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A Voltage Controlled Amplifier (VCA) in a modular synthesizer is used to control the amplitude, or loudness, of an audio signal. It works by accepting a control voltage (CV) input, which is used to control the gain (amplification) of the audio signal. The output of the VCA is the amplified audio signal.

Linear and logarithmic responses refer to the way in which the VCA responds to the control voltage. A linear response means that the gain of the audio signal increases or decreases at a constant rate as the control voltage increases or decreases. A logarithmic response means that the gain of the audio signal increases or decreases at a non-constant rate as the control voltage increases or decreases. Logarithmic responses are often used in VCAs because they mimic the way the human ear perceives loudness changes.

Several types of VCAs can be used in a modular synthesizer, each with its own unique features and characteristics. Here are the main types of VCAs in order of their

This blog post will cover everything you need to know before buying your first Eurorack modular synthesizer, choosing your first modules, and building your system from there. It will also cover some common mistakes and how to avoid them.

Discover why spring reverb eurorack modules are an excellent addition to any modular synthesizer setup. Please read our detailed guide and give your synthesizer some new life!

Until recently, it never occurred to me to use a ring modulator as a VCA. I typically have sizable systems with dedicated VCAs. But if I think about it, why wouldn’t it work? A ring modulator multiplies the X input signal by the Y or carrier signal. Essentially, this is how a VCA works, but the ring mod does not have a CV or gain control. Those with a small system already know this trick and save themselves space in their rack.

But what about a vacuum tube ring modulator? It’s a very different design than a solid state ring mod, even though they both perform a multiplication of the X and Y signals. The module uses tubes and transformers in a 1930s circuit design originally purposed for sending multiple telephone calls down one telephone line.

To test the properties of the Vacuum Tube Ring Modulator, I compared the Dual Lin/Log VCA

Introduction

When I first began my modular synth journey, I had no clue what I was doing. Now mind you, it wasn’t because I was unfamiliar with synthesis. In fact, I was well-versed in sound design. My first synthesizers were the Access Virus TI2 and Roland V-Synth—neither were “simple” synths. Instead, both share complex menus, matrix routing, and effects engines, to name a few. To this day, I spend hours programming the Virus and V-Synth, as well as other complex synths, for hours until I get a “good” patch. So why did I have such a hard time at the beginning of modular synthesis?

MISTAKE #1: Buying a case that I would soon outgrow.

I underestimated how quickly my system would grow. At the time, I looked at my budget and decided on a Doepfer low-cost wood case. It had a total of 252HP or 3 rows of 84HP. For some readers, that may sound like a sizable case, and it is! With proper planning, I would be able to obtain all of the modules I needed.

Overview

At first, providing power to a Eurorack modular synthesizer system might seem daunting and complicated. But in reality, there are only a few components involved in powering a Eurorack case. First, the power supply converts wall power to low voltages that the modules can use. The second is a bus board for distributing power from the power supply to each module in the case. The last part of the chain is a ribbon cable connecting the bus board to the modules. This article will go through each of these in detail and explain the options available.

Power Supply
The power supply is the first component powering a Eurorack modular system. The power supply can be built into the case internally or be an external power supply or power "brick" like a laptop uses. In both cases, the power supply's output connects to one or more bus boards. Power is then supplied to the individual modules from a bus board through multiple connectors for connecting individual