Synth pages
About me
Photo links
Purple Mountain
Contact details
What's new
Cheltenham Circular Footpath
The Trouble with Christmas
this night wounds time
Behold the Computer
Solartron scans

Site map

I have a Facebook page for occasional blog-like articles:

Tim Stinchcombe's Synth Stuff


What's New

I intend to maintain a list of updates to my site on this page, if I can remember to update it every time...

17 Dec 2022 - Mathematics via MathJax

Hopefully replaced all GIFs of LaTeX equations with the real thing, using the MathJax library. Pages amended: Monotron filter, Diode ladders, TB303 filter, LMF100 filter and Filter pole animations.

30 Jan 2021 - link to Frostwave Resonator schematic

Link to a forum thread added to the Korg filter page (second para under 'Clones/copies...OTA-based...').

(Linked from 'synth main'.)

6 Nov 2020 - PE Sound Synthesizer

Scans of the original PE Sound Synthesizer added to the PE Minisonic page.

(Linked from 'synth main'.)

17 Jun 2019 - Fooled by SPICE

SPICE colluded with my stupidity when I placed a cap on the output of an OTA. This is an explanation of how I was taken in.

(Linked from 'synth main'.)

26 May 2019 - Plan B M32 Vector Plotter

Repair of a blown module finally prompted me to investigate better component choices in the kinetic gate circuitry to improve performance and drastically reduce current consumption (by removing a design flaw).

(Linked from the 'mods page'.)

23 Nov 2016 - Plan B M28 Rev 1.2 build error

Details of a possible build error affecting the serial out on later Rev 1.2 units.

17 Dec 2015 - Gnat schematics correction

A new entry under 'errata'—a 33kΩ resistor in the LFO got left out.

(Linked from 'synth main'.)

06 Dec 2015 - Plan B M10 MkI vs MkII identification

A (perhaps overdue) section on how to distinguish a MkII (re-triggerable) M10 from a MkI.

(Linked from the 'mods page'.)

02 Jan Sep 2015 - Plan B M11 Evil Twin filter

An observation on the (mis)naming of the 'twin feedback path' of the M11 Evil Twin filter.

(Linked from the 'mods page'.)

07 Sep 2014 - Cheltenham Circular Footpath

Some detail on the circular path around Cheltenham, including a couple of GPX route files.

(Linked from the front page.)

29 Jun 2014 - Plan B M38A ADSR Expander mod

Modification to the M38A Expander module to actually make it usable

(Linked from 'mods page'.)

24 Feb 2014 - Plan B: Summary of design issues and modifications

A summary page of Plan B modules I've looked at, some of the issues found, documented fixes, and currently undocumented (possible future) fixes

(Linked from 'mods page'.)

25 Jan 2014 - Doepfer A-140 self-cycling mod

Modification to allow the Doepfer A-140 to self-cycle. This is an old mod from 2003, but I've included a whole lot of scope traces showing what the self-cycling waveforms look like.

(Linked from 'mods page'.)

8 Dec 2013 - Plan B M23 mod

Modification to allow correct chaining for the M23 Analog Shift Register.

(Linked from 'mods page'.)

27 Nov 2013 - Plan B M9 mods page

I have completely re-vamped the page on M9 mods, adding a lot of new technical detail!

(Linked from 'mods page'.)

11 Aug 2013 - More Plan B M15 VCO mods

A new page of simple mods (morph, PWM) for the M15.

(Linked from 'mods page'.)

27 May 2013 - New research paper links

A couple of new references added to the page of links to papers.

27 Apr 2013 - Solartron Minispace document scans

Added a page dedicated to the Solartron Minispace Analogue Computer, containing scans of several technical documents related to that old machine.

09 Dec 2012 - Teleton SAQ-206B Amplifier

Added a scan of a Teleton advert to the Teleton SAQ-206B amplifier page.

(Linked from the 'Stereo LED VU Meter'.)

9 Sept 2012 - Plan B M38 ADSR mod

Modification to make the ADSR adjustment range usable

(Linked from 'mods page'.)

25 Sept 2011 - Some PHP processing brought on board!

Crude PHP-based navigation bar added at left of most pages, and general structure re-vamped, though old HTML links should still work - if you find something that doesn't work (it will be a minor miracle if I haven't made a mistake or two editing over 50 pages!), please let me know by getting in touch.

24 Aug 2011 - Plan B M14 Dual Voltage Processor mod

Simple resistor changes (mostly!) to improve the crosfade

(Linked from 'mods page'.)

12 Mar 2011 - Monotron filter pole analysis

A new page of analysis of the Monotron filter poles, which is also largely applicable to the Korg35-based lowpass filters.

(Linked from the 'Korg page'.)

30 Jan 2011 - Teleton SAQ-206B Amplifier

A new page dedicated to the Teleton SAQ-206B amplifier, with a few new scans and photos.

(Linked from the 'Stereo LED VU Meter'.)

27 Dec 2010 - Korg Monotron component layout

An annotated photo showing the component layout of the Monotron.

(Linked from the 'Korg page'.)

28 Nov 2010 - Plan B M17 Triple Event Timer mods

A couple of simple mods to correct and improve the operation of the Triple Event Timer

(Linked from 'mods page'.)

