The Strat SP

[JohnH]

Sorry to hear about the switch problem.

But apart from that, given the superswitch and pickups are wired and you are waiting on the other parts, you can test what youve done, either with meter or 'tap tests'. The upper left and right lugs should give the hot and cold ends of tbe first pickup listed. The lower left and right poles do tbe 2nd pickup of tbe combos. Clip the lugs to tip and barrel of a plugged-in guitar cord and tap tbe pickups with a screwdriver tip. There should be a thump from the amp when tapping selected pickups.

[DanT]

May 30, 2018 10:36:15 GMT -5 reTrEaD said:

Dan, overheating is unlikely to warp a contact. You might oxidize the copper, causing a partially insulating layer or soldering flux might migrate to the contact surface, crystallizing and preventing proper contact with the wiper. But I don't think you can achieve temperatures which will cause warping with a soldering iron or gun.

Thanks. That was my thought, it was definitely bent at an odd angle and the fact that I couldn’t bend it back led me to believe it was a factory defect. Unfortunately there was no way for me to get it to work properly. So, on to a new switch!

[DanT]

May 30, 2018 17:42:21 GMT -5 JohnH said:

Sorry to hear about the switch problem.

But apart from that, given the superswitch and pickups are wired and you are waiting on the other parts, you can test what youve done, either with meter or 'tap tests'. The upper left and right lugs should give the hot and cold ends of tbe first pickup listed. The lower left and right poles do tbe 2nd pickup of tbe combos. Clip the lugs to tip and barrel of a plugged-in guitar cord and tap tbe pickups with a screwdriver tip. There should be a thump from the amp when tapping selected pickups.

JohnH, I pretty quickly clipped off the wires I’d soldered to the faulty switch so I could measure the resistance of my pickups, as newey suggested, which I had not done previously.

Neck=6.88; Middle=6.82; Bridge=6.74

These are the stock pups that came on this 2001 MiM strat, but I removed the bar magnets and steel posts and replaced them with alnico rod magnets. As an experiment I’m trying out Alnico 5 in the bridge, Alnico 2 in the middle, and Alnico 3 in the neck...just curious how different they may sound from stock.

[DanT]

Ladies and Gentlemen, allow me to introduce, on the left below, my 2001 MiM Fender Strat, “Midnight.” She now has the Strat SP wiring installed...



Initial tests have it sounding even better than I had hoped it would.

The only problem spot is the fade control. I hear absolutely no change when in a series combination and I roll the fade control one way or the other. I’ll break out the screwdriver tomorrow and open it up again to see what might be amiss...

[JohnH]

Congrats on getting it this far!

You might try some tests before opening it again. Resistance if you can, and see that the series values are about equal to the sum of the relevant singles. If the fade control is wired as intended, you should see resistance drop as you fade down in series mode.

Tap tests are also easy. plug in and tap the pickup poles to see if the correct pickups are active in each mode.

[lordquilton]

I 'm going to have crack at this scheme too, and I have a couple of questions.

I've been using a mini toggle and a 10k resistor to add bridge to neck or neck to bridge.
I want keep a similar functionality if I can, though adding the bridge when neck is selected isn't much chop, I find adding bridge to N+M and neck to B+M gives subtle but inspiring colours. N+B really needs that resistor too.

It seems to me the easiest way would be to put the current mini switch and resistor between the positive lugs for the bridge and neck pickup, but that's based on the simple 5 way setup I have now.

I see it mentioned above that the  SP design precludes three pickups at once, but if the mini toggle is only engaged in parallel mode will I get away with it without adversely affecting series/phase/series blend functionality "further down the line"?

Or is there a better way to achieve this?  I confess I don't really understand how the super switch works (which would probably help a lot),
but if I promise to educate my self on this could someone please offer a bit of guidance?
I only started yesterday and I miss my Strat already.

[JohnH]

Hi LQ and thanks for your interest in this scheme.

Its usually tricky to add further bells and whistles to this scheme without messing something up, since mostly its design is already maxed out. Joining hot wires between pickups would tend to mess up other modes, hence spoiling the logic of the design.

