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    The Guyatone Ultron Optical Auto Wah and Ultrem Optical Tremolo

    The 1950s and ’60s may lay claim to some of the most valuable guitars and amps ever made, but the decade for effects was definitely the 1970s. Electronics had advanced enough so that effects had become a staple sound for the dominant pop music forms of the decade: funk, rock, and techno, plus the various sub-genres, like disco. Like the muscle cars of the same period, many of these effects were big, robust, with under-the-hood power to spare.

    One of the most revered effects from this time period was the Mu-Tron III, which immediately won favor with bass players and keyboardists. Stevie Wonder used it, as did Bootsy Collins (the flamboyant and talented leader of Parliament/Funkadelic), and later Flea from the Red Hot Chili Peppers.

    Guyatone has produced a modern-day tribute to the Mu-Tron III, in the form of their Ultron Optical Auto Wah. At the heart of the Ultron is the same electronic principle as the M-III and many other effects of the day: photocouplers, a type of optical circuitry used in many high-end envelope filters, phase shifters, and amp tremolo circuits. But the Ultron has quite a bit more versatility and can be configured in many different modes and optimized for guitar, bass, or keyboards via internal DIP switches.

    Guyatone has also released the Ultrem Optical Tremolo, a unit similar to the Ultron, but using photocouplers to produce the tremolo. The two units can be synched together for tempo-dependent applications, or for slaving one unit to the other when the control input comes from the user.

    The Ultron Auto Wah and the Ultrem Tremolo combine digital microprocesser control over analog circuitry, meaning the audio path is 100 percent analog, but with the flexibility, speed and reliability we’ve come to expect from digital control.

    This review will tackle the Ultron -- a unit popular for bass, as the MIII is -- though optimizable for guitar and keybaoards, and the Ultrem, a temolo effect which should find great appeal for guitar players.

    First, take a gander at these two units, and notice two things that stand out:
    • Their size. They are definitely oversized for typical single- and dual-function effects (note the standard-sized stompbox in the left-hand side of the frame for reference).
    • Their front-panel complexity. These knobs, footswitches, and 2- and 3-position DIP switches may look daunting at first, but you get quite used to them in a very short while. Note the inclusion of twin LED ladders and a large alphanumeric LED read-out.

    Jon Chappell
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  • #2
    The Ultron is called an “Auto Wah,” but that’s only one of its three main modes. In Auto Wah mode, the Ultron’s filter effects are controlled by an internal oscillator (whose parameters are set by the user). The Envelope Filter mode responds to the strength of your attack; play the strings softly, the sound goes whol. Strike hard and the sound goes whack! The Manual Wah mode allows you to control any of several parameters with an external expression pedal, such as the Roland EV-5.

    Here's the detailed description of the Ultron's three modes:

    1. WAVE WAH (Oscillator Controlled): In this mode, the wah effect is not depenent on, or related to, the level of the input signal. The wave cycles according to setting made with Speed Control (15) or Tap Tempo (10), with filter settings determined by filter controls (5, 7, 8). When in this mode, the amount of frequency travel (Depth) is fixed at maximum.

    2. TOUCH WAH (Envelope Controlled): With the filter set by Filter controls (5, 6, 7, 8), frequency travel (Depth) is dependent on level of input signal (how hard you strike the strings). In this mode Speed (15) and Tap Tempo (10) do not function.

    3. PEDAL WAH: By connecting to an external Expression Pedal (such as the recommended Roland EV-5), frequency travel (Depth) or Wave Speed are controlled by Pedal movement, within the parameters set by Filter controls (5, 7, 8).

    Check out this short sound clip I recorded using the Ultron in Envelope Filter mode. You’ll hear how the strength of my attacks determines how much the filter opens up.

    Ultron Envelope Filter.mp3
    Jon Chappell
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    • #3
      As I start to get into the Ultron, one realization becomes clear immediately: This is no ordinary auto wah and envelope filter. If you really want to explore the parameters for filter sweeps and waveforms — and the ways to synch them to your playing — the Ultron (and Ultrem) offers you depth like you’ve probably not seen before or possibly even imagined.

      This is not your grandfather's T-Wah! You have control over the waveform shape, speed, peak, range, sensitivity, and frequency-pass qualities. Then you bring in the real-time and performance aspects by selecting the various modes, and everything leaps into action!

