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.
Optocoupler - Xvive, Vactrol, VTL5C Series
High quality vactrols from Xvive. The Xvive vactrols are clones of the original Excelitas / Perkins-Elmer vactrols used in many effects pedals, synthesizers, compressors and other equipment. These vactrols feature a thick epoxy sealed casing. The VTL5C3 and VTL5C3/2 both have a steep slope, good dynamic range, a very low temperature coefficient of resistance, and a small light history memory.
Starting at $6.50
Integrated Circuit - AS3360, Dual VCA, Alfa, 14-Pin Dip
The AS3360 is Alfa’s version of the CEM3360 IC. The AS3360 is a dual general purpose voltage controlled transconductor intended for such applications as voltage controlled amplifiers, filters, and waveform generators. Each transconductor independently provides both linear and exponential control scaling over greater than a 100 dB range. Complete with virtual ground summing inputs, wide voltage compliance current outputs, and control inputs referenced to ground, the AS3360 requires exceptionally few external components and is extremely easy to use. Because of its inherent ultra-low control feedthrough, no trimming is required.
$7.95
Diode - Silicon Rectifier, 3A, 400V, 1N5404
A semiconductor device which passes current in the forward direction(from anode to cathode), and blocks current in the opposite direction.
$0.35
Screws - Befaco, Knurlies, Eurorack, M3
Befaco Knurlies are unique screws designed specifically for Eurorack. These M3 screws can be secured by hand, all common screwdrivers and Allen keys. These are great for saving time when rearranging your synth. Each Knurlie comes with a fitted plastic washer to prevent rack rash. Sold individually.
$0.75
Resistors - ¼ Watt, Carbon Film, 5% tolerance
Package of 5
Carbon Film resistors are made by vacuum depositing a thin carbon film on a ceramic form. A good choice for applications which require a steady, low power drop. Package of 5. These resistors are perfect for pedal builders!
  • 1/4 watt
  • ± 5% tolerance
  • EIA color coded
  • .24" long x .08" diameter
  • Package of 5
$0.45
Potentiometer - Alpha, Audio, Solid Shaft, 16mm, Dual, 100kΩ
100kΩ dual-gang 16mm potentiometers with a solid shaft and an audio taper. These pots have solder lug terminals. The smaller size is useful for builds with limited panel space such as guitar pedals, synthesizer modules, and adding modifications to equipment. Washer and nut included.
  • Threading: M7 x 0.75
  • Distance between terminals: 5 mm (0.197”)
  • Bushing Length: 6.5mm (0.256")
  • Shaft Diameter: 6.35mm ( 0.250")
  • Taper: Audio (Log)
$1.25
Integrated Circuit - SSI2161, Single VCA, Sound Semiconductor
A very high performance single-channel VCA for the most demanding applications, the ProCircuit™ SSI2161 offers industry-leading lowest-noise, and a mode control to optimize noise vs. distortion performance. All at low-cost and in a 10-lead SSOP package. The SSI2161 is a versatile VCA building block for high-performance audio applications. A single channel provides voltage control of current-mode inputs and outputs for a gain range from +20dB to –100dB, with control provided by a ground-referenced –33mV/dB constant. The device offers considerable flexibility for a wide range of design goals and applications. A unique mode control allows selection of Class A, Class AB, or in-between using a single resistor. In addition, improved current handling allows use of lower value input resistors for reduced output noise without loss of headroom.
$5.45
Potentiometer - Alpha, Linear, 9mm, Vertical, Dual Gang
Linear taper, vertical mount, dual gang Alpha pots with a 6.35mm shaft diameter. Dual gang pots are useful for stereo controls and other circuits requiring two separate pots moving in tandem. These 9mm pots are popular in DIY guitar pedals, synthesizers, and other projects. Mounting nut and washer included. See R-VAV-A100K-DUAL for an audio taper version.
$2.55
Op-Amp - OPA134, Single, High Performance Audio, 8-Pin DIP
OPA134 single op amp in an 8-pin DIP package. The OPA134 series are ultra-low distortion, low-noise operational amplifiers fully specified for audio applications. A true FET input stage is incorporated to provide superior sound quality and speed for exceptional audio performance. This, in combination with high output drive capability and excellent DC performance, allows for use in a wide variety of demanding applications. In addition, the OPA134 has a wide output swing, to within 1 V of the rails, allowing increased headroom and making it ideal for use in any audio circuit. The OPA134 SoundPlus™ audio operational amplifiers are easy to use and free from phase-inversion and the overload problems often found in common FET-input operational amplifiers. They can be operated from ±2.5-V to ±18-V power supplies.
$2.95
Capacitor - 50V, 680pF, Ceramic Disc
Ceramic disc capacitor, 680 pF (.00068µF) rated for up to 50 V.
Non linear temperature coefficient of capacitance
$0.55
Op-Amp - AS301AN, Alfa, Single, 8-Pin DIP
The AS301AN is Alfa’s version of the LM301A in an 8 pin DIP package. The AS301A is a general purpose operational amplifier. This amplifier offers many features which make its application nearly foolproof: overload protection on the input and output, no latch-up when the common mode range is exceeded, and freedom from oscillations and compensation with a single 30 pF capacitor. It has advantages over internally compensated amplifiers in that the frequency compensation can be tailored to the particular application. For example, in low frequency circuits it can be overcompensated for increased stability margin. Or the compensation can be optimized to give more than a factor of ten improvements in high frequency performance for most applications. In addition, the device provides better accuracy and lower noise in high impedance circuitry.
