When Japanese engineer Susumu Tamura designed the Maxon OD808 overdrive, he could hardly have known that it and its export twin, the Ibanez TS808 Tube Screamer, would become perhaps the most influential and, probably, imitated pedals in stomp box history. In fact, upon its introduction in 1979, the Tube Screamer, whose smooth sound is characterized by a bass roll off, midrange bump, and slight high-end attenuation, was not an instant success. But as the pedal was adopted by players as disparate as Stevie Ray Vaughan and Kirk Hammett, it gradually became a ubiquitous presence on pedalboards of all persuasions.
Tumura, a guitarist himself, spent several of the intervening decades working on wireless designs. In recent years, however, he began modifying Tube Screamers for Japanese guitar stores. But now in his seventies, he found the pace—almost 1,000 pedals annually—exhausting. Why not, he thought, just make a pedal that incorporated all his refinements? Enter the TWA SC-01 Source Code, which is exactly that. Handmade in the U.S., the SC-01 features improvements on the TS design, including 18V operation via an internal regulator, a +6 dB boost, anop amp that claims toinject “complex harmonics and an amp-like feel,” and, most importantly, a “Bite” control that can mix in asymmetrical, tube-like clipping to the symmetrical clipping-based sound of the original.
Source in Session
Using a Stratocaster and Fender Princeton Reverb as my test platform—a made-for-Tube Screamer rig if there ever was one—I first determined whether the Source Code could speak traditional Tube Screamer by A/B-ing it with a recent Ibanez TS-9 reissue. It does, producing tones indistinguishable from the traditional circuit when the bite control is at zero. That said, if your take on Tube Screamers has always been, “if it could only just…,” you’ll find that the bite knob opens up a whole new world. Goosing it adds the extra measure of sizzle, zing, and teeth that more common iterations of the design always lacked. And adjusting the balance of the drive and bite controls dials in an enhanced and expanded range of overdrive tones that truly transcend the original TS.
The Verdict
Whether you deploy Susumu Tamura’s latest refinement of the TS circuit to hit the input of an amp that’s already breaking up or as your primary source of overdrive, you won’t be disappointed. It offers all the essence of the original, but it’s the extra oomph and range that impresses.
Running two effects of the same kind concurrently can yield amazing results. Stacked fuzzes or RATs? I’m in heaven. Other effects work less reliably well in pairs. Two reverbs, for instance, can sound killer but can turn an otherwise carefully crafted signal to smog. Twin phasers, in my experience, can be counted among the effects that are delicious together. It takes just two simple one-knob phasers to get very weird. Build two phasers into one, though, and add a few extra tone shaping controls, and the weird gets weirder fast.
Keeley’s new U.S.-made, digital Oaxa twin phaser can feel nearly as simple and straight ahead as two Small Stones running side by side, and honors the elegance and ease of that solution in many ways. There’s just three knobs—for rate, feedback, and depth. A small 3-position toggle switches between 10-stage phase, 4-stage phase, and a Uni-Vibe-style mode. Two footswitches select between the individual phaser or a combination of the two. If you want to keep things simple, you can dive in no further than that and have a great time. But Oaxa bears many secrets for deeper diggers.
Working the Waves
The phase effect is fun to use intuitively. And adding it in and out can be low stakes. Feeling that a riff sounds lifeless? Add a phaser and twist the rate. Maybe it’ll be exactly what a song needs. Maybe it will sit like rotten mayonnaise. But it won’t have taken much effort to try, and you’ll probably have fun along the way. The Oaxa is deeply satisfying in this manner.
The brilliant, big rate knob can be adjusted with precision using just a toe (provided you have the right shoes). And while the depth and feedback controls might be an affront to Phase 90 and Small Stone users, Oaxa’s controls open up useful phase possibilities without leaving you feeling doomed to get lost in the weeds. The depth control, for instance, has so much range it can render the phaser all but subliminal—making it a killer always-on sweetener that can be nudged in and out of prominence via the depth knob. Those just-barely-there depth settings can also be subtly re-shaped by the similarly rangey feedback control, which acts like a filter, adding wah-like focus at mild depth. At more intense depths, the feedback adds appreciably more vowelly “wow” tonalities that give Oaxa more than a hint of a Mu-Tron’s beautiful vintage essence. This variation—and interactivity—among depth and feedback colors alone makes Oaxa a great production, arrangement, and guitar layering tool, particularly in spacious arrangements.
