Rhodes Chroma Polaris (1984)

Son of the legendary Arp-Fender Chroma synthesizer: the Polaris is a kind of second version a little simpler but still powerful version.

The machine was originally designed by the ARP engineers, but then ARP society was bought by Rhodes 2 years before the commercial release.

KEYBOARD 61 keys with basic velocity system.
Main panel features 23 sliders and 62 buttons for edit process; central slider is assignable to one of the 14 available parameters while on the right side there are 2 levers for modulation and pitch bender.


Back panel terminal connectors:
- mono audio out (high / low impedances)
- headphones out
- tape interface
- Midi interface
- sync IN or OUT for sequencer synch
- custom chroma interface connector (for APPLE II computers)
- pedalswitch input for sequencer start and sustain.

 

SOUND machine core is a 8-bits CPU Intel 80186 manages 6 voices polyphony.
A voice is composed by 2 oscillators (OSC1 + OSC2) which structure is based on CEM 3374 + a white noise circuit + a sub-oscillator.
System manages different voice allocation modes:
- up to 3 voices assignable to different Midi channels
- 2 sounds can be stacked in UPPER and LOWER part.

	OSC1	OSC2
shapes	sawtooth / square	sawtooth / square
pulse width	yes	yes
volume bal	no	no
hardsynch	yes	yes
ringmod	yes (fixed depth)	as OSC1

ENVELOPE 2 EGs:
- EG1 VCA: 3 stages ADR
- EG2 AUX: 4 stages ADR + 1 extra time.

FILTER resonant 4-poles lowpass filter based on Curtis CEM 3372 with cutoff and 8 fixed resonance levels. Keyboard tracking attenuates filter effect over octaves (to both low or high part).







LFO a single delayed low oscillator (range 0,1 to 10Hz square and sinewave) modulates:
- DCO1 & 2 pitch
- PWM pulse
- VCA amplitude
- VCF filter (the "SWEEP").

 

SEQUENCER single track polyphonic, about 700 notes that can be recording in either real-time or stepmode. Of course Polaris can be also played byt MIDI with a great full Midi implementation: in fact all sliders sends the relative control changes.

 

MEMORY:
- 132 sounds RAM
- 12 RAM sequencers.
Data backup can be done by MIDI SYSEX or tape storage - several hardware modifications expands the storage capacity.

MAINTENANCE some common issues: - buttons membranes is infamous for being highly unreliable and needs cleans or technical cares - keyboard velocity system may need also to be periodically calibrated. - power supply drains too much and it has been reported various issues of faulty power supplies. On the right side a video tutorial for some possible fix

EDITOR some editors available on the market:
- Soundquest

 

RELATED MODELS:

	ARP CHROMA Big, powerful and unreliable machine! previous model VIDEO
	POLARIS II Should be same machine at 100% with different outfit for Japanese market VIDEO

 

VST PLUGIN / SAMPLED VERSION there are some free and commercial samples set:

	name	price	link	demo
	SOLARIS	VST free		n/a
	Create music net	free sample pack		n/a

AUDIO DEMO

100% polaris demo pulse sync bassline NY 1997 pads heretic voices

Soundcloud

VIDEO CLIP SELECTION Analog Synthesizer Vintage Analog Synthesizer Chroma Polaris 100% sounds demo