26 Nov 2010 - M28 Tap Clock mods

A new page detailing the main inverter mod for the M28 upgrade: my instructions for Rev 1.0 boards were already posted at Phil Gallo's site—here I have added those of Rev 1.2 boards. Also a bit about missing resistor R5 on the main M28 page.

(Linked from the main M28 page.)

01 Nov 2010 - Clock and Reset for the A-161

Adding a small board to provide clock and reset signals to the A-161, making it stand-alone from the A-160.

(Linked from 'mods page'.)

26 Sep 2010 - Plan B M10 modifications

A page of modifications for the Plan B M10 Polyphonic Envelope.

(Linked from 'mods page'.)

29 Jul 2010 - Plan B M28 upgrade sound samples

Some simple sound files added to show the upgraded M28's new capabilities.

(Linked from the main M28 page.)

20 Jun 2010 - Plan B M28 mods

Details of two further simple mods to the Plan B M28

(Linked from 'mods page'.)

28 May 2010 - PE Minisonic scans

A complete set of scans of the Practical Electronics magazine Minisonic synthesizer.

(Linked from 'synth main'.)

22 May 2010 - Plan B M28 synchronization upgrade

A new firmware offering and modification to improve the performance of the 'phase lock' feature.

(Linked from 'mods page'.)

21 Mar 2010 - Plan B M15 sine wave adjustment mod

A tricky modification to the Plan B Model 15 VCO to improve the sine wave adjustment method and waveshape.

(Linked from 'mods page'.)

31 Jan 2010 - LMF100 Switched-Capacitor Filter

I finally got around to recording a simple sample of the clock noise of the LMF100 Switched-Capacitor Filter, when modulated with a slow-running LFO.

11 Jan 2010 - How the Serge VCS works

A detailed look at the workings of the Serge VCS

(Linked from 'synth main'.)

14 Dec 2009 - Comprehensive TB-303 Diode Ladder Model

A new page giving some extra data on my large transfer function for the TB-303 filter

(Linked from 'diode ladder filters'.)

14 Dec 2009 - Site map

Added a crude site map to maybe help with navigation.

4 Oct 2009 - LMF100 Switched-Capacitor Filter

I have completely re-written the LMF100 Switched-Capacitor Filter page, to correctly refer to the LMF100 chip actually used (it was originally written around the MF10 chip), and given a lot of design information (though it is not 100% complete yet).

(Linked from 'DIY modules'.)

29 Sept 2009 - Plan B M9 bleed-through mod

A simple modification to the Plan B Model 9 Mixer to help alleviate the bleed-through problem.

(Linked from 'mods page'.)

25 Sept 2009 - New Facebook photo album

Link to some new snaps at Facebook, of a short break to North Wales.

(Linked from 'photos'.)

28 Aug 2009 - Resonance Tuning for the Digital Moog Filter

Link added to Robin Schmidt's paper on the Moog ladder filter.

09 Aug 2009 - Behold the Computer Revolution

Another brief trivia page added, on the never-ceasing frustrations of working with computers.

05 Aug 2009 - Arp 2500 brochure

Scan of an Arp 2500 brochure (a 5.1meg PDF file), courtesy of Ben Ward.

(Linked from 'synth brochures'.)

02 Aug 2009 - Arp 2500 poster

Scan of a large Arp 2500 poster (a 5.6meg JPEG file).

(Linked from 'synth brochures'.)

03 Feb 2009 - Identifying dodgy IEC power inlets

How to tell if your Doepfer G3/G6 case is possibly fitted with a dodgy IEC power inlet, which have been known to fail.

(Linked from 'mods page'.)

17 Jan 2009 - Teleton SAQ206B amplifier schematic added

I've been surprised by the number of hits I get from people searching on 'SAQ206B', so I have scanned the schematic (7.7Meg file) that I have had for years (the copy is not brilliant, but scanned at 300dpi it looks to be mostly readable).

(Linked from 'Stereo LED VU Meter'.)

25 Dec 2008 - New Facebook skiing photos album

Link to a Facebook album of a selection of my old skiing photographs, taken over a number of years.

(Linked from 'photos'.)

10 Dec 2008 - this night wounds time

A brief page of King Crimson trivia added.

7 Dec 2008 - Page of Korg MS-10/MS-20 filter related material added

Reference to my MS20 study moved to a separate page, along with many links relating to the Korg35, the MS-10 and MS-20 filters, and clones/copies of them etc.

(Linked from 'synth main'.)

25 Oct 2008 - Moog Ladder paper - big update!

A major re-write of my Moog ladder filter paper, which now includes diode ladders, poles, frequency responses and more

(Linked from 'synth main'.)

20 Oct 2008 - Correction to Diode Ladder Filter page

Strikeout of an erroneous statement (proper correction to follow once I've got a better handle on it!)

13 Oct 2008 - New Facebook photo album

Link to some new snaps at Facebook, of a recent weekend visit to York.

(Linked from 'photos'.)

19 Sept 2008 - Research paper links

A page of links to some interesting research papers on ladder filters.

(Linked from 'synth main'.)

14 Sept 2008 - Diode Ladder Filters

A page of transfer functions, poles and plots, dedicated to diode ladder filters.

(Linked from 'synth main'.)

[Page last updated: 17 Dec 2022]