Bear in mind that all the phase phenomena I’ve described here were observed in the 4-stage phaser voice—my most natural and familiar phase space. But the 3-way toggle can also be configured for 10-stage voicing or as a Uni-Vibe-style phase effect. The 10-stage voice is a little more binary than the 4-stage, and can obscure some overtone nuance in the wash. At extreme depth settings it can even sound almost tremolo-like. For a lot of players, the more focused modulation waves in the 10-stage voice will be a perfect fit for rhythmic delays or staccato passages begging for a little extra wobble and a more interesting tail. The Uni-Vibe style setting, meanwhile, is a pretty authentic version of the effect and delivers a recognizable take on the drippy “whoop”-like phase created by a Uni-Vibe’s optical circuit. Like the real deal, it sounds fantastic with fuzz.
Multiplied by Two ... and More
When both phasers are on, Oaxa’s jewel lamp flashes blue and red, and the visual suggestion of a party is apt. There are deep and crazy sounds here that can take you deep into the wee hours. But not all combinations are magic. Certain pairings of modulation rate and harmonic peaks can obscure details that might make a single phase voice pleasing. But the option to run the two phasers in parallel or series enables more or less detailed versions of a compound phaser voice, respectively. And just-right phase-rate relationships combined with contrasting voices, depth, and feedback can yield fantastic results. Fast-throbbing U-Vibe style modulations combined with slow, deep 4-stage phases are extra dimensional—as are just about any two high-contrast rates. Nailing these combinations and hearing them via stereo—the other great force multiplier on Oaxa—can pull you deeper still into the pedal’s capacities.
The Verdict
Do you remember what I said at the top about the Oaxa being simple? It’s true. It’s just that Oaxa’s elegant design also has a lot in store for troublemakers willing to dig a bit. And if the stereo and dual-phase settings aren’t trouble enough, you can use the footswitches and knobs to introduce compression or extra filtering, or reconfigure the toggle to include 2- and 6-stage phaser voices. I’d venture that using the most basic functions will make the $199 price well worth it over time. But you’ll likely celebrate the day you stumble across one of Oaxa’s more complex finds. I suspect such days will be many in number, too.
Any effect can color a guitar’s personality and language. But Boss’ new XS-1 Poly Shifter literally stretches the instrument’s vocal range. With the ability to shift input by +/-3 octaves or semitones, it can turn your guitar into a bass, a synth, or a baritone, or function as a capo. It also seamlessly generates harmonies for single note leads and keeps up with quick picking without any apparent latency. Furthermore, the pedal is capable of stranger fare that stokes many out-of-the-box ideas. But if you’re a guitarist that plays more than one role in your band—or musical life in general—the XS-1 can be a utilitarian multitool, too. It’s a pedal that can live many lives.
- YouTube
The XS-1, which was released alongside its bigger, more intricate sibling, the XS-100, is an accessible route to exploring pitch shifting’s potential. Housed in a standard Boss enclosure, it doesn’t consume a lot of floor space like the XS-100 or DigiTech’s Whammy. And while it achieves this spatial economy in part by forgoing a built-in expression pedal (which could be a deal breaker for some potential customers) it’s still capable of +/- seven semitones and a +/- three-octave range that can be utilized in momentary or latching applications.
Slipping, Sliding, and Twitching
Though digital pitch shifters have always been capable of amazing things, early ones sounded very inorganic at times. High-octave sounds in particular could come across as artificial, like the yip of a robot chihuahua plagued by metal fleas. Some very creative players use these colors—as well as the most sonorous pitch shift tones—to great effect (Nels Cline and Johnny Greenwood’s alien tonalities come to mind). In other settings, though, these older pitch devices can be downright cringey.
“The pedal clearly represents several leaps forward from first-generation pitch shifters.”
