Synth & Eurorack Parts / DIY

Our Synth & Eurorack Parts / DIY category is a curated list of items that are commonly found in synth/eurorack projects. The items and filters here do not represent our full lineup of parts. If you don't see what you are looking for, check out our main categories or send us a suggestion and we'll look into adding it.
Knob - Plastic, Knurled Shaft, 808 Style
Black textured plastic knobs with orange infilled indicator lines similar to the original knobs found on Roland TR-808 drum machines.These knobs feature a straight knurled grip. The large and medium sizes both have a skirt with a notched indicator. All sizes fit 6mm T18 knurled pot shafts.
Starting at $0.95
Transistor - OC139, Germanium, SO-2 glass case, NPN
OC139 NPN germanium transistors. The OC139 is a popular NPN for fuzz pedals and boost effects. This transistor is in a glass SO-2 package with long leads commonly found on germanium transistors. The NPN polarity allows for use with standard pedal power supplies. The dot indicates the collector lead. The OC139 can be found in the EarthQuaker Devices Bows germanium preamp.
$5.50
Transistor - OC140, Germanium, SO-2 glass case, NPN
OC140 NPN germanium transistors. The OC140 is a popular NPN for fuzz pedals and boost effects. This transistor is in a glass SO-2 package with long leads commonly found on germanium transistors. The NPN polarity allows for use with standard pedal power supplies. The dot indicates the collector lead.
$5.50
Heat Shrink - 2:1, Thin Wall Tubing, Polyolefin, Black
Thin wall heat shrink tubing available in multiple diameters. The flexible yet durable polyolefin material and standard 2:1 shrink ratio make this heat shrink a great option for electrical insulation, cable bundling, and component protection.
  • Operating Temperature: -55°C to +135°C
  • Minimum Shrink Temperature: 70°C
  • Full Recovery Temperature: 100°C
  • UL Approval
  • RoHS Compliant
Starting at $0.35
Sold by the foot
LED Lens - Fresnel, Polycarbonate, 3mm
Colors Available:
Panel mount LED lenses made of high quality polycarbonate. These lenses provide a clean semi-flush appearance with a small panel footprint and work well in any project using LED indicators. Features:
  • 0.171” mounting hole
  • For panel thicknesses of 0.031” to 0.125″
  • Fresnel lens
  • Low Profile
  • Fits standard 3mm LEDs

For a version that fits 5mm LEDs, see P-L710-X.
$0.85
LED Lens - Square, Fresnel, Polycarbonate, 3mm
Colors Available:
Panel mount LED lenses made of high quality polycarbonate. These square lenses provide a clean semi-flush appearance with a small panel footprint and work well in any project using LED indicators. Features:
  • 0.171” mounting hole
  • For panel thicknesses of 0.031” to 0.125″
  • Fresnel lens
  • Low Profile
  • Fits standard 3mm LEDs
$0.85
LED Lens - Flat Cylindrical, Fresnel, Polycarbonate, 5mm
Colors Available:
Panel mount LED lenses made of high quality polycarbonate. These flat cylindrical lenses provide a unique retro appearance with a small panel footprint and work well in any project using LED indicators. Features:
  • ¼” mounting hole
  • For panel thicknesses of 1/16” to ⅛”
  • Fresnel lens
  • Flat cylindrical shape
  • Fits standard 5mm LEDs
Starting at $0.65
LED Lens - Flat Cylindrical, Fresnel, Polycarbonate, 3mm
Colors Available:
Panel mount LED lenses made of high quality polycarbonate. These flat cylindrical lenses provide a unique retro appearance with a small panel footprint and work well in any project using LED indicators. Features:
  • 0.171” mounting hole
  • For panel thicknesses of 0.031” to 0.094″
  • Fresnel lens
  • Flat cylindrical shape
  • Fits standard 3mm LEDs
$0.85
Indicator Light - Bakelite, Soviet, Incandescent, Screw Base
Colors Available:
New-old-stock Soviet pilot lights that fit screw base bulbs. These lights have a unique bakelite frame and bakelite bezel. The lights come with a 6.3V bulb but can be used with any G-3-½ screw base bulb. The diameter of the light is 0.785” and the diameter of the mounting hole is 0.625”. Includes a bakelite mounting nut. Note: A small 0.2” notch must either be filed into the 0.625” mounting hole or filed off of the light to flush mount with a panel.
$5.95
Diode - KD522B, Silicon, used in Russian Big Muff
New-old-stock Soviet silicon diodes KD522B (КД522Б) in a SOD27 package. These diodes were used in EHX/Sovtek Big Muff models from Civil War to Black Russian. The KD522B is a high-speed switching diode encapsulated in hermetically sealed, leaded glass. The SOD27 packages are similar to DO-35.
$1.65
Indicator Light - Bakelite, Soviet, Incandescent, 9V
Colors Available:
New-old-stock Soviet pilot lights that operate on 9V. These lights have a unique bakelite frame and metal bezel. The lights come with a 9V bulb but can be used with any voltage bulb that fits this type of socket. The diameter of the light is 12mm and the diameter of the mounting hole is 8.1mm. Includes a wavy washer and knurled nut. Note: There can be small differences in the appearance and tint of the lens and color of the bakelite. A small 0.1” notch must either be filed into the 0.625” mounting hole or filed off of the fuse to flush mount with a panel. The small bulbs can come loose during shipping and reseating the bulb is recommended before use.
