ALM-012 ‘SID GUTS DELUXE’ - Operation Manual - Introduction ............................................................................................3 Features ...............................................................................................................4 Technical Specifications .......................................................................................5 Caveats .................................................................................................................5 Core Operation .......................................................................................6 Panel Layout .........................................................................................................6 Overview ...............................................................................................................7 Oscillator control ..................................................................................................7 Filter Section ........................................................................................................8 Wave shape Section ..............................................................................................8 PWM Section   .......................................................................................................8 Modulation Oscillator section ...............................................................................9 Chord section .......................................................................................................9 Limited Warranty .....................................................................................11 Support ...................................................................................................12 APPENDIX I: Technical Info .....................................................................13 Connection of SID chip ........................................................................................13 Manual Version 0.1
 "2 ALM-012 - ‘SID GUTS’ Introduction The MOS Technology 6581/8580 'Sound Interface Device' chip1, aka the ‘SID’, was the sound generator chip used in the Commodore 64 home computer - the greatest selling home computer of all time.  The SID, by the means of 3 wavetable oscillators, a real analogue multi mode filter, an ADSR and various cross modulation options, provided the soundtrack to a generations gaming and perhaps many peoples first exposure to real sound synthesis. The SID’s unique musical aesthetic has lasted well beyond the lifetime of the C64 re-imagined in standalone products such as the SID Station and with in the computer via sophisticated software emulation.  The SID GUTS took the legendary SID chip and tailored it into the eurorack modular environment. By use of a real SID chip the classic sound was taken in a new direction with the levels of direct and voltage control only a modular system can offer.  The SID GUTS DELUXE improves on the original SID GUTS ‘Eurorack SID Voice’ by adding new features to improve usability and further the modular control of available SID chip features. Again the charm and authenticity of the original sound is still preserved with no attempt to 'clean' or reduce noise in the SID audio output.  Both versions of the SID chip are fully supported together with the more modern ‘SwinSID’ hardware emulation. The selected SID can be easy changed at the rear of the module (See appendix I). For instructions on connecting a SID chip to the SID GUTS DELUXE, please refer to Appendix I at the back of this manual. 1 For more info see http://en.wikipedia.org/wiki/MOS_Technology_SID !3 ALM-012 - ‘SID GUTS’ Features As with the original SID GUTS, the DELUXE supports to following SID chip features via modular control; • 1volt per octave control of a ‘core’ SID oscillator. • Direct and voltage control of  oscillator wave shape selection (Pulse, Triangle, Square, Saw) • Filter switchable between 4 modes - 12dB/Octave HP , LP , BP & Notch (HP+LP) • Direct and Voltage control (with offset) of Filter cutoff and Resonance. • 1 volt per octave control of second SID 'modulation' oscillator  • Direct and voltage control of modulation oscillator 'type'; ring modulation, sync or none.  • Direct and voltage control of pulse wave pulse width. • External audio input2 The SID GUTS DELUXE also adds the following new features : • Wider frequency control range (full 8 octaves) with fine and course offset knobs • Improved v/oct tracking, adjustment and stability • Voltage controlled chord mode with inversion and up to 3 voice chords. • Voltage control of filter type selection. • Attenuverters on both PWM and Filter voltage inputs. • All surface mount single PCB construction - lower depth and more skiff friendly. Other features include  • Support for ALL SID chips (6851/8580) & SwinSID chips.  • All settings non volatile • Audio output and input at modular levels.  • Designed and built in England. 2 Not available with SwinSID chip !4 ALM-012 - ‘SID GUTS’ Technical Specifications • Supply: +/-12V • Current Draw: ~50-200ma (up to 200ma with 6581/8580 SID chip installed) • Size: 19 HP  • Depth: 38 mm (slightly more SID installed) Caveats A SID chip is vintage technology! As such there are a number of limitations; • A real SID chip is noisy. • Filter performance varies between chips. • Resonance has very little effect and sometimes even unexpected. • SID chip updates are limited to approx. 50Hz thus very fast (i.e audio rate) modulations will not work as expected. • Vintage SID chips run hot and use a lot of current. Make sure your case is well ventilated and has plenty of available headroom in the power supply. • Vintage SID chips are fragile! Take care in handling. Failed filter sections are unfortunately quite common. • It is strongly recommended for general use a Swin SID is used. !5 ALM-012 - ‘SID GUTS’ Core Operation Panel Layout  Y C Filter Cut off N Pulse wave shape pulse E control. R U width control. E Q M LT E W I R F F P PWM LP BP HP Pulse width CV attenuverter. Filter type Wave selection. Shape - + Filter _ Pulse width CV input. Filter cut off  Chord 0-5V attenuverter.  