The XS-1 belies digitalness in some octave-up situations. But the pedal clearly represents several leaps forward from first-generation pitch shifters. Tracking is excellent and shines in string bending situations. Semitone shifts can provide focused harmony or provocative dissonance depending on the wet/dry mix and which semitones clash or sing against the dry signal. At many settings the XS-1 feels alive and organic, too, with legato lines taking on many of the touch characteristics of a violin-family instrument. You get far less of a note-to-note “hiccup,” and glissandos take on a beautifully fluid feel—with or without a slide—letting the XS-1 deliver convincing pedal- and lap-steel-style textures when you add a single octave up. (Such applications sound especially convincing when you kick back on guitar tone and restrict your fretwork to the 3rd through 5th strings, which keeps digital artifacts at bay.)
Mixmaster Required
The most crucial XS-1 control is the mix. For the most convincing bass, baritone, and 12-string tones, you’ll want a fully wet signal. But composite sounds can be awesome, too. You can use the control’s excellent sensitivity and range to highlight or fine tune the prominence of a consonant harmony. But it’s sensitive enough to make blends with dissonant harmonies sound a lot more intentional and integrated. And many of these eerie, wonky, off-balance textures are extra effective when introduced in quick bursts via the momentary switch. (That switch can also deliver great flashes of drama with more consonant harmonies—like dropping in a 3rd or 5th above a resolving chord in a verse.)
You can get creative in other ways using dissonant blends. Droney open tunings can yield fields of overtones that sound extra fascinating with delay, reverb, or 12-string guitar… or all of them! Dialing in blends that really work takes some trial and error, and you’ll definitely hit a few awkward moments if you’re navigating by instinct alone. But those same experiments often uncover real gems—especially in the pitch-down modes, which tend to produce more mysteriously atmospheric textures than their pitch-up counterparts.
The Verdict
Boss’ most straightforward pitch shifter covers a lot of ground. If you play in a duo, trio, or small band, it can expand that collective’s stylistic and harmonic range. It’s small, at least relative to treadle-equipped pitch shifters, so if you’re not a pitch shift power user, you don’t sacrifice a lot of room for an effect you might only employ occasionally, and you can still use the expression pedal jack to hook up a pedal for dynamic pitch control. The $199 price puts it in line with competitors of similar size and feature sets, but the XS-1 is a great value compared to more elaborate, treadle-equipped pitch shifters. If you’re taking your first forays into pitch shifting, or know that you need only the most straightforward functions here, it will ably return the investment. And along the way, it might even unlock a whole cache of unexpected tonal discoveries.
Reverb and delay. What two effects are better suited to live side-by-side in one pedal? Source Audio’s new Encounter reverb and delay is a mirror image of the company’s Collider, which explores the reverb/delay combo via a vintage lens. The mirror by which Encounter reflects the Collider, however, is more like the funhouse variety. There are many psychedelic, cosmic, and wildly refracted echoes to utilize in the Encounter. There are lots of practical ones that can be tuned to subtle ends, too. But Encounter’s realm-of-the-extra-real extras make it a companion for players that ply dreamy musical seas. It’s incredibly fun, a great spark for creativity, and, most certainly, a place to lose oneself.
Exponentially Unfolding
Of Encounter’s six reverb modes and six delay modes, four of them—the hypersphere, shimmers, and trem verb reverbs, and the kaleidoscope delay—are entirely new. Hypersphere, fundamentally, makes reverberations more particulate. Source Audio says it’s a reverb without direct reflections. In their most naked state, these reverberations can still sound a touch angular and perhaps not quite as ghostly and fluid as “no direct reflections” suggests. But they are still complex, appealing, immersive sounds. Odd reverberation clusters can conjure a confused sense of space and highlight different overtones and frequency peaks in random ways. At settings where you can hear this level of detail, hypersphere shines, particularly in spacious solo phrases. Hypersphere also features phase rate and pitch modulation depth functions via the control 1 and control 2 knobs, and they can further accent and enhance those frequency peaks, creating intoxicating, deep fractal reflection systems.
“Blends of the delay and reverb are the kind of places where you can lose track of a rainy day.”
