
doepfer a1439 voltage controlled quadrature lfo
price : $99.00


this module a1439 is a derivative of our planned thruzero quadrature vco. it is a voltage controlled sine lfo with 4 outputs. the phase
shift between the outputs is 90 degrees. the sine shifted by 90 degrees is also called cosine, the sine shifted by 180 degrees is nothing
but the inverted sine, and the sine by 90 degrees is nothing but the inverted cosine.
the frequency range is from some minutes to moderate audio (a few khz) with three ranges selected by a toggle switch. two frequency
control inputs are available: cv1 without attenuator and cv2 with polarizer. consequently the module can be used even as an experimental
sine vco but does not feature an exact 1v/oct cv input! the precision cv input will be left to the thruzero quadrature vco.
a1439 waveform
two leds display the positive and negative share of the sine output.
the core of the module is a socalled quadrature circuit that generates a sine a cosine signal with very low distortion. the quality of
the sine/cosine signals are much better than those generated by a waveform converter with a sawtooth or triangle signal as starting
point.
the output levels are about 5 vss (+/2.5v) but can be adjusted internally by a trimming potentiometer.
typical applications:
external sine/cosine oscillator for the frequency shifter a126
modulations with pure sine/cosine waveforms
quadrature/barberpole effects (e.g. with the voltage controlled mixer a135)
experimental sine/cosine vco (e.g. for fm sounds)
a1439 spectral analysis
many users suggested to add a common output level control, i.e. four vcas with one common control (manual + cv without attenuator + cv
with polarizer) for the output levels. this is why we also designed the quad vca module a1322 with the
possibility of an internal default connection to the four outputs of the a1439 (no soldering required, short 10 pin flat cable with
removable connectors on both ends).
this module has a maximum current draw of 30ma. it requires 8 hp/te worth of space to fit in a eurorack frame.
