Unusual Synthesizer Circuits

    I built original modular synths when I was a high school student.  Rate 1990’s, 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 SSM2164 Part 1. (Aug. 26, 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. Easily oscillates. Phase compensation needed. (Nov. 21, 2010)

• Temperature compensated exponential current source using PNP transistor array. Easily oscillates. Phase compensation needed. (Jul. 14, 2011)

• Temperature compensated exponential/log amplifiers based on AD538. (Sep. 09, 2011)

• Exponential converters using NTC thermistors. (Jun. 06, 2015) New!

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.  

• 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)

• Single opamp full wave rectifiers. (Jan. 21, 2012)

  • First ideas. Fwr0306.GIF (May 31, 2005)

• Saw to sin converters. (Feb. 24, 2012)

• Through-zero sawteeth VCO with 2 reset circuits. (Oct. 06, 2013)

• Single-supply VCLFO. (Sep. 21, 2014)

• Single-supply VCO. (Oct. 14, 2014)

• Wavemultiplier Pt. 1. (Dec. 18, 2016) New!

• Wavemultiplier Pt. 2. (Dec. 27, 2016) New!

• Wavemultiplier Pt. 3. (Jan. 15, 2017) New!

• Wavemultiplier Pt. 4. (Jan. 15, 2017) New!

• Wavemultiplier Pt. 5. (Jan. 22, 2017) New!

• Wavemultiplier Pt. 6. (Jan. 22, 2017) New!

• Single Supply VCO Pt. 2. (Sep. 09, 2017) New!

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 built in 1984. <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)

  • Circuit analysis of CMOS VCF.  (Jul. 19, 2015) Design process is revealed. New!

• 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 transistor ladder VCF. (Oct. 06, 2010)

• Battery operated totem-pole VCF. (Oct. 14, 2010)

• Phaser based on LM3900. (Aug. 18, 2011)

• VCLPF based on LM3900. (Aug. 19, 2011)

• Battery operated diode ladder VCF. (Dec. 02, 2011)

• Musonic Sonic-V diode ladder VCF. (Jan. 18, 2012)

• Musonic Sonic-V style VCF with temperature compensation. (Jan. 20, 2012)

• Single supply OTA based multimode VCF Pt.1. (Feb. 21, 2012)

  • Single supply OTA based multimode VCF Pt.2. (Feb. 22, 2012)

  • Single supply OTA based multimode VCF Pt.3. (Feb. 24, 2012)

• Variations of all-pass filters using OTAs. (May 25, 2014)

• CEM3320 VCF IC, Pat. US4004141. (May 15, 2015)  New!

• SSM2040-style VCF. (May 20, 2015)  New!

• Second-order all-pass filters.  (Dec. 17, 2016)  New!

• Second-order all-pass filters Pt. 2. (Jan. 27, 2017)  New!

• Variable-Q all-pass filters. (Jan. 30, 2017)  New!

• Phaser using variable-Q. (Feb. 01, 2017)  New!

• OTA-based APF with variable Q. (Feb. 01, 2017)  New!

• OTA-based APF with variable Q, Pt. 2. (Feb. 05, 2017)  New!

• OTA-based APF with voltage controled Q. (Feb. 09, 2017)  New!

• APF using NE570. (Feb. 19, 2017)  New!

• VCLPF using NE570. (Feb. 19, 2017)  New!

• VC state variable filter using NE570. (Feb. 19, 2017)  New!

• Fourth-order APF with variable phase slope. (Mar. 15, 2017)  New!

• Korg35-Style VCF with Photo Coupler IC. (May 06, 2017)  New!

• ARP4075-Style VCF Operated by Single Supply. (May 06, 2017)  New!

• Polivoks VCF . (May 04, 2018) New!

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 ringmodulator using MC1496. (Oct. 26, 2010)

• Ring modulator with dead zone and saturation. (Nov. 05, 2010)

• VCA with selectable CV response. (Dec. 09, 2011)

• Variable-response CV current source Pt.1. (Nov. 04, 2011) 

  • Variable-response CV current source Pt.2. A little simpler. (Nov. 05, 2011)

  • Variable-response CV current source Pt.3.  Far simpler. (Jan. 15, 2012)

• VCA/Ringmodulator using MC1496. (Jan. 17, 2012)

• VCA with selectable CV response Pt.4.  Precision response. (Mar. 10, 2013)

• Ringmodulator using XR2206. (Aug. 29, 2013)

• Variable response current source for VCA. Pt. 1. (Nov. 07, 2015) New!

• Variable response current source for VCA, Pt. 3. (Nov. 14, 2015) New!

• VCA with variable CV response. (Nov. 22, 2015) New!

• Variable response current source for VCA. Pt. 2. (Nov. 11, 2015) New!

• Variable Response Current Source for LM13700 VCA (Oct. 01, 2017) New!

• Exponential/Linear Current Sources for LM13700 VCA (Oct. 07, 2017) New!

• Variable Response Current Source for OTA. (May 01, 2018) New!

• Variable Response Current Source for OTA, Pt.2. (Jun. 03, 2018) New!

