3340 Analog VCO - Synthesizer Electrosmith - Free user manual and instructions

Product Type	Analog Voltage Controlled Oscillator (VCO) Module
Brand	Electrosmith
Model	3340 Analog VCO
Form Factor	Eurorack compatible, 8 HP wide
Dimensions	128 mm (depth) x 40 mm (front panel height) x 40 mm (width)
Weight	120 g
Power Supply	+12V DC (100 mA), -12V DC (60 mA) via Eurorack ribbon cable
Frequency Range	0.01 Hz to 20 kHz (typical, adjustable via range switch)
Control Voltage Range	0V to +10V, 1V/octave scaling
Output Waveforms	Sawtooth, Triangle, Square, Sine (simultaneous outputs)
Main Functions	Voltage-controlled frequency, pulse width modulation, sync input, linear/exponential FM
Panel Controls	Frequency coarse and fine knobs, PWM knob, FM amount knob, range switch
Inputs	1V/oct CV input, FM input (linear and exponential), PWM CV input, Sync input
Outputs	Saw, Triangle, Square, Sine (buffered, 10Vpp typical)
Connector	16-pin Eurorack power header, 3.5mm jack inputs/outputs
Maintenance & Cleaning	Use dry cloth; avoid liquids; check calibration annually if drift suspected.
Safety	Do not reverse power cable; disconnect power before module installation/removal.
Spare Parts & Repairability	Replaceable potentiometers, IC socket for CEM3340 chip; contact support for service.
General Info	Classic 3340 VCO core; temperature compensated; suitable for analog synthesis.

Frequently Asked Questions - 3340 Analog VCO Electrosmith

How do I calibrate the 3340 Analog VCO?

Calibration involves adjusting the tuning trimmers on the PCB: first set the coarse frequency to mid, apply 1V to the 1V/oct input, and adjust the scale trimmer so that the frequency changes exactly one octave. Repeat with a higher voltage for fine-tuning.

What power supply do I need for the 3340 Analog VCO?

The module requires a standard Eurorack power supply: +12V (100 mA) and -12V (60 mA). It uses a 16-pin ribbon cable with red stripe indicating negative rail.

Which waveforms are available simultaneously?

All four waveforms (sawtooth, triangle, square, sine) are available simultaneously on separate outputs. Each output is buffered and can drive multiple inputs.

How do I connect the module to my Eurorack case?

Ensure power is off. Connect the 16-pin ribbon cable to the module with the red stripe aligned to the negative rail (-12V) as marked on the PCB. Then plug the other end into the case's power distribution board.

Can I use this VCO with 5V control voltages?

The 1V/oct input expects 0V to +10V typically, with 1V per octave. It accepts lower voltages but the pitch response may not be accurate below 1V.

What is the frequency range of the 3340 VCO?

The frequency range is approximately 0.01 Hz to 20 kHz, adjustable via the range switch (low/high). Coarse and fine controls allow precise tuning.

How do I use the pulse width modulation (PWM) input?

Connect a control voltage (e.g., from an LFO or envelope) to the PWM CV input. Adjust the PWM knob to set the base pulse width; the CV will modulate it. Works on the square wave output.

What does the sync input do?

The sync input resets the oscillator waveform to its starting phase. It is useful for locking the oscillator frequency to another source (e.g., another VCO) for hard sync effects.

Is the 3340 VCO temperature stable?

Yes, the module uses a temperature-compensated design based on the CEM3340 chip to minimize frequency drift due to temperature changes.

How do I clean the module?

Use a dry, lint-free cloth to wipe the front panel. Avoid using liquids, cleaners, or compressed air near jacks or controls. For deeper cleaning, consult the manual.

