Tube Screamer vs Klon vs Blues Driver vs OCD: Four Overdrives Compared

Four overdrive pedals come up in almost every conversation about drive: the Ibanez Tube Screamer, the Klon Centaur, the Boss BD-2 Blues Driver and the Fulltone OCD. They are often treated as interchangeable “transparent” boxes, which blurs real differences. Each was built with a different problem in mind, and the circuit choices that follow from that problem explain most of what you hear. This guide compares them on what their makers and the gear press have actually said about how they clip and voice, then helps you decide which one fits a given guitar and amp.

We have individual pages on each pedal, linked as we go. This article is the side-by-side view. Where a claim rests on a single source, or sources disagree, we say so in the text.

Quick Facts

What Each Pedal Was Built to Do

Tube Screamer: a pedal that pushes an amp

Premier Guitar’s history of the pedal, written by Lindsay Tucker, describes the Tube Screamer’s aim as adding sustain and edge to a tube amp while keeping the guitar’s tone and the player’s dynamics intact. It was made by Nisshin, the Japanese company that also built pickups for some Ibanez guitars and whose pedals were also sold under the Maxon brand name. The TS808 debuted in 1979, and the TS9 replaced it in 1982 as part of the 9 Series, according to the same article.

The clipping choice comes from former Ibanez product manager John Lomas, as Premier Guitar relays it: Roland’s Boss OD-1 already had a patent on asymmetrical solid-state clipping, so Nisshin went with symmetrical clipping. Lomas said the Tube Screamer and OD-1 schematics are “almost exactly the same thing”. Premier Guitar says he credits the TS808’s sweet, vocal midrange to its JRC 4558D integrated circuit. That is one engineer’s account, and tone-by-chip claims are exactly the kind of thing enthusiasts argue about, so we treat it as his view.

A fact worth keeping in mind when you shop: according to Lomas, 90 to 95 percent of original TS9s used a Toshiba TA75558 chip rather than the JRC part, and the 1992 TS9 reissue used the Toshiba chip for that reason. He also says parts in the originals varied with whatever was available, so tone varied from batch to batch. Our page on the Ibanez TS9 and our guide to the TS808 cover the model differences in more depth.

Klon Centaur: a pedal that keeps your tone intact

The Centaur began as a complaint about the Tube Screamer. In a 2014 Premier Guitar builder profile, Bill Finnegan said he played a Telecaster through a Twin Reverb in the 1980s and could not get a cranked-amp sound at the volumes small venues allowed. He found the TS9 and TS808 lacking: in his words they compressed the transients, had a midrange he did not like and cut bass. His goal was a big, open sound with a hint of tube clipping, from a pedal that would not mess up what players already had and liked. The pedal took about four and a half years to develop with MIT-trained collaborators, including the late Fred Fenning, and debuted at the end of 1994.

The same profile describes diode clipping on top of op-amp clipping in the main gain stage, using a head-to-toe pair of germanium diodes that Finnegan says usually, though not always, sounded more natural to him than silicon, plus a buffered output. Finnegan says that diode has been out of production for decades and doubts clones can match the original. Andertons, in a Klon history article dated June 2025, adds that the Drive control mixes a clean signal with an overdriven one, so low settings behave like a boost and higher settings move toward pure distortion, and that the circuit steps the 9 V supply up to 18 V for headroom. We have only seen those two details from that one article among the pages we opened, so treat them as that retailer’s description. Our Klon Centaur explainer covers why the pedal became a cult item.

The finance side is part of the story. Finnegan told Premier Guitar the Centaur retailed for $329 for its last seven years of production, that he built about 8,000 by hand, and that he no longer builds it except for occasional units for a friend. The KTR, a surface-mount version with the same diodes, was priced at $269 when it debuted in October 2012, according to that interview. Andertons says originals “regularly” fetch over £3,000 second-hand, without citing dates. Our page on the Klon Centaur Professional Overdrive goes into the production eras.

Boss BD-2 Blues Driver: a pedal that follows your hands

Boss describes the BD-2 as a classic in continuous production since 1995. According to the Boss product page, it is designed to respond to playing dynamics the way a tube amp does, with a multi-stage clipping circuit inspired by actual amps that produces harmonic content shifting with pick attack. Rolling back the guitar’s volume cleans it up, and it can also work as a full-range boost for downstream drive pedals or high-gain amps.

Guitar.com’s June 2025 review, by Cillian Breathnach, gives the most detailed circuit reading we found. It says the first gain stage is unusual, a pair of transistors that behave like an op-amp, and that the distortion comes mainly from those amplifying stages being overdriven rather than from the clipping diodes. The review adds that the pedal uses an amp-style tonestack with fixed values derived from a Fender combo circuit. That is one reviewer’s analysis, and we could not find a second published circuit analysis to confirm the details, so we would not treat the transistor-pair description as settled. Our Blues Driver page has settings and the pedal’s variants.

Fulltone OCD: a pedal that clips hard and reacts to touch

Fulltone’s product page for the OCD V2 says the pedal was the first to use MOSFETs as clipping devices, and describes them as wired as hard clippers connected to a voltage reference rather than to ground, which the maker credits for the pedal’s response to hard or soft picking. “First” is the manufacturer’s own claim, and we did not find independent confirmation, so we attribute it rather than state it as fact.

The V2 adds an output buffer, which Fulltone says is active when the pedal is on in True-Bypass mode and always active in Enhanced Bypass mode, and a Class-A 2N5457 JFET input stage that raises input impedance from 330K to 1 megohm, for better interaction with single coils and humbuckers. Tape Op’s Mike Caffrey reviewed the original OCD in the January/February 2006 issue and called it the most amp-like and responsive distortion pedal he had used. He described the HP/LP switch as adding low end and an upper-midrange peak in one position, and a more natural sound closer to the guitar’s own tone in the other. Our Fulltone OCD page covers the version history.

