Before the OCD arrived in 2004, the overdrive market was split roughly in two. On one side sat the mass-market workhorses — Boss, MXR, Ibanez — reliable, affordable, and ubiquitous on every stage in the world. On the other side were true hand-wired boutique pieces, built in tiny workshops, priced accordingly, and largely invisible to the gigging guitarist who didn’t haunt gear forums. The Fulltone OCD landed in the space between those worlds and quietly dismantled the barrier separating them.
Mike Fuller’s Obsessive Compulsive Drive cost more than a Boss pedal and less than a boutique custom shop build. It was produced in California, assembled by a small team, and voiced with a specificity that mass-market competitors simply couldn’t match at the time. It didn’t try to emulate a particular vintage pedal or push one specific sound. Instead, it aimed at something broader and more useful: a cranked tube amp in stompbox form, with enough dynamic range to clean up when you rolled back the guitar’s volume and enough drive on tap to dig into real distortion territory when you needed it. That idea sounds obvious in retrospect. In 2004, it was revelatory.
The OCD became the reference point. Players who had never heard of boutique overdrive started saving up for one. Forum debates about v1.4 vs v1.7 became the entry point through which an entire generation discovered that subtle circuit differences mattered. When Fulltone closed its doors in 2022 — an abrupt end to a 31-year run — the secondary market for OCD pedals responded the way it always does when supply dries up: prices held, demand didn’t collapse, and the used market became the only place to find them. That’s what happens to pedals that actually work.
Mike Fuller and the Fulltone Story
Fulltone was founded in 1991 by Michael Fuller, a Los Angeles session guitarist who had spent years trying to solve the same problem his clients kept bringing to sessions: how do you get the exact overdrive character of a cranked amp without actually cranking the amp? The session world runs on controllability. Studios, producers, and engineers need sounds that can be repeated, shaped, and recorded at manageable volumes. Fuller knew what those cranked amp tones sounded like, and he knew that the pedals available in the early 1990s were falling short of capturing them.
His early designs — the Full-Drive, the Clyde Wah — established Fulltone’s reputation for pedals that felt and responded like amplifier stages rather than effects boxes. The Full-Drive 2, in particular, built a devoted following in the 1990s by offering the kind of touch-sensitive response that players associated with pushed tube circuits rather than silicon overdrive stages. When Fuller turned his attention to a new design in the early 2000s, the goal wasn’t to replace the Full-Drive 2 — it was to push further in the direction of amp-like dynamics and create something with even broader tonal range.
The result was the OCD, released in 2004. It used a JFET input stage — a transistor type known for its high input impedance and smooth clipping behavior — feeding into an operational amplifier gain stage with asymmetrical clipping. The asymmetry was crucial: symmetrical clipping produces even-order harmonics with a more “polite” distortion character; asymmetrical clipping introduces odd-order harmonics that add bite, aggression, and the kind of midrange push that cuts through a band mix. Combined with a wide voltage operating range and the HP/LP voicing switch, the OCD gave players a genuinely broad sonic toolkit in a compact enclosure.
How the OCD Actually Works
Three knobs, one switch, one footswitch. The control layout is deceptively simple for a pedal with this much tonal range.
Volume sets output level. The OCD runs hot — you can push well past unity gain, which makes it useful as a clean boost as well as an overdrive. At low Drive settings with Volume cranked, the OCD becomes a pure buffer-boost with a slight tonal shaping contribution. This two-mode operation — boost mode and drive mode — is something Fuller clearly designed for intentionally.
Drive runs from near-clean at minimum through thick distortion at maximum. The useful range for most players sits between 7 and 11 o’clock — enough saturation for classic overdrive tones without becoming muddy. Beyond about 2 o’clock the OCD gets into genuine distortion territory, which suits some contexts and some players. The key characteristic throughout the Drive range is that the pedal’s compression behavior responds to the guitar’s input signal, not to a fixed threshold. Roll back the guitar’s volume and the OCD opens up and cleans. Hit it harder and it saturates more. This is the behavior that makes it feel amp-like.
