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.
LED - 3mm diameter, diffused lens, 3.6 mCd
Colors Available:
Lens Diameter: 3 mm Overall Height: 5.4 mm Lens Type: Diffused Multiple color options available.
package of 5
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Transistor - BD139, Medium Power, TO-126 case, NPN
The BD139 is a NPN medium power BJT transistor in a TO-126 package. The BD139's typical applications include audio amplifiers and drivers but is also popularly used in silicon fuzz pedals. The BD139 is available in two different gain ranges: BD139-10 and QBD139-16. Type hFE (IC=150mA, VCE=2V) BD139-10 63-160 BD139-16 100-250
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Screw - M3, Phillips, Pan Head, Machine
Phillips panhead machine screw, M3 metric, zinc. Designed to go through a hole or nut that is pre-tapped to form a mating thread for the screw. Phillips drive is the most common drive used and is designed to "camout" when the screw reaches optimum tightness, thus preventing damage to the screw head. See S-HS-M3-6-X for colored 6mm M3 screws.
package of 5
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Nut - Mod® "Top Brass", for Qingpu and other 3.5mm jacks
Mod® "Top Brass" nuts are the easiest way to upgrade your Eurorack module or other 3.5 mm application to a more regal look - we call it "Top Brass". Designed with the same outer dimensions as Qingpu knurled nuts, these round brass nuts will fit any module using Qingpu or other similar metal-bushing jacks without covering up the jack labels. As their name implies, the Mod® "Top Brass" nuts are made out of pure brass, and while they look incredible on their own, their appearance also pairs extremely well with the immersion gold used on Make Noise and other similar modules. Rather than being knurled, Top Brass nuts have a smooth outer edge for a clean look. The nuts are slotted and will work with all existing nut drivers intended for use with the knurled Qingpu-style nuts. "Top Brass" nuts use M6x0.5 threading which matches the bushing on the ubiquitous Qingpu jacks and many of their copies.
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Op-Amp - LM3900, Quad, Norton, 14-Pin DIP
LM3900 quad op amp in a 14-pin DIP package. These devices consist of four independent, high-gain frequency-compensated Norton operational amplifiers that were designed specifically to operate from a single supply over a wide range of voltages. Operation from split supplies is also possible. The low supply current drain is essentially independent of the magnitude of the supply voltage. These devices provide wide band- width and large output voltage swing. Features
  • Wide Range of Supply Voltages, Single or Dual Supplies
  • Wide Bandwidth
  • Large Output Voltage Swing
  • Output Short-Circuit Protection
  • Internal Frequency Compensation
  • Low Input Bias Current
  • Designed to Be Interchangeable With National Semiconductor LM2900 and LM3900, Respectively
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Washer - CTS, Flat, for Potentiometers
Flat washer for 3/8" bushing. Perfect fit for CTS potentiometers. Package of 10.
package of 10
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Transistor - 2N508, Germanium, TO-5 case, PNP
2N508 PNP germanium transistors. The 2N508 is a popular PNP for fuzz pedals and other effects. It can be found in modern classics such as the Sunface. This transistor is in a TO-5 package with long leads commonly found on germanium transistors.
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Nut - Hex, for mounting Qingpu 3.5mm jacks
Hex nut for W-QP-419GR and W-QP-518MA 3.5mm jacks. See W-QP-NUT-K for the knurled, slotted version of this nut. See W-QP-WASHER for compatible washer
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Heat Shrink - Assorted Diameters and Colors, 4" Long, 160 Pieces
2 to 1 heat shrink tubing variety pack with multiple colors in each size. This pack includes six different diameters ranging from 1/16” to 3/8”. Each piece is 4” in length. This set comes in a hard plastic case perfect for sorting and storing heat shrink. 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

Included Sizes (Diameter):
  • 60 pieces - 1/16 in.
  • 35 pieces - 3/32 in.
  • 25 pieces - 1/8 in.
  • 20 pieces - 3/16 in.
  • 10 pieces - 1/4 in.
  • 10 pieces - 3/8 in.
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Box Header - Shrouded, 10 Pin, Right Angle
High quality right angled 10-pin headers. Right angled headers are perfect for compact eurorack builds. The durable glass filled polyester shroud makes soldering these shrouded headers a simple task.
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Transistor Set - tested and selected for Fuzz Face, 2N1309, PNP, Germanium
This is a set of two 2N1309 germanium transistors that have been hand-selected to work in the germanium Fuzz Face circuit. Also included are 4 metal film resistors to use in the circuit. In most cases, the values have been modified from the stock values slightly to ensure that the collector of Q2 biases to roughly -4.5V. A data sheet containing the schematic and the resistor values is included so that you can use your own resistor type if you would prefer. There is a range of bias voltages that can sound nice in a Fuzz Face, and voltages in original units varied. These transistors have been tested with bias voltage, sound, and noise level in mind. Note that due to a variety of factors such as battery/PSU voltage, temperature, and component tolerance, the voltage on the collector of Q2 may not measure at exactly -4.5V, but it should be close in a properly-built circuit.
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¼" Jack - Switchcraft, Enclosed, Stereo
The Switchcraft Type 112BX enclosed ¼” jack is a high quality jack. This jack has three solder lugs. One for the tip, one for the ring, and one for the sleeve. These jacks have been widely used across the industry and can also be found in many popular 5U synthesizers. Includes nut and washer.
  • Type 112BX
  • 0.276" bushing length (standard)
  • Mates with standard ¼" plugs and is available with 0.25" inside diameter bushing.
  • Stereo 3-Conductor
  • Includes nut and washer

