A Range Switch and Pot Pourri Module for The Chemical Brothers

July 23, 2013 in EA Modules, Exclusively Analogue

Recently we had an order from a guy called Tom Rowlands who was after a Range Switch and Pot Pourri to fit into his Emu Modular system. At first glance it was another name at the bottom of an email we received. Tom put in a request and asked if we would go to his studio to fit the modules and it was only after a bit of digging that we realised who Tom actually was – one half of the very successfull Chemical Brothers. If you are not sure who they are you might like to look on YouTube at a video of the “Horsepower’ track by the Chemical Brothers.

Tom has a very enviable collection of analogue synthesizers in his studio, enough to keep any ‘electro-musician’ occupied for ages creating interesting sounds. His Emu modular system was one of the late versions with the improved large VCOs allowing Hard Sync and Linear FM but interestingly the modules were not organised in a ‘classic’ manner and there was no pre-patching at all. After discussing the options with Tom some modules were moved around and the new Range Switch and Pot Pourri added. Tom liked the added functionality the Range switch gave to the VCOs and he agreed that the normal arrangement of having a single turn pot for the Course (10 octave) frequency control on the Emu was not ideal. On the EA VCOs we’ve fitted a 10 turn high quality pot for the Course frequency control which makes life easier. Having the instant, and accurate, octave shifting that the Range switch gives makes life even easier.

The Pot Pourri, with the two LFOs, Noise source, Sample & Hold, and 2 Inverters was fitted between Tom’s two Dual Transient Generator modules so that the inverters were readily available to invert the DTG outputs for use on things like the Universal Active Filter. An inverted envelope is really good on High Pass or Band Pass filters especially if they are resonating slightly. Quite a few synthesizers don’t offer the option to invert the envelope but it was one of the first things that was included in the design of the Aviator.

After a quick look at Tom’s Emu we identified a few things that needed repairing and we’ve also suggested a bit of re-organising of the modules as well as the addition of the pre-patching. If this work goes ahead, and we hope it does, it would be great to think that the Emu system we’ve worked on might feature on the next Chemical Brothers album.

New Modules Available – VCO Range Switch, Pot Pourri, Ring Modulator & Lag Processor

May 3, 2013 in EA Modules, Exclusively Analogue

Following interest in the UAF and conversations about what other modules we’re building this post looks at what’s currently available to order and what’s coming shortly.

  • The Universal Active Filter is a faithful reproduction of the Emu module and although some alternative components have been used to replace the original, impossible to get, dual transistors this change has not affected the sound at all. I have done extensive side by side testing to confirm this and spent a lot of time matching the transistor characteristics.
  • The VCO Range Switch module is a useful addition to a system since it allows instant octave shifting of any 1Volt/octave VCO. 3 individual VCOs can be controlled by this unit and although designed for the Emu system it can be fitted to any modular provided there is a suitable Power Supply.
  • The Pot Pourri module is my take on the Emu Pot Pourri module and includes 2 Low Frequency Oscillators, 2 Analogue Inverters, a basic Noise Source, and a Sample and Hold (S&H). I find having the two LFOs in a system really useful and by having the addition of a S&H, which uses the Noise and LFO2 as the source and clock, adds a lot to any modular. A particularly ‘pleasing’ effect can be achieved by using the Gate signal to clock the S&H which is then fed to the Filter Frequency control. The result is random shifts of the filter frequency, especially good with a high resonance setting, that happen in sync with the notes being played.

We’ll shortly be releasing Lag Processor and Ring Modulator modules and will make sure there’s a post on the site when those are ready to order.

  • The 2340 Voltage Controlled Lag Processor performs a rate-limiting function on its input; it introduces a linear or exponential slide in the output voltage if the input voltage changes faster than a certain rate. Typically it is used to process control voltages—for example, it can give voltage controlled portamento when its input is a keyboard control voltage and it can turn a gate into a voltage controlled attack/release transient generator. One feature I like is that you can set it to only give glide on an increasing keyboard voltage but not a decreasing voltage or vice versa which is subtly different from the normal ‘always glide’ on most synths.
  • The 2430 Ring Modulator is a balanced modulator for electronic music. The module has two inputs, modulation and carrier, which are identical for high signal levels. The output is the algebraic product of the input voltages: Vout = Vmod x Vcar Ă· 5 when the input attenuators are fully clockwise and the coupling switches are in the DC position. AC coupling will level-shift the corresponding input so it effectively centers around zero volts. This can have a striking effect on the output signal, due to the inherent non-linearity of balanced modulation.