Tone is an active control that works differently in HP and LP modes — more on that below. The important thing to understand is that the OCD’s tone control has a wider-than-typical range and interacts significantly with the Drive setting. At low Drive, the Tone control is more subtle. At high Drive, turning it up can add a brittle, cutting quality; turning it down warms and thickens the sound considerably.
HP/LP switch: The labels are slightly misleading. This isn’t a traditional high-pass / low-pass filter in the signal path. Instead, it selects a shelving frequency for the Tone control and alters the overall bandwidth and output level of the circuit. In HP mode, the treble response is extended and the low end is tighter — this is the better choice for most single-coil guitars through clean to moderately-dirty amp settings. In LP mode, the low-frequency response is fuller and warmer, making the pedal thicker and darker overall — this works better with humbuckers, darker-voiced amps, or when you want a less aggressive tone character. Neither mode is “right” — they’re genuinely different voicings that serve different musical contexts.
18V operation: The OCD accepts voltages from 9V to 18V on its standard 2.1mm center-negative input. Running it at 9V produces the familiar sound most players associate with the pedal — slightly compressed, harmonically dense, with the saturation character the OCD is known for. At 18V, the op-amp’s headroom increases substantially: the onset of saturation is pushed higher, the dynamic range opens up, and the pedal becomes more transparent, cleaner at low Drive settings, and more responsive to pick attack. Players using high-output humbuckers often prefer 18V operation because it reduces the “mushy” low-end compression that can make high-output pickups sound undefined through an overdrive. With standard single-coil output levels, the 9V vs 18V difference is audible but subtle. With a hot PAF or modern high-gain humbucker, it can be transformative. Most standard pedalboard power supplies top out at 9V — running at 18V requires either daisy-chaining two 9V supplies (check polarity carefully) or a multi-voltage supply with an 18V output.
The Version Question
No conversation about the Fulltone OCD goes very long without version numbers entering the picture. Fulltone produced the OCD in multiple revisions from 2004 until the company’s closure in 2022, with the most significant milestones being versions 1.4, 1.7, and the 2017-introduced V2.
The early versions (1.0 through 1.3) established the OCD’s core character. V1.4 — often considered the sweet spot by vintage OCD enthusiasts — added a Germanium diode to the clipping circuit, a change that many players describe as making the saturation more “organic” and less defined. The V1.4 units are identifiable by a specific PCB layout and are the versions most actively sought on the secondary market. V1.7 revised the asymmetrical clipping further and tightened the low-end response, producing a slightly more polished, defined overdrive character. Opinions divide on whether v1.4 or v1.7 sounds “better” — the honest answer is that they sound different, and which you prefer depends entirely on your rig and playing style.
The V2, introduced in 2017, brought a genuinely useful addition: an internal switch that toggles between true bypass and “enhanced bypass.” Previous OCD versions were true bypass only, which meant that like all true bypass pedals, they offered no buffering when disengaged and could color the high-frequency response at the end of a long cable run. The enhanced bypass mode adds a buffer to the signal path when the pedal is off, maintaining signal integrity across long cable and pedal chain runs. The V2 also eliminated the clicking sound that some earlier units produced on engage and disengage — a minor but welcome fix for the touring player using the OCD as a primary drive in a performance rig.
From a practical standpoint: if you’re buying new (or from Fulltone’s post-closure inventory), you’ll get a V2. If you’re buying used, the version number is worth knowing but shouldn’t be a dealbreaker — all OCD versions share the same fundamental character, and the differences are real but not dramatic.
Specs at a Glance
| Parameter | Fulltone OCD (V2) | OCD V1.7 | OCD V1.4 |
|---|---|---|---|
| Controls | Volume, Drive, Tone, HP/LP | Volume, Drive, Tone, HP/LP | Volume, Drive, Tone, HP/LP |
| Bypass | True OR Enhanced (internal switch) | True bypass | True bypass |
| Power | 9–18V DC, center-negative, 2.1mm | 9–18V DC | 9–18V DC |
| Clipping | Asymmetrical, op-amp + diode | Asymmetrical, revised | Asymmetrical, Germanium diode |
| Input impedance | High (JFET input stage) | High | High |
| Current draw | ~7mA at 9V | ~7mA at 9V | ~7mA at 9V |
| Price (new, at production) | ~$130–150 USD | ~$120–140 USD | ~$100–120 USD |
| Used market (2024) | ~$100–150 USD | ~$120–200 USD | ~$150–250 USD (V1.4 commands premium) |
Famous Players
The OCD attracted a genuinely diverse roster of working musicians — one of the markers that a pedal has transcended its original design brief and become a tool rather than a trend. The artists using it span country, ZZ Top-style Texas blues-rock, precision fusion, and rock. That breadth is worth noting: the OCD isn’t a “country pedal” or a “blues pedal.” It’s whatever you want it to be.