But I tbink there may be a way to add this fixed parallel blending, just in the combo modes. It would add the resistor in-line with the second pickup listed, just in parallel mode, giving dominance to the first listed. It would therefore do, as a fixed parallel-only tweak, the equivalent of what the fade pot does in series mode, so some logic to it. You could do it as a push-pull switch on the fade pot, or a seperate switch.

Add the resistor in place of the red wire that goes from top-left of SW2 to the volume pot left lug. Move the left end of the red wire between SW3 and SW2 from top-left of SW2, to the same left volume lug. Wire the new switch to short out the resistor when pushed in. I suggest to sketch it out and you should see that with the resistor shunted, there is no effective change. Not shunted, one of the selected coils has to go through that resistor, but only in parallel mode.

[lordquilton]

Thanks John, I'm building the scheme in a program called diy layout creator in an effort to better understand how it works, so I'll "sketch" it in there.

Just a couple of small points of clarification - Between the middle lug right pole of switch 2 and the middle lug left pole of switch 3 there is a black wire. The drawing doesn't show that wire quite reaching the lug on switch 3.
Are the two lugs actually joined by the wire, or is it grounding on the case of switch 3?
The latter doesn't make much sense to me, just want to be sure though.

And the orientation of the push pulls - the lugs on the bottom of the drawing are actually the ones engaged when the knob is pulled up, yes?

[JohnH]

yes that black wire goes to tbe lugs at each end.

And when you pull a push/pull switch it connects to the lugs nearest the pot.

[lordquilton]

One other thing, the middle pickup on this guitar is NOT RWRP.
Does this compromise the OOP sounds, and if so can I just reverse the pickup wires on the super switch to remedy?

[JohnH]

Jun 20, 2018 4:38:07 GMT -5 lordquilton said:

One other thing, the middle pickup on this guitar is NOT RWRP.
Does this compromise the OOP sounds, and if so can I just reverse the pickup wires on the super switch to remedy?

It's ok, don't reverse anything. Obviously there'll be no humcancelling in-phase, but the tones should still be fine. And as a bonus, all the oop sounds will be humcancelling.

[lordquilton]

Can we talk about this switch that brings in the resistor?
I've got a single pole on/on switch, the resistor is wired to the middle lug, the lugs on either side go to ground and the volume pot input lug respectively.
Is that right, or do I need a dipole or something?

EDIT - I think the switch may be working fine, but there's something else.
At the Super Switch, each side of the bridge pickup goes to the first lug of the two poles. After that, does it jump OVER the second lug to the third lug, or does it go THROUGH the second lug to the third lug?
Got a sneaking suspicion it's the latter, and if so there will soon be another edit.

EDIT - I tried running through the second lug to the third and things just got weird.

[lordquilton]

So I've checked everything twice and I am out of ideas.
Here's what I have, green means the pickup responds to tap test, red it does not.
A is with the resistor switch in one position, B is with it in the other.

Parallel A               Parallel B
1 B                       1 B
2 B+M                  2 B+M
3 B+N                   3 B+N
4 M+N                  4 M+N
5 N*                     5 N
*hum                   

Things look very similar in Series mode, But Neck is present in A and B.
Any suggestions?

[JohnH]

The bridge is connscted to the relevant 1,2 and 3 lugs at each pickip wire. It is needed in all three positions. If it wasnt to be connected at 2 the wire would be shown looping past quthout touching. See if that fixes anything.

[lordquilton]

Oh, does that mean that the bottom left and right lugs of Sw2 are connected too?
I currently have the 47nF going over the right bottom lug and only connecting with the left bottom lug.

[JohnH]

Yes they are connected.

[lordquilton]

I wanted to keep the 250k "YJM" volume pot I have in this guitar, so I moved the switching functions to the other 2 pots.
I've left out the grounds out to keep it clearer, but there is definitely continuity from the lug on the Super Switch that goes to ground to the back of all the pots.


