Tag: control

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DIY

A New Tone Control Concept — or Is It?

Hey, smart people — let me get your take on this. I’ve been playing with a new tone control idea that’s so simple, I can’t believe no one’s done it before. (Chances are someone has.)

Here’s the idea: Conventional electric guitar tone controls employ a single pot and single capacitor connected to ground. As you turn the pot, more signal goes to ground for a darker sound. The capacitor value determines the cutoff frequency — the larger the cap, the lower the cutoff frequency and the darker the sound. In other words, the cutoff frequency is fixed, but the percentage of signal that gets cut off changes as you move the pot.

Meanwhile, the Gibson Vari-Tone circuit uses a rotary switch rather than a pot, and a set of capacitors of ascending size. The small caps have a brighter tone, and the large ones sound darker. But once a cap is engaged, it’s engaged all the way. In other words, the cutoff frequency varies as you move the switch, but not the percentage of affected signal—it’s always 100%.  (The Stellartone ToneStyler employs the same concept, with as many as 16 caps arranged around a rotary switch.)

But do you really need all those caps? Why not use the tone pot to fade between a small cap and a large one, like so:

double cap

Here, the brighter/lower-value cap is engaged when the pot’s all the way up. As you roll it back, the larger cap is introduced, producing greater capacitance and a deeper treble cut. When you arrange caps in parallel, their total capacitance is the sum of their values. For example, I tried a .0047µF cap and a .047µF, so the minimum value is .0047µF (a very modest cut) and the maximum is approximately .052µF (a very dark tone).

So far I’ve only tried this on breadboard, though I plan to deploy it in a new “parts” guitar I’m assembling. So far it sounds … really good. A lot like a ToneStyler, actually, but with fewer parts and handpicked values. The only tricky thing was finding a good pot value where all the action wasn’t bunched up at one end of the knob’s range. A reverse-log pot worked best for me—I got nice results with both a C500K and C1M.

I often use similar wiring to alter the value of the input cap on distortion pedals. (High values filter our more bass for a brighter/cleaner sound.) But I’m not aware of anyone having tried this on a guitar tone control.

Another issue is the fact that, in this circuit, the tone pot always has a cap engaged. You could use a really tiny value for the smaller cap so there’s little perceptible cut at the minimum setting, but that can make a substantial part of the pot’s range a little too subtle. So my plan is to combine this with a Ned Steinberger-designed JackPot as the volume control. This part has an “off” setting that bypasses the tone circuit entirely for a maximum-bright sound. That way, I’d choose for the smaller cap a value that provides the minimum treble cut I’m likely to want. (I suspect I’ll wind up with something between .0022µF and .0047µF.)

Have any of you seen or heard of such a guitar circuit? If so, any observations or advice?

 

Categories
DIY guitar

The Fender TBX:
A Cool 2-Band Tone Control

You can TELL it's Photoshopped! There's no TBX!
You can TELL it’s Photoshopped! There’s no TBX!

Thanks again to everyone who chimed in on the “What your favorite mod?” discussion. I got tons of great ideas from your comments.

Like this one, which I’ve been meaning to explore for ages: the Fender TBX tone control circuit, which appears in several Custom Shop instruments, notably the Clapton signature Strats. Like the G&L PTB circuit I’m so apeshit about, it’s a 2-band passive tone control — but one that sounds very different.

The PTB is a two-knob circuit that lets you siphon off highs, lows, or both. I’m agog at how well it works with humbuckers — you can get so many cool sounds by rolling off lows on the way to a fuzz, as heard here.

But TBX (it stand for “treble bass expander”) is a one-knob circuit, tbough that single knob rotates two stacked pots. The control has a center detente. Set here, it’s like a regular tone control, wide-open. Turn it counter-clockwise and highs vanish, per usual. (You could “tune” the roll-off frequency with various capacitors, though I went with the stock .022uF.) But when you rotate clockwise, the absence of lows makes glassy highs erupt.

The dual pot cut highs or lows.
The dual pot cut highs or lows.

Technically, it’s not a boost, but it sure feels like one. Dirk Wacker, my now-colleague at Premier Guitar, dissects the circuit far more capably than I can here. (And he goes way beyond in this subsequent article on TBX mods. Man, I have some catching up to do!) He makes a good case for replacing the stock resistor with another value, but I went with the original 82K to establish a point of reference. I’ll try his mod when I restring, and I’ll update you here.)

BTW, you need the Fender TBX kit for this project — it uses highly customized pots to work its magic, and a standard stacked pot won’t do. But it’s cheap: You can find the TBX kit, with the pot, hardware, and passive components, online for about $15.

I put it into the mongrel strat I’ve been using as my digital synth/looping guitar. I’d been using a Stellartone Tone Styler, a cool Vari-Tone variant that switches between multiple capacitors. I dig it, but it’s the old model which clicks, rather than fades, from setting to setting, and it requires a powerful twist of the wrist to go from maximum to minumum, which I do every time I grab an EBow. Since I hadn’t gotten around to replacing it with the smooth-action version, I figured I’d try the TBX.

And I’m glad I did. It’s a super-easy install, at least to the extent that any job that requires removing both strings and pickguard can be easy.And here’s how it sounds:

I’m going to keep this one around for awhile. You’re hearing it through an analog rig, obviously, but I want to find out whether that extra shot of highs does anything meaningful when playing digitally. I’d also like to experiment with different cap and resistor values.

