Extended Dual Rise/Fall

DESCRIPTION

Dual Slopes is a Swiss army knife of a function generator. Similar to the Dual Slopes Compact, it expands on the feature set adding a Bi-Polar singnal output, and Shape Control with both Log and Expo control slope shaping. Rise/Fall (Attack/Sustain/Release) Envelope Generator, Slew Limiter, Gate/Trigger delay, VCO, LFO, Envelope Follower, VC Clock, Filter, VCA and more! In efforts of eliminating cross talk between slopes, the LED driver circuit has been removed from the Main PCB (LGE114). It has been made available on the I/O Board (LGE114A) but if you are flying wires, you’ll need to use our LED driver chiclets or roll your own. Resistor and LED tapped off the output is not advised.

From the original SMMS Catalog:
”The DUAL UNIVERSAL SLOPE Generator (DSG) is the ultimate patch-programmable control voltage generator in the Serge system. At least one (DSG) is recommended for almost every Serge system. and in most cases, a number of these are desirable. People familiar with our previous series of “slewing” modules know about the importance of this kind of function in a large patchable synthesizer system. For those unfamiliar, it is advised that the various applications as outlined here and in the Serge Owner's Manual are studied. The uses of this module are numerous, some duplicating functions found on other synthesizers, some totally unique to the Serge system. Most systems require a number of control voltage generators to control the various signal processors and modifiers. Sources of trigger, pulses (clocks), control voltage processors (portamento's), regular repeating voltages (LFO's) are standard synthesizer requirements. The Dual Slope Generator is the main module providing these functions in the Serge system.

The Universal Slope Generators are unity gain voltage followers with voltage controllable slopes. The range of control is exponential, extremely wide, and the Rise and Fall times can be controlled independently. The range of the Slope Generator is from sub-sonic to high audio frequency. Trigger inputs and trigger outputs allows each section of this dual module to function as a transient (envelope) generator, pulse delay, or in a “cycling mode” (to produce an LFO or clock). Since the Rise and Fall times are voltage controllable, this adds another dimension to the above functions. Two VC inputs are available, one is calibrated at 1 volt per octave (within about 3%), and the other is fully adjustable in the negative and positive direction. This VC input can control either the positive slope (rise), negative slope (fall), or both. The linearity and accuracy of the slewing amplifiers allows them to be used in the most exacting applications, such as processing the output of a keyboard or sequencer to produce portamento functions. Note that this portamento function has a separate rate control for rising notes and falling notes... An interesting portamento effect. Among the functions which one Slope Generator can be patch-programmed to perform are the following:

• VC Transient Envelope Generator. The envelope is simply started with a trigger, or may be used with a gate input to obtain a steady-state sustain level on the envelope. This envelope will repeat if the END trigger output is connected to the TRIG IN input. 

• VC LFO. Patched as mentioned above, a wide-range, low-cost, space-efficient Low Frequency Oscillator can be patched when needed. The Slope Generator is often used as an LFO since it is more cost effective than a regular oscillator switched to a low frequency range. it has a built-in LED to show its current output level, and it has a synchronized trigger output. The waveform can be set from saw to triangle, and the rising ramp can be voltage controlled independently of the falling ramp. 

• VC Portamento device. The accuracy of these devices makes this portamento function useful with keyboards and for generating control voltages of arbitrary shapes and times with computer control. Analog control of slopes allows the computer to do less “number crunching”, and frees the processor from time-consuming routines that are more easily handled in this low-cost multifunctional hardware. 

• Envelope Follower (Detector). The decay rate is voltage controllable with the unique function that under voltage control, the response may be moved from positive peak detection to negative peak detection. 

• VC Pulse Delay (Monostable). When the unit is triggered, it will produce an envelope set by its Rise and Fall knobs (and VC's) and then the END pulse will go high. This may be used to trigger another Slope Generator, ADSR, or advance a sequencer. 

• Sub-Harmonic Series Generator (Divider). If a series of triggers are applied to the TRIG IN jack that are faster than the total rise plus fall time, then the unit will divide the incoming triggers by a whole number. This allows the user to program synchronized rhythmic relationships (such as 2 against 3, 13 against 11, and so on). If the Slope Generators are set to audio frequencies, and the incoming triggers are in the audio range, then the output will be the sub-harmonic series. This is similar to the “hard sync” sound found in other synthesizers (and is the main reason that it is not included on Serge VCO’s). 

• Audio Oscillator. The range reaches 4000 Hz, and the waveform has variable symmetry (saw to triangle). 

• Non-Linear Audio Processor. The slew limiting is voltage controllable, so a sawtooth wave input will progressively be transformed into a triangle wave. This aspect allows the unit to be used as a low-fidelity VCF! “

DETAILS

• DIY 4 Layer PCB

• Current: TBD

• PCB Size: 6” x 2”

DIY Info:
LGE114 Bill of Materials (V1 & V2)
LGE114 Interactive Bill of Materials V2 (still in the works) 
LGE114 Schematic (V1 & V2)
LGE114 PCB Layout w/ Designators (v2)
LGE114 PCB Layout w/ Designators (v1)
LGE114 PCB Layout w/ Values (v1)
LGE114C Schematic (Wiring Diagram) (v2) (Board has V1.1 and V2 printed on it)
LGE114C Bill of Materials(v2) (Board has V1.1 and V2 printed on it)
LGE114C PCB Layout w/ Designators (v2) (Board has V1.1 and V2 printed on it)

Block Format LGE114 PCB (this typically is what will ship with the orders involving the LGE114C and Panel)
LGE114B Bill of Materials (This is one single Slope Generator, so you will need to order 2X this bill of materials for the Dual Rise/Fall)
LGE114B Layout w/ Designators
LGE114B Schematic

Mechanical Parts BOM generally required for building Low-Gain Electronics Modules

Details:

• PCB Size: 6” x 2” 4 LAYER

• Current Draw: TBD

** 4U Modular is a term used for the format most commonly known as “Serge Format” or “Loudest Warning Format”. Out of respect for the ever growing format, 4U Modular is the easiest way to refer to it. More Specifically it refers to the panel height and mounting hole style. 4U Modular will patch up just fine with other 4U "Serge" formats such as "Random Source", but it will not mount in RS boats or Buchla Boats (or power off Buchla power for that matter). An info page about this will be added to the website soon to make this a lot more easy to understand..