#2101/#2102
10.TECHNICAL DESCRIPTION
1. General
The Leslie 2101 system consists of 3 channels: Rotary, Stationary Left and Stationary Right, all of which are
present at the 11-pin input. Each channel is rated at 50 watts. The Rotary channel has other two inputs - a 1/4"
phone jack, and an 8-pin DIN socket for use with Hammond Drawbar Module XM-1. The high frequency
portion of the Rotary channel consists of a spinning horn rotor driven by a DC servo motor, and the low frequency
portion consists of a 2-channel stereo rotary simulator controlled by a DSP (Digital Signal Processor) system.
The DC servo motor is controlled by the CPU, which allows programmable Rotor Speed, Rise Time, Fall Time
and Brake Time. In addition, both the DC servo motor and the DSP bass rotor can respond to incoming MIDI
commands from external MIDI equipment.
The PWBs consist of:
1. PREAMP & PANEL SWITCH PWB (SWH-492A)
2. CPU Control & DSP Effect PWB (EFH-237A)
3. POWER AMP & POWER SUPPLY PWB (PWH-68A)
2. Operation of PWB
A. PREAMP & PANEL SWITCH SWH-492A
This PWB is composed of three parts: PREAMP & FILTER, SWITCH & DISPLAY and JACK.
The signal for the Rotary channel is supplied through pin 1 of the 11-pin connector. Through
J306-1,PHONE JACK JK-5 and JK-8 In input of PIN(1), to The OPAMP U1A and U1B from VR1 after
Mixed U1A make pass a signal from 125Hz to 12KHz in Band Pass Filter and are sent to DSP of
EFH-237A via J301-1. This signal is divided into HF(High Frequency) and LF(Low Frequency) at
approximately 800 Hz of the crossover frequency in the DSP. The HF is, being returned via J301-3 as
the Rotary Horn signal, through BPF circuit U3B, AMP circuit U3A and VR6, and it is supplied to
POWER AMP via J302-1.
The LF signal is changed into the 2-Channel STEREO signal by Rotary simulator inside DSP. Among
these, the Lch signal returns to J301-9. Then, it is filtered below 1.1KHz by 12dB/oct. Low Pass Filter
in U5A, and the one of this output is sent to LINEOUT JACK.JK3. The other is sent to MIXER U4B.
It is also mixed here with STATIONARY Lch. and the BASS signal, and output is supplied to
PWH-68A POWER AMP via J302-5. Also, the Rch signal returns to J301-7 after that, it is same as
Lch.
On the other hand, only the BASS signal less than 125 Hz is passed by U1B, and it is supplied to U2A,
U2B and U4B, U5B through VR5(ROT BASS ADJUST).
When SLIDE SWITCH SW6 is in Position of STA & BASS MUTE at this time, a becoming BASS
signal is stopped here by Transistor Q5, Q6, Q7 and Q8 which are switched ON.
B. CPU CONTROL & DSP EFFECT EFH-237A
This PWB consists of the MAIN CPU, DSP, ADC, DAC and MEMORY and controls switch functions,
LCD display functions, Motor Control, Leslie simulator, DSP digital filter, etc. The MAIN CPU
program is written in MTP ROM(1M bit) U4. The rotary channel signal sent from J301-1of SWH-492
is converted into digital serial data of 20 bits in AD CONVERTER U10 via J204-1. and is connected to
DSP U9-PIN(55) & PIN(56) via PIN(15) and U12A. It is filtered, and the DIGITAL EFFECT and
ROTARY EFFECT are added here using the DSP. The 24-bit SERIAL DATA output of the DSP is
sent from AX1(pin 48) and AX2(pin49) to U7(DAC1) and U8(DAC2)PIN(2) and converted back into
an ANALOG signal of 4 channels and applied via J202 and J301 to SWH-492A.
10-1
Summary of Contents for LESLIE 2102
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