      Let’s talk about the six performance modes first, as that determines how you work the controls. Each mode also has a submode — another logically related performance mode hotwired to its primary mode through a press of a footswitch. Here’s a description of the six modes, and their typical performance applications.

      Mode 1 is a touch wah, with a toggle to the wave wah (oscillator) submode via a “press & hold” of a momentary footswitch. Touch wah is where your attack intensity determines the filter behavior, and you set the Ultron to respond to your particular brand of touch using the Threshold setting. This takes some practice as you determine just how hard of a hit causes the filter to open up. I sat there whacking my strings with the right hand and moving the Threshold knob around until I got the my version of “soft” to produce one type of sound and my “hard” (but not too hard) strikes to yield the opened-up sound determined by the other controls.

      Once you establish the Threshold, you can fine-tune the other parameters. You select one of the four Filter Modes (high pass, band pass, low pass, and notch), the Peak frequency (higher settings produce a more pronounced effect) and Frequency (the range of travel, from low to high, that the filter takes).

      That’s all fairly straightforward — even the part about stepping on the momentary footswitch to toggle to the wave-driven submode. I found the touch wah good for rhythm scratchings and staccato single-note work. When I would hang on a sustained tone, that’s when I pressed the switch, invoking a rapid, tremolo-like effect, driven by the internal oscillator. I adjusted the speed of the wave using the center Speed knob and noted the read-out in the Speed Display LED, which can be viewed in either milliseconds or beats per minute. (I wasn't playing to an existing track, so I just used my ear, but I was playing about 90 bpm or 666 ms.)

      Mode 2 is similar to Mode 1 in that you still don’t need an expression pedal (as you do for Modes 3 - 6). Here, the oscillator controls the filter, and the footswitch acts as a tap tempo. So there’s really no “submode” here; the footswitch just tempo-modulates the oscillator. You can select the Wave Form shape from one of six, printed on the left side of the face plate (which my wife said looked like the stitch legend on her sewing-machine).

      I found a really good use for Mode 2 was to tap quarter notes in time with the groove, and then begin playing. Quarter notes sound like you’re moving the wah pedal in sync to the beat, but eighth-note lines take on a polyrhythmic quality. Then I reversed the process, tapping out two quick eighth-notes in tempo, and holding longer tones.

      That's when I realized, what the three-position multiplier switch (Tap/PDL Setup) was for (the right-most DIP switch at the top of the unit -- see above photo and schematic). This switch will take your foot taps and times them by 1, 2, or 4, so tapping quarters will produce eighths and 16ths in the top two positions. You have to flip the switch first and then tap; you can’t tap and then flick the switch to get different subdivisions.

      So just with Mode 1 and Mode 2, you have a very powerful touch wah, where you can set the parameters of the wave, tap out a tempo (and achieve multiple subdivisions), and invoke a footswitch for even more features, or a performance-related submode.

      The versatility in this setup is one thing, but the sound quality of the photocouplers is something else again. These are thick, warm sounds, devoid of any digital harshness so obvious (at least to me) in modern units. The Ultron has a lush quality that really does respond in an analog way (meaning it responds correspondingly and dynamically) to the source driving it -- the performer's articulations.

      And since the qualities of the sound change based on the input (unlike, say, a digital reverb or delay), this sensitivity is readily apparent and more interesting to listen to. I won’t say it’s a "wah wah" quality, as it’s a bit more “technological” sounding, but it it’s an earthy technology (if that makes any sense), and a very smooth and responsive one. You get the feeling the Ultron is playing along with you.

      Next up: We'll strap on an expression pedal and visit Modes 3 through 6.
      Jon Chappell
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      • #4
        Calling all Forumites: What’s Wrong with the State of Tap Tempo

        I wonder how many people use tap tempo (as I do, as well as tempo-dependent digital delay), and are baffled at the lack of devices that include this important feature. Not only is there a paucity of pedals that include it, but those that do often implement it poorly.

        Let me give you an example. One well-known pedal that I know of that features tap-tempo tremolo makes the feature very difficult to use. You have to step and hold to invoke the tap tempo, then release your foot, then re-apply your foot to tap the tempo. To turn the effect off you have to press and hold again. Repeat the process to re-activate the effect.

