Module A-110-1 is a voltage-controlled oscillator. This VCO’s frequency range is about eight octaves (ca. 15Hz … 8kHz). It can produce four waveforms simultaneously: rectangle, sawtooth, triangle, and sine wave (triangle and sine shapes are not perfect, see remark below). The output levels are typically 8Vpp for saw and rectangle, and 10Vpp for triangle and sine. The frequency or pitch of the VCO is determined by the position of the octave (Range) switch and tuning (Tune) knob, and by the voltage present at the CV inputs.

Frequency modulation (FM) of the VCO is therefore a possibility. Footage (the octave of the fundamental) is set by the Range control in five steps, and Fine tuning controlled by the Tune knob by about +/-1 one semitone (can be modified for a wider range).
You can control the pulse width of the square wave either by hand, or by voltage control – Pulse Width Modulation or PWM.
For more detailed information please look at the user’s manual A110_man.pdf. In addition the A-110 service manual is available as an example for the A-100 service manual that is available at extra charges. This document describes also how to modify the sensitivity of the tune control, how to re-adjust the 1V/octave scale and the frequency offset (i.e. the absolute pitch). Such modifications should be carried out by experienced users only !

Technical remarks:
The core of the A-110-1 is a sawtooth oscillator (in contrast to the A-111-1, which is based on a triangle oscillator). The other waveforms are derived from the sawtooth by internal waveform converters. As the sawtooth reset (i.e. the back-to-zero slope) is not infinite fast but takes a little bit of time the derived waveforms triangle and sine are not perfect ! At the top of the waveform they have a small glitch or notch that is caused by the sawtooth reset and cannot be eliminated by the waveform converters. The sine is derived from the triangle by a simple diode-based converter and the sine shape is not perfect (only a rounded triangle). To obtain a nearly perfect sine signal the triangle-to-sine converter module A-184-2 is recommended. It includes also a voltage controlled crossfader to fade between two waveforms.

If a perfect triangle is required the A-111-1 or A-111-2 is recommended. For a perfect sine wave the thru zero quadrature VCO A-110-4 or the quadrature LFO/VCO A-143-9 is recommended.

The sawtooth output of the A-110-1 has a falling (or negative) slope as shown on the front panel.

A simpler VCO (without sine, without rotary switch, but with linear FM input) is the module A-110-2.

Module A-110-2 is a low-cost voltage-controlled oscillator. It’s a slightly reduced version of the standard VCO A-110-1. Compared to the A-110-1 the A-110-2 has no sine output and the (expensive) octave rotary switch is replaced by a 3-position toggle switch. In return the A-110-2 is equipped with an additional linear FM input and a soft sync input. A jumper is used to select the range of the tune control between about 1/2 octave and about 4 octaves. The width of the module is only 8 HP compared to the 10 HP of the A-110-1.

All other features are essentialy the same as for the A-110-1.

Explanation of the jumpers and trimming potentiometers:

JP2: CV connection to A-100 bus
JP3: range of Tune control (installed = about 4 octaves, not installed = about 1/2 octave)
JP4: AC/DC coupling of the linear FM input (installed = DC coupling, not installed = AC coupling)
P5: 1V/Oct scale
P6: frequency offset
P7: high-end trim
P8: adjustment +1 Oct. range switch
P9: adjustment -1 Oct. range switch
P10: temperature VCO heater
Technical remarks:
The core of the A-110-2 is – like the A-110-1 – a sawtooth oscillator (in contrast to the A-111-1, which is based on a triangle oscillator). The other waveforms are derived from the sawtooth by waveform converters. As the sawtooth reset (i.e. the back-to-zero slope) is not infinitely fast but takes a little bit of time the triangle is not perfect ! At the bottom of the waveform it has a small glitch or notch that is caused by the sawtooth reset and cannot be eliminated by the waveform converter. If a perfect triangle is required the A-111-1 is recommended.

The sawtooth output of the A-110-21 has a falling (or negative ) slope. The front panel shows erroneously a rising (or positive) slope. This has no influence to the sound but becomes important when the module is used as an LFO or is mixed with the sawtooth output of another VCO.

To obtain also a sine signal the triangle-to-sine converter module A-184-2 is recommended. It includes also a voltage controlled crossfader to fade between two waveforms.

