Do I have a Bad Coil Tap/Split?

Bellycaster

This is not the same issue as Auldreekie's thread. I am getting different tones when engaging mine.

I had my Wolfgang Coil Tapped or Split back in 2000 when I bought it. It was done at the shop I bought it from and I've noticed since I got my VSOP guitar last year, just how noisy the Wolfgang can be.

At the time(2000) I knew less than zero about guitars and I still know very little now, so I can't tell you whether it's split or tapped.

The coil tap/split is operated by the tone knob - Split on 0 and Humbucker on 10. I assume the tone was defaulted to "10" as the work was being done, it sounds like it was.

The main issue is that there is more Hum when the tone knob is on 10 (Humbucking Mode) than there is on Single Coil Mode (0). The noise kicks in around the 7 mark on the tone knob. If you mute the strings with your hand it stops the Hum etc.

It's annoying enough for me to want to do something about it, although it's not catastrophically bad.

Thing is, I don't know if this is normally to be expected or whether there is an issue at all. Maybe it is a guitar that doesn't suit coil tapping?

I did a screwdriver tap test in every config. and found some interesting results, seems some Poles(on supposedly "OFF" coils) are on when they shouldn't be and sometimes, in various confis, the poles make a loud tap when on and sometimes a loud "Humming Tap" when on.

I've got the proper detailed results written down but didn't want to overload the info. I you need me to elaborate, I can.

I tested both my guitars and the VSOP (HSS) is grade A, near zero noise, that also has a Split humbucker option. The Wolfgang must have an issue, IMO.

Thanks for any help.

ICBM

Are you sure it's split on 0 and humbucker on 10?

Does the tone control still work as a normal tone control at 0?

There is a way of wiring these which gives you single coil at 10, humbucker at 7 and normal tone control below that.

Or it may be wired wrong.

steamabacus

If touching the strings mutes the hum it sounds like an earthing issue - have you checked the earth connection with the strings?

Bellycaster

Hi @ICBM

Yep, totally sure it was designed to be split on zero. The "Tone" never changes, so even on zero there is no treble loss etc.

I'll give you the results of a couple of the tap tests I did.

Neck Pup selected on Guitar, tone on zero(Split)

Neck Pup Upper Coil: All poles on

Neck Pup Lower Coil: All poles as good as off(just a tiny response)

Bridge Pup Upper Coil: All Poles OFF

Bridge Pup Lower Coil:All Poles as good as off(just a tiny response)

Bridge Pup Selected on Guitar, tone on 0(Split Mode)

Neck Pup Upper Coil: Poles 1,4 and 5 are on but very weak

Neck Pup Lower Coil: All Poles on moderately

Bridge Pup Upper Coil: All poles on Strong

Bridge Pup Lower Coil: All poles very weak response.

In the humbucking modes I am also getting response from some Pick ups that should be turned fully off.

Don't get me wrong, the guitar has very nice "Playing Tones", it's just noisy as and when mentioned in the OP and the results of the tap tests seems to show it as a Dog's Dinner. It's all over the place with what's on and off, in some configs, a pup that should be off is sounding on some poles and not others.

I know I'm repeating myself but the VSOP is wired bang on, everything that should be on is on and vice versa.

I'm 90% sure that a guy called Stuart Palmer did the job on this Wolfgang guitar and he his, by all accounts, a very good Guitar Tech/Luthier. I got the Guitar from Electro Music in Doncaster.

Could it be an issue that has developed over time rather than being just a shoddy job? It's a well looked after guitar, not gigged and knocked about.

Bellycaster

steamabacus said:

If touching the strings mutes the hum it sounds like an earthing issue - have you checked the earth connection with the strings?

@steamabacus

Thanks, I did suspect that might be an issue, not sure how to do your check you mentioned. I'm not very "hands on" as you can probably guess. Can you explain?

ICBM

OK, more questions!

Is the pot a dual-gang type (like two pots stacked together)? - if not, it can't be used to split both pickups at once so it must never have been wired correctly.