Billy Gibbons (ZZ Top)
Billy Gibbons is one of the most well-documented OCD users, with his use confirmed via visual evidence: the Fulltone OCD label is visible on his pedal switcher in the documentary Fuzz: The Sound That Revolutionized the World at the 1:20:18 mark. Gibbons’ approach to tone is famously multi-layered — his core sound comes from vintage guitars (Pearly Gates, the Muddywood), vintage Marshalls, and a rotating cast of vintage and boutique effects. The OCD’s place in that rig makes sense: it adds tube-amp-like saturation and dynamic response without swallowing the character of the instruments feeding it. Gibbons’ pedalboard is, by his own description, primarily a color palette rather than a fixed signal chain — the OCD appears as one of multiple overdrive options he selects based on the song and the venue. You can explore more of his gear context at billy-gibbons.html.
Keith Urban
Keith Urban is among the most enthusiastic documented OCD adopters, running two of them simultaneously on his pedalboard — a setup documented via the Fulltone official artist page and gear breakdown features from the time of his active endorsement. The dual-OCD configuration allows Urban to have two independently-dialed overdrive voices available without a switcher, one typically set for lighter rhythm overdrive duty and one for harder lead boost applications. Urban’s guitar work sits in the Nashville country-rock intersection where picking dynamics, clean-to-crunch transitions, and note clarity under heavy drive are all premium qualities — precisely the performance characteristics the OCD was designed to deliver. His DB entry: 113-keith-urban-gear-guide.html.
Eric Johnson
Eric Johnson’s documented use of the Fulltone OCD is confirmed via the Fulltone official website’s artist page, which listed the OCD as part of his active gear. Johnson is among the most technically demanding players when it comes to signal chain integrity — he famously hears differences between battery brands, cable types, and transistor manufacturing dates. That he uses the OCD speaks directly to the pedal’s sonic credentials: it doesn’t compress excessively, it doesn’t thin the midrange, and it responds to the guitar’s volume and attack in a way that rewards the kind of highly controlled picking technique Johnson employs. His two DB entries: eric-johnson.html and s4-015-eric-johnson-gear-guide.html.
Mike Campbell (Tom Petty and the Heartbreakers / Dirty Knobs) — with an honest note
Mike Campbell is listed as a Fulltone OCD user in several sources citing the Fulltone official artist roster, and his DB entry is at s5-030-mike-campbell-gear-guide.html. However, the 2013 Premier Guitar rig rundown for Tom Petty and the Heartbreakers — the most thoroughly documented primary source available for Campbell’s effects chain — lists his effects as a Dunlop Camel Toe (distortion), Line 6 DL-4, DigiTech Whammy II, Line 6 MM-4, Boss RC-30, and Boss TU-2. No OCD appears. It’s possible the OCD was used in a different tour configuration, in the studio, or in his work with the Dirty Knobs — the Fulltone artist page connection is real — but the specific application is less documented than for Gibbons, Urban, and Johnson. His DB is linked above; readers interested in his confirmed rig should cross-reference the PG rundown for the definitive live setup.
Other Notable Users
The OCD’s Equipboard entry shows 369 documented professional users — a remarkable number for a boutique-adjacent pedal from a small company. Among the most recognizable names confirmed in that roster: Wes Borland (Limp Bizkit), Mick Thomson (Slipknot), Jamie Cook (Arctic Monkeys), J Mascis (Dinosaur Jr.), Frank Iero (My Chemical Romance), Jonny Buckland (Coldplay), Paul Gilbert, and Joe Perry (Aerosmith). The stylistic spread from Slipknot to Coldplay to Dinosaur Jr. is either a testament to the OCD’s versatility or a reminder that good overdrive responds to what’s in front of it — the pedal doesn’t dictate genre, the player does.
