Synthesizer Circuits
I
built original modular synths when I was a high school student.
Recently I joined synth-diy
mailing
list and resumed synth DIY. I'm not good at English but I am
trying to write most of
the
contents in English for the list members who have inspired me.
[WARNING]
This
page is not for beginners, but for those who are looking for new
synth circuits. Most
of
the circuits presented here are not the usual synth circuits.
Beginners must become
familiar
with ordinary circuits before they can understand these unusual
circuits. I will not
answer
questions from beginners because my English is not sufficiently good
to explain these
complicated
things to beginners.
The
information provided on this website is for non-commercial use only.
Some works
may
be covered under one or more patents. Contact Osamu
Hoshuyama for information
on
commercial use.
Original
Schematics
Exponential Converter
SymExp2.gif (Jan. 21, 2001) Symmetrical exponential current sources (17 Kb) Not tested. But, It should work.
ExpPara.gif (May 31, 2005) Wide-range exponential current source (13 Kb) Not tested.
ExpPent.gif (May 31, 2005) Multiple exponential current sources (14 Kb) Not tested. But, It should work.
Exponential Converter Using MC1496. (Jun. 19, 2008)
Single Supply Exponential Converters. (Jul. 01, 2009)
Temperature Compensated Exponential Converter Using SSM2164 Part 2. (Aug. 29, 2009)
Temperature Compensated Exponential Converter Using Blackmer Cell. (Sep. 02, 2009)
Temperature Compensated Exponential Converter Using Ordinary Transistor Array. (Sep. 02, 2009)
Temperature Compensated Exponential Converter Using Emitter Common Transistor Array. (Nov. 21, 2010)
Temperature Compensated Exponential Current Source Using PNP Transistor Array. (Jul. 14, 2011)
VCO & Waveshaper
VcoMos0212.GIF (Feb. 01, 2003) CMOS VCO (29 Kb)
WvShp0305a.gif (Jun. 10, 2003) Variable slope-ratio triangular waveshaper (26 Kb) Untested but tested on simulater by Masa KUNII.
WvShp0306.gif (Jun. 10, 2003) Voltage-controlled slope-ratio triangular waveshaper (40 Kb) Untested.
Fwr0306.GIF (May 31, 2005) Single-opamp full-wave rectifier (32 Kb) Not tested.
Lfo0509d.gif (Mar. 12, 2006) Single-OTA VCLFO (10 Kb) Not tested.
RossPhLfo0510.gif (Mar. 12, 2006) Hyper-triangular LFO in Ross phaser (10 Kb) Not tested.
Serge VCO Using LM3900s. (Oct. 08, 2007)
AN299 VCO with Extended Frequency Range. (Sep. 30, 2008)
VCO Using LM359 Norton Amp. (Jan. 13, 2011)
VCF
Vcf0111.gif (Jan. 5, 2002) My original VCLPF <Single ended diode ladder> (12 Kb) No diff amp. Older Version: Vcf98.gif
Ph44core.gif (Dec. 5, 2000) Pearl phaser PH44 APF core (8 Kb)
Vcf99081.gif (Dec. 5, 2000) My original VCLPF <Totem pole VCF> (28 Kb)
Vcfhow.gif (Dec. 5, 2000) How the totem pole VCF works (11 Kb)
Vcf0007.gif (Dec. 5, 2000) VCF core variations (HPF and APF) based on the totem pole structure (18 Kb) Tested on breadboard.
Vcf84a.gif (Dec. 5, 2000) Roland style VCLPF <Normal OTA based> (18 Kb)
PhTrR2.gif (Dec. 5, 2000) VCAPF <C-E resistor> (7 Kb) Tested on breadboard. Too much distortion.
VcfMos0206.GIF (Jul. 25, 2002) My original VCF <CMOS VCF> (35 Kb)
CmosOta.GIF (Jul. 25, 2002) How CMOS inverter works as OTA (18 Kb)
PhaseFet0205.GIF (Jul. 25, 2002) VCAPF idea suited to Mike Irwin's VCR structure (15 Kb) Untested.
