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:
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?
It’s almost always a bad idea to label something a manifesto. It’s pretentious, and it makes you sound like a crank, especially if you were born between 1890 and 1990. But it is dramatic. And would anyone pay attention if I gave this post a more accurate title, like “Please Participate in My Stompbox User Interface Focus Group?”
Anyway, I’ve been having this recurring workbench experience. (No, not the solder burns.) Every time I breadboard a stompbox project, I poke through the circuit, looking for places where I might add a switch or knob to unlock cool sounds. I usually find nice variations and build accordingly. But as soon as I plug in the pedal, I always seem to like one setting a lot more the others. Then I rebuild, hard-wiring the preferred value and ditching the switch or pot. Eventually almost everything I build winds up with only one or two knobs. (Unless I’m making it for personal use, in which case it often has no knobs.) It’s not a love of minimalism, and it’s certainly not an assumption that users are too stupid for anything more complex. It’s just that time and again, the simplest solutions sound best to me.
Meanwhile, I just had an interesting experience reviewing a (gulp) $5,000 amp for Premier Guitar, which crystallized some of my thoughts. The amp in question is a Little Walter 50/22 (which is actually two independent amps in a single housing), and I’ll link to the review when it goes live in a few days. But suffice it to say that Little Walter amps draw their inspiration from the earliest Fender tweeds, and have minimal controls to match: one volume knob and one tone knob. Furthermore, builder Phil Bradbury all but advises against using the tone control, pointing out that vintage-stye tube amp tone controls are strictly subtractive, and that you get maximum impact and richness with the tone circuit wide-open. And Bradbury is right. As on many great vintage amps, the Little Walter controls are practically superfluous. If you locate the right sweet spot, you can park the controls there and make any needed gain or tone adjustments the old-fashioned way: by playing them. Dig in harder for more distortion. Back of the volume to clean up. Use your angle of attack as a tone control. Like that.
But you don’t encounter many new-production amps that adhere to the philosophy. I get the sense that a lot of designers would like to create minimalist amps such as these, but they fear that the public wouldn’t get it. How could the one-knob amp possibly sound as good as the one with 11 knobs? But I suspect that the more experience you have with amps, the likelier you are to believe that simple sounds better. Now I want to build a great-sounding tube amp with only an on/off switch.
Three knobs?! What, do I look like Einstein to you?
I’m finding the same to be true with distortion/fuzz/overdrive stompboxes. For many players, the minimum complement of controls is gain, tone, and master volume. But almost every circuit I’ve explored sounds better without a tone control, and it’s hard to make a gain control sound great throughout its entire range. So more and more I find myself fine-tuning circuits to what I feel are the best gain and tone settings, hard-wiring them there, and then just slapping on a master volume for level-matching. (And if the pedal doesn’t add a great deal of volume, I often skip the master as well.) If you “tune” the distortion, you can control the gain perfectly well via your hands and guitar.
“But,” I hear the inquiring player ask, “don’t you need a tone control so you can use the same pedal with different guitars?” (Sadly, I sometimes believe I’m hearing the voices of inquiring players when I’ve neglected my meds.) Increasingly, I think not. In almost all cases, there’s a sweet spot where a circuit sounds good on everything from a bright Tele bridge pickup to a tubby neck humbucker. Those extremes don’t sound the same, of course. But if you’re playing distorted on a Tele, can’t we assume that you want a bright edge? (And vice-versa with the neck humbucker.) And if you do want to modify the tone, isn’t doing so with via fingers, amp, or mixing board a better solution than using a tone-sucking stompbox tone circuit?
Another example: I spent countless hours pursuing a stompbox vibrato circuit. (I mean true pitch-shift vibrato, not tremolo.) I’d obtained great tones, but I couldn’t get the effect to sound good at all rates and depths, because the perceived depth changes along with the rate. Finally, it occurred to me to go the one-knob route, using only a rate control, and letting that determine the depth. That may sound like a half-assed non-solution, but I’ll be danged if I didn’t suddenly have the most gratifying vibrato pedal I’ve ever played. Like the minimal controls on ’50s amps, the arrangement just worked.
Other factors influence my one-knob attitude: Since I’ve spent much of the last few years in the digital guitar realm, analog guitar has become a refuge from that sometimes math-based approach. When I switch on the analog rig, my goal isn’t maximum user options, but a primal experience. Also, there’s probably an element of advanced-player snob appeal. I don’t know much about cars, bicycles, motorcycles, or sporting goods, but there’s probably a parallel between minimalist musical tools that demand a fair amount of technical finesse, and vehicles and sports gear with stripped-down, featherweight, only-for-pros features. Not every bicycle needs a kick-stand, and not every fuzz pedal needs a gain control. (Or something like that.) Additionally, I hope to bring my pedal designs to market, and what a crowded market it is! Sure, it’s mainly crowded by clones, but many brilliant builders are creating complex mad scientist boxes. Maybe there’s a niche for one-knob mad-scientist boxes…
I’m not sure it’s kosher to conclude a manifesto with questionnaire. But I’m eager to hear your replies to these queries—or anything else you feel inspired to add. Thanks!
