Dunlop GCB95 Original Cry Baby

The Dunlop GCB95 Original Cry Baby is a wah pedal: a foot-controlled filter that sweeps a peak through your guitar's frequency range as you rock the pedal. Heel down, the tone is dark and muted; toe down, it is bright, peaky and vocal. Dunlop's manual calls it "The Original since 1967," and the company introduced the GCB95 as its first Cry Baby wah in 1982¹².

There are no knobs. The single control is the rocker pedal itself: by rocking your foot back and forth you change the effect on your tone instantaneously¹. To switch the effect on and off, you push the toe of the pedal down until you feel a click¹. Setup is two cables: one from your guitar into the GCB95's Instrument jack, and one from its Amplifier jack into your amp¹.

What the GCB95 does to your sound

A wah is a band-pass filter whose center frequency follows your foot. In the GCB95 the sweep runs from a low-pass corner of 350 Hz to 450 Hz at one end of the travel to a high-pass region of 1.5 kHz to 2.5 kHz at the other¹. The peak also adds gain: the manual lists a maximum gain of +19.5 dB heel down and +19 dB toe down¹, which is why a wah can push an amp and make notes jump out.

Dunlop describes the GCB95 as having "a more up front and aggressive modern sound, with raised frequency range and more pronounced wah effect" compared with the vintage originals². Reviewers broadly agree it is the familiar Cry Baby character. MusicRadar's review found it is "the same classic tone it's always been," while noting "it does get a little piercing at the top of its range"⁵. Gearnews' Julian Schmauch wrote that "this wah delivers a fast, expressive response that makes the wah effect sing"⁶.

Not everything written about it is flattering. In MusicRadar's wah buying guide, Alex Lynham summed up the pedal's strengths and weaknesses in one line: classic wah sound and use by countless artists on the plus side, with "can cause 'tone suck'" and a sound that is "harsh in the treble overall" on the minus side⁷. The treble character is consistent with the circuit: a technical analysis of the GCB-95 notes it has slightly less bass content than the VOX V847 it is inspired by, because the input buffer filters part of the bass⁸.

Specifications: filter range, gain and impedance

The figures below come from Dunlop's GCB95 manual¹.

The manual notes the signal-to-noise figures are A-weighted, referenced to 0dBV = 1VRMS¹. The 900µA current draw is low enough that a single 9V battery lasts a long time and the pedal is trivially easy to power from a multi-output supply.

Power options, per the manual and Dunlop's product page¹³:

• One 9 volt battery, accessed via the bottom of the pedal
• Dunlop ECB003 AC adapter (ECB003E in Europe)
• Dunlop DCB10 DC Brick power supply
• Dunlop DC Brick, Iso-Brick and Mini Iso-Brick power supplies (not included)

The original Cry Baby circuit and its versions

The Cry Baby circuit predates Dunlop's version by more than a decade. The pedal that would become the Cry Baby was first created in 1966 by engineers at the Thomas Organ Company⁹, and Dunlop's GCB-95 is a copy of the original VOX model made by VOX/Thomas Organ Co in 1970⁸. Dunlop's own history page describes the GCB95 as "a modern interpretation of that sound," with engineers raising the frequency range and giving it a more pronounced wah effect²³. Dunlop's product page likewise calls the GCB95 "a modern interpretation of the original 1966 Cry Baby Wah sound"³.

Inside, the circuit has three stages worth knowing about⁸:

• An input buffer: an emitter-follower (common collector) NPN amplifier with unity voltage gain, high input impedance and low output impedance. Its 0.01uF input capacitor isolates the guitar from the pedal's DC potential and removes hum. Dunlop added this buffer to the VOX-derived circuit, raising the input impedance from 69.5 kΩ to 1 MΩ to preserve the guitar's original tone.
• An active filter stage: a common-emitter amplifier with a voltage-shunt feedback network, built around feedback resistors R6 (470 kΩ) and R8 (82 kΩ to ground).
• The swept inductor-capacitor filter that the rocker pedal tunes across the range listed above.

The gain math is instructive: the analysis calculates the active filter's voltage gain as 56.4, about 35 dB, but the feedback network reduces it in practice to 19 dB⁸, which matches the manual's toe-down maximum gain figure¹. Dunlop also changed resistor values from the VOX design, reducing R4 from 510Ω to 390Ω and R8 from 100 kΩ to 82 kΩ⁸. Over the years, the important changes to the GCB95 have been to reduce RF interference².

Versions and relatives

The GCB95 sits at the base of a large Cry Baby family. The closest sibling is the GCB95F Cry Baby Classic, released in 2003². It takes the modern circuitry of the GCB95 and modifies it to emulate the warm vintage character of early Cry Baby wahs, with a lower frequency range for a darker vibe¹⁰. MusicRadar's review of the GCB-95F noted it "scores big-time by enabling either the use of batteries or Dunlop's ECB03 AC adaptor"¹¹, and its manual lists the same bottom-plate 9-volt battery arrangement and a 1 MΩ input impedance¹².

The GCB95 circuit has also been frozen in time for signature models. MusicRadar reported that the limited edition TBM95 Tom Morello Signature Cry Baby "houses an identical circuit to his early-'80s GCB95 Cry Baby"¹³, and Dunlop's page for that pedal lists the GCB95 at $99.99 alongside it⁴. MusicRadar has also noted the GCB95's price accessibility, observing you can pick one up for $99¹⁴.

For a broader look at the effect type and the rest of Dunlop's wah lineup, see the wah pedals page and the Dunlop brand page.

Videos

Click to load

Click to load

Click to load

Questions