Synth & Eurorack Parts / DIY

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.

2N1303 PNP germanium transistors. The 2N1303 is a popular PNP for fuzz pedals and other effects. This transistor is in a TO-5 package with long leads commonly found on germanium transistors.

The 2N3704 is a general purpose silicon NPN transistor in a TO-92 case. The 2N3704 is primarily intended for general purpose amplification and switching applications.

The BC557 is a silicon general purpose PNP transistor in a TO-92 package. The BC557’s typical applications include signal processing, amplification, and switching.

Carling mini-toggle switch, SPDT. This switch features a flattened actuator.

• 0.354" bushing length
• 2-Position On/On
• ¼" mounting hole diameter
• Single pole/Double throw (SPDT)
• Solder Lugs

Small PCB adapter boards to convert PCB mount 9mm right angle pots to wired panel mount pots. These adapters are great for tight builds allowing for more densely populated panels than 16mm options. They’re also a great way to incorporate sealed potentiometers into builds where larger sized options would be cost prohibitive.

PCB for converting SMD TQFP-64 packages to through hole DIP-64 footprints with 0.9" width (wide DIP). Solder the device to this PCB then attach pin headers (sold seperately) to connect to through hole footprints on PCBs, breadboards and IC sockets.

BC148C NPN transistor in a rare Mullard Lockfit package. The BC148C is the equivalent of a BC108C but in the Lockfit package rather than a TO-18. The BC148C was used in a variety of audio and radio equipment and works well for fuzz and other effects.

The BC558 is a silicon general purpose PNP transistor in a TO-92 package. The BC558’s typical applications include signal processing, amplification, and switching.

The shrink ratio on this tubing is 2 to 1, it is fungus resistant and non-corrosive. It is recommended for tightly sealing connectors, terminals, wire splices, and tool handles. It may be shrunk with heat guns, oven, etc. Comes in 6 inch lengths, quantity of 23.

High-quality USA made knobs from Rogan Corp. These large, puck-shaped, 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 D-shafts.

• Height: 0.45 in.
• Diameter: 0.84 in
• Fits 6mm D Shafts
• Indicator on round side of D-shaft

A variety of different sizes are available from the PT Series.

High-quality USA made knobs from Rogan Corp. These large knobs feature a metal insert, spun aluminum inlay, and a skirt with an infilled arrow indicator. The RB-67 Series from Rogan is popularly used on Buchla 200 Series modular synthesizers and can be found on many contemporary eurorack synthesizers.

• Height: 1.02 in.
• Diameter: 1.52 in.
• Fits ¼" shaft with set screw

A variety of sizes and colors are available from the RB-67 Series. See the links below for the full selection of knobs from this series. P-K770-X Small P-K770S-X Small Skirted P-K771S-X Medium Skirted P-K772S-B Large Skirted

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)

The BA4560, is a dual operational amplifiers which achieves approximately twice the high output current of the BA4558, as well as featuring a higher slew rate of 4V / µs, a gain band width of 10MHz, and an improved frequency characteristic. 8-pin DIP package.

CD4047B consists of a gatable astable multivibrator with logic techniques incorporated to permit positive or negative edge-triggered monostable multivibrator action with retriggering and external counting options. Inputs include +TRIGGER, -TRIGGER, ASTABLE, ASTABLE\, RETRIGGER, and EXTERNAL RESET. Buffered outputs are Q\, Q and OSCILLATOR. In all modes of operation, and external capacitor must be connected between C-Timing and RC-Common terminal, and an external resistor must be connected between the R-Timing and RC-Common terminals. Astable operation is enabled by a high level on the STABLE input or a low level on the ASTABLE\ input, or both. The period of the square wave at the Q and Q\ Outputs in this mode off operation is a function of the external components employed. "True" input pulses on the ASTABLE input or "Complement" pulses on the ASTABLE\ input allow the circuit to be used as a gatable multivibrator.

The CD4053B analog multiplexers are digitally-controlled analog switches having low ON impedance and very low OFF leakage current.

PCB for converting SMD SSOP-20 packages to through hole DIP-20 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.

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.

CD4027B is a single monolithic chip integrated circuit containing two identical complementary-symmetry J-K flip flops. Each flip-flop has provisions for individual J, K, Set, Reset, and Clock input signals. Buffered Q and Q signals are provided as outputs. This input-output arrangement provides for compatible operation with the CD4013B dual D-type flip-flop. The CD4027B is useful in performing control, register, and toggle functions. Logic levels present at the J and K inputs along with internal self-steering control the state of each flip-flop; changes in the flip-flop state are synchronous with the positive-going transition of the clock pulse.

The CD4066B device is a quad bilateral switch intended for the transmission or multiplexing of analog or digital signals. It is pin-for-pin compatible with the CD4016B device, but exhibits a much lower on-state resistance. In addition, the on-state resistance is relatively constant over the full signal-input range. The CD4066B device consists of four bilateral switches, each with independent controls. Both the p and the n devices in a given switch are biased on or off simultaneously by the control signal. As shown in Figure 17, the well of the n-channel device on each switch is tied to either the input (when the switch is on) or to VSS (when the switch is off).

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.

2N321 PNP germanium transistors. The 2N321 is a popular PNP for fuzz pedals and other effects. This transistor is in a TO-5 package with long leads commonly found on germanium transistors.

LM311 single comparator IC in an 8-pin DIP package. The LM311 device is a single high-speed voltage comparator. These devices are designed to operate from a wide range of power supply voltages, including ±15-V supplies for operational amplifiers and 5-V supplies for logic systems. The output levels are compatible with most TTL and MOS circuits. These comparators are capable of driving lamps or relays and switching voltages up to 50 V at 50 mA. All inputs and outputs can be isolated from system ground. The outputs can drive loads referenced to ground, VCC+ or VCC−. Offset balancing and strobe capabilities are available, and the outputs can be wire-OR connected.

The Lehle Transformer HZ is the ideal component to avoid hum loops or to balance and unbalance signals without degrading the sound of high impedance signal sources.