Thursday, 28 April 2016

Funkhaus Fun + Ribbon Tales



Thanks to everyone who came to see the concerts in Saal 2 of the Funkhaus on Friday night of Superbooth. Wolfgang Seidel, Hillary Jeffery, Hainbach, Frank Bretschneider and I had a great time. Thanks also to Andreas Schneider and especially Adam and his team for the wonderful sound and light.



Our trio’s set was improvised but Wolfgang and I did have one ‘get to know you’ musical session, during which I noticed he uses not one but three Doepfer R2M ribbon controllers! I had tried one of these years ago, when Schneider bundled them together with an Analogue Solutions MS-20 filter/ VCA and Doepfer VCO - the Jimi-Box, named for Hendrix.



But the ‘widdle’ wore thin pretty quick so I passed on the analogue version of the ribbon controller. The R2M, of course, can ‘speak’ both analogue and digital. It’s a good partner for the MIDI-equipped Clavia Micromodular, which has only three knobs and no keyboard. For its part, the Micromodular, with its familiar environment and patch recall, is the perfect accompaniment to an analogue modular when playing live. You can see me using them in the second picture above.

Here are two patches from that concert. One is inspired by Peter Grenader’s iconic ribbon video from a few years ago. Note position determines pitch, panning and also speed of the clocking VC-LFO, pressure adds modulation.



I wanted to use a voltage controlled radio during our set at the Funkhaus, the former East German broadcasting house, but was unsure of whether I’d get any reception. The answer was to mimic the random bursts of noise and music fragments with this second patch. Three comparators provide an on-off switch for the virtual radio, tonal and frequency changes.



You can download the patches and R2M preset info here. Let me know how you get on!

Wednesday, 23 March 2016

Live at Superbooth



I’m very happy to present an evening of improvised music on Friday, 1st April at Andreas Schneider’s inaugural Superbooth in Berlin’s historic Funkhaus.

Basic Electricity stalwart, Wolfgang Seidel and I will be joined by Hilary Jeffery on trombone for a clangorous electro-acoustic trio. Hainbach combines recordings and melodic modular electronics and is accompanied by Orca’s hand drawn and animated visuals. And Frank Bretschneider presents his new project Sinn + Form, featuring recordings of vintage Buchla & Serge systems at EMS, Stockholm.

Follow the links in the artist’s names for more information and media. Click this link for a list of evening events.

We’ll play in the wonderful Saal 2, the so-called ‘small’ recording hall!



Click here for more pictures and information about the Funkhaus.

Here’s a taster of some patches I'm preparing for the concert:



Look forward to seeing you at Superbooth!

Modular Minds - eContact! Publication



The latest issue of the Canadian Electroacoustic Community’s online journal is called “Analogue and Modular Synthesis: Resurgence and Evolution”. It’s about the renewed interest in modulars and how we use them live and in composition. The magazine features 20 articles on the basics, practicalities and philosophies surrounding these instruments by authors including Rob Hordijk, Peter Blasser and myself.

You can find it here: http://econtact.ca/17_4/

Many thanks to Richard Scott, jef chippewa and colleagues for their hard work in making this happen.

Enjoy the read and let us know what you think!

Wednesday, 21 October 2015

Tuesday, 13 October 2015

Wowa has been busy



Some silly sounds from some new Cwejman modules.



Cardboard faceplates FTW!

Sunday, 4 October 2015

Doeper/ Serge VCS Expander Schematic



A description of the method I used to add Hold, Burst and EOR functions to the Doepfer A-171-2. An update to this post. The module is a licenced version of the Serge/ CGS DUSG/ VCS, so these mods will work on them too, although the pins may be different.

You can download the schematics and Fritzing file here. I wish I had done this at the time in spring as I've had to retrace my thoughts from incomplete notes. It's been fun but I might have some things wrong and I’m sure some aspects could be done better. So, please continue the discussion and post corrections and improvements to this circuit in this forum thread. I will update this post accordingly.

HOLD



The idea behind the Hold circuit is simple: interrupt the integrator. If you wanted to go no further and keep this mod passive, all you would need to do is cut one trace and hook up a switch. On the A-171-2, I found a convenient place between pin 7 of the TL084 quad opamp and the 8k2 resistor (R39).

If we want to automate this, we need an analogue switch. Transistors can be fiddly and the common CD4066 won’t process all signals, so I used a DG201. This switch is ‘normally closed’, so with no gate on the command input, drain and source are connected and the integrator’s loop is closed. Pulsing it breaks the connection.

EOR

Referring to Tim Stinchcombe’s VCS analysis and comparing with the Doepfer layout, pin 4 of the LM3900 is high during the attack phase. The ‘not attack’ gate, which will become part of our EOR gate, can be found on pin 5 of the LM3900. If you observe this output with an oscilloscope you’ll notice we need to process it as the ‘not attack’ gate remains high until the next attack phase is initiated. This can have its uses, but it’s not what we’re after if we want an EOR/ variable length gate that can be used to ping filters etc.



This is where we have to get creative and ‘patch with ICs’: we use another switch on the DG201 to operate a logical AND function. The signal which chops our ‘not attack’ gate down to the right length is the EOC gate. We can tap this signal from the End Out jack on the A-171-2. As the EOC gate is ‘high’ at the wrong time, we want to flip its activity.