        You might be able to perform this routine at the beginning of a song during the count-off if you’re really, really quick, but it’s unworkable when you want to selectively turn the tempo-dependent function, say, before the bridge. And if the bridge occurs more than once in the song, it’s hopeless.

        Can anyone relate?

        Now for the good news.

        The Ultron and Ultrem get MAJOR points here for the way they implement tap tempo. Mode 2 is where you tap the tempo on one switch while engaging/bypassing the effect with another. But here’s the thing: the tempo light keeps blinking, signaling the tap rate, even when the effect is in bypass. What’s more, you can pre-set the tap tempo by stepping on the Tap switch while the effect is still in bypass.

        This feature has two benefits over setting the tempo live — or simultaneously, as the effect kicks in — as is the case with most other pedals:

        * You can adjust the tap tempo rate in case the song’s tempo has changed.
        * You can set up two independent tap-tempos in the same song. (This might involve flipping the 3-position speed mode DIP switch.)

        This is pretty cool, and has prevented me from getting on with my expression pedal work!

        Speaking of expression pedals, Kevin Bolembach of Godlyke (Guyatone's distributor) advises that you should use the recommended Roland EV-5 ($55), because Guyatone tested the Ultron and Ultrem with this pedal. The manual says to “use only” the Roland, but any CV pedal will work as long as it's +5. But if you don't already own an expression pedal, and are buying one to use in conjunction with the Ultrem or Ultron, consider the EV-5.
        Jon Chappell
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        • #5
          Lighting the Way
          Before we talk about the expression pedal modes, I just wanted to point out one of the cool things about the Ultron and Ultrem: its blue LED pulses not just in tempo, but with intensity in relation to the selected waveform. For example, you can tell just by looking at the LED whether your selected wave is a ramp or pulse, based on whether the LED gets gradually more intense from full-off to full-on, or whether it jumps “quantum style” from off to on. Very nifty.

          Four Modes for Expressive Play
          It’s in the Ultron and Ultrem’s four expression-pedal modes (Modes 3-6) where the interactive, live performance strengths really shine. This is also where the two pedals diverge in terms of their implementation of the pedals, so I’ve broken this section down into two parts: The Ultrem’s four modes and the Ultron’s four modes. Since we’ve been focusing on the Ultron and its sophisticated processing features, let’s step over to the Ultrem for a minute, whose operations are more straightforward (and a quick glance back to the photo showing their front panels reveals that). Here’s a rundown on the Ultrem’s four modes and some cool features and musical uses for them.

          Mode 3: Pedal Volume/Wave: I like this mode, because it turns your Ultrem into a volume pedal. Okay, the CV pedal does that, but the Ultrem devotes a mode to using your expression pedal as a volume pedal. The pedal’s travel range can be defined by the Depth control. This is handy, because whereas a normal volume pedal gives you only one response curve, the Ultrem provides many. In the submode, you get the oscillator-driven tremolo effect, dictated by the current position of the front-panel controls. (The pedal is inoperative here, the only Mode/submode where this is true.)

          I found this to be my most popular mode in actual live performance of varied material. Because I find many uses for volume pedal, and because most of my tremolo work is not synched to tempo (I like a fairly fast triangle wave with medium depth), Mode 3 is for most. Best of all, I can use two different Depth settings for my volume pedal: the more drastic for masked-attack swells (max Depth) and the subtler setting (Depth at 120) for traditional volume pedal work. The manual helpfully provides setting descriptions for the Depth control. This mode also includes a panner function for panning between the two output jacks, typically to two amplifiers.

          Mode 4: Pedal Depth & Wave Tap: The pedal controls the Depth, while the speed is determined by either the tap tempo switch or the front-panel rotary knob. In Mode 4, there’s no real submode, because the effect-mode switch is used for establishing the speed. If you’re really particular about your live tremolo sound, this is the mode for you, as you can adjust both the speed and the depth with your feet. I found that for tempo-synching purposes, I would tap in the tempo (using the appropriate speed switch of 1x, 2x, or 4x. Here I wish the pedal had just one more selections: a 3x switch setting to produce eighth- and 16th-note triplets. Not a big deal, but if you’re a synching stickler, you’ll notice it, too.

          You can vary the curve character of the expression pedal according to A, B, C, where A is exponential (level rises more as pedal advances in its travel), B is linear (level tracks with pedal), and C is reverse exponential. This shares the same switch as the speed mode switch (1x, 2x, and 4x), so if you’re to use both a speed mode and a volume curve simultaneously, you have be aware of that the switch positions must coincide (e.g., linear response = 2x tap value). In practice, this is not typically a problem, or can be worked around.