Tone Recipes and Settings
Classic Blues-Rock Crunch (Gibbons Reference)
Drive: 9 o’clock | Volume: 12 o’clock | Tone: 11 o’clock | HP/LP: LP. This setting puts the OCD in low-overdrive territory where the guitar’s picking dynamics determine how much saturation you get. Play softly and it cleans up to a bluesy shimmer. Dig in hard and it saturates with a midrange push that sits well in a mix. Through a Fender Deluxe Reverb at moderate volume, this captures the sweet zone where the amp and pedal contribute roughly equal amounts of saturation. If it sounds too bright, switch to LP; if it sounds too thin, raise the Tone slightly rather than switching to LP — the tonal character changes more with the switch than with the Tone knob.
Country Hybrid Boost (Urban Reference)
Drive: 8 o’clock | Volume: 1 o’clock | Tone: 12 o’clock | HP/LP: HP. A near-clean boost configuration that adds presence and light saturation rather than heavy overdrive. The Volume well above unity means the amp sees a hotter signal and the tubes work harder, producing compression and saturation that tracks the pedal but originates primarily in the amp. This works best when the amp is already running warm rather than at clean headroom. The HP setting keeps the sparkle on the top end that defines Nashville country tone.
Singing Lead (Eric Johnson Reference)
Drive: 11 o’clock | Volume: 11 o’clock | Tone: 10 o’clock | HP/LP: LP | Power: 18V. The 18V operation is key here — it increases headroom to the point where sustained notes bloom rather than compress, and picking attacks feel articulate and controlled rather than squishy. The Tone rolled back slightly prevents harshness on the high strings. This setting through a clean to slightly-dirty amp produces a lead tone with the sustain and harmonic complexity of a cranked amp at a fraction of the actual volume. Feed this into a Gibson Les Paul Standard and the LP setting handles the humbucker’s extra low-end mass without getting muddy.
Stacked Clean Boost (Before Another Drive)
Drive: 7 o’clock (minimum) | Volume: 2 o’clock | Tone: 12 o’clock | HP/LP: HP. Used not as an overdrive but as a level push placed before a second overdrive pedal. The OCD’s low input impedance and high output level at minimum Drive makes it effective at pushing another drive pedal’s input harder, increasing the gain and compression of the second pedal without adding the OCD’s own saturation character. This is the “always-on boost” use case that some players treat as the OCD’s most important function. Try this into an Ibanez TS9 Tube Screamer for a compressed, singing lead tone, or into a Boss BD-2 Blues Driver for a more aggressive crunch.
Full Distortion (Rock Context)
Drive: 3 o’clock | Volume: 10 o’clock | Tone: 11 o’clock | HP/LP: HP. At this Drive setting the OCD leaves overdrive territory and enters distortion. The tone becomes more compressed and sustain lengthens significantly. Best for high-energy rhythm playing or soloing through a mid-sized clean amp where you want the pedal doing all the work. Volume pulled back slightly to prevent level jump on bypass. This isn’t the OCD’s best use case — if you want distortion, there are more specialized options — but it’s available and works in context.
The following settings use the standard knob position notation where 7 o’clock = fully counterclockwise and 5 o’clock = fully clockwise. These starting points are calibrated for a Fender Stratocaster into a clean amp at bedroom to rehearsal volume. Adjust Drive down ~10% and Volume up ~10% when playing at stage volume where the amp is already contributing its own saturation.
How the OCD Compares
The Ibanez TS9 Tube Screamer is the most-compared pedal in the OCD’s peer group, and the comparison reveals a genuine design philosophy difference. The TS9 cuts low frequencies at the input, producing its signature focused, midrange-forward tone with natural compression. The OCD has a fuller low-frequency response — it doesn’t cut bass at the input, which is why it sounds bigger and more open than a TS9, and why it can also sound slightly looser or less focused with certain guitar/amp combinations. The TS9 stacks brilliantly with already-saturated amps because its frequency shaping complements the amp’s own compression. The OCD pairs better with cleaner amp settings because it’s providing more of the full-spectrum saturation itself.