VcfSvf0206.GIF (Nov. 09, 2002) State variable type VCF using CMOS. (20 Kb)
Vcf0210.GIF (Nov. 09, 2002) My original VCF structures using current-input-current-output OTAs. (19 Kb)
Vcf0211a.GIF (Nov. 09, 2002) Four-pole VCF with asymmetrical distortion. An attempt to simulate SSM2040 for cheap. (20 Kb)
Vcfv0212.GIF (Dec. 31, 2002) How to add HPF input to ladder filter. Sallen-Key ladder filter is possible! (19 Kb)
VcfTp0211.gif (Jun. 10, 2003) Totem pole VCF. (26 Kb) A little easy to build. Tested on breadboard.
VcSvf01a.gif (Jun. 10, 2003) My original multimode VCF. (20 Kb) Function is similar to Steiner VCF. Untested.
Vchp0302.GIF (Jun. 10, 2003) Horizontal transistor ladder VCF (30 Kb)
VcfCtp0211.gif (Jun. 10, 2003) My original VCF <Cascaded totem pole VCF> (32 Kb) Tested on breadboard.
VcfStn0505b.gif (Mar. 12, 2006) Modified Steiner style VCF. (20 Kb)
Svf4023.GIF (Mar. 12, 2006) Transformation from ordinary state-variable filter to Arp4023. (18 Kb)
VcfSSM0602a.GIF (Mar. 12, 2006) Four-pole VCF using SSM2164. (20 Kb) Main signal path was tested on breadboard.
Vcph0505.GIF (Mar. 12, 2006) My original VCAPF using SSM2164 for phasers. (18 Kb) Tested on breadboard.
Buchla 191 VCF. (Jul. 11, 2007)
OSCar VCF & VCA. (Mar. 07, 2008)
Battery Operated VCF. (Dec. 06, 2009)
Battery Operated VCF Pt.2. (Dec. 06, 2009)
Battery Operated Ladder VCF. (Oct. 06, 2010)
Battery Operated Totem-Pole VCF. (Oct. 14, 2010)
VCA
Vca84.gif (Dec. 5, 2000) Normal OTA based. (12 Kb) CV part has an error.
VcaMos0210.GIF (Oct. 14, 2002) My original VCA. CMOS VCA (17 Kb)
Vca0302.gif (Jun. 10, 2003) Discrete VCA with improved dynamic range (9 Kb) Untested.
VCAs Using MC1496. (Jun. 18, 2008)
Class-B Ring Modulator Using MC1496. (Oct. 26, 2010)
Ring Modulator with Dead Zone and Saturation. (Nov. 05, 2010)
EG
eg0104a.gif (Jan, 2, 2002) HADSR using CMOS inverters (17 Kb) Older Version: eg0104.gif
eg0105.gif (Jan, 2, 2002) HADSR using single-supply bipoler quad opamp (18 Kb) Corrected.
EgMos0210a.GIF (Jun. 10, 2003) ADS using CMOS (17 Kb) Old version: EgMos0210.GIF
Eg0301d.GIF (Jun. 10, 2003) Very simple AD/AR using CMOS 555 (15 Kb) Old version: Eg0301c.GIF
Trapezoid Generator Using LM3900. (Jun. 23, 2011)
Others
NgMos0211.GIF (Feb. 01, 2003) Noise generator using CMOS (11 Kb)
ShMos0212.GIF (Feb. 01, 2003) Sample and hold using CMOS (12 Kb)
EfMos0301.GIF (Feb. 01, 2003) Amplifier and Envelope follower using CMOS (15 Kb)
LfoMos0211.GIF (Feb. 01, 2003) Dual LFO using CMOS (17 Kb)
Glide0301.GIF (Feb. 01, 2003) Glide, Inverters, and Headphone Amplifier (12 Kb) Nothing special. Just for Lunch box modular.
