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.
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 - AS395H, Matched Pair, Alfa, TO5-8 case, PNP
The AS395 dual monolithic PNP transistor offers excellent parametric matching and high frequency performance. Low noise characteristics (1 nV/√Hz typ @ 1 kHz), high bandwidth (190 MHz typical), and low offset voltage (100 µV max), makes the AS395 an excellent choice for demanding preamplifier applications.Tight current gain matching (3% max mismatch) and high current gain (100 min), over a wide range of collector current, makes the AS395 an excellent choice for current mirrors. A low value of bulk resistance makes the AS395 an ideal component for applications requiring accurate logarithmic conformance. To ensure the long-term stability of the matching parameters, internal protection diodes across the base-emitter junction clamp any reverse base-emitter junction potential.
$5.50
Transistor - AS3046, Array of 5, Matched Pair, 14-Pin DIP, NPN
The AS3046 is Alfa’s version of the CA3046 (LM3046) IC. The AS3046 consists of five general purpose silicon NPN transistors on a common monolithic substrate. Two of the transistors are internally connected to form a differentially-connected pair. The transistors are well suited to a wide variety of applications in low power systems. They may be used as discrete transistors in conventional circuits however, in addition, they provide the very significant inherent integrated circuit advantages of close electrical and thermal matching. The AS3046 is available in a 14-pin DIP package. Features
  • Matched pair of npn transistors
  • VBE matched less than ±1 mV
  • 5 general purpose monolithic transistors
  • Wide operating current range

Applications
  • Filters
  • Custom designed differential amplifiers
  • Temperature compensated amplifiers
$5.65
Felt Strip - 51.5", for Korg & Yamaha Keyboards
For Yamaha DX7, DX7 II, FX20, Korg M1, Trinity and T Series.
$5.65
ProtoBoard - Fits 1590BB, 1 sided, 2-hole strips
Prototyping circuit board (PCB) designed to fit the Hammond 1590BB die-cast aluminum enclosure. It has a convenient 2-hole pattern, which provides an easy way to connect parts while maximizing usable board area. It can be used as a stand-alone prototyping board, or installed in a Hammond 1590BB enclosure. For fastening your project to a surface see our adhesive standoffs (S-H190). Features:
  • Single-sided high-quality FR4 glass-epoxy circuit board.
  • Convenient 2-hole pattern provides an easy way to connect parts.
  • 1oz/ft2 copper with an anti-tarnish coating for easy soldering.
  • 0.042" holes are drilled on 0.1" (2.54mm) centers. 4 mounting holes.
  • PCB Size 3.20 x 4.25 in (81.3 x 108.0 mm)
$5.75
Integrated Circuit - AS3310, VC ADSR, Alfa, 16-Pin Dip
The AS3310 is Alfa’s version of the CEM3310 IC. The AS3310 is a self-contained, precision ADSR type of envelope generator intended for electronic music and other sound generation applications. Attack, decay and release times are exponentially voltage controllable over a wide range, and the sustain level is linearly voltage controllable from 0 to 100% of the peak voltage Vp. All four control Inputs are Isolated from the rest of the circuitry so that the control pins of tracking units may be simply tied together.
On the negative power output, there is an internal Zener diode at 7.4 volts ± 10%, which allows the chip to supply a maximum voltage of ± 15 volts with a current-limiting resistor REE, and a minimum positive supply voltage of + 11 volts and a minimum negative supply voltage of -5 volts.. A series current limiting resistor must be added between pin 6 and the supply.
$5.85
Indicator Light - Bakelite, Soviet, Incandescent, Screw Base
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
Integrated Circuit - SSI2130, VCO, Sound Semiconductor
The FatKeys™ SSI2130 Voltage Controlled Oscillator provides beautiful triangle, sawtooth, pulse, and square waveforms with unprecedented temperature stability; and adds an on-chip mixer, low distortion sine wave generator, through-zero FM/PM capability and more in an ultra-compact PCB footprint.
$5.95
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
Integrated Circuit - AS3320, Multi-Mode VCF, Alfa, 18-Pin Dip
The AS3320 is Alfa’s version of the CEM3320 IC. The AS3320 is a high performance voltage controlled four-pole filter with on-chip voltage controllable resonance IC. The four independent sections may be interconnected to provide a wide variety of filter responses, such as low pass, high pass, band pass and all pass. A single input exponentially controls the frequency over greater than a ten octave range with little control voltage feedthrough. Another input controls the resonance in a modified linear manner from zero to low distortion oscillation. For those demanding applications, provision has been made to allow trimming for improved control voltage rejection. Each filter section features a variable gain cell which is fully temperature compensated, exhibits a better signal-to-noise ratio and generates its low distortion predominantly in the second harmonic. The device includes a minus two volt regulator to ensure low power dissipation and consequent low warm-up drift.