And now I can’t help wondering whether this would sound cool with humbuckers. Anyone have any experience with that?

Categories
DIY guitar

What’s Your Favorite Mod? (Here’s Mine.)

How am me make guitar thing better?
How am me make guitar thing better?

What’s your favorite guitar mod? The kind that changes how you play. One you’ve become so accustomed to that you wince when you pick up an axe that lacks it?

I’ll choose pickup wiring mods as a starting point: During the year that Seymour Duncan sponsored tonefiend.com, I devoted many posts to the under-appreciated wiring schemes I found in the company’s wiring diagram database. Some faves:

…and of course, the suicidal soldering mission known as the Pagey Project.

I’ve still got the “advanced” version of the Pagey wiring in my nothing-special beater Les Paul, and I like it so much, I want to fix up the guitar so it feels as nice as it sounds.

But of all the wiring experiments I tried, my absolute favorite is one that doesn’t appear in the Duncan archives: the so-called “PTB” tone control (for “passive treble and bass”). It’s a cliché to call a neglected idea “ahead of its time,” but in this case, it happens to be true. Being able to roll off lows as well as highs is unbelievably useful when sculpting sounds. It makes me want to run into the nearest Bain Capital Guitar Center, grab players by the collar, and shout, “You need to know about this!” (But I probably won’t, ’cause G.C. customers aren’t accustomed to receiving that sort of personal attention, and I wouldn’t want to freak them out.)

Allow me to repost last year’s video, demonstrating the circuit in action:

Over a year later, I remain totally addicted to this circuit, and I recommend it to anyone who doesn’t require a guitar with independent volume controls per pickup. (Everyone, basically.) It seems especially relevant for drop-tuned and 7-string metal players who realize you must sometimes cut a little bass to keep the lowest register tight and articulate. And the circuit is a godsend when used with bass-heavy fuzz pedals (such as vintage-style Fuzz Faces). In fact, I’ve even been building the circuit into the front end of certain loud fuzz pedals for use with guitars lacking this magnificent mod.

But I remembered something interesting this week when I opened up the Hamer 20th Anniversary guitar used in the video:

Continue reading “What’s Your Favorite Mod? (Here’s Mine.)”
Categories
DIY guitar Pickups

“Nashville” Tele Wiring . . . in a Strat?!

What do you get when you cross . . .
What do you get when you cross . . .

I’ve been coveting one of those “Nashville-Style” Telecasters — you know, the hot-rodded, three-pickup versions popularized by Nashville session superhero Brent Mason, and now a regular Fender production model.

Then it dawned on me: Since some of Mongrel Strats I’ve been playing with have strong Tele tendencies, why not flip the equation? Instead of a Tele that acts like a Strat, why not a Strat that thinks it’s a Tele?

The Fender version replaces the usual Tele 3-way switch with a 5-way, as shown in this wiring diagram, though many players prefer to keep the 3-way switch and add the middle pickup via a blend knob, as in this other wiring diagram.

I took the latter approach, and I am flipping out over all the new tones it unlocks. Check out this little video demo:

Continue reading ““Nashville” Tele Wiring . . . in a Strat?!”
Categories
Bass DIY Pickups

A Cool Alternative Tone Control for Bass

Looks vintage, but it ain't.
Looks vintage, but it ain't.

After auditioning so many different tone-control schemes over the course of the Mongrel Strat Project, I wound up with more tone circuits than I have Strats, so I figured I’d victimize a bass — specifically, a 1954 Fender P-Bass reissue with a Seymour Duncan Quarter-Pound pickup, which I’ve written about here. It’s a minimalist one-pickup model with basic volume and tone controls.

I was eager to audition a multi-capacitor tone control like I wrote about here. (Actually, it’s literally the same tone control — the guitar where it used to reside now houses the Stellartone ToneStyler tone pot covered here.) And while I had the patient on the operating table, I figured I’d also install the Black Ice distortion cube I wrote about here. (My friends in the medical profession assure me that patients always appreciate it when surgeons indulge in improvisational operating-theater mods.)

Demo and details after the break:

Continue reading “A Cool Alternative Tone Control for Bass”
Categories
Bass DIY guitar

A Modern Vari-Tone Alternative…

Looks like a pot — but it's not!

In the comments on my post on the Mongrel Strat with the Obsessive-Compulsive Tone Control, reader Dave mentioned a related product: The Stellartone ToneStyler. I ordered one and popped in into my dual-humbucker Hamer 20th Anniversary guitar (which still boasts the Seymour Duncan Joe Bonamassa pickup set I demoed here.)

(Quick memory refresher: The Vari-Tone appeared in several historic Gibson guitars, notably the ES-345. It uses a half-dozen different-sized capacitors to alter the voicing of the tone pot. It also adds an inductor, which preserves lows while the capacitors remove highs. Result: the rolled-off settings have a somewhat piercing, nasal character, as opposed to the usual dark, wooly sound of a rolled-off tone pot.)

Like some cool DIY versions of the project, the ToneStyler omits the inductor. And while it looks like a conventional tone pot,it’s actually a 16-position switch that selects between stepped capacitors, all of them smaller than in a conventional tone control. Result: rolled-off tones that maintain more volume and impact than in a conventional tone control.

Have a listen:

Continue reading “A Modern Vari-Tone Alternative…”