 

When I tap test in Parallel mode this is what I get:

1 Dead

2 Knock from middle, buzz from bridge

3 Bridge dead, knock from Neck

4 Middle dead. knock from Neck

5 No knock from neck, earthing buzz

One side of the toggle for the resistor kills the signal.


When I tap test in Series mode this is what I get:

1 Bridge dead, earthing buzz

2 BxM loud and clear

3 BxN, loud and clear

4 NxM, loud and clear

5 Neck dead


If my diagram above checks out, I'm starting to think there's something wrong with this Oaks Grigsby Super Switch.

[JohnH]

I had a look. I think we need to temporarily remove the extra parallel blending resistor and its switch to get back to the base diagram (but its ok that the pp switches can be on different pots). As drawn, the extra resistor and switch arent what I was trying to describe, so I think Ill mark it on the base diagram rather than try more words. A weekend job.

Also, your diagram is just partial. To help confirm, would it be possible to make (or cut/paste) a full wiring for what you have built.?

Finally, you should do multimeter tests. Measure resistance of the whole guitar in each setting with all knobs at max. And then check that the tone pot never affects resistance, and that when you sweep the volume pot (in a working setting), you get an appropriate pickup resistance at 10, that then rises to about 1/4 of pot plus pickup at about 6-7, then falls to zero with knob at 0.

Hopefully out of all that, a fix will be revealed!

[JohnH]

Here is how I was thinking to do the extra switch for partial mixing in parallel:




In parallel mode only, the second coil listed is added partially, via the orange resistor. SW4 bypasses the resistor for full mixing as before.

[pete12345]

I thought here was the best place to post my version of this design.



The main alteration here is the addition of a half-out-of-phase capacitor within the phase switch. To make this work properly, it was necessary to swap the phase switch around, so the pickup connects to the middle terminals. To remove the capacitor in the series positions, and in positions 1 and 5 where only one coil is selected, an additional jumper connects the capacitor to the series midpoint. So in series mode, the capacitor is bypassed through the series/parallel switch, and in positions 1 and 5, both sides connect to ground.

This also gives an additional function 'for free'. With the original design, the blend knob does nothing in the parallel modes, being connected to the series midpoint. Here, the midpoint is in circuit, so it allows a variable half-out-of-phase in the parallel settings by providing a variable bypass of the capacitor to ground. In-phase it still does nothing, though it may help discharge the capacitor and prevent popping when it's switched in.

[JohnH]

Hi Pete, that's an interesting tweak! How would you describe the differences in the sound that the half out of phase makes?

[pete12345]

I'll let you know when my superswitch arrives! I'm in the process of refurbishing my red Squier and this conversion is part of that. I guess if it doesn't sound good, with the blender I can turn it back to a normal out of phase. I'm not using push-pull switches as the body is a little on a shallow side and I wasn't sure about the depth, so there will be two extra holes drilled between the potentiometers for regular DPDT switches.

[gckelloch]

Jun 7, 2018 0:13:16 GMT -5 DanT said:

Ladies and Gentlemen, allow me to introduce, on the left below, my 2001 MiM Fender Strat, “Midnight.” She now has the Strat SP wiring installed...



Initial tests have it sounding even better than I had hoped it would.

The only problem spot is the fade control. I hear absolutely no change when in a series combination and I roll the fade control one way or the other. I’ll break out the screwdriver tomorrow and open it up again to see what might be amiss...

I'd be curious what wire gauge was used in those pickups. The inductance would be 3~3.5H range with the AlNiCo poles if it's 42AWG. That's a bit hotter than standard Strat pickups but might still get decent 4kHz+ chime with a very low capacitance cable. Full strength AlNiCo 5 can produce a harsh attack and sound a bit thin combined with the relatively low permeability. A good way to get a fatter note timber without the harsh attack is to either weaken the A5 poles by pressing the opposing ends together with some other A5 poles for 2-5 seconds (as outlined by Antigua in another thread) or use A2 poles and add some Steel on the bottom to increase permeability. I suggested attaching some galvanized Steel nails on the bottom with Cu tape in another thread (if you don't want to spend money on a Cu-coated Steel plate). You can also significantly reduce EMI noise without affecting the pickup tone by applying ~10 layers of Cu tape in the pickup cavities. 1 layer won't do much.

