I'm pretty new to all of this so i have some pretty basic and most likely senseless questions.
What i have; -HSS pickups -Megaswitch E -2x 250k pots -500k pot with push/pull
What i want to accomplish: - -250k tone pot for neck -250k tone pot bridge with no-load (can this be done with push-pull pot?) -500k master volume with single coils picking it up as 250k ( I have read that this is possible by adding resistors)
There isn't much out there about megaswitches except std. diagrams. If this is not doable what are my other choices do you think?
The Megaswitches come in various types. They were originally sold by Schaller, but are also available from EYB. EYB's website offers this:
This would seem to be exactly what you want to do (assuming your HB is at the bridge position). What we don't know is whether this switch is exactly what you have, since this seems to be for version "Megaswitch 3.0". I don't know whether this is a newer version than what you have, or whether the new version changed the internal switch logic in any way.
If you have a multimeter, you can easily discern the internal switch logic (i.e., what connects to what in each switch position), thereby clearing up any question as to whether EYB's instructions hold true for your switch. Or, you can trust to luck that the two versions are the same and wire it up as directed, then see if it works as intended.
I know that the megaswitch-e does the exact pickup combination i want. My problem is with pot values.
I kinda want to use the humbucker with 500k volume pot, but i don't want to mess the sound of singles. Why do you oppose messing with resistors JohnH?
So my alternatives are; -500k vol pot for humbucker, 250k vol for singles, 250k master tone with no-load. -500k master vol, mess with resistors for singles, 250k tone neck, 250k tone mid, no tone pot for humbucker. -500k master vol, mess with resistors for singles, 250k tone neck, 250k tone humbucker with no-load. -500k master vol, mess with resistors for singles, buy a 500k pot for bridge tone, 250k tone for mid.
I really dont want to use 250k tone and volume with the humbucker becuase i want to full paltte. It is why i decided to switch from sss in the first place:)
Which one of these options make more logical sense? This stuff is pretty overwhelming for a beginner. Just getting some ideas from the forums and blogs i read. Oh btw if that Eyv megaswitch has 12 terminals, then they are not the same with Schaller since mine has 7 terminals only.
Edit: To add another question to my wall of text, this "no-load" switching can be done by push-pull since has a dpdt built in? Or do i have to mess with the pot too?
Ok, so the Megaswitch is the right thing. I wasnt sure before.
The general practice is 500k for humbuckers, 250k for singles. This standard advice can/should apply to both the volume and the tone pots.
At max settings the effect of loading due to the tone pot is identical to that of the volume pot in terms of the way each takes the edge off of the high treble. (So the tone capacitor, although it has an influence at lower tone settings, is virtually irrelevant at max tone, where its all about the pot values)
The effect of 250k vs 500k is not a huge difference actually. But still its worth considereing.
If you find the tone with singles is too bright with 500k, you can just turn the tone down a bit. For the same reasons as above, turning the tone down in the range say 6 or 7 is virtually identical to having lower value pots for tone or volume or both.
When the usual advice is 500k for humbuckers, this can be considered as two such pots in parallel, which is like one x 250k. If you have an actual 250k volume, and a no-load tone pot (which cuts out to infinite at max), then this is equivalent.
Your first proposal, with 500k volume and no-load tone pot, offers a tiny bit of extra brightness again, since it can cut out to just the 500k volume pot. Its definately doable. Id say that it would become significant if you have a hot bridge humbucker (which are most sensitive to pot values). Otherwise, Id expect a 250k volume plus no-load tone is fine.
My HSS has an 8.4k Fender humbucker, 250k volume and no-load tone. Its clear and bright.
You can indeed wire up a resistor if you want to, if you need to tame the single-coil tones while keeping the pot combinations that you propose. In your case, this would best be done with a 470k resistor between the neck hot wire and ground. You could add it later without changing any other wiring. I reckon with your scheme, you wouldnt need it. It wouldnt add any available tones, just take a little away from your brightest single tones. You can always turn the neck tone down and leave it there. The resistor would only be helpful if you found that to be annoying or tricky to set in a live performance.
These are usually such that the track cuts out at just before 10 on the knob, suddenly changing from the max pot value to infinite ohms. I like them a lot since they provide that brighter option. The step from say 250k to infinite, on a tone pot, is significant but not enormous. Ie, its a nice step to have available, but the fact that you cant sub-divide that step is not a problem. Once its set at 9 or below, you can have the smoith tonal transition that is available from a moderate tone pot value, ie, more controllable than going to a much higher value standard pot just to add max brightness.
You can buy a no-load pot, which have a detent feel as they approach the cut-off at max. Or, you can readily convert a standard 24mm pot by opening it up and scraping off part of the track. Its very simple ti do. If it goes wrong the only risk is one sub-$10 pot.
But, as an alternative, there's no reason why you cant hook-up the switch on a push pull tone pot to cut it out when you pull it. If you wanted, that same switch could cut out both tone pots at once.
So, back to volume pot values, there's one more factor to consider. Everything above is based around full volume settings. Once you turn down volume, treble can drop away due to caoacitance losses in the guitar cord. 250k volume pots are less suseptable to this effect than 500k volume pots, and this effect is just about the volume pot. It seems that most makers do nothing about this effect and its just accepted. It annoys me though. You can mostly compensate for it with a 'treble bleed' circuit, an extra cap and resistor in parallel across hot snd centre volume lugs. If it bothers you, the best values are 1000pF cap and 150k resistor, or 120k if you use 250k volume.
