Doing the SplitS – part 2
In last issue’s Mod squad we looked at the basics of coil splitting – here Dave burrluck investigates some different concepts
You’ll already know that if you want to get the most from your humbucking pickup, then you’ll need fourconductor wiring. Don’t worry, you won’t lose your ‘vintage’ tone, but it’ll give you maximum flexibility, especially if you want to get some single-coil sounds.
One seemingly new concept is the ‘partial’ coil split. This was explained to me by luthier Brinsley Schwarz who, at the time, worked at Chandler Guitars in Richmond. As we said last issue, a coil-split is achieved by knocking out one coil. But that, on a lower-powered humbucker, can lead to a thin sound. The partial coil-split, however, puts a resistor between the split point and ground so some of the dumped coil is retained producing a slightly thicker, bigger sounding split. PRS is one mainstream company that, since the launch of the David Grissom DGT, installs a different value resistor for the neck and bridge pickup to achieve these ‘bigger’ sounding coil-splits. You can even use a variable resistor, like a volume control or (more usually) a smaller trim-pot, so you can tune in exactly how much of that dumped coil you want to hear.
This turning down, rather than dumping, of one whole coil can also be achieved by taking the split output to your tone pot, so fully ‘on’ the pickup is split and, as you turn it down, the dumped coil is gradually reintroduced to voice the full humbucker before the tone cap reduces the high end as you’d expect. This humbucker-to-single coil graduation is the principle behind Trev Wilkinson’s Vari-Coil that you’ll find on various Fret-King and Vintage guitars. Another idea, the VCC (Voice Contour Control), used by Washburn, is to use a 500k linear ganged stereo pot to move from full series humbucking to that thinner and brighter (but still humcancelling) parallel mode.
You don’t have to use the traditional coil-split to thin out a humbucker. Again, with an additional pot (or switch) you can filter the humbuckers, removing some bass, to simulate a single coil. This is the concept behind Reverend’s variable Bass Contour Control and Yamaha’s Dry Switch that was introduced on certain Revstar models. The neat thing is you don’t need a pickup with four-conductor wiring and it’ll also work on a fat-sounding P-90 or indeed any single coil. Aside from that extra pot (Reverend uses a 1meg ohm pot) all you need is a tone capacitor, again Reverend uses a .022microfarad. If you don’t want to install an additional pot, you can do the same thing on a switch for a pre-set bass cut – pretty much what you’ll find on Charvel’s Guthrie Govan models, called the ‘secret’ switch.
Some companies call our classic coil-split a coil-tap. This is actually a different concept. When a coil has been wound to a certain percentage an output can be attached. The coil is then continued and the finish wire becomes the normal full coil output. This gives, for example, an overwound single coil, or a P90, two voices. When the two coils of a humbucker are both tapped we can achieve, for instance, a ‘hot’ and ‘vintage’ humbucking output.
I’m not saying Paul Reed Smith was the first to exploit this to achieve a more realistic single coil voice from a humbucker but he was the first I was aware of. The concept means one coil of the humbucker is tapped and the smaller percentage of that coil tap is added to the voiced single coil, increasing the number of coil winds we’re hearing and reducing the volume drop associated with a basic coil split. As a result it beefs up the single coil sound. The trouble is any of PRS’s ‘multi-tap’ humbuckers come only with a guitar and a £3k plus price tag – you can’t buy them without the guitar (aside from on eBay or Reverb). We’ve written about the UK’s Catswhisker S-bucker before and, as well as offering this tap function, the slug coil (the one that’s voiced in the tapped split mode) has six Fender-like magnetic poles to create one of the nicest-sounding humbucker/ single coil pickups we’ve heard.
Seymour Duncan offers options too. The Stag Mag loads two Fender-style single coils into a humbucking format, which can be wired in normal series humbucking or voiced as single coils. Then there’s the SH-16 59/Custom Hybrid. It uses the screw coil from a 59 and the slug coil from the higher output Custom (with a measured DC resistance of 7k ohms) and it’s that one that’s voiced with a standard split.
A conventional coil-split, where one coil is dumped to achieve a single coil sound from humbuckers, is so last year.