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) 

• Single-supply envelope follower/generator. (May. 20, 2012) 

• AD/AR envelope generators using CMOS flipflops.  (Jul. 01, 2013)

• ADSR envelope generators using CMOS flipflops.  (Jul. 03, 2013) 

• ADSR envelope generators using CMOS CD4053.  (Jul. 06, 2013)  Extremely simple.

• Atack-Release, Decay, and Gate Delay Using CD4053. (May 06, 2018) New!

Modification

• 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. (Photo)  (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)

  • Noise gate.  (May. 26, 2012)

• Gakken SX-150 Modifications.  (2008)

  • Traced schematic. (Sep. 06, 2008)

  • Modification schematic. (Oct. 15, 2008)

  • Panel design. (Oct. 18, 2008)

  • Short demo. (Nov. 11, 2008)

• Paia 9700 Modifications. (Nov. 2002, Mar. 2006) New!

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. 4. (Oct. 23, 2016) New!

  • 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)

• Negative series regulators 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.

• VCLFOs based on OTA with various waveforms. (Sep. 18, 2011)

• Gate sequencers based on 8-step cascading blocks Pt.1. (May 24, 2012)

• Gate sequencers based on 8-step cascading blocks Pt.2. (May 28, 2012)

• Sinusoidal LFOs (Boss VB-2 and Ibanez PH99). (Nov. 06, 2012)

• Sinusoidal LFO with voltage controlled amplitude. (Nov. 07, 2012)

• Dome filter based on twin-T network. (Nov. 08, 2012)

• Dome filter in JH FS-1a. (Nov. 14, 2012)

• Sinusoidal oscillators with bridged-T filter. (Jul. 13, 2013)

• One-knob tone filters for noise Pt. 1: Passive filters. (May 25, 2014)

• One-knob tone filters for noise Pt. 2: Baxandall style filters. (May 29, 2014)

• One-knob tone filters for noise Pt. 3: Blue-to-red filters. (May 30, 2014)

• Low-power noise generators. (Jun. 02, 2014)

• Shot noise generator. (Oct. 24, 2014) New!

• Shot noise generator Pt. 2. (Dec. 13, 2014) New!

• Band pass filter based on FDNR. (Apr. 19, 2015) New!

• Band pass filter based on FDNR Pt. 2. (May 04, 2015) New!

• Parametric equalizer using FDNR-based BPFs. (Apr. 21, 2015) New!

• Pink noise filter (-3dB/oct LPF). (Jun. 12, 2015) New!

• Dome filter based on bridged-T network. (Jan. 29, 2017) New!

• Mixer with phase shift. (Jan. 29, 2017) New!

• Sallen-Key 4^th order BPF. (Mar. 16, 2017)  New!

• Sine Wave Oscellator with Distortion Cancellation (Mar. 17, 2018)  New!

• VCLFO and Modulation Control VCA (May 06, 2018)  New!

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).

• 2010 (2010)    Monodular. (Modularized Monotron) Link to analog-synth.jp

Scanned Schematics

VCF

• moritaVCF76.gif (Jan. 30, 2001. 32 kb)   Transistor ladder VCF. (LP and HP) Designed by Shin'ya MORITA when he was a high school student.

• moritaVCF77.gif  (Jan. 30, 2001. 31 kb)  Transistor 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.

Circuit Analysis and Links to Interesting Schematics (in Japanese)

• Ibanez (Maxon) UE400 phaser. (Sep. 07, 2005)

• Tremolo of Guitar magazine Oct. 2005 issue. (Sep. 25, 2005)

• LFO from Guitar magazine's tremolo. (Sep. 28, 2005)

• VCLFO from application notes of LM13700. (Oct. 02, 2005)

• Triangular VCLFO using LM13700. (Oct. 04, 2005)

• VCLFO with 2 waveshapes using LM13700. (Oct. 05, 2005)

• Vibrato from "The Stompbox Cookbook" Pt. 1. (Oct. 25, 2005)

• Vibrato from "The Stompbox Cookbook" Pt. 2. (Oct. 26, 2005)

• Vibrato from "The Stompbox Cookbook" Pt. 3. (Oct. 27, 2005)

• Steiner style VCF. (Oct. 29, 2005)

• Pearl PH-03 phaser Pt. 1. (Nov. 05, 2005)

• Pearl PH-03 phaser Pt. 2. (Nov. 13, 2005)

• Pearl PH-03 phaser Pt. 3. (Nov. 14, 2005)

• Pearl PH-03 phaser Pt. 4. (Nov. 25, 2005)

• Pearl PH-03 phaser Pt. 5. (Dec. 02, 2005)

• Korg Delta VCF. (Dec. 04, 2005)

• Auto wah of Guitar magazine Jul. 2005 issue. (Dec. 10, 2005)

• Maestro stage phaser MPP-274A Pt. 1. (Dec. 16, 2005)

• Maestro stage phaser MPP-274A Pt. 2. (Dec. 31, 2005)

• Korg X911 guitar synthesizer. (Dec. 25, 2005)

• Electro harmonics Bad stone phaser Pt. 1. (Jan. 06, 2006)

• Electro harmonics Bad stone phaser Pt. 2. (Jan. 17, 2006)

• Roland SH1000. (Mar. 02, 2006)

• Orban 674A equalizer. (Mar. 05, 2006)

• Drumfire DF500 drum synthesizer. (Mar. 19, 2006)

• Oberheim OB-MX. (Apr. 21, 2006)

• Korg synth pedal FK-1 by Univox (Korg V-C-F). (Apr. 24, 2006)

• Amdek Hand clapper. (Jul. 03, 2006)

• ADA Final phase Pt. 1. (Jul. 07, 2006)

• ADA Final phase Pt. 2. (Jul. 07, 2006)

• ADA Final phase Pt. 3. (Dec. 17, 2016) New!

