A friend lent me his BIT 01 Rack Expander (serial no 67), so I'm able to give you sort of a review of this Crumar synth from 1986. The BIT 01 is the expander version of the BIT 99, which is the successor of the BIT ONE from 1985. The front panel The BIT 01 is a 19" module, 3 units high. On the left side there are 4 two digit 7 segment LED's labeled VALUE, ADDR/S.D.PROG No, LOWER PRG, UPPER PRG, a PARK/WRITE button(*), a tune pot with small knob. Next row OFF(-), ON(+) button, numeric buttons 1-5, COMPARE(*), STEREO OUT(*). Next row numeric buttons 6-7, SPLIT/LOAD(*) button. Last row two sliders LOWER/UPPER VOL, ADDRESS(*), LOWER(*), UPPER(*), DOUBLE/SAVE(*) and TAPE(*) button. The marked (*) buttons have an indicator LED. On the right side there is a block diagram of the synth engine, to remind you of the 73 possible ADDRESS values (cool light blue color). The panel is black, white symbols and green lines. Later they turned from black to white and symbols in black, red lines. There are two handles left and right (for this high-tech profi look) so you can carry the BIT with you easily. And not to forget the power switch. The synth engine The signal path is DCO1/2 - VCF - VCA plus LFO1/2, classical analog. The DCOs are almost similar. Range 32', 16', 8' or 4'. Waveform tri, saw, pulse or combinations. Tune in semitones, only up, only on octave. Pulsewidth. PW modulation by velocity. No PW mod by LFO. Now the only difference. DCO1: noise, DCO2: detune. Oh, 6 voices. The VCF has its own ADSR with attack modulation by velocity. Keyboard tracking, cutoff, resonance, envelope amount, modulation of env amt by vel. One can invert the envelope. (technical remark: the filters are CEM 3328, Four Pole Low-Pass VCF) The VCA has a ADSR with attack mod by vel, amt mod by vel and total volume. The LFOs have tri, saw and sqr as waveforms, one can mix them. They can modulate any combination of DCO1, DCO2, VCF or VCA. Delay, rate, rate mod by vel (funny isn't it), depth and wheel amt (that's common for both LFOs). The difference is 1 has saw up, 2 has saw down. Misc features MIDI - One can enable/disable pitch bend, mod wheel, rel pedal, prog change, omni mode and select the recv chanel. SPLIT/DOUBLE - Split point, lower trans, lower/upper vol. With the two seperate outs a glance of multitimbrality. User interface What? Press ADDRESS button, type in the two digit parameter number, use +/- keys to change value. That's the harsh charme of the mid '80s. The Rear Panel Memory Protect on/off Release Pedal in Midi in/thru Tape in/out Lower out Upper out Power in Sound Rich, warm, fat ... well ... analog. But a drawback of the DCOs is anoying CLOCK NOISE in the bass, thats bad. I miss the LFO PWM, OSC SYNC and RING MOD. There is a good piano over one octave :-). Another shortcoming of the digital ADSRs is, imagine a slow high resonance filter sweep by env, you expect to hear a DIIAAOOUUWW, but you get DIDIDADADODODUDUW. The fc decreases in steps, that can be heard. ---------------------------------------------------------------------------- + Georg Mueller, Darmstadt, Germany + georg@nlp.physik.th-darmstadt.de + ----------------------------------------------------------------------------