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Build Notes

With the FET switching in the original, there are two capacitors in series here, 470n and 47n. A

calculation

puts the "consolidated" value for this at 42n. However, since 42n is a pretty rare value for a

capacitor, the more common 47n can be used instead and won't be noticeably different.

Electrolytic or film. The original uses electrolytics as coupling capacitors, so for "vintage tone" the lower

fidelity of electrolytic capacitors may be desired. The layout has room for full-sized film capacitors, but the

polarity is marked if you want to use electrolytics.

Don't use both of these. Hopefully this goes without saying, but you only want to use one of these op amps

depending on which version you want to build. Bad things might happen if you were to use both of them.

Stacking diodes: The original diodes in the MIJ version are 1S2473, which are long out of production and

very difficult to find. There is not anything special about these diodes to warrant tracking them down and

paying high prices for them. Their notable characteristic is that they clip between 1 and 1.2 volts, which is far

higher than the standard 1N914s used in the modern DS-1 and will give a more open and less compressed

sound which is critical for a MIJ clone. I recommend combining a 1N914 (0.6V) and a BAT41 (0.4V) in series

on each side to get an equivalent clipping threshold, which will require standing them on end. You could also

try a BA243, BA278 or BA282 here, which all clip at around 0.9v and are easy to come by.

Your choice. LEDs are very commonly used as alternate clipping diodes in a DS-1 mod.

Modifications

The BOSS DS-1 is one of the most frequently modded pedals out there, and on a personal note, was both the

first guitar pedal I owned and the first one I ever modded. Despite its popularity, the off-the-shelf $40 version is

shrill, brittle and uneven. Fortunately it doesn't take much to turn it into a very good distortion pedal!

The IC is the first thing upgraded in most modifications, and the single thing that makes the biggest difference.

Since this layout was made for a DIP8 op amp rather than a single-in-line like the original post-'94 version, you

have an abundance of excellent options available, but a couple of good choices are the TL072, JRC4558, and

Burr-Brown OPA2134 (more expensive but much higher fidelity).

Beyond that, here are a few value changes inspired by mods from Keeley, Monte Allums and Analogman.

Mod 1

IC1

OPA2134

100n

1uF

C10

47n

C12

100n

Big Muff mod: The DS-1 has a couple of building blocks in common with the Big Muff, notably the tone control

and the gain stage before the op amp. Some have experimented with adding a couple of parts to the DS-1's

gain stage to make it identical to a Big Muff clipping stage. To do this, put a 100n cap in CX1 and two 1N914s

for DX1 and DX2. This will clip the signal before it gets amplified by the op amp.

DS-1 DISTORTION / COMET DISTORTION

Mod 2

All changes from Mod 1, plus...

470pF

100n

220pF

R10

2k4

R12

1k5

R23

20k

series