2018 Note: Obsolete! This chip has been superseded by the TAPLFO 3 The new chip adds several features, has additional waveforms and improved resolution, and also no longer requires a crystal. It’s an improvement in pretty much every way! Head over and check out the data sheet. This simple Tap Tempo LFO is based on the […]
Author: Tom Wiltshire
A clone of a classic using my PIC code by J-P Desrochers Jean-Pierre Desrochers wanted to copy the response of the Moog 911 envelope generator using more modern technology. He asked me if it would be possible to tweak the response of my PIC envelope generator to do this, and I told him that it […]
A pure white audio noise generator using an 8 pin PIC 12F675 This pages describes a simple digital noise source that produces pure white noise over the whole audio band – out to more than 40Khz, in fact. With filtering, you can derive pink noise and other colours. The circuit diagram included below was developed […]
The linear feedback shift register is one of the most useful techniques for generating psuedo-random numbers. I’ve used this method for creating noise generators and as an element in the random modulation generators I spent a long time developing for my Protowave synth. If you’re not really clear how an LFSR works, have a look […]
A CEM 3312 / SSM 2056 clone using cheap PIC microprocessors This page describes a cheap clone of the CEM 3312 and SSM 2056 voltage-controlled envelope generator chips. Both of these chips include voltage control of A, D, S and R, but both include other inputs too. The CEM 3312 chip has a input which […]
The code follows the same general principles as the LFO, in that it divides into two sections. The main code loop polls each of the A/D channels in turn (one channel per time round the loop) and then does something with the value that was read. The values are not used directly, but instead are […]
Like my SSM2044 page, this page is a look at how various synths implemented the CEM3320 filter, with the datasheet design as a reference standard. Whereas the SSM2044 is a dedicated lowpass filter, the CEM3320 is just a set of filter building blocks. In this respect, it is more like the earlier SSM2040. The CEM […]
This page is a look at how various synths implemented the SSM2044 filter, with the datasheet design as a reference standard. I’ve redrawn all the schematics to make comparisons very easy. First, the datasheet design. The datasheet suggests using the two differential inputs (+audio and -audio) as individual oscillator inputs for a two-oscillator synth […]
This page is intended to be a look at some of the key technical aspects of the B3 Hammond organ that contribute to the “Hammond sound”. My personal slant is towards copying this sound using other technology. Perhaps one day I’ll build a “clonewheel” organ, but then again, Clavia might have nailed it! Still, building […]
This voltage-controlled LFO is based on the PIC 16F684, which is a pretty basic chip. Nonetheless, this LFO has more features than your average LFO. For a start, it can produce 7 basic waveforms, and also includes a noise source. It can also morph its waveforms under CV control, well beyond basic PWM. There is […]