• ADA Final phase Pt. 4. (Jan. 30, 2017) New!

• ARP Avatar guiter synth. (Jul. 16, 2006)

• Moog 3-band parametric equalizer. (Aug. 10, 2006)

• Electro harmonix Small stone phaser. (Aug. 16, 2006)

• Korg PS3100 polyphonic synth Pt. 1. (Aug. 20, 2006)

• Korg PS3100 polyphonic synth Pt. 2. (Sep. 01, 2006)

• Korg PS3100 polyphonic synth Pt. 3. (Nov. 04, 2006)

• Korg PS3100 polyphonic synth Pt. 4. (Jan. 17, 2007)

• Korg Lambda polyphonic ensemble. (Dec. 22, 2006)

• Star Synare3 percussion synthesizer. (Jan. 22, 2007)

• Simmons SDS800 electronic drums. (Feb. 21, 2007)

• Polyvoks monophonic synth. (Mar. 04, 2007)

• Alisa 1377 monophonic synth. (Apr. 13, 2007)

• EMS VCS3/Synthi oscilator. (Apr. 16, 2007)

• Aelita monophonic synth. (May 02, 2007)

• Elka Synthex polyphonic synth, multimode VCF. (Jun. 14, 2007)

• Roland CR-8000/CR-5000 CompuRythm drum machine. (Jul. 04, 2007)

• Electronica EM-26 vocoder. (Oct. 30, 2007)

• ARP2500 multimode VCF 1047. (Feb. 11, 2008)

• OSCar VCF & VCA. (Mar. 07, 2008)

• Korg VC-10 vocoder. (Jun. 12, 2008)

• Casio DH100 digital horn. (Sep. 10, 2008)

• Analysis of transistor/diode ladder filters. (Oct. 31, 2008)

• Boss DR-55 (Dr.Rythm) noise generator. (Nov. 05, 2008)

• Syntovox 222 vocoder. (Mar. 12, 2009)

• March (Marsh) UDS electronic drums. (May 11, 2009)

• Korg Sigma performance synth. (Feb. 27, 2010)

• PAiA 6710 vocoder. (Mar. 14, 2010)

• Hammond 102100 monophonic synth. (Mar. 30, 2010)

• APF using THAT2180 VCA for phaser. (Jul. 28, 2010)

• Mini Korg VCF - Keio TS201012. (Aug. 06, 2010)

• ARP 4014 balanced modulator. (Oct. 20, 2010)

• Korg Monotron Pt. 1: power supply. (Nov. 06, 2010)

• Korg Monotron Pt. 2: ribbon and VCO. (Nov. 07, 2010)

• Korg Monotron Pt. 3: VCF. (Nov. 07, 2010)

• Korg Monotron Pt. 4: LFO. (Nov. 07, 2010)

• Korg Monotron Pt. 5: parts layout. (Dec. 30, 2010)

• Alisa 1387 mono synth. (Jan. 22, 2011)

• Simmons SDS-V electronic drum. (Jan. 25, 2011)

• Steiner Parker Synthacon. (Feb. 01, 2011)

• Steiner Parker Microcon. (Feb. 05, 2011)

• Steiner Parker Synthasystem. (Feb. 10, 2011)

• Ibanez PH-99 Classic Phase. (Nov. 26, 2011)

• EMS HiFli. (Jan. 20, 2013)

• Pearl Syncussion percussion synth. (Feb. 07, 2013)

• Steiner phase shifter. (Feb. 16, 2013)

• Univibe phaser transfer function. (Feb. 20, 2013)

• PAiA dual ribbon controller. (Jul. 13, 2013)

• SSL equalizer based on Wein bridge BPF. (May 11, 2014)

• Temperature compensated logarithmic circuit by Barrie Gilbert. (Jul. 13, 2014)

• Gakken SX-150 Mk2. (Aug. 21, 2016) New!

• Pearl PH-44 phaser. (Jan. 23, 2017) New!

• Sontec MEP250 series parametric equalizers. (Jan. 24, 2017) New!

• Rebis RA204 parametric equalizer. (Jan. 25, 2017) New!

• Rolls RPQ160 Parametric Equalizer . (Mar. 17, 2018) New!

• Rolls RPQ160 Parametric Equalizer Pt.2 . (May 01, 2018) New!

• Polivoks VCF . (May 04, 2018) New!

• Oberheim SEM (Synth Expander Module) . (May 06, 2018) New!

Mail to Osamu Hoshuyama