This comes up a lot, so I decided to expand a bit about it elsewhere and I’m doing a shameless self-copypasta here.
The question was basically what happens on position 4 (neck/middle) on your typical Strat wiring, with Tone 1 for the neck and Tone 2 for the middle pickup.
The usual stuff was mentioned, the “Eric Johnson” type wiring, the 1 Volume 1 Tone wiring, the “do I have two capacitors when two tones are active” thing came up… yeah, so, copypasta:
I think I can answer most of this. Skip to the bold letters if you don’t care about electronics.
[I inserted a quote here about the aforementioned deal with two tone circuits at once, many people, myself included until I actually had a Strat, assume there’s two tone capacitors]
Okay yes, putting two identical tone circuits in parallel as mentioned, would basically equal halving the value of the pot and doubling the value of the capacitor.
So take your typical 6k-ish Strat pickups with 47nF tone capacitors and 250k tone pots, set the switch to position 4 (neck/middle) and all the sudden you’re doubling the tone controls; you now have a 125k pot and a 94nF cap. (Note that this is following the idea of two identical tone controls with one capacitor each as mentioned above, which is not the norm; Fender typically uses one shared capacitor and I assume this is actually the reason, but more on that later).
So, what does it actually mean in numbers?
With both tone pots on 10, not much really. The frequency response will still peak at around 5kHz before decaying, only a few hundred Hz lower than it’d do with a single tone circuit, and the resonant peak will be slightly less pronounced, but not by much.
Now with both knobs on 0 the change is actually quite big, since the cutoff frequency of the filter will go from roughly 1.1kHz down to 550Hz (these are very rough numbers but they’ll do for the example). That I assume is the main reason why Fender typically uses a single, shared capacitor for both controls instead of two caps.
But since we’re already here, there’s one more thing to consider about this scenario: Two redundant tone controls, unless operated in perfect tandem (which you’d probably not do anyway), would not act twice as heavily compared to a single one.
First, since you’re most likely to use just one knob at a time and leave the other one alone, the perceived taper on the one you DO use would feel a bit different, with most of the tonal change happening in a lower region than expected; you can live with that though.
What’s really important though, is that using only one tone knob and leaving the other one on 10 would render the capacitance on the other control irrelevant. This way you’d still effectively work over the original cutoff frequency of 1.1kHz, as if you had just one tone connected.
There’s lots of in-betweens, but I won’t bore you with the math.
Still, most Strats only use one capacitor anyway, so when two tone controls are active at once, it is as if you had a 125k tone pot instead of a 250k one, but with the regular 47nF capacitor and with the observations I made earlier about taper behavior. Having an equivalent 125k value also equals a 250k tone set to roughly 8.5 or 9, but no big deal, especially if instead of having both pots active on position 4, you have both when on position 2, which leads me to the next thing…
HOW DO YOU PROPERLY WIRE A STRAT SO THAT ALL 5 POSITIONS ARE USEFUL?
Here’s what works for me:
First off, Tone 2 goes directly to the Bridge, we need a tone there, and it is active on positions 1 and 2.
Tone 1 works on positions 2 through 5, i.e. on all but the bridge position, this tone is always engaged. You simply wire that tone pot to both the Neck and Middle tabs on the tone side of the 5-way switch, instead of only the neck. I never understood leaving the middle pickup to die without a tone, it completely disrupts the balance for me and there’s no reason to leave it out when you can afford not to.
Now you have a dedicated bridge tone which is key, this is the one that always causes trouble.
You also have the closest tone knob available for positions 3 to 5 to make quick adjustments when switching around.
Yes, this also means position 2 has two tone pots engaged at once, but only one capacitor, which is key and directly related to the original question by [forum member].
So is this bad? Not at all. If you didn’t read the electronics rambling, I expanded a bit on this but you missed nothing, really. The point is there’s a great balance this way.
For example, say you have the bridge tone set on 5 and the neck tone set on 10. Switch to position 2 which is quite bright anyway, and tone 2 is already sort of low for the bridge. “But there’s two pots!” Yeah, but only one capacitor, and because of the way two pots at once interact and how the taper is changed, it’s more as if you had only one set to 6 or 7.
If you could have three tone controls on a Strat, 10, 7 and 5 settings for these positions would seem like a reasonable starting point for many. I’m more of an 8 on the neck and 4 on the bridge, and this wiring still works great. Also, if you do need to raise the tone on position 2, you have plenty of room, with top brightness still accessible.
So to round it up, wire tone 1 to both neck and middle tabs, and dedicate the other one to the bridge. Now you have a balanced way of accessing a tone control on all 5 positions.