Studio Electronics Boomstar - Manual (Page 5)

Studio Electronics Boomstar Manual 1 Design Behind the ‘Stars
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THE DESIGN BEHIND THE ‘STARS
As SE fans know, we’ve been doing the multiple filter thing for some time, and while our approach has never been
one of exact emulation of the original synthesizers—that could only be accomplished if the entire signal path were
cloned as well—the focus and purpose was, and remains, to bring the main essence—the “spirit” of the classic
originals into our own unique, performance-based platforms, and in the case of the Boomstar accomplish that
with as many hardware features, i.e., crossmod, ringmod, overdrive, feedback, that would fit! Judging from the
many flattering remarks (from owners, well-wishers, followers), and downright effusive praise, satisfaction has been
achieved—and thanks to all!
Critical Circuit Details: For oscillators we’ve essentially been using the same Moog-based design since our reissue
of the MiniMoog® stabilized oscillator board. In the Boomstar synths we replaced the Fairchild cans with 3046s,
which are stabilized with temperature compensating resistors placed on top—something very similar to what is in
an S.E.M: it gives us just the right amount of warmth and tuning stability. The Moog® filter employed in all our own
synths is a clone, except that in the Boomstar 5089, a 3046 replaces the original hand-matched transistors in the
top and bottom of the ladder. The resonance produced is lovely; it sits perfectly along with the signal, singing out,
but never dominates. The 4075, 3003, and S.E.M. are faithful to the original circuit designs, with some license taken
by Tim Caswell in case of the SE80 filter, due to 1970s custom filter ICs employed in Yamaha’s design. The VCA in the
BoomStar is the MiniM—g® VCA, which we used in the SE-1(X) as well, while the Omega and ATC series synths use
a VCA incorporating an LM13700, in case you were wondering.
These are “through-hole” (to be contrasted with “surface-mount”) and decidedly discrete analog synthesizers: the
Holy Grail of PCB assembly procedures, built to last and remain completely serviceable—bound to be necessary if
they stick around making people happy as long as we expect them to!
Greg St. Regis 5.3.14
El Segundo, CA USA