Side by Side

How They Sound in Practice

The descriptions above explain the design choices. What a pedal does with your rig is a different question, and here the published evidence is thinner, so this section mixes attributed reports with our own reading.

Mids and bass

The Tube Screamer is the one pedal in this group whose midrange character is part of its reputation. Lomas’s comment about the vocal midrange is the clearest published statement we found. Finnegan’s objection to that same midrange, and to the way the TS cut bass, is the reason the Klon exists. In our view, if you want your guitar’s own balance to survive the pedal, the Klon and the BD-2 were designed with that goal, while the Tube Screamer is designed to push the middle forward.

Touch and volume-knob response

Boss, Guitar.com and Fulltone all describe their pedals in terms of dynamics. Guitar.com says playing softly leaves the BD-2 nearly clean and hitting harder breaks it up, and compares the way it cleans up with the guitar’s volume knob to a Fuzz Face. Fulltone credits the OCD’s MOSFET arrangement for its response to pick attack. Tape Op’s reviewer says he often left the OCD on and controlled gain with his volume knob and touch. This is a claim all three pedals share, which is why we would not use “touch sensitive” as a reason to pick one over another. The more useful split is how much each pedal adds to the signal when you are not playing hard.

Gain range

Guitar.com says the BD-2’s gain runs from near-clean to substantial saturation but does not reach thick distortion on its own, and that its output is moderate: it can push a preamp or give a solo boost but is not meant to overwhelm an amp. Caffrey, on the other hand, found the OCD reached heavy saturation at maximum gain, which he said was less one-dimensional than a Mesa Boogie Triple Rectifier; that is a single reviewer’s comparison from 2006. For the Klon, Premier Guitar’s profile quotes Finnegan on how the pedal is meant to be used: its output has to drive the amp hard enough for the pedal to act as an overdrive, and he says he did not want a pedal that would mess up what players already had and liked. We found no published measurement comparing all four, so settle that with your own ears.

Bass, headroom and pedal position

The Klon’s 9 V to 18 V step-up, per Andertons, and the OCD’s V2 input and output buffering, per Fulltone, are both attempts to keep the pedal from loading or squashing the signal. Finnegan makes a related point about the Centaur’s buffer: he says cable capacitance noticeably degrades the signal without it.

Who Uses Them

Named players are the easiest claims to get wrong, so we only list the ones we found in a published source, and say which.

For the Tube Screamer, Premier Guitar’s history credits Stevie Ray Vaughan with popularising the TS808 and names Eric Johnson, Trey Anastasio and Brad Paisley in its introduction. It also notes that John Mayer used the later TS10. Which model Vaughan used on which record is disputed in the sources we read, and our Stevie Ray Vaughan gear guide and our TS9 page treat it in more detail than we can here.

For the Klon, the same builder profile lists Jeff Beck, John Mayer, Joe Perry, Nels Cline and Matt Schofield. Our John Mayer gear page lists a Klon in his 2010 rack and in a 2019 board report, and says his current setup is unconfirmed.

For the BD-2, Guitar.com names Gary Moore and Eric Clapton, but as examples of the dynamic, amp-like tones the pedal was aiming at, not as users, and the review says the pedal turns up on professional and hobbyist boards alike. We did not find a primary source we trust for a list of famous BD-2 users, so we leave names out here. Our BD-2 page lists some and attributes them.

For the OCD, the pages we opened from the maker and from Tape Op do not name users. Our OCD page names several players and is the place to look.

Which One Fits Your Rig

This section is our own synthesis, built from the descriptions above rather than from a listening test.

If your amp is already at the edge of breakup

A Tube Screamer is the traditional answer, and Premier Guitar’s account of its purpose, adding sustain and edge to a tube amp, supports that role. Our TS808 page makes the same point and suggests it works best with single-coil guitars into amps near breakup.

If you want the guitar’s tone to stay intact

In our view this is the case for the Klon, with the caveat that you are buying an idea more than a pedal at this point. Originals are scarce, Finnegan says the original diodes are out of production, and the clones we link to, such as the Wampler Tumnus and the Electro-Harmonix Soul Food, make different diode and circuit choices by their own descriptions. The Soul Food’s silicon diodes versus the Klon’s germanium are an example our Soul Food page raises.

If you want something cheap and responsive

The BD-2 fits here. Boss says it works as a full-range boost or as a standalone drive, and Guitar.com’s review says it can turn harsh in the treble depending on the amp, with the tone control normally fixing it. We have not found a current Boss price on a page we opened, so we do not quote one.

If you want more gain without changing pedals

The OCD is the pedal in this group that its own reviewer describes as reaching heavy saturation, and the HP/LP switch gives two voicings. Fulltone lists the OCD V2 at $179 on its USA store as of 16 October 2026. One caution: our own OCD page says the company closed in 2022 and the pedal is only available used, which conflicts with a live Fulltone store listing, so check current availability before you plan a purchase around it.

Stacking and Overlap

Two of these pedals can share a board. Caffrey’s Tape Op review mentions placing another pedal in front of the OCD for larger gain jumps. Boss says the BD-2 can push other drive pedals. Our Stevie Ray Vaughan page describes his Tube Screamer as a boost into the amp rather than his main distortion. If you would rather have several voicings in one box, our pages on the Strymon Sunset and the EarthQuaker Devices Palisades look at two such pedals. As a rule, two pedals that do the same job (two mid-forward drives, say) add little. A mid-forward pedal and a flatter one cover more ground.

Frequently Asked Questions