North Coast Synthesis Ltd.

Q: The analog synth circuit I'm building calls in the schematic for ferrite beads on the power rails, but it doesn't give any further information. What kind of beads should I use? READ MORE

Testing and adjustment are often underestimated in DIY circuit design. It's all very well to choose exactly the right topology and component values for a circuit; but even with a perfect design on paper or in the simulator, how does one get from there to a physical construction that correctly realizes that design? READ MORE

If you've been following the North Coast Synthesis email newsletter you'll probably know that I've had ongoing quality problems with the knobs I use in most of my products.  The main issue is with the setscrews used to hold the knob onto a shaft:  in many instances, the threads are stripped, or so weak that they immediately become stripped when tightened, so that it's not possible to attach the knob securely.  The problem becomes clear as soon as the knob is installed, so although it is not good in the case of modules I sell assembled, at least with those I can recognize that the knob is bad, replace it, and be sure of shipping a good one to the customer in the finished product.  It's more serious with knobs that ship unassembled in my Eurorack SDIY kits, because then it may be the customer who discovers the problem. READ MORE

When I draw the first draft of a new circuit design, I'll usually work out the topology of the circuit first, and leave out any component values unless it's instantly obvious what they need to be. The topology means which components exist and how they connect to each other, and it's a separate step from deciding their values. I'll come back and fill in the missing values later. There's interaction between these two steps, and I may well modify the topology in later drafts of the schematic as the requirements become clearer, but there's still a definite progression from working on the topology to specifying the component values. READ MORE

I've written before about the music of Dwarf Fortress - not just music to listen to while playing (which is the main thing you can find if you search the Web for this topic) but the music described in-game. The game simulates a procedurally-generated fantasy world full of different species of intelligent creatures (dwarves, elves, humans, etc.); game characters sometimes are described as playing music; and for each simulated culture, the game software generates a description of that culture's music. READ MORE

In the last four articles (start here) I've gone through a lot of the technicalities of flux: what's in it, how it works, and how to make your own. Now, let's bring it together and try out all these experimental fluxes. READ MORE

My two previous DIY solder flux formulations are both designed to be cleaned away after use, with alcohol or with water. In both cases the cleaning is more or less necessary: traditional resin leaves a sticky residue that will attract water, and the citric-acid water-wash flux remains active and corrosive at room temperature, so it will damage boards if left in place. But there are many solder joints, such as those involving stranded wire or liquid-trapping components like potentiometers, that cannot or should not be cleaned after soldering. Those mandate a no-clean flux. READ MORE

The current trends in electronics are to smaller and smaller surface-mount components; lead-free solder alloys and a diversity of surface platings; higher temperatures which mean soldering must be faster to avoid component damage; and avoiding toxic or environmentally-damaging cleaning solvents. All these trends make traditional solder fluxes, like the one in my last article, less effective or appealing.  In this article, let's look at water-wash fluxes, which address some of the issues of the older style. READ MORE

For most of the history of electronics, rosin has been the main ingredient in electronic solder flux. Anybody who learned electronics Back In The Day™ will be familiar with the piney smell of solder smoke. In this second article of the series on flux, we'll look at how to make your own traditional rosin or resin flux. For some background on the chemistry and physics of how flux works, see Part 1: "What is flux?" READ MORE

The details of soldering are always popular discussion topics in synth DIY fora: what kind of soldering iron should I use for building something like a Coiler VCF kit? What temperature? What kind of solder? And that last topic, in practice, is often really a discussion of what flux to use, because flux is usually built into the solder and the differences among fluxes are often the most important differences among solder products. There's been a lot written on recommendations for what kind of flux to use in different SDIY applications, but in this entry I'm going to take a different perspective on flux: the chemistry and physics of the flux itself. What is this stuff that we use every day, and how does it work? In planned future entries, I'll go through flux formulations you can make at home, videos of my own experiments with homemade flux, and so on. READ MORE

In the last entry I described the electrical requirements of LEDs and how to drive them in the context of analog circuitry. When you want to indicate information with the brightness level of a single LED, as in my Transistor ADSR where the LED directly shows the progress of the envelope, it's appropriate to use an analog driver which provides current proportional to the desired light output. But another common use of LEDs is many of them at once, to display information like the shift direction in an octave switch, or even numeric digits in a 7-segment display. For those kinds of applications, it's appropriate to use a digital style of driver circuit. READ MORE

Light-emitting diodes! They're all over our electronic equipment; but what are they all about, really? The underlying concepts are simple, but there are a lot of frequently-asked questions that show there's confusion among hobbyists about how LEDs work and how to apply them in circuits. Here are some notes on that. READ MORE

I recently switched to a new cable Internet modem, because the cable company (which provides my home Internet service) assured me that the package that came with the new modem would be cheaper for the same service compared to what I'd been paying with my old modem. And that was true, for Internet service. Except for a minor issue of needing to switch my laptop's wireless connection to use dhclient instead of dhcpcd, the Internet connection worked fine. But I quickly discovered a problem. READ MORE

In this final part to the green modular series I'll talk about environmental and related issues associated with the modular business, going beyond the manufacturing of the modules themselves. We began this series with RoHS and there may be a temptation to end it there as well: if the actual products are free of a short list of toxic chemicals, they're environmentally friendly, right? Someone who really cares about the environmental impact of buying and using modules should be looking at the whole business. READ MORE

In this part of the Green Modular series, I'd like to talk about wood, and toxic waste. Part 1 focused mostly on saving energy; in parts 2 and 3 I wrote about metals, and some of the environmental issues related to metals are caused by their toxicity during waste disposal. But there are also other kinds of toxic substances relevant to synthesizers, and those become important during manufacturing rather than at the end of the product's life. READ MORE