Chapter 1 - Introduction

1.1 - PRODUCT DESCRIPTION

The Kurzweil 250 uses artificial intelligence principles and a Motorola 68000 microprocessor to create complex models of acoustic sounds. The Kurzweil 250's design gives the instrument a velocity-sensitive keyboard so that a note's volume and timbre relates to the force on the key. The 12-note, polyphonic keyboard can accurately reproduce the sounds of several instruments at once and each key on the 88 note keyboard can be individually assigned to play a different sound.

Currently, the Kurzweil 250 comes with 36 different instruments arranged into 98 keyboard setups in the basic Enhanced Resident Sound Block excluding Sound Blocks A thorugh D. The original Kurzweil 250 came with 30 different instruments arranged into 40 keyboard setups.

The Kurzweil 250's sequencer is a built-in, 12,000-note multi-track digital recorder, which can be used to build up to 12 different tracks. Older Kurzweil 250's may have either 4,000 or 8,000 note sequencer. These units can be updated to the current 12,000 with the purchase of available options.

All Kurzweil 250s are currently manufactured with the Kurzweil Sound Modeling Program for user sampling. Older Kurzweil 250s may not have this option, but may be updated with the purchase of the Sound Modeling Program option.

There are many configurations of Kurzweil 250s currently in the field. The Kurzweil 250 Product Line also includes the Kurzweil 250X, an expander unit without keyboard, and the Kurzweil RMX 250 or 225, a rack mount expander unit. Please see the Product History, Chapter 2, for more information.

1.2 - SPECIFICATIONS

1.2.1 - Kurzweil 250

Keyboard: 88 keys with velocity-sensing and piano action.

Pedals: 2, assignable piano-type in the POD, 2, external volume-type

Dimensions (Cabinet): 56"(L) X 27"(W) X 9"(H)

Dimensions (POD): 22"(L) X 11"(W) X 4.5"(H)

Weight (Cabinet): 95 lbs.

Weight (POD): 22 lbs.

Power Consumption: 110/220 VAC, 50/60Hz, 380 watts max.

Operating Conditions: 0 to 50°C Ambient 20 to 80% Relative Humidity

Storage Conditions: -25 to 125°C,10 to 90% Relative Humidity

Audio Outputs: High level, Low level, Balanced, Stereo headphones

External I/O: High-speed parallel computer port, MIDI In, MIDI Out and MIDI Thru ports, Sync In, Sync Out, Trigger In, Click Out, MIC, Line In, 2 External volume-type pedals, cartridge slot

1.2.2 - Kurzweil 250X

Dimensions (Cabinet): 49 1/2" (L) X 20 1/2" (W) X 6 3/4"(H)

Dimensions (POD): 22"(L) X 11"(W) X 4.5"(H)

Weight (Cabinet): 45 lbs.

Weight (POD): 22 lbs.

Power Consumption: 110/220 VAC, 50/60Hz, 380 watts max.

Operating Conditions: 0 to 50°C Ambient 20 to 80% Relative Humidity

Storage Conditions: -25 to 125°C,10 to 90% Relative Humidity

Audio Outputs: High level, Low level, Balanced, Stereo headphones

External I/O: High-speed parallel computer port, MIDI In, MIDI Out and MIDI Thru ports, Sync In, Sync Out, Trigger In, Click Out, MIC, Line In, 2 External volume-type pedals

1.2.3 - Kurzweil 250 RMX AND 225 RMX

Dimensions (Cabinet): 19" (L) X 22" (W) X 10 1/2"(H)

Weight (Cabinet): 53 lbs.

Power Consumption: 110/220 VAC, 50/60Hz, 380 watts max.

Operating Conditions: 0 to 50°C Ambient 20 to 80% Relative Humidity

Storage Conditions: -25 to 125°C,10 to 90% Relative Humidity

Audio Outputs: High level, Low level, Balanced, Stereo headphones

External I/O: High-speed parallel computer port, MIDI In, MIDI Out and MIDI Thru ports, Sync In, Sync Out, Trigger In, Click Out, MIC, Line In, 2 External volume-type pedals

1.3 - HOW THE KURZWEIL 250 WORKS

This section describes briefly how the Kurzweil 250 controls work. Refer to the Kurzweil 250 User's Guide for more detailed information. Since this is a complex instrument, always confirm that a problem truly exists before attempting to service the instrument.

1.3.1 - Masters Section

The group of slider controls in the Masters section controls the overall sounds that the instrument makes.

TUNE - Use this slider control to control the overall pitch of all active voices.

INSTRUMENT GROUPS A & B - These two sliders move two different, assignable instrument groups from left to right in the stereo image.

VOLUME - This controls overall volume.