A-110-4 is a so-called Thru Zero Quadrature VCO. The term “quadrature” means in this connection that the oscillator outputs sine and cosine waveforms simultaneously. The term “Thru-Zero” means that even “negative” frequencies are generated. But this a bit a misleading term as negative frequencies do not really exist. “Negative” means in this connection simply that the sine/cosine waves will stop when the linear control voltage reaches 0V and continue with the opposite direction as the linear control voltage becomes negative and vice versa.

The module has two control sections: linear and a exponential. The exponential section consists of the XTune control, the 1V/Oct input and the XFM input with the corresponding attenuator XFM. The exponential control voltage is the sum of these three voltages. The linear section consists of the LFrq control and the LFM input with the corresponding attenuator LFM. The linear control voltage is the sum of these two voltages. A dual color LED is used to display the polarity of the linear control voltage (red = positive, yellow = negative). The pitch of the sine/cosine outputs is determined by the control voltages of both sections. The linear section is used to control the pitch in a linear manner. When the LFrq control (LFrq means Linear Frequency Control) is fully CW the module works like a normal Quadrature VCO (e.g. like the A-143-9) and the LED lights red (red = positive). The pitch is then controlled by the exponential section with the manual Tune control XTune and the exponential frequency control inputs 1V/Oct and XFM. 1V/Oct is used to control the pitch by a 1V/Oct CV source (e.g. sequencer or Midi/USB-to-CV interface). XFM is used to apply an exponential frequency modulation with adjustable depth (e.g. from an LFO or another VCO). As the LFrq control is turned counterclockwise starting from the fully CW position the frequency is lowered in a linear manner until the sine/cosine waves (nearly) stops at the center position of LFrq (provided that no LFM signal is present). As the LFrq control is moved from the center towards the CCW position the wave starts again but into reverse direction and the LED turns yellow. When the fully CCW position of LFrq is reached the module works again like a normal Quadrature VCO. But much more exciting is the usage of the LFM input to modify the linear control voltage by an external control voltage (typically another sine VCO like a second A-110-4 – but even normal VCOs can be used). Linear modulation by another oscillator using the thru zero feature generates audio spectra than cannot be obtained from an oscillator without the thru zero function. The reason is that a “normal” VCO will simply stop as the linear control voltage becomes zero or negative. But a thru zero VCO will start again with “negative” frequencies as the the linear control voltage becomes negative.

The main advantage of the A-110-4 compared to other Thru Zero VCOs is that the design uses a sine/cosine core. The sine/cosine waves are not derived from other waveforms (e.g. sawtooth or triangle) by means of waveshaping. Rather the sine and cosine waves are the core of the VCO which results in very pure waves with a minimum of distortion and overtones.

The output level is about 3Vpp. Audio examples and oscilloscope pictures will follow soon.

Important note: Please remove the bus jumper (JP3 “BUS CV”) if no CV transmitter is installed on the same bus (e.g. a Midi/USB-to-CV interface A-190-x or a bus access module A-185-x). The A-110-4 applies a small voltage with high impedance (100k) to the CV line of the bus when the bus CV jumper is installed. This may affect other modules that pick-up CV from the bus (e.g. other VCOs). As soon as a CV transmitter is installed on the same bus the high impedance voltage of the A-110-4 is overwritten and no problem occurs !

Additional technical notes:

The document A110_4_trimming_potentiometers.pdf explains the functions of the trimming potentiometers. The document is planned only for experienced users ! Please do not change the settings of the trimming potentiometers unless you are sure that you want to change certain settings. Modules which are returned with (mis-)adjusted trimming potentiometers cannot be treated as case of warranty !

The output levels of the module are connected with the waveforms. The two trimming potentiometers P5 and P8 are used to adjust both the level and waveform simultaneously (P5 for the positive share, P8 for the negative share). In the factory they are trimmed for lowest distortion of sine and cosine which results in about 3 Vpp. The settings of the trimming potentiometers P5 and P8 can be changed for higher output levels. But in this case the distortion will increase (i.e. the waveform is no longer a perfect sine/cosine). If the settings are changed one has to pay attention that the levels are the same for the positive and negative share. We think about a small dual amplifier board that can be added to obtain higher levels without the disadvantage of higher distortion. Independent from this an external amplifier can be used to increase the level (e.g. A-183-3).