attmix0301.GIF (Feb. 01, 2003) Attenuators/Mixer for Lunch box modular (15 Kb)
Hfe Doubler for Low Gain Germanium Transistors. (Apr. 26, 2006)
Quick Method for Matching Diodes/Transistors. (Nov. 10, 2006)
Simple Noise Generator Using TL431 Part 2. (Dec. 03, 2009)
Simple Noise Generator Using TL431 Part 1. (Jan. 21, 2009)
16 Step Analog Sequencer Using CD4017s. (Nov. 28, 2009)
16 Step Gate Sequencer Using CD4017s. (Jun. 20, 2009)
Filter Bank Using Graphic Equalizer IC Pt.1. (Jan. 26, 2010)
Filter Bank Using Graphic Equalizer IC Pt.2. (Feb. 01, 2010)
Filter Bank Using Graphic Equalizer IC Pt.3. (Mar. 09, 2010)
Photo of the Module. (Apr. 24, 2010)
Monotron Modifications. (Apr. 2010 – May 2010)
Modification Pt.1. (May 10, 2010)
Modification Pt.2. (May 19, 2010)
Modification Pt.3. (May. 29, 2010)
Modification Pt.4. (Jun. 03, 2010)
Ribbon Pitch Range Extension. (Jun. 10, 2010)
Transforming LFO to EG. (Jun. 11, 2010)
VCO Mute. (Jun. 12, 2010)
External Pitch CV Input. (Aug. 03, 2010)
Additional VCO. (Apr. 20, 2011)
Slow Attack VCF Envelope. (Apr. 21, 2011)
Additional LFO. (Apr. 23, 2011)
Negative Series Regulator Based on TL431. (Feb. 22, 2011)
Multifunction LFO/EG. (Jun. 25, 2011)
Multifunction LFO/EG Pt.1. (Jun. 07, 2011) Not recommended.
Multifunction LFO/EG Pt.3. (Jun. 26, 2011) Exponential curve.
Photos
of My Modular
1982-1985 (Dec. 23, 2000. 74 kb) VCO x 2, Noise, VCF, VCA x 2, S&H, ADSR x 2, AR, Gate delay, RM, Mixer, and Piecewise linear function.
1985-2000 (Dec. 23, 2000. 92 kb) VCO x 2, VCF x 4, VCA x 2, ADSR x 2, Spring reverb, Parametric EQ, Digital delay, DNR, Noise gate, ...
2002-2003 (Feb. 01, 2003. 65 kb) MOSular (CMOS Modular Synth in Lunch Boxes.) Midi-CV (Synhouse Midijack), VCO x 2, VCF, VCA x 2, ADS x 2, AD/AR x 1, LFO x 2, Envelope follower, Inverters, and Headphone Amplifier. All the signal paths are CMOS. Block diagram (41 kb)
Mike Irwin's Works
Space for Mike Irwin (May. 2002) He is a mastery of modulation effects.
Scanned
Schematics
VCF
moritaVCF76.gif (Jan. 30, 2001. 32 kb) Tr ladder VCF. (LP and HP) Designed by Shin'ya MORITA when he was a high school student.
moritaVCF77.gif (Jan. 30, 2001. 31 kb) Tr ladder VCF designed by Shin'ya MORITA in 1977.
moritaVCF783.gif (Jan. 30, 2001. 29 kb) Diode bridge type 2 pole VCF designed by Shin'ya MORITA. Untested.
moritaVCF785.gif (Jan. 30, 2001. 48 kb) Diode bridge type 4 pole VCF designed by Shin'ya MORITA. Untested.
moritaVCF786.gif (Jan. 30, 2001. 23 kb) Re-invention of Moog-Musonics Sonic-V style VCF by Shin'ya MORITA. Tested on breadboard.
EG
moritaEG78.gif (Jan. 30, 2001. 42 kb) Simple ADSR designed by Shin'ya MORITA. 1978. Untested.
gx1eg.gif (Jan. 30, 2001. 19 kb) VC ADSR of Yamaha GX1. Redrawn by Shin'ya MORITA.
KB
moritaKB.gif (Jan. 30, 2001. 34 kb) Dual voice KB designed by Shin'ya MORITA. 1977 or 78.
