HSS Strat: spin-a-aplit wiring problems

[rhythmthief]

Hi folks. I've been wiring up an HSS Strat with a master tone control, a no load blend pot to split the humbuckers and a push-push pot to switch the neck pickup on independently. Here's the diagram I've used.

www.guitar-mod.com/rg_dialatap_11.html

Everything works, except that, when the humbucker is split, the master tone control doesn't work, instead acting as a volume control and killing the signal. On every other setting, it functions as a tone control. Any Ideas what I might have done wrong, or is this simply a problem with this wiring scheme? All help and advice gratefully received!

[newey]

The diagram is fine, as I see it.

I don't have any ready explanation for the odd behavior of the tone control, unless perhaps the "spin-a-split" pot is somehow grounding out the third lug of the tone pot as it is rotated. Grounding the third lug of a tone pot will make it operate similar to a Vol.

[rhythmthief]

Cheers for the response. I've pulled it to bits and rewired it using a push-push pot to split the coils and a no load blend pot to bring in the neck pickup. I hoped that would sort the issue out, but when the tone pot is rolled off with the humbucker in split mode, it still drops out the signal to more or less nothing. It's still there - just! - but it's not a usable setting.
It's a standard Fender humbucker, so far as I know, and I have the black and white wires going to the centre lug of the push - push switch: these are connected to ground when the switch is down. The neck pickup lug on the five way is connected to the outside lug of the no load blend pot, and the centre lug of that pot is connected to the centre lug of the master tone pot. The common pole of the five way switch is connected to the outside lug of the volume pot and the centre lug of the tone pot. I've been running it with the green wire of the humbucker connected to the five way switch, and the red wire from the humbucker connected to ground: testing each coil with a multimeter and a screwdriver laid across the poles indicated that this was the right way to connect it all, but I'm happy nough to try a different way if anyone thinks that'd make more sense! I'm using a combination of this diagram www.seymourduncan.com/support/wiring-diagrams/schematics.php?schematic=coil_splitting and a diagram I now can't find a link to for the neck pickup blend pot.

Any help at all would be appreciated: I've had the wiring for this apart more times than I can count in an effort to get it working properly and am now at the point where I'll be happy if I never see the guts of another electric guitar!

[newey]

Rt-

This is one of those situations where a picture is worth a thousand words. It's very difficult for me, or anyone, to follow a verbal description of wiring. To be able to tell you very much, we'll need a diagram of exactly how your guitar is wired.

Just to zero in on the problem, you said:

but when the tone pot is rolled off with the humbucker in split mode, it still drops out the signal to more or less nothing. It's still there - just! - but it's not a usable setting.

So, this behavior has now occurred with the HB wired to a "spin-a-split" pot, as well as with the HB wired to a Push/push switch? And the tone control operates fine with all other pickups, in all other switch positions?

Your post indicates that you have a multimeter available. One possibility here (and it's only a possibility, not a likelihood . . .) is that, for whatever reason, this HB has a very low output from one of the coils, which is exacerbated by using the tone. To check this, you would need to either disconnect the pickup entirely and check the resistances of each coil individually, or you can leave it wired and test it in this fashion:

Discerning parallel resistances, or "brain scanning through a nostril"

The other possibility here is that the tone pot is faulty. If so, however, we have the question of why it's only a problem with the split position.

If you have a (known-good or tested-good) spare, try swapping it out. (You can also test the pot with your meter, but the pot needs to be disconnected first. Because the problem occurs as you turn the pot down, it can be tough to tell what is happening with a meter and turn it at the same time, and you really need a known-good pot for comparison. So, it's really just easier IMO to swap the pot out.)

[rhythmthief]

Thanks Newey. I've tried three different tone pots, all known good ones. I'll disconnect the humbucker wiring and test each coil separately: my own feeling is that the coils are just a bit weak and feeble on their own, since even with the tone control on ten there's a pronounced drop in volume when the coils are split. I think what I'm going to do instead of a coil split is wire a switch which will put the coils either in series or parallel, which should have a similar effect only without quite such a pronounced volume drop.

[newey]

wire a switch which will put the coils either in series or parallel, which should have a similar effect only without quite such a pronounced volume drop.

Count me as a fan of the parallel HB sound. I'm a SC guy at heart, so maybe that's why the parallel HB sound seems sweet to these ears. Most of my HB-equipped guitars have a parallel/series switch. On my single-HB Strat, the default (i.e., P/P "down") setting is for the parallel HB, while "up" is for the series setting since I use that less.