Do you tend to change tone settings on amps and pedals when you switch guitars?
How often do you fiddle with stompbox knobs mid-performance?
Do you use your guitars’ tone knobs much? If so, how and why?
Does anyone out there actually use their guitar volume knobs to veer from clean to dirty sounds? Or is just the wishful thinking of pompous guitar “journalists?”
Would you consider using a no-knob stompbox that pretty much requires you to use your guitar’s knobs?
I was trying to decide which self-indulgent experiment fascinating project to demo this week when my hand slipped, driving a sharp soldering iron tip into the meat of my fretting-hand index finger. It didn’t hurt all that much—until I tried to play. Ye-OWCH! (No, of course I wasn’t using the tool properly! I was trying to pick loose a knot of wire with the iron’s tip rather than the recommended wire-picker-thingy.)
So no guitar recordings for me this week while my poor l’il finger recuperates. But I’ll try to compensate for this dog-ate-my-homework post by sharing three works in progress. If they turn out well (and they might!), audio and video will follow.
1. Lipstick Tubes Revisited. For more than a year, the generic Mexican Strat I fitted with lipstick tube pickups has lived, disassembled, in a filthy cardboard box next to my workbench, guilt-tripping me every time I fired up the soldering iron. There were a number of experiments I’d been meaning to perform on it, and in a spectacularly bad example of scientific methodology, I incorporated them all at once, making it pretty much impossible to discern what’s doing what. But I hear some things I like. Here’s what’s new (beside the blood spatters):
Not everything is working as desired yet — but there are some promising directions here, and it’s so nice to have a lipstick tube instrument again. :pacman:
Joystick fuzz: like giving a loaded gun to a monkey.
2. The Joy of Stick. Anyone tried a joystick effect, like Devi Ever’s Drone Fuck Drone? I bought a few joysticks from 4Site and have been having a blast. I thought they’d be difficult to wrangle, but it’s really just two pots, each with the standard three-lug connection, deployed in X/Y configuration. Two things to bear in mind, though: They’re generally available only with identical resistance values for each pot, and more important, you need two controls that have meaningful values throughout their ranges. Fortunately, I had just the circuit for it: my Filth Fuzz (which Fuzzbox Girl was kind enough to demo and review in 2011). I’d even labeled the controls X and Y! (I’m not selling these, but I do hope to bring it to market before long. Honest.)
3. A Reanimated Amp. This one’s personal: I’m finally refurbishing the 1951 “TV front” Fender Deluxe amp that I received for as a bar mitzvah present in the ’70s. (I was mature enough not to express my disappointment over getting some crummy old tweed. But how I longed for that shiny post-CBS crap!) My mom procured it from the son of one of her fellow elementary school teachers, who worked at Fender in nearby Fullerton. (Sadly, I’ve forgotten his name.) I also got to pick from three early-’70s Fender guitars: a sunburst Strat, a paisley Tele, and a black Jazzmaster. I, of course, chose the Jazzmaster — at the exact moment when no one on earth gave a crap about that model. And naturally, I sold it just when new wave arrived and Jazzmasters became cool again. See? I established my pattern of buying and selling the wrong things at the wrong times while still in my teens!
I didn’t wreck the amp by myself — the process started with the black paint job it acquired long before I entered the picture. Over the years it received a preamp mod from Paul Rivera, and later got totally ruined by an overambitious repairman who added mods I never requested, and who probably stole most of the original electronic parts. But the cab, chassis, speaker, and output transformer are original, and there’s no reason why it shouldn’t sound bitchin’ after I restore it to its original 5A3 circuit. I’m getting expert help from Tube Depot’s Rob Hull, who helped me source parts and make a grommet board to house the components.
So my apologies for all talk, no audio. My boo-boo is healing, and I should be back able to, like, actually play some of this stuff soon!
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.
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?
UPDATE:I’ve added a page listing all the “How To” posts on this site. Just click the cleverly titled How-To Posts Are Here! box at upper-right of each page.
There’s got to be a better way!
Several readers asked for more specific tech advice on how to wire up battery-powered effects inside a guitar or bass, so I created a step-by-step tutorial, which you can download here.
Some historical background: Since the ’60s, many guitar companies have toyed with the notion of installing battery-operated effects inside guitars.
And “toyed” is probably the perfect verb for it. Onboard effects have earned a reputation as cheesy, low-budget products. In many cases this reputation is justified. (And sometimes it’s not — the Electra guitars of the ’80s were never particularly popular, but their simple onboard distortion circuit has generated hundreds of “boutique” clones, not to mention our own Bad-Ass Distortion project).
And why would you want to put an effect inside a guitar or bass? You can use a stompbox with any electric instrument, but an onboard effect is married to one axe till solder-do-they-part.
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.)