The new trem verb mode can be practical or insane. The two effects together are a pillar of vintage electric guitar atmospherics. But the Encounter’s trem verb explodes those templates. As with the hypersphere mode, trem verb can zest simple chord melodies by using extreme effect settings at low mixes, where chaotic, half-hidden patterns dip in and out of the shadows, sometimes creating eerie counterpoint. But I loved trem verb most at extremes—mostly high mix, feedback, and decay settings with really slow modulation. Sounds here can be intense and vague—like strobe flashes piercing drifting fog. It might not be an ideal place to indulge fast, technical fretwork, but it’s a wonderland for exploring overtones, drone, and melodic possibilities.
Incidentally, the trem verb is a great match for the six delays, and the new kaleidoscope delay in particular, which fractures and scatters repeats in a million possible directions and spaces. Blends of the delay and reverb are the kind of places where you can lose track of a rainy day. The sound permutations often seem endless, and finding magic can take some attention and patience. But you can strike gold fast, too. You have to take care to save settings you really love (you can store as many as eight presets on board, and 128 total via midi) because it’s hard to resist the urge to meander through— and meditate on—hours of sound without stopping. Not all of the Encounter’s sounds are perfectly pleasing. Some combinations reveal peaky little chirps that betray digital origins—the merits of which are subjective and contextual. For the most part, though, the combined sounds are liquid and vividly complex, and can be especially enveloping at high mix and feedback.
Extended Reach
If the onboard controls don’t get you in enough trouble, downloading the Neuro 3 app, which unlocks deep control and functionality, is a minor wormhole. Take the case of trem verb—you can use Neuro 3 to change the wave shape or set up the reverb to affect the wet signal only, just the dry signal, or both of them. All of these changes open up a new system of tone caves as the sound evolves. If you’re deep in the nuance of a mix or arrangement, this functionality can be invaluable. And it’s a boon if you have nothing but time on your hands. In a state of engaged, intuitive workflow, I like to avoid these kinds of app dives. But having that much extended power on your phone or computer is impressive.
Neuro 3 extends the capability of the Encounter in other ways, too. The SoundCheck tool within Encounter is home to prerecorded loops of various instruments that you can then route through a virtual Encounter pedal. That means you can explore Encounter’s potential while stuck in a train station. It’s a real asset if you want to understand the pedal as completely as possible, and certainly a way to extract the most value from the unit’s considerable $399 price.
The Verdict
About that price. It looks steep. For most of us, it’s a significant investment. But when I consider how many sounds I found in the Encounter, how compact it is, and the possibilities that it opens up in performance and portable production (especially when you factor in the stereo ins and outs), that investment seems pretty sound. I must qualify all this by saying I was happiest with the Encounter when exploring its spaciest places—the kind of atmospheric layer where Spacemen 3, ambient producers, 1969 Pink Floyd, and slow-soul balladeers all hang. But there is room to roam for precision pickers that background radical effects, too.
Still looking to justify the cash outlay? Consider the Encounter as a portable outboard post-production and mixing asset. If you’re creating music built on big, shape-shifting ambience, it’s a cool thing to have in your bag of tricks. Different artists will mine more from the Encounter than others, so you should consider our ratings scores on a sliding scale. But as you contemplate the Encounter, be sure to factor in mystery paths that will beckon when you dive in. There’s lots of fuel for creation along most of them.
Most amp kits are Fender flavored, typically recreating historic 5F1 Champ, 5F2-A Princeton, or 5E3 Deluxe tweed-style circuits. And since an actual late-’50s Princeton, for example, costs about $3,000, at well less than a third of that price a DIY kit is an affordable alternative for any guitarist with soldering skills and the patience to follow instructions. But what if Fender isn’t exclusively the taste you’re looking for? What if Valco, Ampeg, Marshall, or modern takes on classic tones also float your rubber raft?
Enter StewMac’s mighty little Valve Factory 18 head kit, a 12-pound beast that punches above its weight class, offers a variety of classic-inspired sounds, and hints at modern boutique amp voices.