A3 has higher permeability than A2 or A5, so it partially makes up for the lower Gauss. To get a progressively stronger punch toward the bridge without the harsh attack of full strength A5, you could try taping 2 nails on the middle pickup bottom, and 4 on the bridge. It will just slightly increase inductance, but nowhere near as much as Steel poles inside the coil core. What it will do is pull the string flux lines down more through the coil -- increasing efficiency, while slightly damping the high end. You might prefer thatfor the bridge. Maybe something to try next string change?

[pete12345]

I finally got mine built and restrung. I went for a pair of toggle switches nestled between the pots as there wasn't the dept for push-pulls. One miscalculation was that the routing under the pickguard doesn't really leave enough space for one between the tone pot and blender. I managed to squeeze it in by bending up the unused tag on the blend pot. Gave the body a good cleanup and replaced the tired old pickguard with a nice new three-ply one to go with the black pickups and knobs.

So far, so good- all the pickup combos work as expected. The half out-of-phase doesn't have much variability to it, with the control not appearing to do much until it's turned down to 2 or 3. But that function was a free side-effect anyway, and it does nonetheless give the option of half or fully out-of-phase in the parallel modes. The capacitor values could do with some adjustment too as the tone control doesn't have as much authority as I'd like. But I used a lower value than on the schematic, and it's probably affected by the individual choice of pickups as well.

But overall, it gives a good range of sounds! The best out-of-phase tones seem to come from neck+bridge, which makes sense as they have the most separation. I need to play around more with use of the blender to figure out how best to use it.

[stevewf]

Here's Esmeralda, another Start SP convert:



This little strat copy came from Glarry for $79, doomed to be an experimentation subject. There've been a handful of changes and upgrades since then, including a couple rewirings. Strat SP is the current demon that resides in this body, and I liked it so much that it inspired me to upgrade the pickups. Thanks, JohnH! You should get kickbacks from pickup mfrs

I don't have good measuring tools for pickups, but the DC resistance of the factory Glarry pickups probably tells a lot: N=3.4KΩ, M=3.5KΩ, B=3.6KΩ, which is low. The other measure I took: they're scrawny! Barely any wire on the bobbins. Bar magnets. They do give lots of sparkle.

The new Guitar Fetish KPS28 29 & 30 coils go 5.4KΩ to 5.6kΩ by comparison. First time I've gotten to A/B single coils, and the new ones are louder and warmer. Keeping' 'em in.

I'm considering going back in and raising the value of the tone capacitor so it'll have broader effect.

Also, has anyone else noticed increased hum when switching to serial? Even in the humbucking modes, I get a lot of hum when I pull up the knob. Maybe I've got something wired wrong.

[JohnH]

Hi Stevewf, that's a nice looking guitar, no matter what it's value is!

In series,and in phase, you should get a fuller thicker sound than single or parallel wiring. And if its between two pickups that are normally hum cancelling in parallel (like N and M), they should also have less hum when in series. Humcancelling is more complete in parallel than series, unless coils are perfectly matched. But there should be less hum than single.

An exception might be N and B, which generally are not hum cancelling when combined in phase.

[stevewf]

Mar 24, 2022 3:41:52 GMT -5 JohnH said:

Hi Stevewf, that's a nice looking guitar, no matter what it's value is!

In series,and in phase, you should get a fuller thicker sound than single or parallel wiring. And if its between two pickups that are normally hum cancelling in parallel (like N and M), they should also have less hum when in series. Humcancelling is more complete in parallel than series, unless coils are perfectly matched. But there should be less hum than single.

An exception might be N and B, which generally are not hum cancelling when combined in phase.

Thanks, JohnH, and thanks mostly for the design.

