Toronto, Ontario, Canada

Delta-sigma DACs and CODECs

In the first part of this three-part series on DACs and bit counts, I described what it means to have a certain number of bits in terms of voltage accuracy and signal to noise ratio. Then in the second part I described some ways that DACs are built, basically out of resistors and switches. There are a lot of details along the way, but the big picture in both articles is that you can't really have a DAC with more than about 16 bits. Past that point, the cost of actually building it increases rapidly and the possible benefit drops away. For control voltage generation, the level of absolute voltage accuracy is often closer to 12 bits. READ MORE

DACs, resistors, and switches

In the previous entry, on DACs and bit count, I talked about the relation between how many bits a DAC has and how accurate its voltage can possibly be, both at the limits of modern technology (liquid-helium-cooled superconducting Josephson references) and in the abstract for theoretically perfect DACs. In this entry, let's look at the details of some more realistic DAC designs that would actually be used in Eurorack modules. READ MORE

DACs and bit count

The connections between modules in a modular synthesizer are made with analog voltages, both for audio and control signals. Many popular modules use digital processing internally, but they need to convert to and from analog voltages to communicate with other modules. Even a non-modular synth that might use entirely digital signalling internally, has to convert those signals to analog at some point in order to drive a speaker. So digital to analog converters (DACs), and the corresponding analog to digital converters (ADCs), are important in synthesizers and people say and think many things about them, not all of which are correct. READ MORE

Inrush current and measuring it

Sometimes I get questions about what the questioners call the "inrush current" of North Coast Synthesis modules. I think people who ask about this are usually hoping I can give them a single number in answer - "The inrush current of X module is Y number of milliamps" - and then they'll be able to compare it against some specification of a power supply and know whether it'll be safe to connect that module to that power supply, or compare it against other modules to decide which one is better and which one to buy. Maybe they think it would make sense to compile a spreadsheet or start a "List of module inrush currents 2023" forum thread. Unfortunately, inrush current isn't as simple as that. No simple answers are possible, and attempting to reduce the matter to a bare number per module is counterproductive. Let's look at the issues in more detail. READ MORE

Dispensations

The MSK 015 Quad VCA is an important milestone for North Coast Synthesis because it's the last missing piece for building a complete synthesizer: with this module and the rest of the North Coast line, it's possible to make music without needing any modules from other manufacturers. Partly to celebrate the release, and partly because I needed some better audio demos to post in the storefront, I spent most of June writing and recording music with my own modules. READ MORE

What's your soldering success rate?

Soldering mistakes are by far the most common thing to go wrong in do-it-yourself electronics. It seems like I spend most of my tech-support time gently urging customers with failed kit builds to re-check their soldering, and when I have problems in my own builds, those also usually turn out to be soldering-related. Everybody, myself included, tends to think of failed components as a likely cause of problems, and we spend a lot of time doing differential diagnosis to figure out which components might have failed; but then once the problem is narrowed down to a single component, the actual issue usually turns out to be a bad solder joint on that component, not the component itself. The real point of the debugging is often just to figure out which solder joints to look at more closely. READ MORE

MSK 015 release

FOR IMMEDIATE RELEASE READ MORE

More about DC coupling

Operational amplifiers ("op amps") are popular analog building blocks, especially in synthesizer electronics, because it's easy to analyse what they do to voltages. The first rule of op amp analysis is that (in negative feedback configurations, and when this is possible) the amplifier moves its output voltage in order to make its input voltages equal. That is useful in building circuits to manipulate DC voltages. READ MORE

Electrolytics for AC coupling

There are some special considerations relevant to electrolytic capacitors in AC coupling applications, and that's the topic of this second part of the series on AC and DC coupling. Low impedances and low cutoff frequencies require high capacitance values, and electrolytic capacitors may be the only practical way, or at least a very appealing way, to achieve those values. READ MORE

AC and DC coupling

I overheard somebody asking about the plusses and minuses of DC coupling, and AC coupling capacitors, and being told to read the detailed explanation of such things I'd written on this Web site. I was flattered to think the speaker found my article helpful, especially because I'd never actually written one about that! READ MORE

New Gracious Host firmware ideas

The MSK 014 Gracious Host can load alternate firmware from me or third parties, just by reading it off an inserted USB flash drive. Although I conceived this module as primarily a MIDI interface with hosting capability, it's really a general purpose hardware platform with Eurorack control voltage input and output, and it could do many other things beyond hosting USB-MIDI controllers. Here are some ideas I've been looking at for possible alternate firmware or features to add to updated versions of the standard firmware. READ MORE

It's the sales, silly!

The industry has lost several important modular manufacturers in the last year or two, and there's been some talk about why. I obviously don't know all the details of what happened in any company except my own, and at least one of the biggest examples on everybody's mind is pretty clearly an exceptional case, with the founder making a career change for personal reasons not directly related to the general business climate. But I recently heard a claim made that it doesn't matter to the health of the industry whether individuals buy Eurorack modules this year because the "real" problem killing manufacturers is supply-chain disruption. I want to speak against that. READ MORE

All about levels

There's a lot of confusion in the modular synth world about signal levels. We often don't have a clear idea of what can plug into what, even within the modular rack; let alone when it comes to interfacing with other equipment. I've been working on guitar pedal designs recently and connections between those and modular often raise level-conversion issues. A whole lot of unnecessary "external input" and "external output" modules are sold to newbie wigglers who've been told that modular and other-equipment levels are fundamentally different and need to be converted - but although usually unnecessary in most modular racks, such modules do also serve useful purposes in certain contexts. What is really going on with signal levels? In this article I'll go through some of the concepts used for describing signal levels accurately, then talk about some of the levels commonly seen in audio work. READ MORE

Power cycling and extra switches

As human beings we're quite familiar with the idea of things wearing out with use. If you hang a piece of clothing up in a closet and seldom wear it, then unless something happens like moths eating it, you can take it out years later and it'll still be good - whereas if you're wearing it every single day and washing it frequently, it may show visible damage and no longer be as good after just a few weeks. Many things in our world are like that, and we naturally expect electronic equipment to be included. Many synth users have, consciously or unconsciously, the idea that for each module there's an hour meter ticking away somewhere, like a car's odometer, measuring the time until the module will die or need servicing, in terms of the number of hours power is applied. READ MORE

Module wear and aging

There's a lot of confusion and worry over the idea that modules wear out or age over time, and what can be done to prevent or deal with that process. It's a part of human life that many things including our own bodies do change with use and time; and if you've spent a lot of money on musical instruments, then it's reasonable you might be worried about wearing them out or hurting them. Electronic equipment and the physics behind it are mysterious to many people. We know that invisible things like "voltage" can possibly damage electronics; it's not obvious what those invisible things are, or where they come from or how to protect the equipment; we have some idea that things in general can wear out, but may be unsure of exactly how that applies to electronics; and so modular users, and especially beginners, end up with a lot of confusion, worry, and misconceptions about wear and aging of equipment. READ MORE

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