1.3.2 - Assignments Section

This section of the Front Panel controls are used primarily during live performance.

Each of the three vertical sliders can be assigned to control one of approximately 20 different functions such as tremolo, pitch bend, vibrato, legato, attack, decay and sustain. By using these controls, you can simulate a wide variety of playing techniques, including a full variety of synthetic effects.

Musicians can also assign the foot pedals and Mod Levers using switches in this section.

1.3.3 - Selection Section

The Selection area on the Front Panel contains the switches that allow users to control the main functions of the system. With the LCD display, they tell what operating mode the instrument is in and allow the musician to make changes and answer questions.

SPLIT KEYBOARD - This is another control used at performance time. It allows you to assign a certain section of the keyboard temporarily to a certain instrument.

CHORUS - When you press this button, you can turn one sound into many. The "Chorus" capability can be used for doubling, built-in echo and flanging.

SELECTION SWITCHES - The YES, NO and SELECT switches are used to choose options and answer questions displayed on the LCD.

NUMERIC KEYPAD - Use the numeric keypad to enter choices and to select functions (with the "F" switch).

1.3.4 - Program Section

This group of controls, along with the numeric keypad, allow you to program the Kurzweil 250. These controls are generally used for setup before a performance.

CURSOR KEYS - The cross shaped group of keys below PLAY are the cursor controls. The center key (R) is for resetting when you have made a mistake or want to return to the initial cursor placement.

SEQUENCER - The Kurzweil 250's sequencer is a built-in, 12,000 -note multi-track digital recorder. You can use it to lay down one instrument and then play a second instrument on top of it. By repeating this process, you can build up to 12 different tracks.

Other keys in this section speed up or slow down the tempo of a piece, modulate to another key, change modes or edit keyboards, instruments or sequences.

1.3.5 - Media Section

The Media section lets you program, store and recall your own set of keyboard setups, instruments and sequences.

LIST - This key allows you to run through, in any order, every keyboard setup stored in the Kurzweil 250's memory. You can reprogram this list to meet you own performance needs. You can also list sequences using this switch.

STORAGE - The Storage READ switch is used to prepare the instrument to use a cartridge. In future versions of the instrument, the STORAGE switches will be used with external media options.

1.3.6 - Back Panel

The back panel contains all the input/output connections for the Kurzweil 250.

COMPUTER - This is the parallel computer port for attaching a personal computer to the Kurzweil 250.

TRIGGER IN - The Trigger In is a TTL-compatible input used for starting a sequence from an external device. The sequence triggers on the positive edge of the supplied pulse. Minimum pulse width is 1 microsecond. The input impedance is greater than 10k ohms. The trigger level is 2 volts. This I/O port takes a 1/4 inch phone jack.

CLICK OUT - The Click Out is a TTL-level output pulse. When enabled from the Front Panel, a positive pulse appears at this output. Its repetition rate is the selected sequencer tempo. Driving source is a low power TTL gate through a 51 ohm resistor. This I/O port takes a 1/4 inch phone jack.

SYNC IN - The Sync In is a TTL-compatible input used to drive the Kurzweil 250 from another instrument. The other instrument is to provide a square wave at X12 to X96 the tempo. The input impedance is greater than 10K ohms. The trigger level is 2 volts and this I/O port takes a 1/4 inch phone jack.

SYNC OUT

- The Sync Out is a TTL-level square wave output used to drive other instruments in synchrony with the Kurzweil 250. The repetition rate is normally X12 to X96 the tempo. The driving source is a low power, TTL gate through a 51 ohm resistor. This I/O port takes a 1/4 inch phone jack.

MIDI IN

- This is a 31.2K baud, 5 milliamp serial input.

MIDI THRU

- This is a 31.2K baud, 5 milliamp serial output.

MIDI OUT

- This is a 31.2K baud, 5 milliamp serial output, the same as MIDI IN buffered.

LO

- These are 2 VPP audio outputs, with a 600 ohm driving source impedance. These require 1/4 inch phone jacks and are suitable for line level inputs.

HI

- These are 20 VPP audio outputs, with a 600 ohm driving source impedance. These require 1/4 inch phone jacks and are suitable for directly driving power amplifiers and other high level inputs.

BALANCED

- These are 20 VPP audio outputs. They have XLR connectors, floating outputs and a 600 ohm driving source impedance.

EXTERNAL PEDALS 1 & 2

- The 1/4 inch phone jacks accept assignable pedal functions (K250 and K250X only).

MIC

- This digitizer input is a 200 mVPP full scale input. It has a 47K ohm input impedance and accepts a 1/4 inch phone jack.

LINE IN

- This digitizer input is a 1 VPP full scale input (300 MV rms). It has a 10K ohm input impedance and accepts a 1/4 inch phone jack.