Pedals
  Subzombie
  Contour Boost
  Splonkulator Distortion

About, Mods, Repair

 

Splonkulator TM
Distortion Processor

ARCHIVE: not currently in production. Inquire regarding custom version, or check out the other pedals ... also a pedal that can do all this and more may be forthcoming ...

        

... MIX YOUR OWN DISTORTION ...

Two different, seperate distortion circuits, a clean boost, and mix and control circuitry to combine these in parallel, all in one box. These sections can each be used seperately, but the real magic is in their interactions. Use conventional blending for additional control and sonic complexity. Or use antiphase blending for exaggerated distortion effects ... a technique l have dubbed splonkulation. The possibilities form a continuous range from smooth sustain and clean blends to anti-clean and anti-sustain. This is a very powerful and serious sonic experimentation tool!

 

This splonkulator creates a wide array of sounds on its own, but just as importantly is made to combine with other distortions. To be useful for this kind of distortion modification, it produces strong effects at low gain and is highly tweakable. Only one of its distortions have medium-high gain and this can interact with the lower gain distortion and/or clean. Through a distorted amp, this device can "work with" the amp, or work against it with dramatic distortion which cuts through the effect of the amp. For example, distortions can be generated down in the clean part of the amp's input signal range or otherwise tweaked specifically to antagonize the response. Or, driven by another distortion, splonkulation adds a controllable edge and can even approach a synthesizer sound.

The first distortion is a bipolar transistor stage of my design with controlled characteristics. This has similarity to fuzz circuits but mostly makes a good crunch. The second distortion is a CMOS (complementary MOS FET) type distortion popularized as Craig Anderton's "Tube Sound Fuzz" and several commercial products (although I developed my own version from the raw concept before seeing any of the other designs). This stage has a smooth sound and more gain. Both distortions have drive levels controls and a versatile filter function to shape the driving signal. In addition, there is a "clean" control in parallel to the distortions for mixing in clean sound at low level or as a substantial boost. The lower row of knobs control this mix, and also includes post-distortion filter that can be applied to either distortion. One or both distortions can be placed in reverse polarity, producing a cancellation effect useful for harsh "turbolated" sounds with hints of "ring modulator" and "up octave distortion" tonalities, "gated" sounds with reduced sustain, and more. Since even these more tortured sounds are produced by cancellation between otherwise natural-acting distortions, natural decay without sudden cutoff (etc.) results, and many variants can be dialed in easily. In a clean system, the Splonkulator clean path (if used) is heard primarily as a seperated sound from the distortions, injecting normalcy into the mix. But, with external distortion, the clean path essentially becomes a third distortion control, with pronounced interaction, and the clean can be subtracted from one of the distortion paths for a low-gain version of splonkulation.

Note that you can produce some similar effects by combining normal distortion pedals with your own splitter, mixing device, and loop switcher. However, this would be more complicated and the strong filtering in most distortions limits the interaction effect. It also would allow additional possibilities -- and mess. The Splonkulator is a convenient, powerful, and focused device for nonlinear waveform manipulation. But a little bizarre. The circuitry used to control, mix, and switch the distortions is more complex than the distortions themselves. Since it handles the parallel paths internally, combining it with other effects is done through the normal series connections.

Housed in an impressive extruded aluminum enclosure with end plates and clearcoat finish to provide room for 8 knobs and footswitch access, the Splonkulator is a little smaller than a Big Muff.

SOUND SAMPLES
(Newest:) splonku-cleanish1.mp3 (124 KB) -- clean amp, brighter pickup sound, clean + distortion, 1st a smooth one, then turn up one mix for the rattier sound where chords get banged.

splonku-dryand2sounds.mp3 (101 KB) -- Demos the light crunch from the dry amp, and then two strong interaction sounds.
splonku-drycleanbicmosx.mp3 (170 KB) -- amp crunch, and then with clean boost only, bipolar distortion only, CMOS distortion only, and finally a combination sound.
splonku-wDODammetal1.mp3 (445 KB) -- Uses the DOD Super American Metal as a predistortion, except about 6 seconds in the Splonkulator and then the DOD are turned off, then the Splonkulator on and then the DOD back on. Also recuced guitar tone control later.
splonku-wDODammetal2.mp3 (223 KB) -- Another with the DOD Super American Metal as a predistortion, this time with the DOD's presence turned up a bit for a more radical sound.

=> 64 Kbps Mono MP3s (use "Save Target As" to download instead of just play it)

=>
These samples were all made at the same (comfortable) volume level, using an Ibanez RG-550 w/bridge humbucker and unfresh strings, through my old prototype 15W tube amp (preamp distortion) ... perhaps an odd choice but it is a rather neutral, basic amp. 3 12ax7 stages with about 20 dB interstage attenuation and some EQ in preamp, 6V6s. Through Cele V30s (2x12), EV N/DYM 257A, Porta2 as preamp (flat as reasonable), soundcard. More to come (also better pictures), including samples with other amps ...

