# 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.

#### Alfa

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 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
Integrated Circuit - AS3109D, VCF, Alfa, SOIC-16
The AS3109 is Alfa’s version of the Roland IR3109 VCF in an SOIC package. The AS3109 is a high performance voltage controlled four-pole filter. 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 a range greater than 15 octaves with little control voltage feedthrough. AS3109 features high input impedance buffers. Features
• Voltage controllable range – 15 octaves
• Accurate exponential frequency scale
• High input impedance buffers
• Wide transconductance range
• Low input offset voltage
• Low control voltage feedthrough - 45 dB typical

Applications
• For electronic music
$7.95 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
Integrated Circuit - AS3372E, Synth Voice, Alfa, 24 Pin DIP
The AS3372E is Alfa’s take on the CEM3372 µP Controllable Signal Processor in a DIP-24 package. The AS3372E features an additional two VCA’s so an adapter board is required when using as a replacement for the CEM version. The CEM version was used in multiple classic synths, including the Oberheim Matrix 12, Oberheim Xpander, Sequential Prophet T8, Sequential Prophet 600, Akai AX80, Rhodes Chroma Polaris, and more.
$10.95 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$3.99
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 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.$6.50
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 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$5.95
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 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
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
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