studio electronics tonestar 2600 price : $549.00

tonestar 2600 is an arp® 2600-styled synth voice, 31 years in the shaping, pre-patched like pearlman's prized 2600, and fully "outs to outs" modular. connect cv / gate and twist 'n' switch, or pull its tones and voltages apart one 3.5mm cord at a time. 26 knobs, 7 switches, and 21 jacks make for complex and satisfying signal flow, color and collisions. if it gets reedy, route the triangle wave 'round the vcf.

caswell knowledge (circuit designer):
"the vco is the same affair as the oscillation, the boomstar, and the omega. it's kind of a combination of arp®, oberheim® and moog® circuits (sort of a greatest hits), time-tested, very stable-very good tracking over a very large range; certain parts have to be hand selected to achieve that level of performance.

envelope fyi: the tonestar sustain control replicates the behavior of the 2600 and odyssey: after the initial decay, it continues to move (sink) very slowly, adding a little extra texture to the sound. it's technically a flaw, but after digging out my odyssey, it is for sure a desirable "quirk", and the perfect companion to the 4072 filter.

another bit of fun: the lfo is voltage controlled, so you can envelope, lfo, or otherwise modulate both the rate and the depth; the adsr amount is also voltage controlled, so it can be manipulated by midi dynamics, midi volume, an lfo, etc. greg [st. regis] has decreed that anything must be patchable to anything, so some technically wrong patchings (for example pulse wave out to adsr out) may often do unexpectedly interesting and pleasing things.

the tonestar was greg's concept, but as i understood it, the goal was a single oscillator, 2600 vcf, pre-patched and yet fully modular classic synth voice, at a specific size, wielding every trick we could cram in. main use would be as a go-to bassline/lead tool, or a premium quality, entry-level, complete synth module (sans case and power) [for root-to-leaf sound design and multiform electronic illumination]."

( ) represents normalled connections, which will be explained in greater detail before long.

26 knobbed and "shafted" potentiometers
vco: frequency, pulse width, lfo (^), glide, mod (adsr), saw*, square*, sub, tune; noise: noise, level; vcf: frequency, resonance, track, drive, adsr, mod (lfo); lfo: depth (osc), speed; envs: (adsr) attack, decay, sustain, release, (ar) attack, release; vca: feedback (filter), volume

7 switches
vco: oct (up/down), freq/pw, no vcf; vcf: freq/reso; lfo: triangle/square*; envs: drone, master; vca: in/mix

21 jacks
vco: triangle*, sawtooth*, square*, mix, 1v/o, mod in; noise: noise; lfo: depth, triangle*, square*, speed; vcf: ext in, fil out, mod in; envs: mod in, adsr out, ar out, gate in; vca: in/mix, vca in, output

vco:
frequency - oscillator frequency attenuator.
pulse width - variable pulse wave width control.
oct - +1/-1 octave switch.
lfo (^) - triangle wave low frequency oscillation to pulse width control.
freq/pw - oscillator frequency, or pulse (square wave) width to adsr modulation routing switch. center off.
glide - slew generator control.
triangle*/no vcf - triangle to vca switch-bypasses vcf.
mod (adsr) - oscillation modulation via adsr control.
sawtooth* - sawtooth wave attenuator.
square* - square wave attenuator.
sub - square wave sub oscillator attenuator.
triangle* - waveform output.
sawtooth* - waveform output.
square* - waveform output.
mix - composite waveform output.
1v/o - one volt per octave control voltage input.
tune - master fine tune (approx. -5/+ 5 semitones).
mod in - modulation cv input. normaled to adsr; adsr is replaced when alt. source connected.

noise:
noise - white noise generator on/off switch.
level - noise attenuator.

vcf:
frequency - frequency, or cut-off attenuator
resonance - resonance, or q attenuator.
track - keyboard/voltage tracking attenuator.
drive - oscillator output to filter input attenuator.
freq/reso - filter frequency, or resonance to lfo modulation routing switch. center off position.
adsr - filter to adsr envelope attenuator.
mod (lfo) - filter to lfo attenuator.
ext in - external audio input.
fil out - filter audio output.
mod in - frequency or resonance modulation cv input.

lfo:
triangle/square* - waveform select switch (triangle core).
dpth (osc) - lfo to oscillator control.
speed - speed or rate attenuator.
depth - control voltage input.
triangle* - triangle wave output.
square*- square wave output.
speed - speed or rate cv input.

envs:
attack - attack stage control.
decay - decay stage control.
sustain - sustain stage control.
release - release stage control.
drone/master - indefinite/instant sustain, and master mode for adsr routing switch. center off.
attack - attack stage control
release - release stage control.
mod in - modulation input.
adsr out - adsr output.
ar out - ar output.

vca:
feedback - oscillator/filter feedback loop control.
volume - master volume control.
vca/cv - amplifier control voltage output.
in/mix - vca mix input switch switch (normalled jack). when set to in, external audio replaces filter output to vca; when set to mix mix, filter output is fed along with the filter audio to vca.
vca in - audio input.
output - main output.

vitals:
pcb mounting scheme - through-hole.
filter - discrete, voltage controlled, 24/db/oct cascaded transconductance low-pass filter, employing six pairs of hand-matched transistors.
size - 32hp.
depth - 35mm including connectors.

production notes
units #2-15 - noise is pink not white, and a bit low in level. we've since switched to white and pumped up the volume. however, the pink might appeal to some who would yet enjoy more of it. easy install custom mod. information/tutorial available 6-6-16.

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