The need for a logic inverter conveniently also answers the question of how to buffer the inputs for this mod. I used an HCF4049UBC Hex Inverter. As the supply voltage also determines the logic threshold for this chip (lower voltage = lower threshold/ faster response), I chose to run it off 5V, supplied by a 78L05A regulator. I sent the new EOR signal from pin 15 of the switch to a jack and an LED.

BURST

Now that we have the means to process logic, the burst function is relatively simple. It’s a circuit adaptation of the classic Maths Trills patch where we used a logic gate to interrupt the loopback of the EOC signal to the trigger input. As with the EOR gate, we use a switch to function as a logical AND gate. The DG201 is ’normally closed’, so we need to keep the switch open when there is no burst command present. To do this, we use a spare inverter to flip the activity of the burst input. Looking at the schematic on Ken Stone’s site, the trigger and cycle inputs are OR-combined by diodes, so the VCS can be triggered and burst/ cycled at the same time.



The DG201 is powered from +/- 12V. Filter the supply as usual and add 0.1uF bypass caps for the ICs. The burst and hold inputs were conditioned by cutting negative voltages. The schematic says 4001, but I used 4148 diodes.  I added a manual gate by tapping 5V and sending it via an ON-ON switch to either the burst or hold jack’s switching contact.

It sounds more complicated than it is. Once I’d thought it through, I built it on stripboard on the fly, without the need for a detailed schematic. Lesson learned on that score! I hope these notes help and look forward to your comments and improvements.

Thanks to Dieter Doepfer and Chrisi & Erik at Koma Elektronik for their help on the subject of switches.

The usual DIY disclaimer: do this at your own risk, take care and have fun.

Saturday, 18 July 2015

Most Hazarai

Deriving a Beat clock and End of Loop pulse from the Electro-Harmonix ‘Stereo Memory Man with Hazarai’. An update to these previous posts.



Background:

I recently attended a talk with Charles Cohen, a musician who has improvised with a Buchla Music Easel for several decades. The Easel is a monophonic instrument but Cohen’s music is multi-layered. To achieve this, he uses long, looping delays to record in a ‘sound-on-sound’ fashion. In Berlin, he used an Electro-Harmonix ’16 Second Delay’, a vintage pedal that’s long out-of-production. A modern equivalent which is also capable of looping is the SMMH.

A stock SMMH will record loops and allow the user to over-dub. It’s fine for guitarists or other manual players, who can keep time with the previously recorded ‘template’ loop. But what if you want to record a clocked sequence from a modular? Laying down the first loop is simply a matter of starting and stopping the recording in time. The problem arises when you want to add a second layer. Although it may be at the same speed, it will probably be out of sync.

I didn’t realize this limitation until I tried Charles Cohen’s layering technique at home. He didn’t seem to have this problem, so what to do? I found a solution that requires a simple modification to the SMMH and - from watching Cohen improvise - a change in playing approach.

Here's what's possible: ehx-smmh-looper-mod.mp3

Build:



Unlike the ’16 Second Delay’, the SMMH does not have a clock output. However, its Beat and Loop LEDs do keep time, so this gives us the possibility to derive a clock and, importantly, a reset pulse from the logic signals that drive them.

If we unscrew the base of the SMMH and then compare the positions of these two LEDs with the PCB, we can see where their legs protrude (see above JPEG). If we locate the current limiting resistor R27 + R30 we see that each is linked to a ‘via’, or tiny hole in the PCB. This is where I chose to extract the signal by inserting and soldering a slim solid-core hook-up wire. You could use stranded, but solid gave me an easy, snug fit. A 1K output protection resistor could also be inserted here. I later added mine to the connection at the output jack.

As with the previous SMMH mod, I chose to drill holes in the enclosure with the PCB still mounted as it’s difficult to remove. I protected the PCB with paper and, fortunately, it survived.

In Use:

So, what do we have? The Beat clock is as we expect, but the Loop pulse goes high at the end of the loop. To use it as a reset signal for a sequencer we need to condition it. I use an A-162 Trigger Delay to stretch the pulse just long enough for it to overlap with one of the Beat pulses. This allows me to 'AND-combine' them in an A-166 Logic module. This gives a pulse on the first beat of the bar/ loop. I may find other workarounds or a fix, but for the moment this patch works well.

There’s one last mod I could envisage: a switch carrying 5V to hold the SMMH in perpetual record mode, like the 16 Second Delay. As I already have a trigger input, I just feed it a gate from one of the A-166’s inverters. New material can be added by opening a mixer’s Aux send.

Playing Technique:



Charles Cohen seemed to meditate before playing, taking a moment to consider his next performance. Having done this modification, I now wonder whether this artistic reflection might also have had a technical reason. On the SMMH, the Beat LED does not start pulsing until after the first, template, loop has been recorded. This gives us the opportunity to set the loop length and tap tempo before recording properly: just activate the loop with no signal and ‘record’ a blank template. Yes, that means we also gain a tap-tempo clock!

This modification is a ‘hack’: it’s quick and simple and opens up new possibilities. The great thing about the SMMH is that we can also record the effects in loop mode. Using the SMMH’s looper, I’ve been surprised by how little equipment I need to make interesting music - many of the quick ditties in the above demo were recorded with just one VCO, a set-up not too dissimilar to the Easel used by Cohen.