See W-SC-111X for mono version
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Potentiometer - Alpha, 300kΩ, Linear, Knurled Shaft, 16mm
Miniature Alpha pot for guitars. 300K linear taper.
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Transistor - 2N2907, Silicon, TO-18 case, PNP
The 2N2907 is a silicon planar epitaxial PNP transistor in a TO-18 metal case type. The 2N2907 is designed for use in high speed saturated switching and general purpose applications.
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Op-Amp - TL082, Dual, Wide-Bandwidth, JFET Input, 8-Pin DIP
Dual wide-bandwidth TL082 opamps in an 8-pin DIP package. The TL082 offers a high input impedance and 4MHz bandwidth.
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Capacitor - Kemet, R82 Series, Polyester, 5mm Spacing
High quality R82 Series box film capacitors from Kemet. These polyester film capacitors have 5mm lead spacing, a minimum voltage rating of 63VDC, and a tolerance of ±10% or better. The small size, high specifications, and radial mounting makes them an excellent choice for PCB builds of pedals, synthesizer, and other audio equipment. The R82 Series is constructed of metallized polyester film with radial leads of tinned wire. Radial leads are electrically welded to the contact metal layer on the ends of the capacitor winding. The capacitor is encapsulated with thermosetting resin in a box of material meeting the UL 94V–0 requirements.
  • Voltage rating: 63 VDC Minimum
  • Lead Spacing: 5 mm
  • Capacitance tolerance: ±10% or better
  • Operating temperature range of -55˚C to +105˚C
  • RoHS compliance and lead-free terminations
  • Self-healing
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Knob - Plastic, Set Screw, Vertical Pointer, 0.51" Diameter
Colors Available:
Small plastic control knob with set screw and brass insert. This knob features a radial-brushed metal top, a fine straight-knurl grip, and a vertical pointer. Fits ¼” (6.35mm) pot shafts.
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Transistor - NOS 2N404A, TI, Germanium, Gold Lead TO-5 Case, PNP
New old stock 2N404A PNP germanium transistors manufactured by Texas Instruments. These TI 2N404A feature gold plated leads. The 2N404A is used in many fuzz pedals along with other effects. The 2N404A is the same as the 2N404 but with a higher voltage rating. This transistor is in a TO-5 package with long leads commonly found on germanium transistors.
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Power Jack - Lumberg, DC Panel Mount, Low Profile, 5.5mm External, 2.1mm Internal
Low profile Lumberg panel mount barrel jack with solder lugs. This high quality jack is the perfect size for smaller builds where additional space is necessary. The Lumberg low profile DC jack is also great for builds where aesthetics are a priority. For use with barrel plugs with a 5.5mm external diameter and 2.1mm internal diameter. Mounting nut included.
Note: As of 2023, Lumberg has updated the design of these jacks.
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PCB - SMD to Thru-Hole Adapter, SOIC-8 to DIP-8
PCB for converting SMD SOIC-8 packages to through hole DIP-8 footprints. Solder the device to this PCB then attach pin headers (sold seperately) to connect to through hole footprints on PCBs, breadboards and IC sockets.
package of 5
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Integrated Circuit - SSI2131, VCO, Sound Semiconductor
The FatKeys™ SSI2131 Voltage Controlled Oscillator provides the core VCO function with buffered triangle, sawtooth, and variable-width pulse waveform outputs over a ten-octave range. The device offers unparalleled temperature stability, exponentiality, waveform integrity, and ease of use while requiring an absolute minimum of external components. The SSI2131 is a new-generation voltage controlled oscillator for high-performance electronic musical instruments and other systems requiring accurate audio-band waveform generation. The device offers unprecedented levels of temperature stability, exponentiality, waveform integrity, and ease of use.
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CMOS - CD4049, Hex Inverting Buffer and Converter, 16-Pin DIP
The CD4049UB devices are inverting hex buffers, and feature logic-level conversion using only one supply voltage (VCC). The input-signal high level (VIH) can exceed the VCC supply voltage when these devices are used for logic level conversions. These devices are intended for use as CMOS to DTL or TTL converters and can drive directly two DTL or TTL loads. (VCC = 5 V, VOL ≤ 0.4 V, and IOL ≥ 3.3 mA.) Features:
  • Inverting
  • High Sink Current for Driving 2 TTL Loads
  • High-to-Low Level Logic Conversion
  • 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

Applications
  • CMOS to DTL or TTL Hex Converters
  • CMOS Current Sink or Source Drivers
  • CMOS High-to-Low Logic Level Converters
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OTA - AS3080ED, Linearizing Diodes, Alfa, SOIC-8
The AS3080ED is Alfa’s version of the CA3080 IC in an SOIC package. The AS3080ED is a gain block which is the operational-transconductance-amplifier (OTA). The AS3080ED has differential input and a single-ended, push-pull, class A output. Amplifier bias input may be used either for gating or for linear gain control. High output impedance and transconductance (gM) is directly proportional to the amplifier bias current (IABC). Linearizing diodes are provided at the inputs to reduce distortion and allow higher input levels. The result is a 10-dB signal-to-noise improvement referenced to 0.5 percent THD.
The AS3080ED is notable for it’s high slew rate (50V/µs), which makes it especially useful for multiplexer and fast unity-gain voltage followers.
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Microphone Condenser - Korg, EM197K
Korg condenser microphone EM197K, used on the Korg MicroKORG.
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