The Boss BD-2 Blues Driver occupies a similar intention space — amp-like overdrive response — but achieves it through a different circuit. The BD-2 uses a JFET input and a different clipping arrangement that emphasizes higher harmonics, producing a slightly brighter and more cutting overdrive character. At moderate Drive settings the BD-2 is thinner and more aggressive-sounding than the OCD; at high Drive settings it gets harsh in ways the OCD manages to avoid. The BD-2 costs less and is more durable (Boss construction), which matters for some players. The OCD sounds more “expensive” in the sense that its saturation is more complex and less consistent across the Drive range — which is either a feature or a bug depending on what you’re using it for.
Against boutique alternatives like the Analogman King of Tone or the Klon Centaur circuit clones, the OCD trades some transparency and low-end articulation for a more aggressive, present midrange. Klon-type circuits prioritize amp transparency and bloom; the OCD prioritizes drive character and tonal push. They serve different musical needs and the choice isn’t about quality — it’s about what you want the pedal to contribute to your sound.
Buying Guide: Post-Closure Market Reality
Fulltone closing in 2022 created a finite supply of genuine OCD pedals. There is no new production to look forward to, no upcoming firmware update, no official support channel. The used market is the only market, and prices have reflected this. Used OCDs in good condition generally sell in the $100–200 range depending on version, condition, and regional market. V1.4 units, which built a devoted following during the forum-era golden age of OCD discourse, consistently command premiums at the top of that range and occasionally above it.
Version-specific buying advice: if you’ve never owned an OCD and want to understand what the fuss was about, buy any version in good condition at a fair used price. The differences between versions are real but subtle enough that they won’t determine whether the OCD works in your rig — your amp and playing style will determine that. If you’re a confirmed OCD owner looking to upgrade to a specific version, the v1.4 is the one to seek if you want more organic, slightly looser saturation character; v1.7 for tighter and more defined; V2 for the bypass flexibility.
Condition considerations: the OCD is a mechanically simple pedal. Inspect the footswitch (common failure point after heavy use), the input and output jacks (look for bent or oxidized contacts), and the knobs (originals are smooth-turning with no roughness indicating dirty pots). The HP/LP switch should click firmly between positions with no crackling. The LED should illuminate cleanly with no flickering. A pedal that passes these checks is likely to be electrically sound even if its cosmetics show wear.
Watch for fakes. The OCD’s reputation has made it a target for counterfeits, primarily on international auction platforms. Authentic units have consistent graphics, a clearly molded Fulltone logo on the enclosure, and specific PCB markings visible through the battery compartment. If the price is dramatically below market and the seller has no return policy, exercise caution.
Ownership Notes and Signal Chain Placement
Signal chain placement matters more with the OCD than with many overdrives because of its high input impedance and dynamic response. The JFET input stage is sensitive to the impedance of what’s driving it — a buffer placed before the OCD changes its character slightly, making it feel less dynamic and more consistent. Many players prefer to run the OCD first in the chain (after only a tuner) to preserve the guitar-pickup interaction that makes it feel responsive. If you’re running a buffer-bypass tuner at the front of your chain, pay attention to whether the OCD sounds as dynamic as you expect — the buffer may be the variable.
True bypass vs. enhanced bypass: If you’re running a longer cable from your pedalboard to your amp and find that your guitar sounds dull when the OCD is off (and it’s set to true bypass), either switch to enhanced bypass mode or add a buffer elsewhere in your chain. True bypass preserves circuit purity at the expense of high-frequency rolloff at long cable lengths. The V2’s enhanced bypass option solves this without adding an external buffer pedal.
Stacking the OCD with other drives is one of the most productive uses of the platform. Running it at low gain before a TS9 gives you a compressed, mid-forward drive that sits precisely in a guitar mix. Running a low-gain TS9 before the OCD gives you a broader, more open result with the OCD’s saturation character dominating. Either combination works — the order determines the character.
