Studio Electronics Tonestar 8106

Here's What Studio Electronics Say About The Tonestar 8106:

TONESTAR 8106, an ARP® 2600-inspired complete synth voice, infuses Tim Caswell's "Jupiter to Juno" filter alchemy—a 6db/oct hi-pass filter followed by a recreation of the Roland IR3109 module—into our Tonestar 2600 platform; this chirpy yet full-bodied 8106 model is also fully #OutsToOuts modular featuring 27 pots—one more that the 2600 model for the high-pass filter, 6 switches—one less, sacrificing resonance modulation for that high-pass filtering, and 21 jacks. If the Tone☆ 8106 thins somewhat with resonance excess, route the triangle wave 'round the VCF with the "NO VCF" switch setting, and keep this juicy reimagining of the Roland® IR3109 module boomin' and gloomin'.

Caswell Knowledge (circuit designer talk): "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 exacting 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 produce unexpectedly interesting, x-mod/notch filtering—quite pleasing effects.

The Tonestar was Greg's concept, but as I understood it, the goal was a single oscillator, 2600 VCF (initially), 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, for root-to-leaf sound design, and multiform analog exploration/expression."

Features

27 Knobbed and "Shafted" Potentiometers

• VCO: Range, PM MAN, LFO, PORTA, MOD (ENV), Triangle, Saw, Square, Sub, Tune
• Noise: Level
• VCF: Freq, Res, KBYD, Drive, HPF, ENV, MOD (LFO)
• LFO: AMNT (OSC), Rate
• ENVs: (ADSR) Attack, Decay, Sustain, Release, (AR) Attack, Release
• VCA: Feedback (filter/VCA), Volume

6 Switches

• VCO: OCT (up/null/down); Freq/PW (frequency/null/pulse width); NO VCF (VCF/null/no VCF);
• VCF: Triangle/Square (triangle/null/square)
• ENVs: Hold, MSTR (hold/null/master)
• VCA: In/Mix

21 Jacks

• VCO: Triangle, Sawtooth, Square, Mix, 1V/O, Mod In
• Noise: Noise (white)
• 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

Vitals

• PCB Mounting Scheme: Through-hole.
• Filter: A 6db/oct hi-pass filter followed by a recreation of the Roland® IR3109 module, which is a 4 pole, 24 db/oct voltage controlled lowpass filter with voltage controlled resonance. 3 dual OTAs with similar topology to the BA662 used in the Jupiter 8 (and the IR3109 module) were employed, 1 amp for the hi-pass filter, 4 (with added buffers) for the low-pass, and 1 for the resonance. This filter takes a wide range of input signals, and tracks control voltage extremely well. Tap points are available for 6db, 12db, and 18db/oct. Although the topology is similar to the 4072, the tonality, especially when over driven, is distinct.
• Size: 32hp.
• Depth: 35mm including connectors.
• Power Usage: 130mA, 80mA (+12 / -12)