North Coast Synthesis releases all modules like Leapfrog VCF , Fixed Sine Bank, Dual VC Octave Switch and more now as SDIY KIT

North Coast Synthesis releases all modules like Leapfrog VCF , Fixed Sine Bank, Dual VC Octave Switch and more now as SDIY KIT.

Earlier these modules were only in the assembled version, so now you can get them and assemble yourself.

More info here : https://northcoastsynthesis.com

a bit about the modules themselves

MSK 007 Leapfrog VCF 

Not Your Grandmother's Synth Filter (Yet)
There are hundreds of analog synthesizer VCFs, but only a few core designs. You've got your Moog transistor ladder and imitators that use diodes or other substitutes; you've got your two-pole state variable filter, maybe cascaded to get additional poles; and that's about it. Your grandmother was making electronic music with these designs in the 1960s, and not much has happened since. There are a few more options available in digital and semi-digital (such as switched-capacitor) architectures, but most analog designers have given up trying to create really new filters. Instead, they compete on how well they can imitate or clone specific "vintage" filters.

The North Coast Synthesis MSK 007 Leapfrog is new and different, with a sound all its own. The fifth-order "leapfrog" core topology, with five integrators and multiple feedback loops, originates in scientific work more recent than the 1960s and as far as we know never before available in a modular synth VCF. The near-elliptic response curve has an extremely sharp cutoff, with ripple in the passband and nulls in the stopband at frequencies chosen to be musically relevant.

Sweep the cutoff and hear each harmonic pop into existence and wobble around before the next one arrives. Choose a timbre, and the temperature compensated volt per octave tracking will keep it consistent across the frequency range. Change it up with exponential and linear frequency modulation. There's even a built-in VCA, because you can never have too many VCAs.

The MSK 007 is available as a pre-built 16HP Eurorack module or a DIY kit. It's the perfect gift for Grandma or any other electronic musician in your life.

High-quality potentiometers with bushings fastened to the panel for wobble-free operation; conductive plastic for smooth feel; rated for one million operations lifespan (compare to fifteen thousand or less for typical cheap pots)
All-new design, not a clone or imitation of anything else
Ultra-sharp five-pole near-elliptic low-pass response, 61dB / octave at the least steep part of the main cutoff slope, with peaks and nulls at musically relevant frequencies
Built-in VCA switchable to feedback or output modes from the front panel - no jumpers
Temperature compensated V / octave tracking
Through-hole for easy hand construction and maintenance
Connectors between boards, and panel controls mounted on a board - no flying wires
No compromises on build quality: real aluminum panel, not PCB material, with color printing; panel screwed solidly to both the PCBs and the pots and jacks, for maximum ruggedness; nickel and gold plating on the circuit boards; polystyrene integrator capacitors; close-tolerance metal film fixed resistors; multiturn trimmers.
Fully open design - no lock-in

MSK 009 Coiler VCF

A filter with a twist
The Coiler Multi-mode Filter and Rectifier packs an entire nest of sound-shaping features into a single 8HP Eurorack module. It's a two-pole state-variable filter based on a unique integrator design which stores energy in both inductors and capacitors depending on the frequency range. The transition region between the two components, and the saturation characteristics of the traditional OTA-based amplifiers, offer warmth and ever-shifting timbres in the midrange, along with hissing highs and slithering lows. This is a somewhat unpredictable filter.

With simultaneous low-pass, band-pass, and high-pass outputs, the Coiler works well in traditional subtractive patches. But its built-in full-wave rectifier is also great for adding harmonics and distortion in patches from the other coast. When combined with low-pass, the rectifier allows the Coiler to serve as a basic envelope follower, for compression and external-signal patches. It's a lot of bite for the buck, and for the rack space.

MSK 012 Transistor ADSR

Versatility and versimilitude
North Coast's Transistor ADSR is a four stage traditional envelope generator for Eurorack synthesizers. With full control of four stages, it can shape percussion notes like an AR envelope, organ notes like an ASR, but also the complete range of acoustic-style and classic-synth notes which the simplified envelopes in some popular multi-modules just cannot handle. Use it in subtractive patches for amplitude or filter cutoff, or branch out into controlling other functions, like vibrato amount.

At a svelte 6HP and only 33mm deep, the Transistor ADSR can fit in almost any rack. A Schmitt-trigger input allows it to trigger from slowly changing voltage sources, opening the door to special effects like gate delay when the MSK 012 is triggered by another envelope (or another MSK 012). Three timing ranges controlled by a rugged front-panel toggle switch cover a wide range of musical applications, with the fastest settings allowing the envelope to run well into the kilohertz range for audio-rate effects and signal conditioning. The smooth conductive-plastic potentiometers are a tactile joy to play and pay for themselves with increased lifespan.

MSK 008 Dual VC Octave Switch

Master of Melodies
The MSK 008 Voltage-Controlled Octave Switch is a multifunction voltage processor. The module has two channels, each containing a whole-volt quantizer that maps its input to the nearest integer number of volts from -2 to +2; a three-position toggle switch that shifts the quantizer boundaries up or down by a volt; and a precision adder (with optional subtraction function).

If you simply route a pitch CV through one of the unquantized CV1 inputs, it can be a performance control, allowing easy transposition up or down an octave at the flip of a switch. That might be useful for VCOs without their own built-in octave switches. With no input signal, it generates a selectable offset of -1, 0, or +1 volts; feed that into an attenuated exponential FM input somewhere and you get the same tactile control over any other interval transposition you choose.

But the possibilities really open up when you start using more inputs. An LFO into the quantized input gives the effect of flipping the octave switch under CV control, keeping your hands free to wiggle elsewhere. Using the unquantized inputs, which are normalled across the two channels, you can transpose one sequence by another. The CV2 input can add or subtract, selectable during build by a solder jumper on the circuit board; in a default build, CV2 adds on the left channel and subtracts on the right, but do-it-yourselfers can change this selection, or design their own expanders to make it switchable on the fly.

Combining the two channels, with or without other utility modules, allows more complex melody-shifting effects. And it doesn't have to be just for oscillator pitch control. Switching fixed-voltage offsets on filter cutoffs also makes for great drops and timbral shifts. (And try putting the result through a slew limiter!) The default sum and difference configuration allows the module to act as a "mid-side" encoder or decoder. With other patching it can be a flip-flop or a wavefolder.

The MSK 008 is fast enough to work on audio. The quantizer is built from hardware comparators, without a microcontroller, and it can do simple bit-crushing effects across the whole audio spectrum. Each channel can also be a unity mixer for audio, with two regular inputs plus the output of the bit-crusher.

The MSK 008 is available as a pre-built 8HP Eurorack module or a do-it-yourself kit. Prices can be as low as zero (if you download the plans and source all the parts yourself). It has blinky red and green lights on it.