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.
P-QOC139 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
P-K808-X 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
P-QOC140 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
S-MHS-X 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
P-L320-X 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
P-L310-X 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
P-L330-X 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
P-L720-X 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
P-L191-X 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
P-QKD521V 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
P-QGT309E 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
P-QKD522B 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
P-L190-X 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
C-CX-500 Capacitor - 500V, Ceramic Disc, ± 10%
Radial ceramic capacitor.
  • Voltage rating: 500VDC
  • Tolerance: ± 10%
Starting at $0.20
P-PC-STD15-2-BLK StripBoard - Single Sided, 6.14” x 3.15”, Vintage Spacing, Black
Black stripboard featuring a 0.15” vintage spacing. This spacing is great for vintage-style builds and more easily accommodates axial capacitors and other larger sized vintage parts like resistors and transistors. The board has 40 x 20 holes (20 strips). Each strip is HASL coated making soldering easier than most protoboards and also ensures a long shelf life. Features:
  • High-quality 1.6mm FR4 glass-epoxy circuit board
  • HASL coated strips
  • 40 x 20 holes (20 strips)
  • 6.14” x 3.15”

Looking for projects? See our Wide Stripboard projects in our Pedal Layouts & Build Guides section for ideas.
$6.49
P-QMPSA18 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
P-RBTDR-3H 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
P-Q2N4123 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
W-QP-419GR 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
S-MHS-ASST-1 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
P-PATCHCABLE-X 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
P-QCD4094 CMOS - CD4094, 8-Stage Shift-and-Store Bus Register, 14-Pin DIP
CD4094B is an 8-stage serial shift register having a storage latch associated with each stage for strobing data from the serial input to parallel buffered 3-state outputs. The parallel outputs may be connected directly to common bus lines. Data is shifted on positive clock transitions. The data in each shift register stage is transferred to the storage register when the STROBE input is high. Data in the storage register appears at the outputs whenever the OUTPUT-ENABLE signal is high. Two serial outputs are available for cascading a number of CD4094B devices. Data is available at the QS serial output terminal on positive clock edges to allow for high-speed operation in cascaded systems in which the clock rise time is fast.
$0.69
R-VT62P-X 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
P-RBTDR-1H-X 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
Don't see what you're looking for? Send us your product suggestions!