Flexible Fryer
Part of the Valve Factory 18’s versatility is due to the two preamp tube options provided in the kit: a 12AX7 or a 12AY7. But it’s mostly the result of a concise-but-flexible set of controls. On the front panel, there are volume, gain, and tone dials, but the way they shape sound depends on whether your guitar is plugged into the low- or high-input jack. The low input is the clearer of the two and hews close to Fender tweed world. But the high input offers gentle breakup that, to my ears, gets into gnarlier old amp voices. Both channels offer plenty of headroom and work well with pedals, but if your primary sources of tone color are stompboxes, the low input may be best for you. Both also benefit from a clean boost footswitch that pumps up the volume without altering the tones in play too much.
On the back, there’s an impedance switch with 4-, 8-, and 16-ohm settings, so the Valve Factory 18 can be used with most cabinets. There’s a single speaker-out jack, and on/off and standby toggles. And as its name implies, the amp delivers 18 watts, and it’s a loud 18 watts at that—fitting for today’s small-amp sweepstakes.
Brick By Brick
Confession: StewMac sent me an immaculate, pre-assembled review model rather than a kit. But I still settled into a meticulous reading of the highly detailed and lavishly illustrated instruction book. It begins with a menu of the included parts, which are metal film and metal oxide resistors, plus a single wire-wound resistor, two 1N5408 diodes, nine various capacitors, a pair of custom-built Pacific Trans transformers (power and output, naturally), wire, heat-shrink tubing, sockets and tubes (more on the tubes later), the fuse and fuse holder, the pilot lamp, screws and locknuts, input jacks, control pots, front and rear faceplates, the fully assembled footswitch for the boost, and a very solid anodized metal chassis.
Point-to-point assembly begins with the filter cap and works through the sockets on up to populating the circuit board, and so on. It’s advisable to have a digital multimeter handy to check each resistor before installation. Our test Valve Factory 18 arrived ready to go save for installing the tubes, which was easy, since this amp does not have a cabinet, so, it's merely a matter of plugging the tubes into the slots on the top of the chassis. Two JJ 6V6s live atop the amp’s crown next to the filter cap, which is also adjacent to the 18-watt power amp. I inserted the provided 12AT7 phase inverter tube and then decided whether to plug the 12AX7 or 12AY7 into the preamp slot.
Totally Tubular
Those aren't the only tubes that can be swapped in the preamp slot. The amp will function happily with 7025, 5751, 12AT7, and 12AU7 valves. But I stuck to the provided 12AX7 and 12AY7. Both performed true to their tendencies. I used the Valve Factory 18 to power a Sam Hill Custom 1x12 cab with a 50-watt Eminence Private Jack and plugged in a two-humbucker Les Paul, a PRS SE Silver Sky, a Dean electric resonator with a lipstick pickup and a piezo, and a Steinberger Spirit. In all these combinations the 12AY7 yielded a little more headroom than the 12AX7, little breakup when pushed, and a cleaner sound profile overall. That is not to say the 12AX7, my favorite of the two, lacks headroom—especially when I plugged into the low-input jack. But playing through the high-input side, the 12AX7 gave me exactly what I want from an amp: enough clean tone to stay articulate along with a gritty patina that speaks the language of rock and blues.
For me, that sound sings best with the tone between 10 and 2 o’clock and the gain between 10 and 12 o’clock which generates genuine old-school breakup. The tone control has great range. Turned hard to the left, it creates a booming, bass dominated voice; hard right, it’s bright and cutting, but never piercing. I did not find an unsatisfying sound within its scope. Dialing the gain to the top and the tone to about 8 o’clock, visions of doom rock danced in my head. With the tone at noon and higher, and the gain all the way up, I could hear the hard rock and metal applications, though the Valve Factory 18 isn’t a 5150 by any means. The volume dial simply makes things louder without significantly impacting the tone, which is ideal.
The Verdict
Short story: I dig this amp in all its sonic variations. Although the Valve Factory 18 is simple to use—and seems relatively easy to build—it is cleverly designed too. Playing it is a joy. So much so that I am disappointed that it’s not gig-ready. Without a cabinet or some cover to protect the tubes, transformers, and filter cap, it’s easily damaged. That said, the power, versatility, tonal range, and sense of accomplishment in building a point-to-point packed with character seems well worth $599.