Operation

The top row of controls are the drive controls. The center position of the drive controls (DRV and FILT) for each distortion is the minimum setting. Turning the drive control right of center produces normal positive drive, while left of center drives the distortion in reverse polarity; either far rotation produces maximum gain. The DRV (drive) control is the main gain setting. FILT (filter) works in tandem and affects the highs only. Turn the FILT control in the same direction as DRV, but slightly less, to produce a flat response. Turn the FILT control more to boost the highs; reduce DRV for even more highs. Turn FILT less or even slightly in the opposite direction to reduce the highs. Turn the FILT knob further in the opposite direction from DRV to produce reduced midrange with strong highs and lows, and to place the highs in opposite polarity from the lows. The drive controls precede their associated distortions in the signal path, and therefore strongly affect the response to the guitar or other source. The Clean signal cannot be altered in polarity, so when combining it with distortion, set the polarity of the distortion(s) accordingly.

The lower row of controls is the mix section. Volume control B is for the Bipolar section, C is the CMOS section, and CLEAN is the clean level/boost. With suitable drive settings, many sounds are available just by adjusting these levels. Also part of the mix section is the FILTER control. This reduces high frequencies of the Bipolar distortion output when turned towards B, and reduces high frequencies of the CMOS distortion output when turned towards C. When centered (there is a detent), little influence on either results.

The various filter responses are different, as suited to the characteristics of the distortion stages. Experimentation is essential to maximum results, however not all playing situations will require the full range of sounds available. Do not hesitate to use the Splonkulator in such situations, and also to use sounds that "underuse" the circuits, because otherwise its flexibility becomes a weakness.

Particularly when experimenting with cancellation sounds, it is useful to learn to "tune" the levels. Here is an exercise: start with C and clean volumes at minimum, and with B set for negative DRV and FILT, and moderate level. While playing softly, turn up the Clean volume slowly. You should first hear the volume decrease due to cancellation, and then begin to increase again. Playing at different volumes will change the point of maximum cancellation. The best setting for a purpose is often not this "critical" cancellation point, but it still helps to be aware of it. A similar tuning exercise can be done with the distortions only. When all three paths are combined with one or more in reverse polarity, things get more complicated, but are still rooted in such interactions. A good sound which uses this interaction is with C in high positive drive and highest volume, B at (necessarily) lower negative drive, and Clean at low level. As input signal increases, C hits full distortion first, then B increases in cancellation -- notching the waveform --, and then the clean level becomes substantial and swings the waveform back in the positive direction.

Example Settings (uses old graphics)
Owner's Manual

Splonkulator Technical Information

About 20 dB of flat-response boost is provided by the Clean volume control. The output stage is an OP-amp integrated circuit with "rail-to-rail" output capabilities, which means that it will deliver to your amplifier almost everything a 9 volt battery will put out (of course, the output level of your guitar pickups will determine the maximum gain beyond which any boost device will distort). This is a better match to pushing the first stage of a tube amplifier into significant distortion than lower output boosters, without the extra trouble of requiring two batteries or power-supply-only operation. More gain, lower levels to the amplifier, and tone changes can be added by mixing in the distortion(s). If other effects are used, boost is normally placed last in the chain in order to avoid overdriving the other effects and deliver full signal to the amplifier. Unusually high output levels can be avoided by keeping the mix volumes set below two-thirds, however.

The standard electronic switching provides a selection circuit featuring no signal interruption, low signal degradation, and consistent output characteristics at all times. "True Bypass" is available as an option as it is also a good system, and is favored by many players. The primary advantage of True Bypass is minimum alteration of the signal path, including unlimited headroom, when bypassed. However, the electronic switching circuit has high headroom, a simple and clean signal path in deselect, and improved transition characteristics that make it worth consideration and the extra trouble of including as part of the design's capabilities. There is no drop-out when switching; the electronic switching has a "soft" switching characteristic which results in a slightly gradualized transition, rapidly cross-fading between the sounds, which avoids a jarring effect when switched (Note, soft switching is not intended for volume switching of high levels in a completely clean environment as there can be some transitional distortion, but in the intended application this is unnoticable -- if this effect was a standard distortion there would be no case of high levels and no distortion). Also, the buffered output will consistently drive long cables (and possibly even reduce noise or lossiness of following circuits due to its low output impedance). Both switching options use a "click" type footswitch as this simplifies circuitry, provides decisive operation, and retains the last used setting.

More Features:
* High 1 M (megaohm) input impedance which does not load down guitar pickups, which would cause a loss of highs. Same as most better amps.
* Low noise ("hiss").
* Good battery life. Battery drawer for convenient access and no irritating battery clip.
* Bright LED indicator with filtered switching.
* Bass response not limited to guitar range -- useful for bass. Bandwidth slightly controlled at high gain settings.
* Components, construction and design for excellent audio quality.

GUTS:

 

Copyright 2004 Bill Spencer/Spencer Amps [tm]
Other trademarks are property their respective companies.