A-143-1 Modification

Adding voltage control and a combined trigger output to Doepfer's Complex Envelope Generator. An update to these posts (1, 2).



The A-143-1 is king of the shonky rhythm. There's something about the swing generated by its four chained envelopes and comparators that is hard to replicate with a VC-LFO and sequencer. This modification provides two features I wanted when using the A-143-1 as a wonky clock: a combined pulse stream to control other modules and an automated means of influencing the rhythm.

For the latter, I chose to add simultaneous voltage control to the threshold of all four comparators. For me, this is the parameter that makes the A-143-1 tick. It means a single CV can be used to stretch and shrink the rhythm without affecting its inherent groove. Think 'Funk Soul Brother'. Just as importantly, the modification can be accommodated on the original panel.

The Comparator outputs are chopped down to 1ms pulses, so they can easily be mixed without the need for a 'proper' logic circuit. They are also hot enough to ping filters. Add a Sample & Hold to grab values from the A-143-1's bipolar mix out and the results can sound like this:

a-143-1_mod.mp3



The star of this mod is the H11F1 Photo FET Optocoupler. It may not have the cachet of a VTL5C3, but this vactrol alternative might make a better choice for some synth mods. It's smaller, cheaper and, most importantly, has a fast, linear response.

The circuitry used in this mod is simple. The difficulty arises out of the need to quadruple the parts. You can download my build-notes here (the usual DIY disclaimers apply!) to see how I went about it. See this thread for more A-143-1 modification ideas.

To close, today's Patch of the Day offers a musical example of this modification:



The patch uses just two envelopes, sometimes chained, sometimes running as LFOs. The new combined trigger was multed to ping a Cwejman RES-4 and trigger a S&H and CTG-VC envelope. The A-143-1's mixout was sampled by the S&H and sent to the RES-4's FCV and CTG-VC's Attack CV-in. The RES-4's audio output was sent to a VCA-4MX and multed to an A-199 Spring Reverb. The 100% wet signal was sent to a second VCA/ mixer channel and opened by the CTG-VC's envelope. Altering the threshold changes the timing and also the CV that is sampled from the mix output.

Basic Electricity - Concert Today!

A reminder about tonight's gig with Derek Holzer, Vanessa Ramos-Velasquez and JenaMu6. The venue is the Kino on Kastanienallee 77, 10435 Berlin Prenzlauer Berg. Doors at 21:00, music at 22:00 sharp.



I won't be playing, but had some fun with this patch last night:



Inspired by the sound of Japan's Gentlemen Take Polaroids, it features a Plan B M15 VCO FM'd by Doepfer's A-143-9 QLFO. The gated sound was fed to an A-199 spring reverb with the feedback routed through Cwejman's FSH-1 frequency shifter. I added a touch of Logic's Ensemble, but 90% of the effect is the shifting reverb. Lovely.

Look forward to seeing you tonight at BE#6!

PotD - Mutant Horse 2

A gentle gallop into Basic Electricity #5 on Friday. This is a take on the patch Tom & I played at BE#4, likened by Ian Boddy to "riding a mutant horse".



A Sport Modulator provides both timing information and CVs, driving Maths, a VCO-2RM, Triple Wave Folder, A-112 Sampler/ Delay and VCA-2P panner. The oscillators are FM'd before being gated, folded and sampled. A stepped and manual CV controls the rhythm, delay time and panning. Flipping between track- and sample-and-hold on the SM delivers the final crack of the whip.

Patch of the Day - Basic Variations

Two takes on a theme. One involving FM, the other AM techniques. My Basic Electricity #2 epilogue.



This first patch was inspired by Richard & Rastko's jam on Friday night. It features the FM and Low Pass Gate action of the former and the lo-fi Ciat-Lonbarde sound of the latter. I recorded two passes of a Wogglebug & Maths driving Plan B's models 15 & 13 and Doepfer's A-112 sampler delay.





This second patch has a similar core, but the sound is based on amplitude modulation. The dual peak sine of a Cwejman MMF-1 modulates a VCA-2P. The carrier was the sine of an A-143-9. I altered the C:M relationship throughout the patch. Delay was courtesy of the EHX SMMH.



These patches show the types of complex timbres that can be achieved with modulation. With the current trend for 'West Coast' synthesis, FM is a familiar technique. AM seems to be regarded as ring modulation's poor cousin, but it can be a rich source of sounds.

For me, part of its strength lies in the fact that the carrier, effectively the fundamental, is still present in the resulting signal. To get the most from AM, you'll need two VCAs and possibly some form of offset/ attenuation. As ever, Gordon Reid has the dope.

Thanks to everyone who came to the gig and to Rastko, Hayden & Richard for the wonderful performances.

Patch Tips #21 - Getting Animated

Doepfer's A-137-2 'Wave Multiplier II' does more than just super-saw.



This module uses a set of comparators to generate four 'fake' phase-shifted versions of the input material. The offset of each saw can be modulated, generating a large sound from a single oscillator. As the module is DC-coupled, it can also be used to process CVs.

