DIY: Simple Tone Mods
WHAT STARTED AS A NEED FOR AN OFFSET TURNED INTO A TONE MODIFYING SWITCH-FEST. DAVE BURRLUCK INVESTIGATES SOME SIMPLE TONE MODS, SOLDERING IRON AT THE READY…
For a considerable number of years, gigs and rehearsals have been the platform to inform my guitar reviews, unleashing a diverse array of instruments on my bandmates and whatever audience was in attendance. In recent months, like many of us, I’ve been recording to fill the void of those cancelled gigs, not to mention the endless task of learning new songs. Aside from putting my playing under the microscope, recording has shifted my own needs. Whereas with my gig-head on I’d be looking at an instrument to get me through a couple of sets of typically diverse covers, I’m now looking for a guitar, or guitars, that suit the song I’ve been asked to work on.
One example is the good ol’ offset. Reviewing
Nik Huber’s Piet was a bit of a game-changer: I fell for its charms hook, line and sinker. I also made the foolish mistake of recording some guitar parts with that unique vibrato at the forefront. “Great,” said the singer and MD. “Would you mind trying those sounds on the outro? Oh, and I think we might need to change the key.” Normally, that’s not a problem, but the Piet – actually, both of them – is long gone.
Then I remembered an offset that I’d got in for review a couple of years back but was still waiting to be returned. No, it wasn’t a classy
Fender or anything, instead a pretty lowly Hutchins
Beachcomber. A what? With its “retro sexy” claim left to one side, it has plenty of boutique style: an altered and more compact offset body, three P-90s, an abundance of Jaguar-style chrome and, importantly for my aim, a Jazzmaster-style vibrato. Under the ‘limited edition’ red sparkle gloss finish the body wood is spec’d as alder, which contributes to a pretty standard weight of 3.19 kilograms.
INVESTIGATION
Like many of the numerous offset solidbodies that have appeared since the late 50s and early 60s, the Beachcomber ditches the dual rhythm/ lead circuit concept of the original Fenders and, of course, adds a third middle pickup. In basic terms, then, we have standard Strat wiring but with a master tone control. If that was all we had, each pickup would pass to the five-way lever switch (unhelpfully) mounted on the large scratchplate and from there to the master volume and tone on the lower chromed metal plate.
But what does the upper chromed control plate, with its three slide switches, do? Well, each switch engages a pre-set treble cut for each pickup (plus we have that master tone that provides a progressive treble cut as usual). Why? Good question – and one I can’t answer. What it does mean is that we have three mini-switches already mounted that we could potentially put to good use for a host of tone shaping and/or experimentation. And there’s another plus: aside from that five-way lever switch, the controls and switches are on those chromed plates, which means we can access the wiring a lot more easily than on a Strat, for example.
Like any other modification, you really need to think about what the problem might be first and then consider the remedy. Although the Hubers are absent, I have plenty of tracks that I recorded with them to compare to the Beachcomber. And with a Helix LT providing the guitar sounds I effectively have the same signal chain. Listening to the Beachcomber I’m hearing a hotter voice with less clarity, or indeed high-end, and a thicker single-coil
“REVIEWING NIK HUBER’S PIET WAS A BIT OF A GAME-CHANGER: I FELL FOR ITS CHARMS HOOK, LINE AND SINKER...”
voice. The measured DCRs of the three soapbars run from 9.43kohms at the bridge, 9.52k in the middle and 9.25k at the neck. Now, while DCR should never be used as an indication of sound, what I’m hearing certainly supports the hotter, less crisp P90 voice. Those preset treblecut switches aren’t doing much for me, either, especially if I’m chasing the clarity and note separation of that Huber Piet.
Unscrewing the upper control plate you can see that the simple switching uses a 473 code (.047 microfarads) green polyester film capacitor on each DPDT slide switch. The pickups are wired to
these switches first then onto that fiveway pickup selector and finally to the master volume and tone. The same capacitor is used on the master tone control, too; both volume and tone pots measure a little under 500kohms.
