Yerasov Gamma DS-1 Distortion

The Yerasov Gamma DS-1 Distortion is a distortion pedal from the Russian maker Yerasov, part of the company's Gamma series. From the outside it borrows the look of a Boss compact pedal, but the electronics inside are Yerasov's own design rather than a copy of the Boss circuit¹. It is an IC-based op-amp distortion with two LEDs doing the clipping, designed to run on a 9V supply¹.

The pedal is best known today among DIY builders, because a stripboard (vero) layout for it was published by the Guitar FX Layouts blog in October 2013, along with the schematic details that describe how the circuit works¹. Yerasov's own higher-gain designs, such as the Yerasov FETube Uber Higain UH-5 and the Yerasov FETube Vital Higain VH-5, are covered elsewhere on this site.

Boss-style enclosure, different circuit

The first thing anyone notices about the Gamma DS-1 is the box. As the Guitar FX Layouts blog put it when the layout was posted¹:

That distinction matters, because the Boss DS-1 it resembles is a genuinely different circuit under the hood. The Boss DS-1 has a very simple circuit based on a single op-amp, followed by a passive tone filter and volume control². Its distortion is produced using a variable gain circuit with diodes shorting the output to ground, producing hard clipping of the input waveform². The original DS-1 was not even op-amp based in its earliest form: as Guitar Player's reviewer Alex Lynham noted, it used the Toshiba TA7136AP preamplifier for a gritty and warm overdrive tone³.

The Yerasov Gamma DS-1, by contrast, is an IC-based op-amp circuit with its own clipping arrangement, so the family resemblance stops at the enclosure. Where the Boss pedal's clipping approach has been compared to the Pro Co RAT's², the Yerasov design takes a different route with LED clipping diodes¹.

A comparison of the two designs:

How the Gamma DS-1 clips the signal

The clipping stage is the heart of any distortion pedal, and the Gamma DS-1 uses two LEDs for the job¹. The blog's author was enthusiastic about the choice:

The schematic calls for 3mm LEDs, though the layout's author added that builders can use what they want¹. LED clipping differs from the silicon-diode hard clipping used in the Boss DS-1: LEDs have a higher forward voltage, so the signal can swing further before it is clipped, which changes the character of the distortion. For comparison, the Boss DS-1's approach of diodes shorting the output to ground produces hard clipping of the input waveform², and Guitar Player's reviewer described the DS-1 as using two hard-clipping diodes for an aggressive edge³.

Op-amps and build reports

Because the circuit is IC-based, the choice of op-amp affects how a build behaves. Builders have tried both the JRC4558 and the TL072 in the Gamma DS-1, with mixed results. The layout's author reported¹:

In other words, the JRC4558 produced a high-pitched squeal in that build while the TL072 produced no sound at all, which points to build-dependent behavior rather than a simple preferred op-amp. A later builder, commenting in February 2021, reported that the completed pedal sounded great after fixing a missing component¹.

The stripboard layout itself was posted as unverified, though it was reported to sound great¹. For players interested in modifying a Boss DS-1 rather than building the Yerasov circuit, kits such as the Griffin Effects DS-1 The One Kit alter the clipping of the original Boss pedal instead.

Power

The Gamma DS-1 is designed for a 9V supply¹. One builder found their power supply was delivering 10.50V rather than the intended 9V and planned to change it¹, so builders should treat a clean 9V feed as part of the design rather than a loose requirement. For reference, the Boss DS-1 it resembles runs on a 9V DC power supply or battery⁵, and the vintage Boss DS-1's current draw is listed at 10mA⁶.

Where the Gamma DS-1 sits among distortion pedals

The Gamma DS-1 belongs to Yerasov's Gamma series, an older line of distortion pedals from the Russian maker¹. Its place in the wider distortion landscape is an interesting one: it looks like the most famous distortion pedal of all, the Boss DS-1, which RockBoard's PedalPedia describes as "without a doubt one of the most famous distortion pedals out there"⁶, but it delivers its distortion through a different circuit with different components. Players comparing it against modern Boss options may also want to look at the Boss DS-1X Distortion, a digital-era take on the same concept.

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