# 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 - AS194DE, Matched Pair, Alfa, SOIC-8, NPN
The AS194DE is a junction isolated ultra well-matched monolithic NPN transistor pair with an
order of magnitude improvement in matching over conventional transistor pairs. Electrical characteristics of these devices such as drift versus initial offset voltage, noise, and the exponential relationship of base-emitter voltage to collector current closely approach those of a theoretical transistor. Extrinsic base and emitter resistances are very low, giving very low noise and operating over a wide current range.
To guarantee long term stability of matching parameters, internal clamp diodes have been added across the emitter-base junction of each transistor. These prevent degradation due to reverse biased emitter current, the most common cause of field failures in matched devices.
$4.50 Transistor - AS3046, Array of 5, Matched Pair, 14-Pin DIP, NPN The AS3046 is Alfa’s version of the CA3046 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$3.99
OTA - AS3080E, Linearizing Diodes, Alfa, 8-Pin DIP
The AS3080E is Alfa’s version of the CA3080 IC. The AS3080E is a gain block which is the operational-transconductance-amplifier (OTA). The AS3080E 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 AS3080E is notable for it’s high slew rate (50V/µs), which makes it especially useful for multiplexer and fast unity-gain voltage followers.
$3.95 OTA - AS3280, Dual, Linearizing Diodes, Alfa, 16-Pin DIP The AS3280 is Alfa’s version of the CA3280 IC. The AS3280 consists of two variable operational amplifiers that are designed to substantially reduce the initial input offset voltage and the offset voltage variation with respect to changes in programming current. This design results in reduced "AGC thump," an objectionable characteristic of many AGC systems. Careful design of critical places of the circuit reduces the amplifier dependence upon thermal and processing variables. The AS3280 has all the generic characteristics of an operational voltage amplifier except that the forward transfer characteristics is best described by transconductance rather than voltage gain, and the output is current, not voltage. The magnitude of the output current is equal to the product of transconductance and the input voltage.$7.95
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 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
Transistor - AS394CH, Matched Pair, Alfa, TO5-8 case, NPN
The AS394CH is a junction isolated ultra well-matched monolithic NPN transistor pair with an order of magnitude improvement in matching over conventional transistor pairs. Electrical characteristics of these devices such as drift versus initial offset voltage, noise, and the exponential relationship of base-emitter voltage to collector current closely approach those of a theoretical transistor. Extrinsic base and emitter resistances are very low, giving very low noise and operating over a wide current range. To guarantee long term stability of matching parameters, internal clamp diodes have been added across the emitter-base junction of each transistor. These prevent degradation due to reverse biased emitter current, the most common cause of field failures in matched devices.
$4.95 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
OTA - LM13700, Dual, Linearizing Diodes and Buffers, 16-Pin DIP
The LM13700 series consists of two current controlled transconductance amplifiers, each with differential inputs and a push-pull output. The two amplifiers share common supplies but otherwise operate independently. 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. High impedance buffers are provided which are especially designed to complement the dynamic range of the amplifiers. The output buffers of the LM13700 differ from those of the LM13600 in that their input bias currents (and thus their output DC levels) are independent of IABC.
$2.35 Transistor - AS194H, Matched Pair, Alfa, TO5-8 case, NPN The AS194H is a junction isolated ultra well-matched monolithic NPN transistor pair with an order of magnitude improvement in matching over conventional transistor pairs. Electrical characteristics of these devices such as drift versus initial offset voltage, noise, and the exponential relationship of base-emitter voltage to collector current closely approach those of a theoretical transistor. Extrinsic base and emitter resistances are very low, giving very low noise and operating over a wide current range. To guarantee long term stability of matching parameters, internal clamp diodes have been added across the emitter-base junction of each transistor. These prevent degradation due to reverse biased emitter current, the most common cause of field failures in matched devices.$4.50
Transistor - AS3046D, Array of 5, Matched Pair, SOIC-14, NPN
The AS3046 is Alfa’s version of the CA3046 IC in an SOIC package. The AS3046D 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 AS3046D is available in a 14-pin SOIC 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
$3.95 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.$4.75
OTA - AS3280D, Dual, Linearizing Diodes, Alfa, SOIC-16
The AS3280 is Alfa’s version of the CA3280 IC in an SOIC package. The AS3280D consists of two variable operational amplifiers that are designed to substantially reduce the initial input offset voltage and the offset voltage variation with respect to changes in programming current. This design results in reduced "AGC thump," an objectionable characteristic of many AGC systems. Careful design of critical places of the circuit reduces the amplifier dependence upon thermal and processing variables.