If it is, then a poor connection between the pot ground and ground elsewhere could allow some of the unselected coils to become active - and if the pickup grounds are also connected via that, could possibly make the unselected pickup itself appear to work, or at least make noises when you tap the poles. (Some poles making tap noises but not others simply means that some are in contact with the baseplate and others not, it shouldn't matter too much but isn't ideal.)

Can you see where the ground wires go to? A ground fault could have occurred over time if some of the ground path goes via non-soldered connections, eg pot casing to shielding - this is also bad practice, ideally you want all grounds brought to a single point (the volume pot casing in a master-volume guitar) by soldered wiring.

Bellycaster

@ICBM

Yes, it is a dual-gang pot by the looks of it.

Pictures paint a 1000 words, better than I could ever explain.

The photos accentuate specs of dust, the guitar is actually very clean. Don't know if you can make out the wiring questions you asked. I don't see a Green and Yellow wire(earth), USA built, so is the Ground wire the Grey coloured one?

Thanks.

Bellycaster

ICBM

There's no "earth" wire in a guitar. It's a circuit ground, which is not quite the same thing. It's usually done with black wires, although often the shield (outer braid or foil of a screened cable) is used.

It does look as if it's done right - all soldered wiring to all the right places as far as I can see. The only bit I can't see is the ground connection at the switch, between the shields of the black cable that goes to the volume control and the two grey cables from the pickups - they all should be soldered to the centre (thick) terminal of the switch frame. The grey cable with the red and blue cores that goes to the splitter pot shouldn't need to be connected at the switch - it's just a shield, the actual ground connection is carried by the black cable.

You want to put those trem springs straight too .

Bellycaster

@ICBM

Blimey, I can't remember adjusting the trem springs. They aren't even are they,lol. Only not sure whether to tighten one or loosen the other to even them up? Seriously cannot remember ever touching them.

Some more pics of the wiring if that helps.

If it is all done right,is it something I will just have to live with? It seems a bit all over the place to me with the tap test. Maybe I should get it re-done, i'm just not happy with it. Would it be a big job if I took it to a tech and told him to get rid of the Hum/Buzz issue and for me to still have the split option?

Can you hazard a guess as to whether this guitar has been Split or Tapped, there is a difference?

Do you know what steamabacus meant by checking the earth connection with the strings?

Thanks.

steamabacus

Earth / Ground - I tend to use them interchangeably. I thought it was a UK / USA thing.

As ICBM said, I'm talking about the thin black wires and the cable screens.

The ground wire to the strings is the one that goes from the back of one of the pots, through the body and into the trem spring cavity. It should be soldered to the underside of the spring claw.

It's worth having a cheap multimeter or continuity tester for problems like these. If you put one probe on the strings and the other to the jack screen connection you should see continuity (or close to zero resistance). If there is a break somewhere you will read open circuit on the meter (or at least a large resistance if it's a solder connection gone bad).

With a meter you could narrow down the exact bit of ground wiring that was at fault.

As ICBM pointed out, it could also be an issue with the grounding at the switch or the pot.

As far as the Tap / Split thing goes, it's probably a 'coil-split', A humbucker has two coils connected in series with one end ('hot') connected to either a pot or switch - and ultimately to the input jack tip - and the other end connected to the ground - and ultimately to the input jack screen. A coil-split works by connecting the join between the two coils of the humbucker to ground. This leaves one coil connected to hot and ground (and therefore 'active') and one coil connected to ground at both ends (and therefore 'off').

OilCityPickups

A tap is where a pickup ... usually a single coil ... has a wire taken out to form an output at a set number of turns of wire, then also has an final output wire at the end of the coil. For example my own Diesel Tap Tele bridge pickup has a tap wire so it has a 'full' output (9.5k) and a reduced power output from that inner 'tap'  (6.5k) This allows the sound of both a high power and a moderate to low power single coil in one unit.
You could of course make a 'tapped' humbucker ...  where each coil had a full and  reduced power output ... but it would require six core hookup wire and the motor coordination of a brain surgeon to manage all those internal connections. Then I would imagine the sound wouldn't be that great for all the effort ... unless you had a mahoosive output bucker to begin with