Arp Quartet

String processor (1979)

String paraphonic processor, a rebrand of Italian Siel orchestra, 100% the same

Overview

OVERVIEW C-C 49 keys with full polyphony, the Quartet a 4-part string processor synthesizer with 4 sounds presets: Brass, Strings, Organ and Piano, of which up to two can sound at the same time.

RELATED MODELS:
- Siel Orchestra: the same
- Siel Orchestra II: upgrade with more sound control

Terminal connectors:

- audio out Hi/low
- footswitch for sustain
- 5-Dinfor volume pedal

Sound

OSCILLATORS Divide down tone generation , the 4 tone color families can be played individually or two can mixed. Some parameters can be changed.A 12-note TOS Mostek 50242, is used the main core then TDA 1008 chip is used as a frequency divider - amplification is provided by an LM 13600 OTA OpAmp. Chorus is generated by 3 BBD TDA1022

EDIT some section have some tweaks:
- Brass section with independent attack and sustain controls EG.
- String section with independent attack and sustain controls EG.
- Organ section is 2-voice and offers a Celeste sound
- Piano section has two variations:, traditional piano or Hony Tonk. .

LFO a single Vibrato

FILTER only brilliance control for brass section