It is also possible to convert the A-110-4 into a Thru Zero Quadrature VCLFO by adding two capacitors to the frequency determining capacitors (C1 and C2). For details please refer to the document A110_4_trimming_potentiometers.pdf.

Module A-113 is a new sound source that derives from an incoming pulse signal four so-called subharmonics (German: Subharmonische). The term subharmonics was introduced by Oskar Sala in connection with his so-called Mixtur-Trautonium. A subharmonic means in this context a sawtooth wave (German: Kippschwinger) whose frequency is derived from a master frequency and the master frequency is an integer multiple in the range of 1…24 of the subharmonic – in other words: the master frequency is divided by an integer 1…24 to obtain the subharmonic. Pay attention that the output waveform of a subharmonic is sawtooth (as also used in the original Trautonium) and not sine. The term subharmonics is somewhat misleading. The master frequency comes e.g. from an A-110 or A-111 to the frequency input of the A-113. The frequency dividers of the 4 subharmonics is adjusted with up/down buttons as displayed with 2 character LED displays. The subharmonics are available as single outputs and as mix output with adjustable levels for the subharmonics.

Two gate type control inputs enable to select between 4 different mixtures, i.e. 4 different settings of the frequency dividers. In the original Trautonium these are controlled by foot switches to switch between 3 mixtures while playing (the original Trautonium has only 3 mixtures available but with the 2 gate inputs of the A-113 four different settings can be adressed).
Additionally the A-113 features a mixture memory with 50 presets. Each preset consists of 4 mixtures that can be selected with the gate inputs, each mixture contains the values of the 4 frequency dividers.
More detailed information about the Trautonium can be found on our internet site in the Trautonium project article. These additional Trautonium modules are available: Trautonium Manual A-198, Trautonium Filter A-104.
Inputs : master frequency (rectangle/pulse input), foot contr. 1 + 2 (gate 1+2)
Outputs: 4 single outputs, 1 mixture output

Module A-114 contains two separate ring modulators. A ring modulator outputs the product (Multiplication X • Y) of the signals at inputs X and Y. It’s similar to a VCA, but whereas a VCA only responds to positive voltages at the inputs (2-quadrant multiplication), the ring modulator responds to both positive and negative voltages (4-quadrant multiplication).

The ring modulator thus provides a refinement of amplitude modulation (AM). Ordinary amplitude modulation will output the original carrier frequency fC as well as the two side bands (fC – fM, fC + fM) for each of the spectral components of the carrier and modulation signals – but ring modulation cancels out the carrier frequencies, and just lets the side-bands pass to the output (see Fig. 1).
A ring modulator is used for the production of bell-like sounds, alien voices, or just to produce new timbres.

Module A-115 is a four-way frequency divider. The frequency of a signal at the input is halved (half frequency = first sub-octave), quartered (1/4 frequency = second sub-octave), and so on. In this way, the DIVIDER produces four sub-octaves (F/2 down to F/16).
At the output, the A-115 produces a summed mix of the original and the four sub-octaves. There are attenuators to control the amount (ie. Amplitude) of the original signal and each of the sub-octaves.

Bear in mind that the sub-octaves output by the A-115 are all true square waves. At the output there are always four square waves and the original signal available.

Module A-116 provides voltage-controlled dynamic waveform modification of audio signals. It can produce new waveforms from the standard VCO shapes, and modulate these changes in real time. The signal first of all goes through an input amplifier, which can attenuate the signal as well as amplify it by up to a factor of 2.

After the input amplifier, the signal goes through two parallel processors: a clipping circuit, and an asymmetrical amplifier. The processed signals are added together and sent to the output.
Clipping-Level and Symmetry amounts are not just manually controllable, but can also be modulated by control voltages, to produce complex, constantly changing waveforms.

Module A-118 is (as you might have guessed) a noise and random voltage generator. It produces three types of signal: white noise, colored noise, and random voltage. The noise signal is generated 100% analog by amplification of the noise of a transistor. White and colored noise can be used as audio sources, and also, in conjunction with a sample & hold module, as control voltages, and the random voltage is a useful source of voltage control, especially for its low frequency content.

The A-118 gives you the ability to mix the relative amounts of Red (low frequency component) and Blue noise (high frequency component) in the colored noise output.
There are knobs to control the rate of change and amplitude of the random voltage, and two LEDs indicate the state of the voltage at any one time.