USER MANUAL 3340 Analog VCO Electrosmith

Contents

Description 3

Installation 4

Specifications 4

Diagram 5

Functional Overview 6

1. Coarse Frequency Knob 6

2. Fine Frequency Knob 6

3. V/Oct 6

4. Linear FM Knob 6

5. Linear FM 6

6. Exponential FM Knob ..... 6

7. Exponential FM 6

8. PWM Knob 7

9. PWM 7

10. Sync Toggle 7

11. Sync 7

Example Hard Sync 8

Example Falling Edge Soft Sync 9

Example Rising Edge Soft Sync 10

1. Sine Wave Output 11

2. Triangle Wave Output 12

3. Sawtooth Wave Output 13

4. Square Wave Output. 14

Description

The Electrosmith 3340 VCO is an all analog, voltage controlled waveform generator that uses a reissue of the legendary Curtis CEM3340 IC. Many believe this chip to be the greatest sounding analog oscillator of all time. Simultaneous outputs of sine, triangle, sawtooth, and square waves are available along with linear/exponential FM, hard/soft sync, and PWM capabilities.

Volt per octave tracking covers a huge 10+ octaves and is extremely stable across all temperatures. Snag a piece of history with the Electrosmith 3340 VCO.

• CEM3340 based architecture
• Analog waveform generator
- 10+ octave range with accurate 1V/Oct tracking throughout
• Linear and exponential FM
- Hard and soft sync
- PWM control

Check out a list of famous synths that use the 3340 IC here: https://en.wikipedia.org/wiki/CEM_and_SSM_chips_in_synthesizers

Installation

To install, locate 6 HP of space in your Eurorack case and confirm the positive 12 volts and negative 12 volts sides of the power distribution lines. Plug the connector into the power distribution board of your case, keeping in mind that the red band corresponds to negative 12 volts. In most systems, the negative 12 volt supply line is at the bottom. The power cable should be connected to the module with the red band facing the front of the module.

Specifications

• Size: 6 HP
• Depth 31 mm
• Current Consumption:
• +12V: 38mA
• -12V: 28mA

Diagram

Functional Overview

1. Coarse Frequency Knob

Controls the frequency of the output waveforms. Offers a wide frequency range: 3.45 Hz to 34.5kHz.

2. Fine Frequency Knob

Controls the frequency of the output waveforms. Offers a smaller frequency range: 7 semitones up or down from center.

3. V/Oct

Volt per octave control voltage input.

Input range: -7.5V to +12V.

V/Oct trimpots on submodule allows for tuning and fine adjustments.

4. Linear FM Knob

Acts as an attenuator for incoming CV at the Linear FM input.

5. Linear FM

Control voltage input for linear frequency modulation of waveforms.

Input range: -10V to +10V.

6. Exponential FM Knob

Acts as an attenuator for incoming CV at the Exponential FM input.

7. Exponential FM

Control voltage input for exponential frequency modulation of waveforms.

Input range: -10V to +10V.

8. PWM Knob

Controls the duty cycle of the square wave.

Allows for duty cycle control between 15% and 90%.

9. PWM

Control voltage input for the duty cycle of the square wave.

Input range: -12V to +12V.

Allows for duty cycle control between 1% and 98%.

10. Sync Toggle

Allows for selection between soft or hard sync.

11. Sync

Trigger input for frequency synchronization of output waveform.

Hard sync triggers on a falling edge of at least 3V (unipolar or bipolar) and causes output waveform phase to reset to 0^ .

Soft sync input triggers on both rising or falling edges of at least 0.6V. Soft sync does not cause complete phase reset to 0^ , but rather phase reversal.

On either edge of a soft sync input trigger, the output waveform will mirror itself in time with respect to the trigger edge.

Example Hard Sync

Example Falling Edge Soft Sync

Example Rising Edge Soft Sync

12. Sine Wave Output

Output for sine wave. Waveform is bipolar with 11Vpp amplitude.

13. Triangle Wave Output

Output for triangle wave. Waveform is bipolar with 10Vpp amplitude.

14. Sawtooth Wave Output

Output for sawtooth wave. Waveform is bipolar with 10Vpp amplitude.

15. Square Wave Output.

Output for square wave. Waveform is bipolar with 11Vpp amplitude.