          The most significant ramification of the curve choices is that it gives your expression pedal versatility. By using the three-position curve switch and the Depth control, you can use your pedal for vastly different function (masked attacks, and subtler swells, as previously mentioned). Viewed another way, it makes your pedal behave like two different pedals — a Cry Baby and a Morley, say. If you use a volume pedal more than a tremolo pedal, the Ultrem could be thought of as an expansion module for your pedal!

          Mode 5: Pedal Speed 1/Wave: The pedal controls the speed, so it’s the counterpart to Mode 4, where the pedal controls the depth. The range is from 70 to 1,000 ms, and the depth is controlled by the front-panel Depth control. The submode here, Wave, is the same as in Modes 1 and 3 — a switch over to oscillator-driven control.

          Mode 6: Pedal Speed 2/Wave: This is the same as Mode 5, except that the range is from 70 to 4,000 ms. The submode works in the same way as in Modes 1, 3, and 5.

          I really got to appreciate the intelligent choice and placement of the submodes. The repetition of the Wave submode in three of the primary modes was actually a relief, as this is really the way most fixed-parameter tremolo units function anyway. Using the pedal to dial in depth or speed is very exacting but is often an unusual musical requirement. Perhaps it only occurs in a slow intro or in a bridge, say, where as the more staple sound, the oscillator, comes up frequently.

          “Mode 5½ and 6½”
          Just when I thought I was getting a handle on the 6 modes, the manual reveals there’s a Bonus Mode, provided you’re using an expression pedal and are in Mode 5 or Mode 6. In Bonus Mode (accessed by pressing and holding the Control switch for one second), you have two submodes: in one, you can change the waveform (sawtooth, triangle, square, etc.) with the pedal position; in the other, you can change the waveform and the speed of the waveform. The range of speed is determined by the main mode (Mode 5 or Mode 6). This second mode was more useful in practice, at least to me, because I’m used to something dramatic and emotional happening when I push a pedal to the floor.

          It may be hard to imagine needing a pedal to change waveforms, but to change waveforms and speed was a refreshing new spin, and I instantly could ply this feature to musical purpose. I liken it to the "bouncing ping-pong ball effect": the bounces get gradually closer together. Prokofiev used it, so why not me? Anyway, as you increase the speed, the waveform change serves to punctuate the effect, causing at least one listener I tried it out on to exclaim, "What the ---?"
          Jon Chappell
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          • #6
            The more I get into these pedals, the more I realize how deep they are, despite all the parameters being in full view -- sort of like the analog synths of the past, with their filters and routing capabilities. If you're wondering why you'd want one of these pedals instead of an ordinary dedicated effect, or one from your amp, here some points to consider.

            • The photocoupling sound-generating produces rich, complex textures not usually seen in normal solid-state or digital circuitry.

            • The Ultrem is the best "amp trem" you'll ever hear, and is massively configurable to boot.

            • The Ultron and Ultrem turn your expression pedal into a super wah-wah pedal, by giving it different modes and varied response curves.

            • The more time you devote to learning the pedals' capabilities, the more your playing evolves to reflect the dynamism of their features. In other words, the pedals' power helps take your playing into new directions.

            • The two pedals can be linked for unprecedented synching capabilities.

            • The pedals are complex, but not inscrutable, as all the parameters reside on the front panel. The bonus modes, the ability to switch between ms and bpm, the volume curves, the variable intensity LED, and the synching ability of the pedals are world-class features.
            Jon Chappell
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            • #7
              I'd absolutely love to hear the trem. I have a Voodoo Labs Trem now, and a Moog MF-102 Ring mod, which does a killer trem. My favorite trem sounds were from a Vox AC30HW and a Selmer Zodiac however.


              • #8
                It may be hard to imagine needing a pedal to change waveforms, but to change waveforms and speed was a refreshing new spin, and I instantly could ply this feature to musical purpose. I liken it to the "bouncing ping-pong ball effect": the bounces get gradually closer together. Prokofiev used it, so why not me? Anyway, as you increase the speed, the waveform change serves to punctuate the effect, causing at least one listener I tried it out on to exclaim, "What the ---?"