Yes, my other experience on a "poor LP" with series/parallel and phase match what you've said. So what I'm observing in Esmeralda is unexpected. When in serial, the "fuller, thicker sound" is achieved, but there's lots of hum added. I'm talking about the normally hum-cancelling positions of the 5-way: 2 and 4 plus 3OoP. Along with the fuller sound, I might expect a small amount of added hum, or, more likely, a different sort of hum, but Esmeralda gets noisy in Serial. Gonna have to troubleshoot. Whatever's causing the trouble might also account for Tone knob's unexpectedly small amount of effect. (The Fader knob does work as described). Off to trouble shooting.

Have done the pickup tap test - the coils are active/silent when they should be. Haven't yet checked resistance at the jack. From there, it's crack open the pickguard, I guess.

I'll have my eye open for short outs involving signal conductor touching the cavity shielding - this import-style Strat's body is pretty shallow, so the cavity is not very deep; I already had to insulate against the 5-way shorting there. Any other T-shooting hints gratefully accepted.

[stevewf]

After having tinkered with faders a bit, I felt it was time to revisit good ol' Strat SP, and offer a second fader, for parallel mode.
Here are two versions [edit: corrected an error in which lugs to use on the new pot. Should use CW and middle, not CCW]
------------THESE DIAGRAMS NEED VETTING--------------

------------THESE DIAGRAMS NEED VETTING--------------

If designed/written correctly, the top version adds a fader to the 1st coil (B/M); the bottom version adds the fader to the 2nd coil (N/M). In both cases, it applies only in Parallel mode.

For this, one would need to add a potentiometer. Up to this point, Strat SP has been a "stealth" mod - no visible outward changes - so to maintain that, a dual-gang pot could replace the existing series fader pot. Outside of that, if converting from a Strat SP, there are just a couple changes, which amount to a) diverting a wire that goes to the volume pot, and instead solder it to the new pot, and b) adding a new wire from the new pot to the volume pot. The cyan-colored wire that I added to the drawings should help indicate where the changes are.

I made two versions of the drawing. The difference between them: which pickups get faded when in parallel. If consistency gets priority, then fade N/M (as that's consistent with what the serial fader does); but it might make more sense to fade B/M (think: Serial fader favors the brighter pickups, whereas parallel fader favors the warmer pickups). That's why I made two versions for y'all's consideration.

[JohnH]

hi stevewf good luck! I hope you like it.

For myself, I tried a few different blending schemes but was never happy with the results of parallel blending. It always seemed that there were two good tones, one at each end of the range, but the in-between sounds weren't very compelling to my ears. Whereas the series sounds do several nice tones along the way. Also, getting series and parallel to each blend well with a smooth transistion is tricky! Lets see how it goes!

[stevewf]

Jun 3, 2023 17:34:47 GMT -5 JohnH said:

For myself, I tried a few different blending schemes but was never happy with the results of parallel blending. It always seemed that there were two good tones, one at each end of the range, but the in-between sounds weren't very compelling to my ears. Whereas the series sounds do several nice tones along the way. Also, getting series and parallel to each blend well with a smooth transistion is tricky!

Thanks for the words from experience, JohnH. Much appreciated.

I haven't yet gone back into the guitar that I made into a Strat SP a little while ago; no need! It's a really good guitar, with a broad range of sounds. Maybe the Parallel Out-of-Phase sounds could be the weakest of the bunch... but as it turns out, my friend is curious about what Serial versus Parallel sounds like, and InPhase versus OutofPhase too, and the Strat SP juxtaposes those in an easy-to play, easy-to-understand way. It will be a great guitar for showing typical characteristics of those four things. Then, add in the fader... I gush. But I do like Esmeralda. She was made from cheap stock, but as a Strat SP she sounds good... I gush again.

In any case, the P-Fader experimentation is being directed at a different guitar, which has P-90 pickups in the outer positions and a HotRails (-type) in the middle, so maybe the blended sounds will be different enough to... to have warranted the time I've sunk into this baby. Report forthcoming, one dey.

Would you mind telling about what you meant when you said that getting a smooth transition is tricky?