The 18V power option is worth experimenting with at least once regardless of your pickup type. Run it at 9V first, dial in your tone, switch to 18V without touching the knobs, and compare. Many players find the 18V version of their 9V setting to be strictly superior — more open, more responsive, equally saturated at the same Drive setting. A few prefer 9V’s slightly softer top-end and more compressed character. This is a free upgrade hiding in the spec sheet that most players never try.
Frequently Asked Questions
Is the Fulltone OCD still available to buy new?
No. Fulltone closed in 2022 and ceased production of all its pedals. The OCD is only available on the used market. Secondary market prices remain healthy, generally in the $100–200 USD range for used units in good condition, with certain versions (particularly V1.4) commanding higher prices.
What’s the difference between HP and LP mode?
HP mode extends the treble response and tightens the low end — best for single-coil guitars (Strat, Tele) and brighter rigs. LP mode adds low-frequency content and warmth — better for humbuckers (Les Paul, SG) or darker-voiced amps. Neither mode cuts or boosts frequencies in the traditional filter sense; the switch affects the shelving frequency of the Tone control and the overall bandwidth of the circuit.
Can I use the OCD at 18V?
Yes, and many players prefer it. The OCD accepts up to 18V on its standard center-negative 2.1mm input. At 18V, headroom increases significantly: the op-amp saturation threshold is pushed higher, the tone becomes more open and less compressed, and the pedal responds more dynamically to pick attack. This is particularly beneficial with high-output humbuckers. Use a multi-voltage power supply with an 18V output, or carefully daisy-chain two 9V supplies (verify polarity before connecting).
How many versions of the OCD exist, and do the differences matter?
Fulltone produced approximately 8 hardware revisions of the OCD from 2004 to 2022, with V1.4, V1.7, and V2 as the most-discussed milestones. The differences are real — V1.4 has a Germanium diode that adds a slightly softer, more organic clipping character; V1.7 tightened the low end and refined the asymmetrical clipping; V2 added selectable true/enhanced bypass and eliminated switching noise. For most players at most stages in their OCD ownership, these are fine-tuning differences rather than fundamental character changes. Start with any version, then seek specific versions if you’ve identified what you want to change.
Is the OCD good for metal or high-gain playing?
The OCD maxed out produces real distortion, but it’s not a metal pedal. Its saturation character emphasizes midrange presence and dynamic response over wall-of-gain saturation. It lacks the tight low-end compression and scooped EQ that metal contexts typically require. Players who need genuine metal distortion will be better served by dedicated high-gain designs. The OCD’s distortion at maximum Drive works for hard rock and aggressive rock rhythm playing, but for metal, look elsewhere.
What amps does the OCD work best with?
The OCD responds to what’s in front of it, but it performs best with amplifiers that have some natural breakup character at playing volumes. A Fender Deluxe Reverb at moderate volume, a Vox AC30 at rehearsal level, or a small tweed-style amp at any volume — these amps contribute their own saturation to the OCD’s drive, producing a layered, complex result that neither the amp nor the pedal produces alone. Through a high-powered clean amplifier like a Fender Twin Reverb at low volume, the OCD works but sounds somewhat clinical — the amp isn’t contributing its own character, so all the saturation has to come from the pedal. The ideal OCD scenario is a warm, slightly pushed amp with the OCD adding the final layer of drive.
What happened to Fulltone?
Fulltone was founded in 1991 by Mike Fuller and operated in California for 31 years. Fuller closed the company in 2022. The closure was abrupt — there was no clear public successor or production continuation. All Fulltone products became immediately discontinued at that point. The used market absorbed the supply without a price collapse, which is a reasonable measure of how valued the products were by the people who used them.
Should I buy a Fulltone OCD clone instead?
Several companies offer circuits inspired by or licensed from OCD-adjacent designs. The honest answer is that clones vary significantly in quality, and the used OCD market is healthy enough that buying an original is usually the better path. A genuine OCD in good condition at $120–150 is likely to sound more authentic than a $50 clone and retain its value better over time. If budget is a real constraint, clones have their place — just audition them before buying, and understand that the secondary market pricing difference reflects something real about the original design’s execution.