Mod Osc Res  Mod Sync - + Filter resonance Modulation oscillator offset & attenuator. type selection control. Shape Type V/Oct Filter Resonance CV input. Modulation oscillator 0-5V 1 volt per octave input. 0-5V V/Oct Ext In Type Inv T U O Filter Cutoff CV input. Modulation oscillator 0-5V type selection input. 0-5V External Audio Audio Output. Input. Filter type Oscillator Wave shape Chord mode control. selection Selection. Selection and inversion CV input 0-5V 0-5V control / CV input 0-5V Oscillator 1 Volt per Octave Frequency input and course/fine offset. !6 ALM-012 - ‘SID GUTS’ Overview The SID GUTS DELUXE panel provides both direct user and interfaced voltage control of the various SID chip audio parameters. The SID GUTS DELUXE can be best thought of as a core wave table based oscillator with a built in multi mode filter and a second cross modulation oscillator. This provides classic SID type sounds but with modular levels of control. Synthesised audio is output through the 'output' jack. The external input allows external audio to be passed through the filter. Note this feature is not available with a SwinSID chip. Oscillator control The frequency of the core oscillator is controlled by the 1 volt per octave input the the lower left hand corner of the panel. It responds to approximately 0-8v tracking a range of 8 octaves.  The oscillator base frequency can be offset via the large course and small fine knob controls in the middle top of the panel. The core oscillator can also be turned off by holding the Waveform and Mod Osc buttons simultaneously. All wave shape LEDs will turn off indicating that the oscillator is de-activated. The oscillator can be turned back on by pressing just the wave shape button. This feature can be useful when using an external audio signal (though the oscillator signal can still be apparent at very low volume on some SID chips) The oscillator one volt per octave tracking can be calibrated via the trimmer on the rear of the module. To calibrate apply 1V to v/oct input. Now tune the oscillator via front panel course and fine controls to C1. Change input voltage to 3V and now adjust trimmer on reverse until a C3 is produced. You may want to use a bigger or different voltage/octave interval. Adjust to taste. An ALM Beasts Chalkboard makes a good stepped voltage source but you could use a sequencer, offset through quantiser, offset with a multi-meter etc.. !7 ALM-012 - ‘SID GUTS’ Filter Section The SID chip provides a multimode filter which acts on both its internal oscillator and any external audio signal. The filter mode can be switched cycled between low pass, band pass, high pass and notch (low pass & high pass combined) by pressing the blue filter button. The associated LED's will light indicating the mode. The filter mode can also be voltage controlled via the ‘Type’ input - the mode corresponding to applied voltage level (0-5v). The cut off point of the filter is controlled by the large filter control knob. The cut off point is further offset by the control voltage input and associated attenuverter knob. A voltage applied here will further change the cut off in respect to the filter knob position. The resonance attenuator control behaves differently in that with no jack inserted it acts purely to set the filter resonance. With a jack connected, it becomes an attenuator. There is no offset control. Generally the actual resonance effect provided by the SID is very subtle. Some SID chips exhibit the issue where low (or high) resonance settings will actually cut audio out. Wave shape Section The SID provides 4 different waveform types; pulse, sawtooth, triangle and noise. The wave shape can be selected by either pressing the associated blue button to cycle through types or by applying a 0-5v to the wave shape control input.   PWM Section With the pulse waveform selected, the pulse width of the waveform can be controlled by adjusting the PWM knob. The pulse width can be further controlled via the control voltage input and associated attenuverter knob. A voltage applied here will further change the pulse width in respect to the PWM knob position. !8 ALM-012 - ‘SID GUTS’ Modulation Oscillator section This section provides access to a second onboard SID oscillator which can be used to modulate the main oscillator in interesting ways. The frequency of the modulation oscillator is controlled by the 1 volt per octave input (0-5V range). Modulation type is controlled by both the voltage control input (0-5V) and via cycling through type with the push button. The modulation types are None, Sync and Ring Modulation.  With Sync, The main oscillator is synced to the modulation oscillator frequency.  With Ring modulation, The main oscillator is ring modulated to the modulation oscillator. Ring modulation forces the triangle waveform to be selected (two triangle waves are ring modulated together).  Chord section The SID GUTS DELUXE able to produce up to 3 voice chords which the V/Oct input providing the root frequency of a selected to chord. The type of Chord is selected by the ‘Chord’ control offset and/or a control voltage at the associated Chord input. Like with the resonance control, the Chord attenuator control behaves differently in that with no jack inserted it acts purely to set the selected chord. With a jack connected, it becomes an attenuator. There is no offset control. Further to this Chords may be inverted by applying a voltage to the Chord ‘Inv’ input. Increasing the voltage increases the amount of inversion. If the modulation oscillator is enabled it will take priority over a chord voice and can produce unexpected results. Experiment. Please note Multiple voice chords can increase levels quite dramatically and cause distortion. !9 ALM-012 - ‘SID GUTS’ The chord selection is as follows; 1. Fifth 2. Major 3. Minor 4. Suspended 5. Augmented 6. Diminished 7. 1 Octave 8. 2 Octave 9. Detuned 10.Detuned !10