
    With all of the signal returns going to the ground on the jack I don't see where you would be getting the pop (all of the other grounds are isolated from this ground point by the big cap). So what value cap did you use? (I think I used 2.2uF/250v.) Did you shield your pickups (and use shielded cable with 2 conductors)? NTW did you line the back of your pickguard with copper or aluminum foil? (That gets rid of static noises that had been bugging the heck out of me since my fingers and knuckles are all over the pickguard when I play.)  
 
 
 
Steve Ahola
 
8/3/1999 5:04 AM
charlie

Nah, went the cheap route and used simple coax. I s'pose that would probably be part of the difference. I'll probably update soon (time for new strings anyways) and see if the isolated "balanced" approach helps.  
 
 
 
I currently have a .68uF/400V cap, and did the pickguard and cavity with a conductive PSA-backed fine-pitch wire mesh - pricey Mil-Spec stuff leftover from some project at work... seems to work good so far.  
 
 
 
Thanks! - Charlie
 
8/4/1999 4:15 AM
Steve A.

charlie:  
 
 
 
    Did you shield the pickup coils? I usually do with copper foil tape but Lindy Fralin says that the capacitance effect kills some of the high freqs. I've heard from other folks that using shielded cable inside a shielded cavity also kills the highs and they recommend just twisting the two unshielded leads together very tightly. Lots of different opinions out there- all of them right! < g >  
 
 
 
Steve Ahola
 
8/5/1999 4:16 AM
charlie

I shielded the wooden cavity and under the pickguard. I didn't pay much heed to wire routing, didn't twist.  
 
 
 
I was considering sleeving the pickup wires with some wire mesh sleeving - the expandable kind like in coax - and then adding heatshrink tubing over the conductive sleeving to keep it in place; grounding the sleeves at the common point. Now maybe I won't! Probably won't help with the popping.  
 
 
 
As Doc mentioned it could be the switch... I replaced it a few years back with a non-stock replacement (this was a 1976 American-made junker when I got it, had the 3-position switch). So I'll see if it's not make-before-break.  
 
 
 
I have a DiMarzio humbucker in the bridge position so the split tone caps was an essential change for me, .022uF cap and a 500K tone pot used here. Middle position is direct (no tone control). Stock cap and pot on the neck position.  
 
 
 
One of my favorite guitarists is Adrian Belew, and lately he doesn't even use tone controls on-board! But he uses synths.  
 
 
 
Thanks for all the tips, guys. Sounds like a lot of you guys are in the UK!
 
8/4/1999 2:45 PM
Doc

Regarding the switching noise:  
 
 
 
The stock 3-way & 5-way switch (used by Fender) has overlapping contacts. The 5-way switch is identical to the 3-way, but with extra mechanical detents (notches) to hold the lever between positions. It's a "make-before-break" type switch. There should be no pops or switching noise with this type of switch, if the contact surfaces are clean.  
 
 
 
Many of the newer multi-pole super switches, like my favorite 4-pole, 5-position switch from AllParts, has individual non-overlapping contacts. In other wods, "break-before-make" contacts. If you've used one of these multi-pole switches to customize your strat, you may very well get some switching noise that must be accepted with the hot-rodding.  
 
 
 
I'm not sure how the pre-programmed Megaswitches (the pcb-wafer type that Stewart MacDonald's sells) are set up with regard to overlapping contacts. I haven't used any yet.  
 
 
 
The plastic cased 5-position imported switches that one finds on almost all but American-made guitars develop poor contact efficiency after a few years. DeOxit-5 contact cleaner helps, but these switches will eventually fail, or at least drive you crazy. I have an otherwise great old squier strat (japanese) with a stock import switch that oxidizes when sitting for a week without use. It crackles when changing positions, so I have to rapidly run it up & back a number of times to allow the wiper to clean the "track". In this case, it's a matter of lesser quality metal on the contacts. These import switches all have a knob mounting blade that's not as wide as on the US fender switches. The knob for these has a rather pointed look to it, where the US strat knob is more pear-shaped with a broader rounded tip.  
 
 
 
Separate tone caps:  
 
 
 
I first learned about this, not sharing a single tone cap, when the Lone Star strat came out. The tone controls had to be separated, because switch contacts were needed to utilize the stock 2-pole switch and be able to split the bridge humbucker coils in the bridge-mid position. I've since routinely used separate caps on each tone pot to be able to choose different cap values for bridge and neck p/u's. I've found a .01uf is nice for a strat bridge pickup.
 
8/5/1999 4:24 AM
charlie

Thanks, Doc!  
 
 
 
I'll see what I got, and try spraycleaning if it is make-before-break. Not a stock switch, I slapped a replacement in there a couple of years back. Wiring changes definately brought out the noise. I'll look for a new 5-way switch, possibly Fender stock.  
 
 
 
Cheers
 

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