Alright, first of all thanks a lot! This was a lot information to digest.
Your perspective of pots being parallel was especially interesting to me. Does this mean in a traditional SSS strak with 250k pots, pos 2 (neck+middle) has a resistance of 250k/3?
As for my pots, i just bought another 500k and decideed to go 500/500 for the humbucker (it is pretty hot) and 250 tone for neck pickup. With your advice i'm not gonna wire any resistors at this point. Maybe later if i find the tone of my singles too bright. (which seems likely but we'll see )
Not gonna bother with no-load tones or treble bleeds at this point see how like it stock first.
That leaves me with a free push/pull which i'm going to use as a humbucker series/parallel switching. Hope this works out. Down the rabbit hole i go!
Does this mean in a traditional SSS strak with 250k pots, pos 2 (neck+middle) has a resistance of 250k/3?
Close. If you measure the resistance, you would still only be measuring the resistance of the volume pot. The tone cap blocks DC. But the reactance of the capacitor is quite low compared to a 250k pot or resistor. So the effective loading of a traditional SSS would be fairly close to ...
So i tried the wiring and everything works but singles are way too shrill for my taste. Guitar being alder/maple probably plays some role on that but now i can't ever keep the tone on 10. I want to return my singles to original values.
JohnH said that to add a 470k resistor to neck hot wire and ground. And if i add another 470k between middle hot and ground my thinking is that i can get close to the original values. Is that correct? Note that i don't have a tone control on middle pup, it is connected to bridge.
Your thinking is correct, Ohm's law being what it is. The reason why JohnH was trying to steer you away from using a resistor to achieve this is that the resistor isn't a benign addition to a pot. Yes, the overall resistance is where you want it to be, but adding the resistor also changes the operation of the pot as you turn it down.
That may or may not bother you. If you're one who seldom uses the knobs, you probably won't care at all. But don't think adding the resistor gets you "something for nothing".
If it were me (and of course it isn't), if the goal is to keep the single coils sounding "Strat-ish", then use 250K V and T pots there. Since your other tone is bridge only, raise that pot's value instead. A 1M bridge tone pot gives you an effective resistance of 200K- close enough to the 250K on your chart that it probably wouldn't be a detectable difference. And, since that pot isn't in the circuit with the SCs, no effect on their tone.
You have two problems here, and they're hard to keep separate, so no fault of yours.
One is that you've forgotten reTrEaD's mini-course on reactance, posted above. To cut to the chase, whenever you have capacitance in a circuit, you are no longer dealing with simple DC resistance, you are now in AC reactance territory. That said, your chart posted just above is too simplistic, since you included tone controls in your "loading specifications". Go back and re-read the aforementioned post, and re-calculate... I think you'll see some different results.
The other thing getting in your way is Ohm's Law, combined with Kirchhoff's Law. Somewhere in there, we need to consider that a pair of resistors in parallel will split (on a ratiometric basis) the total signal presented to said pair. If one resistor is fixed, and the other is variable, then we have a gen-u-wine headache in calculating what happens to the signal as the variable pot is changed via rotation of the wiper.
Without a drawing to aid me in this discussion at the moment, consider this: you place a fixed resistor across a pot, then measure the total value of the combo with the wiper rotated all the way up - the measured value is as calculated, right? But now, turn the wiper down half-way - what's the measured value between the wiper and the upper combination point? Or between the wiper and the lower combo point? You now need to consider that the fixed resistor is in parallel with half the signal, and of course, in order for that signal to get back to the signal return point (i.e. ground), you also have to consider what's going on with the fixed resistor in parallel with the "lower" portion of the pot (between wiper and ground). Those two numbers will not add up a simple "half the total value of the pair", trust me on that one.
Why not? It's simple math, right? No, it's not. Because now we have to bring in whatever is connected to the wiper itself, and how the signal got from there back to signal return (i.e. ground). For our purposes, that usually means an amplifier's first stage, or at the least, a stomp box or some other method of modifying the signal on its way to the amp. And that means we have even more stuff in parallel with that "simple" combination of fixed and variable resistors. Are you beginning to see why this throws most players for a loop?
The net effect of the last two paragraphs is that we've changed what's called the pot's taper. Taper is a description of how much change in resistance is made by how much rotation of the pot's shaft. A linear taper is (more or less) a 1:1 correspondence - 25% rotation should give us a 25% reduction of resistance (or 75%, if you're measuring from the other terminal on the pot). In addition, your postings have not addressed taper, and you should know that there is another common, indeed a popular taper in the works, and that is called a log taper, or as it's sometimes known, an audio taper. Here, the amount of change does not coincide with the shaft's rotation, it's a variable correspondence. In fact, this log taper is used more often for most controls in most guitars, which is why I bring all of this up - what I said moments ago applies to all the pot tapers to be found, but for pure orneriness when calculating the effect of adding a fixed resistor to a variable pot, the log taper will give you Excedrin Headache Numbers 1 thru 50, hands down.
In summary, adding a fixed resistor will mess with how the pot operates, and if you're used to getting a certain result as you twist the knob, then expect to be challenged by making this addition. I gar-own-tee you that the results will be significantly different than you are used to, and you will either be facing a learning curve, or you'll be having another session with your soldering iron and a solder-sucker.
* I see now that this particular topic is popular enough to deserve its own thread in the Reference sub-Forum. I'll see what I can whomp up in the next day or two.