Too rushed for an amusing title…
Here are a number of ADSR circuits, taken from the fantastic Yusynth website (which I came across after reading StackExchange – Building a synthesizer with no prior experience) – in particular the Archives page.
The circuits are described within PDFs, and I drew up the corresponding schematic and board files in EagleCAD.
The EagleCAD files available on github, although seeing as Micro$oft have just acquired Github, they may not be there for very long… Five minutes later – #movingtogitlab!
The EagleCAD files available on Gitlab: Testkins/ADSR-Waveform-generator
Three ADSR circuits
- Adjustable exponential generator colors synthesizer’s sound – Randall Kirschman – Electronics, July 1980
- Two chip generator shapes sound – Jonathan Jacky – Electronics, September 1980
- Get an ADSR waveform for a few components – Orley Gabor – Electronic Design, August 1980
There is a fourth, from Yusyth – Elektor Synth:
- La carte DUAL ADSR, LFO et noise – ADSR à base de CEM3310 or DUAL ADSR, LFO and noise board – ADSR based on the CEM3310
but it uses a CEM3310
The schematic below is taken from Adjustable exponential generator colors synthesizer’s sound, which is necessary reading to understand the circuit.
A dual rail power supply is needed, which could be problematic. Four ICs are used as well.
The schematic below is taken from Two chip generator shapes sound, which is necessary reading to understand the circuit.
This is the simplest circuit of the three, with only two ICs and a single rail +15V power supply.
The schematic below is taken from Get an ADSR waveform for a few components, which is necessary reading to understand the circuit.
Only one IC and two transistors, a relatively simple circuit, although a dual voltage (5/10V) power supply is required.
BC212 and BC182 do not exist on EagleCAD
I would use a 2N3904 NPN to replace the BC182, and a 2N3906 PNP to replace the BC212
The 2SA1015 is the complement of the 2SC1815.
And the connections are also reversed.
BC182 > BC174, BC190, BC546
BC212 > BC256, BC266, BC556
- Github: https://github.com/greenonline/ADSR-Waveform-generator
- Gitlab: https://gitlab.com/testkins/ADSR-Waveform-generator