$5.95
PadBoard - Double Sided, Plated Holes, 3.94” x 3.15”, Mounting Holes
The PadBoard-2 prototyping circuit board has a general purpose pad-per-hole pattern which is good for analog and digital use. It is a double-sided board with plated holes, which allows components to be soldered to either side of the board. A square pad is provided every 5th hole, which makes it easy to align components on the top and bottom of the board. Features
  • Pad-per-hole prototyping board with plated-thru holes. A square pad every 5th hole makes it easy to align components on top and bottom.
  • Double-sided high-quality FR4 glass-epoxy circuit board with plated holes. Components can be soldered to either side.
  • 1oz/ft2 copper with an anti-tarnish coating for easy soldering. Lead free and RoHS compatible.
  • 31 x 39 holes, 0.037" holes are drilled on 0.1" (2.54mm) centers. Four 0.125” mounting holes.
  • Size2 = 100 x 80mm (3.94 x 3.15in), 1/16" thick (1.6mm)
$5.95
Switch - Carling, Mini Toggle, DPDT, 3 Position, Solder Lugs, Flatted
Genuine Carling DPDT 3-position mini toggle switch with solder lugs. These switches feature a flattened actuator.
  • 0.354" bushing length
  • 3-Position
  • ¼" chassis hole diameter
  • DPDT ( Double Pole/ Double Throw) switch
  • Solder Lugs
Starting at $6.45
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
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
Wrench - Befaco, Bananut Driver
Custom wrench tool for Bananuts. The two pegs slot into the notches on the Bananuts for an easy installation. Note: This wrench is only compatible with Befaco Bananuts
$6.50
Switch - Carling, Mini Toggle, DPDT, 2 Position, Solder Lugs, Flatted
Carling mini-toggle switch, DPDT, ideal for phase switching, coil-tapping, series/parallel pickup switching in guitars. This switch features a flattened actuator.
  • 0.354" bushing length
  • 2 Position On-On
  • ¼" mounting hole diameter
  • Double pole/Double throw (DPDT)
$6.55
Integrated Circuit - AS571D, Compandor, Alfa, SOIC-16
The AS571D is Alfa’s version of the NE571 or SA571 in an SOIC package. AS571 is a versatile low cost dual gain control circuit in which either channel may be used as a dynamic range compressor or expandor. Each channel has a full-wave rectifier to detect the average value of the signal, a linearized temperature-compensated variable gain cell, and an operational amplifier. AS571 is well suited for use in VCA blocks, noise reduction systems, compandors/expanders ,etc. Features
  • Complete compressor and expandor
  • Temperature compensated
  • Channel separation >86 dB
  • Greater than 110 dB dynamic range
  • Levels adjustable with external components
  • Distortion may be trimmed out

Applications
  • VCA
  • High level limiter
  • Low level expandor − noise gate
  • Dynamic filters
  • Dynamic noise reduction systems
$6.95
Key Contacts - Korg, Rubber, for Keyboards
For N364 and X5, 5 are required. for N264, 2 are needed. May be cut. Sold individually. These are also used in the Kurzweil MK (MARK)-Series of electronic pianos.
Starting at $6.95
Wire - 22 AWG Stranded Core, PVC, 300V, 50 Foot Roll
Colors Available:
22 AWG stranded hook-up wire on a 50 foot roll. This wire is smaller than our other wire options which makes it perfect for tight spaces like effects pedal and other small electronic projects. Strands are tinned individually. See photo for detail.
$7.50
Transistor - OC46, Germanium, SO-2 glass case, PNP
OC46 PNP germanium transistors. The OC46 is a popular PNP for fuzz pedals and boost effects. It can be found in vintage electronics and modern fuzz pedals. This transistor is in a black glass SO-2 package with long leads commonly found on germanium transistors.
$7.50
Resistor Kit - ¼ Watt, Carbon Film, 5% tolerance, 5 of each value
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 Resistance Values (5 each) 100 470 1K 2.7K 4.7K 8.2K 10K 22K 33K 47K 100K 150K 220K 470K 560K 1M
$7.68
package of 80
Integrated Circuit - AS3340A, VCO, Alfa, 16-Pin Dip
The AS3340A is Alfa’s version of the CEM3340 IC. The AS3340A is a completely self-contained, precision voltage controlled oscillator, featuring both exponential and linear control scales and up to four buffered output waveforms: triangle, sawtooth, square, and pulse with voltage controllable pulse width. Full temperature compensation makes these VCOs extremely stable, and eliminates the need for a temperature compensation resistor. The highly accurate exponential and linear control inputs are virtual ground summing nodes, allowing multiple control voltages to be mixed within the device itself.
Also included is provision for hard and soft synchronization of the frequency, and an output for easy adjustment of high frequency tracking. Special care in the design ensures oscillation start-up under any power-on sequence and supply conditions.
An on-chip 7.4 volt Zener diode allows the device to operate off ±15 volt supplies, as well as +12, -5 volt supplies.
$7.95
Op-Amp - AS301AH, Alfa, Single, TO5-8 case
The AS301AH is Alfa’s version of the LM301A in an 8 pin TO5 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.
$7.95
Wire - Bus, 100 foot Spool, tinned copper
Solid tinned copper bus wire. 105°C temperature rating, 600V.
Starting at $7.95