Help with matching pickups/pot values

[cdub]

Hi, all. This is my first post at UW. I have some hot-rod strat-type guitars I've built with Warmoth parts and all top-tier components. I've gravitated towards Dimarzio pickups, mostly in HSH type config that is actually a strat-size humbucker in the neck, a stacked single in the middle, and either another strat-size hum or a full-on humbucker in the bridge. I think all Dimarzio rail type humbuckers and full size buckers sound the best through brighter pot values and I usually use a single 500k volume and no tone pots. Some guitars need a 1 Meg pot to really come to life and some guitars this is too much and breaking glass treble will ensue. However, the virtual vintage and area pickups that i love to use in the middle slot hate the 1 Meg pot, and the 500k is even pushing it in most of my guitars. What value resistor do I need to add between the middle pickup's hot lead and the switch, so that when the mid PU is engaged, it "sees" a 250k load from the 1 Meg pot? Setup is a 25.5" scale strat, roasted flame maple 1 pc VM neck in a 1 3/4"/'59 roundback size with 6100 nickel frets. Guitarfetish multipiece poplar body in seafoam which sounds AMAZING for seventy bucks btw......... Vintage fender wide trem with big steel block and tusq saddles. Fast track 1 neck, VV '54 pro middle, Duncan custom TB-5 bridge. She screams... but the VV '54 pro by itself is too loud, hot, nasally, and uncontrolled sounding compared to the bridge and neck positions. 2+4 sound ok but I have to back the mid PU off pretty far height-wise so it doesn't dominate the tone.

So can I 'resist' the urge to swap to darker mid PUps? Bad puns are my specialty.

 

[cdub]

Ok, so I googled the issue. It would seem I can only get a 1 Meg ohm pot to appear as a 500k pot to my area/vv PUps, using a 1Meg resistor from the pickup switch lug to ground. What if I use 2 1 Meg resistors in parallel? Will the pickup see a load of 333k in that instance? Forgive the advanced electronics questions, but I know if you parallel wire 3 speakers that are, say, 8 ohms each, you get a load of 2.66 ohms at the amp. Since we are still talking about resistors in parallel, does my morning math hold true?

 

[stratamania]

Welcome to the forum.

The same principles of resistance for series and parallel apply to speakers and other things in the same manner.

 

[BigSteve22]

The short answer is yes. Total resistance in a parallel resistor network is equal to the reciprocal of the sum of the reciprocals of the individual values. Meaning R(total) = 1 / ((1/R1)+(1/R2)+(1/R3).....)

So three 1meg resistors in parallel is equal to approx. 333,333.333 Ohms.

 

[Logrinn]

Or you could check out Mad Hatters products that address this very issue.

 

[cdub]

Thanks all. I will skip mad hatter and go the resistor route. Will let you know if it works out once I change strings/pull the pickguard/add a treble bleed and the resistor or two on the VV'54pro. Elixirs last me a long time so in the queue it goes...

 

[cdub]

Update: The addition of a resistor wired in parallel with a pickup is turning out to be a great concept. You can use any mix of pickups with a 1 meg or no-load volume pot and still have each individual pickup see a "proper" resistive load. Maybe some folks use 1 meg pots with single coils, but for me, I found the manufacturer recommended pot values were better, more natural-sounding choices on the vv/area units. Since you can't remove resistance to brighten the darker pickups, adding resistance to the brighter ones is the thing to do. The resistor goes from the lug on the selector switch for the pickup you are trying to smooth out to ground. I heatshrinked mine to avoid any shorts. With a 1 megohm pot and resistor, the pickup sees roughly 500k ohms and I am in strat heaven. The '54 Pro is the bee's knees in my chambered korina strat. I added resistors to both neck (54 pro) and mid (currently an area 58) while the AT-1 in the bridge runs wide open on the 1 meg pots. This hss combo is devastating...! Quacks like crazy. Super fat bridge tones. I should post a pic and clip. One day when I grow up I'll learn how to use this fancy intarwebz thing.

 

[Cagey]

Actually, while you're adding resistors, you're not adding resistance. You're removing it. Putting resistors in parallel has that effect, basically because you're giving the electricity more than one path to follow to get to the same place. Also counter-intuitive is the idea that removing resistance decreases the load. It actually increases it by lowering overall impedance to current flow. Because lower impedances present heavier loads, there's generally a greater loss of signal. That's why higher R value pots sound "brighter" than lower ones. The high value unloads the pickup by allowing less signal flow to ground.

A similar counter-intuitive thing happens with motors, and is most obvious when running vacuum cleaners. If you increase the impedance to air flow by blocking the nozzle, you hear the motor wind up a bit faster. It sounds like it's working harder, but what's actually happening is you're blocking air flow so there's less load on the pump impellers trying to pull air through the thing. As a result, the motor speeds up. Sounds like it's killing itself, but it's actually happier because it's not working so hard :laughing7:

 

[bagman67]

Yet another in a series of counterintuitive explanations from Cagey, who knows all KINDS of stuff.

 

[Cagey]

My father was a highly cynical/skeptical man, and questioned everything. Wouldn't even accept/believe the evidence of his own senses half the time, knowing how easily they can be fooled. He could barely watch TV for all the subterfuge Hollywood employed in film work, and watching a magic show was always more educational than entertaining. I'm not quite as permanently angry about it all as he was, but I suspect some of that curiosity about how things really worked rubbed off on me.

 

[BigSteve22]

Yet another in a series of counterintuitive explanations from Cagey, who knows all KINDS of stuff.

Always something to learn from Kevin!  :headbang:

 

[cdub]

Totally makes sense.  Higher resistance values leak less. Also the part about more paths to ground. I am an electrician by trade. Of course, 120 V AC is a whole separate bag, baby. Sort of.