Boss DS-1

The Boss DS-1 is a distortion pedal for guitar, manufactured by the Roland Corporation under the brand name Boss since 1978. The first distortion effects unit made by Boss, it has become a classic effect, used by many notable guitar players.

Boss released a successor, the DS-2. The DS-2, "Turbo Distortion" was released in 1987, and is very similar to the DS-1 except that it features a "turbo" setting, which produces a sharper midrange tone. Boss released a black limited edition 40th Anniversary model of the DS-1 in 2017.

Variations
DS-1 – The original pedal, released in 1978. DS-1 BK – a Guitar Center exclusive with orange font on a black body, released in 2016 and limited to 3,000 units.

DS-1-4A – A 40th-anniversary addition with gold font on a black body, released in 2017.

DS-1W – WazaCraft version, released in 2023.

DS-1-B50A – Orange metallic paint to commemorate the company's 50th anniversary; released in 2023 and limited to 7,000 units.

Circuit
The blueprint of the DS-1 circuit is simple, with a pair of in- and output buffers surrounding a transistor boost stage, an operational amplifier gain stage with hard clipping diodes, and a tone control.

It features the same JFET switching circuit as almost all other Boss effects units, allowing a simple momentary push button to reroute the signal, either bypassing the effect or engaging it. In either state, the signal will pass through the input and output buffer stage of the effect, and this is the key differentiating factor between Boss pedals and "true bypass" pedals. The buffers themselves are similar, both Common collector amplifiers with unity gain. They each feature a 2SC2240 Toshiba transistor, which is only special insofar as it is cheap and reliable.

The transistor boost stage consists of two highpass filters in series, followed by a Common emitter amplifier. This serves to remove unnecessary bass frequencies before the distortion stage, preventing the signal from accumulating muddiness as it is amplified. This stage provides a 35 dB boost to the signal, and introduces a small amount of distortion.

The operational amplifier gain stage is the most important part of the Boss DS-1 circuit, featuring the clipping diodes, Op-amps and further filters which refine and color the sound. The op-amp stage is the only part of the circuit which has undergone any real changes over the pedals history. Originally, in 1978, the circuit was built around the Toshiba TA7136AP pre-amplifier, not an op-amp, and this gave the effect more of a warm, rich sound. In 1994, the Toshiba pre-amps were nearing the end of their stock life, and so the circuit had to be modified in order to play host to an easier to find dual op amp, the Rohm BA728N. This version is slightly quieter than the original, but is otherwise essentially the same. The Rohm op-amp was replaced in 2000 by the Mitsubishi M5223AL op-amp, which remains the centerpiece of the circuit to this day. Most of the distortion itself is handled by the silicon 1N4148 clipping diodes organized in a hard clipping arrangement, clipping any signal above 0.7v and below -0.7v. One of the popular modifications to the DS-1 consists of replacing one or both of the diodes, labeled D4 and D5, with LED or germanium diodes. Depending on the diodes, the pedal can take on many different sonic characters. A diode with a low forward voltage will make the pedal quieter but with a more saturated distortion, a diode with a high forward voltage will be louder but with less available distortion.

Last but not least, the humble "big muff pi" style tone control immediately preceding the output buffer is a fixed cutoff lowpass filter and a fixed cuttoff highpass filter which attenuate either the low or high end, depending on the position of the potentiometer. The way the two filters are interconnected creates a notch, or scoop, around 500 Hz when the potentiometer is in the center position. The seasaw nature of the tone control leads to a -12 dB volume loss which gives the pedal an output of 350mV , which is suitable for most applications but does create issues with the DS-1 being able to achieve unity gain with higher level inputs.

Notable users

 * Billie Joe Armstrong
 * Bruce Kulick
 * Chuck Schuldiner
 * Dave Grohl
 * Dave Navarro
 * Doug Aldrich
 * Gary Moore
 * George Lynch
 * Joe Satriani
 * John Frusciante
 * Kurt Cobain
 * Mark Speer
 * Matthias Jabs
 * Mike Stern
 * Ola Englund
 * Peter Steele
 * Steve Rothery
 * Steve Vai