$1.95
Screws - M3-0.5 Socket Head Cap, 8mm Length
Package of 5
Colors Available:
Ideal for precision assembly work with close tolerances and applications needing a well tooled appearance.
Starting at $0.75
Capacitor - 50V, 0.047µF, Used In Pedal Kits
Polyester Film Capacitor used in MOD® Pedal Kits. Rated at 0.047µF 50V. Tolerance: 10%. Operating temperature: -40 C to +85 C
$1.00
Knob - Rogan, PT Series, 2PS, Medium, Skirted, Pointer, Knurled Shaft
High-quality USA made knobs from Rogan Corp. These medium, skirted pointer knobs from Rogan’s PT Series feature a soft rubber grip molded over a solid polymer knob. PT Series knobs can be found on synthesizer modules from Make Noise, Mutable Instruments and others. Fits 6mm T18 knurled shafts.
  • Height: 0.84 in.
  • Diameter: 0.62 in.
  • Fits T18 Knurled Shafts

For a D-shaft version of this knob, see P-K282PS-W. A variety of different sizes are available from the PT Series. See the links below for the full selection of knurled shaft knobs from this series. P-K271P-W 1P Small Pointer P-K271PS-W 1PS Small Skirted Pointer P-K272P-W 2P Medium Pointer
$1.65
Potentiometer - Alpha, Linear, Solid Shaft, PC Lead, 16mm
Alpha Mini Pots with solid shaft and short PC mount terminals.
  • Threading: M7 x 0.75
  • Distance between terminals: 5 mm (0.197”)
  • Lead Depth from Panel: 3.8 mm (0.150”)
  • Lead Distance from shaft center: 12.5 mm + 3.5 mm (0.492” + 0.138”)
  • Lead Thickness: 0.5 mm (0.020”)
$1.10
Transistor - MPSA64, Darlington, -500mA, -30V, PNP
MPSA63 PNP Darlington transistor (TO-92 package) - designed for high gain, low noise general purpose amplifier applications.
  • Max collector to emitter voltage = -30V
  • Max collector to base voltage = -30 V
  • Max emitter to base voltage = -10 V
  • Max collector current = -0.5 A (continuous)
$0.25
Switch - Carling, Mini Toggle, SPDT, 2 Position, Solder Lugs, Short Bat
Carling, SPDT mini toggle, 2 positions, ¼" mounting hole diameter, 0.354" bushing length.
$3.50
Diode - 1N4741A, 11V, Zener, 1W, 5% Tolerance
1N4741A 11V zener diode in a DO-41 package. A semiconductor device that, above a certain reverse voltage(the zener value) has a sudden rise in current. If forward biased, the diode is an ordinary rectifier. When reverse biased, it exhibits a sharp break in its current-voltage graph. Voltage across the diode remains essentially constant for any further increase of reverse current.
$0.20
Banana Jack - Johnson Cinch, For 4mm Plugs, Panel Mount
Colors Available:
High quality banana jacks with tinned brass contacts and strong nylon housings. These jacks come in a wide variety of colors and work well with any 4mm banana plug. Cinch Johnson banana jacks are used in test equipment, audio equipment, as well as modular synthesizers such as DIY Buchla, Serge, and others. Features:
  • Formed brass contacts
  • Bright tin finish
  • Durable nylon 6/6 body
  • Nickel plated nut
  • 0.010Ω maximum contact resistance
  • Keyed mounting with two flatted sides
$1.45
Transistor - 2N4061, TO-92 case, PNP
2N4061 PNP transistors. This is a silicon PNP transistor in a TO-92 package. The 2N4061 has been used in a variety of effects pedals and is most notably used in the Zonk Machine II.
$0.50
Power Jack - DC Panel Mount, 5.5mm External, 2.1mm Internal
Colors Available:
½" panel mount with solder lugs. Round plastic with normally closed switch. For barrel plugs with a 5.5mm external diameter and 2.1mm internal diameter.
$0.95
Transistor - BC338, General Purpose, TO-92 case, NPN
The BC338 is a silicon general purpose NPN transistor in a TO-92 package. The BC338’s typical applications include signal processing, amplification, and switching. The BC338 is available in three different gain ranges: BC338-16, BC338-25, and BC338-40. Type hFE Range (IC=100mA, VCE=1V) Typical hFE (IC=100mA, VCE=1V) BC338-16 100-250 160 BC338-25 160-400 250 BC338-40 250-630 400
$0.25
Potentiometer - Alpha, Reverse Audio, 9mm, Right Angle, 25KΩ
Reverse audio taper (antilog), right angle, Alpha pots with a 6.35mm shaft diameter. These 9mm pots are poplar in DIY guitar pedals, synthesizers, and other projects. Mounting nut and washer included.
$1.85
Regulator - LT1054, Voltage Converter w/ Regulator, 8-Pin DIP
LT1054 switched-capacitor voltage converter with regulator in an 8 pin DIP package. The LT1054 device is a bipolar, switched-capacitor voltage converter with regulator. It provides higher output current and significantly lower voltage losses than previously available converters. An adaptive-switch drive scheme optimizes efficiency over a wide range of output currents. Total voltage drop at 100-mA output current typically is 1.1 V. This applies to the full supply-voltage range of 3.5 V to 15 V. Quiescent current typically is 2.5 mA. The LT1054 also provides regulation, a feature previously not available in switched-capacitor voltage converters. By adding an external resistive divider, a regulated output can be obtained. This output is regulated against changes in both input voltage and output current. The LT1054 can also shut down by grounding the feedback terminal.
$2.25