Crumar Bit One, courtesy of Sound on Sound.

A polyphonic analog synth introduced by Crumar in 1984. (It should not be confused with the Bit-01, a rackmount synth that appeared later.) It was Crumar's attempt to get into the budget analog polysynth market which, at the time, was dominated by Roland and Korg. As introduced, "Bit" was originally intended to be the brand name -- Crumar's marketing department felt, with some justification, that the Crumar brand name was not highly regarded by most performers at the time. The Crumar name did not appear anywhere on the case. (The high-end Synergy synth had been previously introduced under the name of Crumar's U.S. subsidiary, Digital Keyboards.) Ultimately three Bit models were produced, of which the Bit One was the first. Unlike the later models, the Bit One was only available with a black panel.

The voice architecture was more generous than the competing products from Roland and Korg. Six voices each consisted of two DCO's, two LFOs, one envelope generator, one VCF and one VCA. (The DCOs formed the triangle and pulse waveforms by adding trains of square waves, in a manner similar to the Korg Poly-800, and they had some audible artifacts.) The synth had a bitimbral mode, in which the keyboard was split, with three voices assigned to each half, and each group could play a separate patch. There was also a "double" mode in which each note played two voices, which layered two patches. Unison mode was also available; if it was selected when the keyboard was split, each half of the keyboard stacked three voices on each note. In any bitimbral mode, it was possible to obtain the outputs of the two patches via separate jacks on the rear panel.

The five-octave keyboard included velocity sensing, which was unusual for a lower-priced synth of that era. Performance controls included a pitch wheel and a modulation wheel, on the panel and in a vertical arrangement with the mod wheel above the pitch wheel, which performers disliked. The pitch wheel only had a range of +/- three half steps. The modulation wheel was hard-wired to control the amount of the LFOs fed to the pitch inputs of the DCOs. Patch memory consisted of 63 memory locations, and the user selected a two-digit patch number using a numeric keypad. Patch editing was via a one-knob interface and could not be done on the fly. To edit a patch, the performer dialed up an "address" (a parameter selection number) using a rotary encoder. The value could be changed only using a pair of increment/decrement buttons, which was cumbersome when changing a parameter with a large adjustment range. A large graphic silkscreened onto the panel guided the user as to which addresses corresponded to which parameters.

Weirdly, there were two important parameters that were not memorized by the patch memory: the detune amount between the VCOs, and the white noise level. These were controlled by sliders on the panel, and had to be manually adjusted between patches. two other sliders controlled the relative levels of the "upper" and "lower" patches; the manual noted that when not operating in a bitrimbral mode, it was necessary to set the "lower" slider all the way up in order for all six voices to sound at the same volume. Signal and control routing were generally fairly flexible, but there were a few odd omissions. In particular, performers complained about not being able to route the LFOs to pulse width modulation, and not being able to adjust the relative levels of the two DCOs. Saving the memory contents was provided via a cassette interface.

The MIDI implementation was very limited; this might have been the Bit One's most significant limitation. The synth transmitted only Note On (with velocity) and Note Off messages, and it transmitted only on channel 1. It received note, Program Change, Pitch Wheel and Modulation messages. Normally, it received in Omni mode, but it would recognize Omni Off and then receive on channel 1. It accepted a few sysex messages to change the split/layer modes, and to change the keyboard split point (which otherwise could only be changed by holding down a keyboard key while powering the synth on). It could not load or save patches, or change patch parameters, via MIDI.

The Bit One was manufactured through about 1987. There were several revisions; most of these were circuit revisions that were transparent to users. The first production units used SSM 2044 VCF, but somewhere in the range of serial numbers 250-300 (sources differ), Crumar switched to the Curtis 3328. The units with the SSM filters seem to be slightly preferred by collectors. A "Rev 2" model may have been produced, or at least prototyped, containing some of the changes that would later appear in the Bit-99, including making the DCO detune and noise level patch parameters, and adding a front panel master tune control. (The numbering of the three Bit models ended up being confusing. The Bit One and Bit-99 are keyboards; the Bit-01 is a rackmount.)


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