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switching Am. Std. Strat


 
9/28/1997 10:23 AM
Jules
email
switching Am. Std. Strat
Hi,  
 
Can anyone tell me how the fender DeltaTone system works?  
What pickups are selected with the 5-way switch?  
How does this work with the tone knob set to 10?  
 
Jules
 
10/3/1997 1:27 PM
Doc
email

Jules:  
 
Normally, the Stratocaster has no tone control connected to the bridge pickup position, so the pickup runs wide open (rather bright). If you connect a conventional 250K tone control in parallel, you will notice a treble attenuation due to the loading effect, even with the knob on "10". (This is how a Tele is wired.)  
 
So, if you'd like to have a tone control available for the bridge pickup, but still be able to go back to the brighter response of the traditional strat, you can install a pot that is wired to the bridge switch position but automatically disconnects when it's turned up to "10".  
 
The DeltaTone tone pot has this feature built in. Basically, the carbon resistance trace has been made slightly shorter than the full travel arc of the wiper contact. The wiper goes beyond the end of the resistance trace and becomes electrically disconnected, thus opening the shunt. This pot has a mechanical detent at "10". I think the new bridge pickup has a few more turns on it. What I'm not sure of is whether Fender wires this tone pot to the bridge pickup only, or it's connected in the mid position also,  
 
Most Strats that I've wired have a similar control that's homemade. Carefully remove the metal case on a standard pot, and slide the rotor out. On the high side of the resistance trace (the end the wiper comes to rest at when knob is on "10") scrape away just enough of the carbon with a sharp x-acto knife to completely disconnect it from the solder terminal, with a spot for the wiper contact to park and still not contact any of the carbon trace. Carefully reassemble the pot (pay attention to the travel stop locations), crimp the cover back in place, and wire it up with a capacitor value of your choice. You might want to check your work with an ohmmeter before you solder it in.  
 
Hope this helps.  
Doc
 
10/8/1997 1:51 AM
Steve Ahola
email

.. I'd never heard about that trick with an x-acto knife before, but it sounds like a great idea!  
.. Have you had any luck taking apart a push-pull pot? (I melted one together soldering on a mini audio transformer/inductor for a passive midrange control and at $12 to $15 a pop that hurts! After doing that once I decided to GLUE the part onto the switch section...)  
.  
Steve Ahola
 
10/9/1997 1:12 PM
Doc
email

Steve:  
 
I haven't taken apart one of those miniature push-pull pots yet, but I'm gonna try sometime soon. It shouldn't be a problem unless during the factory assembly process they used some kind of rivet type crimp inside which, if pryed open, might not be a reversible operation.  
 
Referring to your "overheat" problem, you may have melted something inside the switch, and I don't know where a separate replacement switch is available. Sometimes I feel that they carry this plastic stuff a little too far. They'd make your whole car engine out of plastic if they could !  
 
An idea that just came to me for mounting that piece of iron would be to make a thin sheet steel strap (el-cheapo version would be to unfold the case of a Duracell 9 volt battery & flatten it) . Cut it about 3/4" to 1" wide and punch two hles in it so it can be mounted under and between two pots, or a pot and selector switch, wherever there is room to fit the inductor. Before you actually mount the strap, solder or epoxy the inductor to the right spot on the strap.  
 
If you want solder to stick to the metal such as those switch cases are made of, that golden/greenish looking chromate plating has to be scraped off down to the steel, then tinned right on the bare steel. Some pots are cadmium plated, same deal. Use the edge of a small screwdriver (don't waste knife blades here) and scratch the plating off the size of the spot you want your solder connection to end up.
 
10/11/1997 8:01 PM
Steve Ahola
email

.. After using fluxes that would eventually damage components and STILL have ground connections fall off pots, I finally figured out that trick of scraping the surface of pots and switches!  
.. Since we're swapping tricks, how about this one: for multiconductor pickup leads, add a short piece of clear 1/16" heat shrink tubing to each of the signal leads to protect them, and slip a piece of 3/16" or 1/8" heat shrink tubing over the cable to keep the shield from causing shorts. The 1/16" heat shrink tubing on the signal leads acts as a heat sink to soak up any excess heat which might otherwise cause a hidden or future short in the cable. I've been doing this for many years and finds that it really does cut down on problems with pickup leads shorting out or getting fused together from too much heat.  
.. Oh, the inductors are fairly small and fit nicely on the side of a push-pull pot section. They have two mounting tabs and you can solder one of them onto the end of the switch to establish a ground and then add a dab of silicon to keep it from vibrating. (It was when I tried to solder the SECOND tab to the side of the switch section that I screwed up the pot).
 
10/16/1997 12:17 PM
Jules
email

Thanks for the info.  
I'd totally forgotten that I posted the message.  
Well, the switch is probably wirde like this:  
- bridge PU  
- bridge PU + middle PU  
- middle PU  
- middle PU + neck PU  
- neck PU  
 
Jules
 
11/5/1997 2:32 AM
Steve Ahola
email

Doc:  
. Thought I'd let you know that Lindy Fralin is marketing a blend pot that has been modified using your x-acto blade trick... (You could call them up and ask for your royalty check!)  
.  
Steve Ahola
 
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