The AS3280D has all the generic characteristics of an operational voltage amplifier except that the forward transfer characteristics is best described by transconductance rather than voltage gain, and the output is current, not voltage. The magnitude of the output current is equal to the product of transconductance and the input voltage.
$7.95 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
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.
$5.95 Transistor - AS394H, Matched Pair, Alfa, TO5-8 case, NPN The AS394H is a junction isolated ultra well-matched monolithic NPN transistor pair with an order of magnitude improvement in matching over conventional transistor pairs. Electrical characteristics of these devices such as drift versus initial offset voltage, noise, and the exponential relationship of base-emitter voltage to collector current closely approach those of a theoretical transistor. Extrinsic base and emitter resistances are very low, giving very low noise and operating over a wide current range. To guarantee long term stability of matching parameters, internal clamp diodes have been added across the emitter-base junction of each transistor. These prevent degradation due to reverse biased emitter current, the most common cause of field failures in matched devices.$4.25
Op-Amp - OPA2134, Dual, High Performance Audio, 8-Pin DIP
OPA2134 SoundPlus™ Audio dual op-amp with low distortion, low noise and precision. The OPA2134 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 OPA2134 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 OPA2134 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.
$4.95 On Backorder Op-Amp - LM324, Quad, Low-Power, 14-Pin DIP Quad low-power opamps in an 14-pin DIP package. The LM324 offers a 1MHz bandwidth and can be powered from a single supply.$0.18
IC Socket - Dual in-line package, 2.54mm Pitch, 7.62mm Spacing
IC component sockets for dual in-line package chips (DIP, PDIP, DIL, DIPP.) These sockets feature ladder style cases with tinned stamped and formed connections.
Starting at $0.15 Integrated Circuit - SSI2140, Multi-Mode VCF, Sound Semiconductor The SSI2140 is a new-generation voltage controlled filter that provides four highly-configurable variable transconductance cells for a wide variety of pole and mode combinations, and adds significant new features.$6.50
Op-Amp - 4558, Dual high-gain, 8-Pin DIP
Dual Operational Amplifier. The 4558 integrated circuit is a dual high-gain operational amplifier internally compensated and constructed on a single silicon chip using an advanced epitaxial process. Combining the features of the NJM741 with the close parameter matching and tracking of a dual device on a monolithic chip results in unique performance characteristics. Excellent channel separation allows the use of the dual device in single NJM741 operational amplifier applications providing density. It is especially well suited for applications in differential-in, differential-out as well as in potentiometric amplifiers and where gain and phase matched channels are mandatory. Features:
• Operating Voltage (±4V~±18V)
• High Voltage Gain (100dB typ.)
• High Input Resistance (5MΩ typ.)
• Bipolar Technology
$0.75 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
Op-Amp - M5201, Dual, With Switch, 8-Pin DIP
The NJM2120 is a dual operational amplifier of 2-INPUT and 1-OUTPUT with analog switch. The NJM2120 can be used as analog switch under the condition of GV=0dB, as Switch + Amp in order that each gain (A or B) can be adjusted independently. Each amplifier of the NJM2120 has the same electrical characteristics as the NJM4558. The NJM2120 is suitable for audio, video, electrical musical instrument, etc.
$4.50 Integrated Circuit - SSI2164, Quad VCA, Sound Semiconductor The FatKeys™ SSI2164 is perhaps the most flexible VCA available, with four independent channels for lowest cost-per-VCA. The user-selectable mode control allows Class A, AB, or intermediate biasing, and current inputs and outputs provide great design freedom. Ideal for voltage-controlled filters. The SSI2164 is a versatile VCA building block for high-performance audio applications. Four independent channels provide 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 SSI2164 will directly retrofit existing SSM/V2164 positions while offering improvements that include significantly lower overall distortion, on-chip protection against asymmetrical power failure, and a substantial increase of input current handling. The device offers considerable flexibility for a wide range of design goals and applications.$6.95