CAPACITOR 101
Capacitors are primarily used in two ways within a guitar circuit: to cut higher frequencies as on a standard tone control or to retain higher frequencies when used on a volume control as a socalled ‘treble bleed’. Put simply, a capacitor wired in series will favour those higher frequencies
and that’s how a treble bleed works on a volume control or the Jaguar’s basscut switch.
Relatively small value capacitors are used from around 180 picofarads to around 1 nanofarad
(.001 microfarads). The Jaguar and Yamaha’s Dry Switch use a .003 microfarads cap for their basscut switches, the latter with a parallel resistor, also used by many in a treble bleed circuit. Maybe resistors are a subject for a future column…
But when a capacitor is wired in parallel (between the hot and ground, for example) those favoured high frequencies are shunted to ground creating our standard tone control with a pot,
or – as with these Beachcomber’s mini-switches – a pre-set instant higher-frequency roll-off.
The value of the capacitor affects what we hear. Again, in simple terms if you use a .047 microfarads cap on your standard tone control the darker the effect will be as the tone control is rolled back. A .033 will be less dark, followed by a .022, and if you use a .015 or .01 the roll-off is slight.
Now, with our three DPDT slide switches we have plenty of options, particularly if we want to experiment. At present, each switch is wired to its own pickup. The Jaguar’s bass-cut, like the Yamaha Dry Switch, is a master switch that cuts
bass on any of the pickup selections. So we could rewire the setup like a Strat, with the pickups going firstly to the five-way lever then the common output running to one or more of the mini-switches then onto the standard master volume and tone controls. We don’t have to use the three switches as tone modifiers, however. We could have one acting as a master high-pass filter, another as a kill switch (on/off) and the third as the seven-sound mod, for example, where we get two extra sounds – all three pickups on and, like a Telecaster, neck and bridge together.
As my head begins to explode considering all these options, the real world kicks in and I realise I have deadlines to meet: one for this copy and the other for the track I’m halfway through recording. I’m not sure I have the time to completely disassemble the guitar so I can completely rewire it. Instead, I consider my options to hopefully narrow the gap. Basically, I have those three pickup-specific switches and the existing volume and tone to play with.
TUNING TIME
Aside from thinning out the sound from the Beachcomber’s thick-sounding soapbars, I need to maximise the highs to try to match (or at least get closer to) the Huber. With a passive circuit you can’t add, only subtract. Because the volume and tone load the pickup they effectively dampen the highs to a greater or lesser extent. Simply wiring the output from the pickup switch directly to the jack socket, bypassing the volume and tone, means I’m hearing the most high frequencies I can. Now we can look at thinning the sound of those P-90s.
I start with the Jaguar-standard cap (.003 microfarads) in series and it immediately cleans up the neck P-90, creating a thick/thin switch. Yamaha’s Dry Switch uses the same capacitor along with a resistor placed in parallel with that cap, but its effect is much harder to evaluate, certainly in our recording project context. Despite mucking about with different values, and even a trim-pot, I’d offer that it seems to narrow the gap but not enough to be particularly useful here. Much more noticeable is a lower value cap, a .002 or
.001 microfarads, which provides a progressively thinner sound.
Now, this is the point. Whatever the electrical theory might be, experimenting in this fashion allows you, the musician, to call the shots. Many, many people will tell you that a 250k pot is darker than a 500k pot. Try it. We’re told cap A will do one thing; cap B will be different. Try it. If you can hear a difference in the context of the sound and environment in which you’re working, all good. If not, well, you tried.
Did I manage to match the sound of that Huber? No. But with the combination of these minimal capacitor tuning tweaks and some track EQ, what’s the saying? It’s close enough for rock ’n’ roll
“WHATEVER
THE ELECTRICAL THEORY MIGHT BE, EXPERIMENTING IN THIS FASHION ALLOWS YOU, THE MUSICIAN, TO CALL THE SHOTS...”