$5.95
Diode - KD521V, Silicon, used in Russian Big Muff
New-old-stock Soviet silicon diodes KD521V (КД521B) in a SOD27 package. These diodes were used in EHX/Sovtek Big Muff models from Civil War to Black Russian. The KD521V is a high-speed switching diode encapsulated in hermetically sealed, leaded glass. The SOD27 packages are similar to DO-35.
$1.65
Transistor - GT309E, Germanium, USSR Saucer Case, PNP
New old stock Soviet GT309E transistors manufactured in Ukraine. The GT309E is a germanium PNP transistor in a very low profile case. The case has a 0.29” diameter and is only 0.1” thick. These have very low leakage and work well in a variety of fuzz pedal builds.
$4.95
Transistor - MPSA18, Low Noise, 200mA 45V NPN
NPN low noise transistor (TO-92 package) - designed for high gain, low noise general purpose amplifier applications.
  • Max collector to emitter voltage = 45 V
  • Max collector to base voltage = 45 V
  • Max emitter to base voltage = 6.5 V
  • Max collector current = 0.2 A (continuous)
$0.15
Reverb Module - Accutronics Belton, Digi-Log, Adjustable Decay
A great digital reverb sound that easily replaces a spring reverberation unit. Stereo outputs may be summed for mono operation. Simple interface: input, output, +5V, and ground
$16.95
Transistor - 2N4123, Silicon, TO-92 case, NPN
The 2N4123 is a general purpose silicon NPN transistor in a TO-92 case. The 2N4123 is primarily intended for general purpose amplification. It is a popular choice for silicon fuzz pedals due to its low hFE specifications.
$0.45
3.5mm Jack - Qingpu, Eurorack, Stereo, PC Mount
PCB mounted 3.5mm stereo jacks commonly found in DIY Eurorack projects. These are the newest version from Qingpu Electronics featuring a square bushing plate for added durability. Hardware sold separately. See accessory items below.
$0.55
Heat Shrink - Assorted Diameters, 6" Long, 24 Pieces
2 to 1 heat shrink tubing variety pack. This pack includes six different diameters with four pieces of each size. Each piece is six inches in length. Features:
  • Resistant to common fluids and solvents
  • UL and CSA listed
  • UV resistant
  • Meets DEF. STAN 59.97
  • Meets UL 224, 125°C and CSA C22.2 No. 198.1
  • Meets MIL-DTL-23053/5 Class 2 & 3
  • Flame retardant (Does not include transparent)
  • Seals and protects cable splices and terminations.
  • Thin wall tubing
$5.45
Patch Cables - 3.5mm, Mono
Colors Available:
Low cost, high quality 3.5mm patch cables in a variety of lengths and colors. The cables are super flexible, have a great droop, and are shipped coiled so no permanent kinks are formed. With the large selection of lengths and colors, these cables are the perfect choice for any sized system.
Starting at $1.11
Save 20%
Originally: $1.39
Partially Out of Stock
CMOS - CD4093, Quad 2-Input NAND Schmitt Triggers, 14-Pin DIP
CD4093B consists of four Schmitt-trigger circuits. Each circuit functions as a two-input NAND gate with Schmitt-trigger action on both inputs. The gate switches at different points for positive- and negative-going signals. The difference between the positive voltage (VP) and the negative voltage (VN) is defined as hysteresis voltage (VH). Features:
  • Schmitt-trigger action on each input with no external components
  • Hysteresis voltage typically 0.9 V at VDD = 5 V and 2.3 V at VDD = 10 V
  • Noise immunity greater than 50%
  • No limit on input rise and fall times
  • Standardized, symmetrical output characteristics
  • 100% tested for quiescent current at 20 V
  • Maximum input current of 1 µA at 18 V over full package-temperature range, 100 nA at 18 V and 25°C
  • 5-V, 10-V, and 15-V parametric ratings
  • Meets all requirements of JEDEC Tentative Standard No.
$0.75
Trimmer - Bourns, 3362P, Single Turn, Top Adjust, PCB Mount
High-quality Bourns 3362P trimpots. These single-turn cermet trimmers can be found in countless guitar pedals and synthesizer modules. Sealed trimmers are built with an o-ring seal to prevent entrance of moisture and serve as a mechanical restraint to prevent unwanted wiper movement. ±10% tolerance.
Starting at $1.25
Reverb Module - Accutronics Belton, Digi-Log, horizontal mount
A great digital reverb sound that easily replaces a spring reverberation unit. Simple interface requires only input, output, +5V, and ground. Output requires no external capacitors.
Starting at $12.95
Transistor - 2N1711, Silicon, TO-39 case, NPN
The 2N1711 is a silicon planar epitaxial NPN transistor in a TO-39 metal case. It is intended for use in high performance amplifiers, oscillators and switching circuits. The 2N1711 is a great choice for amplifiers where low noise is an important factor.
$1.00
Op-Amp - TL062, Dual, Low-Power, JFET Input, 8-Pin DIP
Dual low power opamps in an 8-pin DIP package. The TL062 offers a high input impedance and 1MHz bandwidth.
$0.95