Roland SH-5 Service Manual

3-2-1. CIRCUIT BOARD ASSEMBLY OP-19
Contains: ±10V Regulator, PHONES, LFO-1, LFO-2, S/H, and NOISE GEN, circuits.
A. ±10V Regulator
The constant voltages +14V and -14V of the input are converted into highly stable D.C outputs: +10.00V and
-10.00V.
Generally speaking, the more accurate the adjustment (the more zeroes after the decimal point) the more
accurate the VCO tracking will be.
B. PHONES
Controls the LEVEL without any relat/on to the OUTPUT LEVEL of VCA.
C. LFO-1
This is a Low Frequency Oscillator to produce both inverted and non-inverted Sawtooth waveforms with a phase
difference of 180°.
D. LFO-2
Produces Sine wave, Square wave (inverted and non-inverted), and Triangular wave for use in modulation, and
TRIG, for AR. and ADSR.
DELAY TIME utilizes Sine wave alone.
E.S/H
This circuit is for sampling voltages from different waveforms, using LFO-1 ( |)j^ ), LFO-2 ( AA ), and
RANDOM (NOISE) for its input source. The output can be used to control VCO-1 and the VCF for getting
special effects.
Sample time decides the timing of the sampling operation.
Lag time uses an RC filter to add lag to quick voltage changes.
F. NOISE GEN.
The sound source here is the white noise produced at the B-E (base — emitter) junction of a reverse biased
transistor.
It is amplified and, through filtering, is changed to either WHITE or PINK at the output.
3-2-2. VCO BOARD ASSEMBLY
VCO-1
A VCO is an oscillator whose frequency is controlled by a control voltage coming from the Keyboard or other
external sources.
Incoming linear control voltages are first converted into voltages with an exponential increasing ratio.
The oscillator itself is a sawtooth generator. Wave shapers convert this sawtooth to triangle and square waves.
This assembly functions as VCO-1, and is capable of synchronous driving of VCO-2 by means of the synchronizing
pulses generated in this assembly.
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Roland SH-5 Specifications

General

Brand	Roland
Model	SH-5
Category	Synthesizer
Language	English