Splitting HB coils works best with so-called "hot" or "overwound" pickups. But, then of course, one must be a card-carrying member of Shredder Nation to use the HB setting . . .

I tried splitting the coils of one of those "dual-rail" style pickups(a humbucker in a SC form factor) and found the volume drop so severe as to render the split coil setting unusable. This wasn't dependent on the tone control, mind you, it was very low output across the board. So, in went the series/parallel switch instead, just as you are doing.

[rhythmthief]

I must admit to being a fan of single coils myself, and in fact if this was my Strat we're talking about, I'd put the humbucker on Ebay and replace it with a standard Strat single coil, possibly with some out of phase switching options just to make it interesting! But as it belongs to a friend who's asked me to make it more versatile, I'm stuck with th humbucker. I'll try the series / parallel switch mod and let you know how it goes. Cheers, John.

[JohnH]

I love HSS. But split hb's will always be around 6db below the humbucker in output level.

But comparing the Hb to the other singles, so long as the Hb is not too hot, and if the singles are a bit overwound, you can set a rough match by adjusting pickup heights...singles down lower, humbucker up higher and I find the split hb is a match for my Texas Specials. Then, full hb gives a strong drive boost, which is what its for. If you want humbucker to match singles, then drop it down.

Parallel is a fuller sound than split, but about the same volume.

Another approach us to set gain to just breakup with singles, then the hotter Hb signal will crunch harder, but not be too much louder

If you are casting around for different scheme ideas for hss, this is my favorite:

SSM2 - HSS Strat

Its not complex but gets most of the best sounds including split and parallel, and series for the singles and several 'quack' sounds. It will give all the possible pairs of humcancellng coils in series or parallel. Or it can just run as a normal Strat

[rhythmthief]

Now I'm really baffled. I've wired it up according to www.tdpri.com/forum/attachments/tele-technical/146143d1349149047t-humbucker-series-parallel-switch-image-1290854317-jpg and the problem is still there ... when the tone is turned down and the humbucker is in parallel mode, the signal all but disappears. Everything else works fine, and I love the sound of the parallel humbucker, but the problem with the tone pot is beginning to annoy me! I've tried three different tone pots and two different capacitors, and none of it has made a difference.
I haven't fitted a jumper wire between the pots, but there is continuity between them through the foil shielding.
This - i1371.photobucket.com/albums/ag313/Dadou93/toneblender_zpsf31e0d42.jpg - is the wiring I'm using for the rest of the guitar, including the neck/bridge blend and the master tone. If anyone's got any ideas what it is I've done wrong, or if it's just a feature of the wiring as I've done it, I'd be grateful for any guidance!

[sumgai]

rt,


The diagram in your second link is incorrect - it shows the Tone control as being connected to the wiper of the Volume pot, whereas it should be connected to the same terminal (on the Vol pot) as the wire coming from the pup selector switch (the 5-way jobbie). Try that, and see if it doesn't work a wee bit better, by and by.


As for your first statement, and its associated link, I'm confused. You say that the Tone control works in an odd (and unacceptable) manner, yet your linked image is for a Ser/Par switch for humbuckers - what's the story here?






sumgai

[rhythmthief]

Hi sumgai,
the story - briefly! - is that I've been given a friend's HSS strat to wire up with a coil split on the bridge humbucker and a neck on blend pot. I wired up the coil split and not only was there an unacceptable drop in volume when the humbucker was split, but the master tone pot cut the signal on the split coil, and I couldn't work out why since it worked fine on everything else. I rewired the humbucker switch to provide series / parallel switching instead of a coil split, but the tone pot problem is exactly the same, viz. when the humbucker switch is operated and the humbucker coils are put into parallel mode, the tone pot all but cuts the signal completely.
My diagram is indeed wrong - well spotted! - but as it turns out, I already had the guitar wired as you suggest, with the switch terminal connected to the tone pot via the volume pot input. Although I'm now so confused by the whole thing that I'm wondering whether to wire it up according to the incorrect diagram, just to see if it works any better!

[newey]

This is mystifying indeed. My only guess here, after all the swapping of components, is a fault in one of the coils of the HB. Did you ever test the HB as I suggested earlier?

Does manipulating the blend pot change anything when the problem occurs with the tone?