When I first got the A-137-2, I considered building an expander to gain access to its pulse outputs and avoid having to unscrew the module from the system to remove stages from its output. Two discoveries I've made this week happily mean this isn't necessary.

The first relates to the manual shift knobs: when set at zero, a stage is effectively removed from the output. This is great news if, for example, you only want one additional animated saw. It also has implications when using the A-137-2 as a comparator-based timing delay.

Secondly, the A-137-2 will function without the usual input. Activate a stage by setting its manual shift to something other than zero and feed your signal to its CV input. The result: those hidden pulses! With some careful setting, you can get some mad waveforms:



I'm not sure if this is a bug or a feature - a comparator needs two signals - but, as you can hear from today's Patch of the Day, it offers an additional palette of sounds.



To use the A-137-2 as a shonky beat machine à la A-143-1, feed it a ramp LFO. I've found using a positive-only CV from Maths works best as the comparators switch on both the rising (on) and falling edges (off) of a wave. Patch its output to an A-162 or similar to get clean pulses.

The A-137-2 is another Doepfer gem, offering several uses for not much money. If you want to learn more about the workings of this module, read the ETI article on the Digisound Waveform Multiplier or, if your French is up to it, the Elektor article linked at the bottom of the Doepfer product page.

Patch of the Day - Highly Strung

Kicking off the new year with the rediscovery of the Doepfer A-137-2 Wave Multiplier and a frenzied take on a duet for two acoustic guitars:



I bought this module when it first came out, then sold it two years ago because I'd run out of space. I've been working on a track that needs a big fuzzy, 'super-saw' bass but wasn't getting the right sound with multiple VCOs and wondered if the A-137-2 might fit the bill. As you can hear from today's PotD, that's not what I ended up using it for: the A-137-2 will do phasing saw sounds, bar the subtle detuning, but I found it's also great for EML-sytle abrasive tones that can then be tamed with a filter.

The patch involves CV-ing the WM II at audio rate, LP filtering the result with the Cwejman MMF-1 and then accentuating various frequencies with a low-bandwidth setting RES-4. Gordon Reid goes into much detail about how to achieve this in his synth secrets, but I just used my ears. A Wiard/ Make Noise Wogglebug generated the timing and note information. It was kicked about by one channel of Maths, which received a mult of the stepped output, thus varying the pace and intensity of the ratchets and completing a timing feedback loop. I recorded two passes of the result, varying the patch by hand.

Patch of the Day - Analog Heart, Digital Mind

Using Silent Way's CV Input & Osculator to control your DAW.

Ok, so you've managed to recover CVs from you modular. Now what?

Rather than just process and/ or replay those recorded CVs, how about using Logic's Transformer to convert and redirect the MIDI CCs generated by the pairing of SW's CV to OSC component and Osculator?

In today's patch I've siphoned Osculator's output and used a handful of Transformers to generate pitch & pan information for an electric piano virtual instrument and bypass & downsample parameter data for Logic's Bit Crusher plug-in.

PotD - Analog Heart, Digital Mind by navs

In the first section you can hear me manually adjusting a positive offset voltage from a Doepfer A-138 mixer, followed by a sequence from an A-Sol. SQ-8 plus manual offset and, finally, the stepped output of a Make Noise/ Wiard Wogglebug. In the latter example, I used automation to gradually increase in the bitcrusher's mix level to about 50%.

This is a lot of fun and yields unusual and sometimes unpredictable results. For example in the sequence excerpt, the CC to note conversion isn't always 'clean'. However, I'm sure it's nothing a little additional MIDI processing couldn't solve.

The biggest problem I encountered was the lack of 'note off' data and hanging notes when converting CCs to pitch. There are other ways of generating clean note information, for example using a Novation Bassstation Rack's built-in CV-MIDI converter or the Moon Modular 552, but If anyone has a Logic-based solution, I'd love to hear it!

Here are some screen-grabs of the Environment I used.

For those of you daunted by Logic's Environment, and in particular its Transformer modules, check out this great tutorial by Toby Pitman at audiotuts+.

Thanks to Scaff for providing the inspiration for this patch with his Moon Modular 552 demos!

Patch of the Day - Quad Event Timer

This patch was inspired by the Plan B Triple Event Timer and marks a bit of a departure for me: it was realized using the Clavia Nord Modular 2 Demo.

I tried the M17 years ago but couldn't get my head round it at the time. However, my last PotD featuring the A-143-1 showed the limitations of using fixed comparator timing/ threshold levels. The spacing between events is always absolute, rather than relative.

I tried Doepfer's A-167 Comparator, which is a fine module and actually more flexible than a single M17 output. However, to emulate the functions of the TET, you'd need three of them. Before building my own quad comparator using Ian Fritz's LM339 design, I wanted to try out the musical applications of such a module and that's where the NMG2 came in.

Here's what it sounds like:



I used a VC ramp to determine the timing/ spacing of the four events and fed the EG with a negative pitch CV. As you can hear, the result is similar to the effect of a sampled phrase: the relative spacing remains intact despite the change in speed/ pitch.

Here is the NMG2 patch.