The Yamaha A4000 represented in 1999 a revolutionary approach to sampling technology, transcending the traditional boundaries of what a sampler could be. Released alongside its higher-end sibling the A5000, this professional sampler emerged as an affordable yet powerful alternative to the prohibitively expensive E-MU and Akai samplers of the mid-1990s era.

Unlike conventional rackmount samplers that merely recorded and played back audio, the A4000 combines comprehensive sampling capabilities with an advanced synthesis engine, creating a hybrid instrument that can both capture sounds and extensively manipulate them. This dual nature makes it not just a sampler, but a complete sound design workstation capable of creating entirely new timbres from basic waveforms.

The A4000's synthesis capabilities are particularly noteworthy, featuring multiple filter types with rich, full-bodied character that surpassed Yamaha's earlier SY series offerings. The machine excels at creating classic synthesizer patches from simple waveforms like sawtooth, square, and sine waves, with patches created from samples as small as 712 bytes demonstrating the unit's efficient sound generation capabilities.

Advanced Features for Modern Production

The A4000 includes sophisticated tools specifically designed for contemporary music production, particularly dance and electronic music. The Loop Divide/Remix function can automatically slice loops into discrete sections and randomly rearrange them while adding various effects, creating unique remixed variations non-destructively. The complementary Loop Divide function maps these sliced sections across the keyboard for manual remix composition.

The Resampling function addresses one of sampling's most common challenges by allowing independent manipulation of pitch and tempo. Pitch Convert mode changes pitch without affecting speed, while Time Stretch mode alters tempo without pitch changes, with calculations possible based on tempo, length, beat, or time parameters.

User Experience and Interface

Operation is streamlined through an intuitive user interface centered around a large 320x80 dot full-graphic LCD panel that displays waveforms, effect routing, and parameter data in clear, understandable formats. Five panel knobs work in conjunction with mode and function buttons to provide efficient navigation and real-time control. The Panel Play function transforms four right-panel knobs into real-time MIDI controllers for both internal samples and external synthesizers.

Known Limitations

Potential buyers should be aware of two significant issues. The rotary encoders beneath the main display are prone to failure, often beginning to output incorrect values or respond in reverse directions. This problem affects all A-series Yamaha samplers and may be exacerbated by the rear-mounted exhaust fan drawing dust into the front-panel encoders. Additionally, the A4000's slow loading times make it unsuitable for live performance applications where quick sound changes are essential, unless you use it within the "one sound-one instrument" paradigm.

Technical Specifications

Core Specifications

• Polyphony: 64 notes
• Multitimbral Parts: 16
• Sample Memory: Expandable up to 128 MB via 4 SIMM slots

Synthesis Engine

• Filter Types: 16 different types with complete parameter control
  • Standard: Low-pass, High-pass, Band-pass
  • Specialized: Band eliminate, Peak, Dip filters
  • Multi-mode: Dual independent filters per sample
• Filter Characteristics: Ultra-fat filters with powerful resonance
• Q (Resonance): Velocity-controllable on many filter types
• LFOs: 2 per patch + 1 master Program LFO (MIDI syncable)
• Envelope Generators: 3 per patch
• Layer Limit: Unlimited tones/waveforms per patch (polyphony dependent)

Effects System

• Effect Blocks: 3 independent blocks
• Effect Algorithms: 96 onboard types
• Effect Types: Reverbs, distortions, modulation effects, delays, Auto Synth, Tech Modulation, Digital Scratch, programmable Lo-Fi
• Routing Options: Series, parallel, or individual connection
• Real-time Application: Effects can be applied during sampling process
• Standalone Processing: Can function as effects processor for stereo analog inputs

Sampling Capabilities

• Sample Formats Supported: AIFF, WAV, Yamaha EX7/5/5R, SU700, and other manufacturer formats
• Resampling Functions:
  • Pitch Convert (pitch change without speed alteration)
  • Time Stretch (speed change without pitch alteration)
• Consecutive Sampling: Automatic new sample creation with "New+" record type
• Loop Processing: Loop Divide/Remix with non-destructive editing

LFO System

• Program LFO Waveforms: 6 types including StepWave
• StepWave Features: Up to 16 programmable steps per LFO cycle
• Waveform Generation: Manual programming or random generation options
• Waveform Smoothing: Adjustable slopes between steps
• MIDI Sync: Master Program LFO synchronizable to MIDI clock

Display

• 320 x 80 dot full-graphic LCD panel

Connectivity & Expansion

• SCSI Interface: Built-in with internal SCSI and IDE connectors
• Storage Options: Internal hard disk and ZIP drive simultaneous support
• External Drives: Hard disk, ZIP, CD-ROM, CD-R compatibility
• Optional I/O Expansion: AIEB1 board providing:
  • 6 assignable analog outputs
  • Digital coaxial input/output
  • Digital optical input/output

Control Interface

• Panel Knobs: 5 for parameter control and menu navigation
• Real-time Controllers: 4 right-panel knobs for MIDI control
• MIDI Control Recording: Knob movements recordable to external sequencers
• Matrix Interface: Mode and function button matrix system

Included Content

• Sample Data: CD-ROMs with sample library
• Audio Sources: CD-ROMs with source material for sampling
• Software: Sample and Parameter Editing Software
• Requirements: External SCSI CD-ROM drive needed for CD-ROM data loading

Performance Characteristics

• Sound Quality: Professional-grade with superior sound and performance
• Loading Speed: slow - unsuitable for live performance
• Applications: Break-beat production, phrase sampling, musical instrument sampling, sound design

Unique Synthesis Features

• Expand Detune/Dephase: Proprietary synthesis functions
• Fully Programmable LFO Waveforms: Custom waveform creation capability
• Unlimited Layering: No restriction on tones per patch beyond polyphony limits
• Direct-to-CD Burning: Integrated CD burning capability

Known Issues

• Encoder Reliability: Rotary encoders prone to malfunction (outputting wrong values or reverse operation)
• Dust Sensitivity: Rear exhaust fan may draw dust into front-panel encoders
• Repair Costs: New encoder set approximately USD50
• Live Performance: Be cautious due to slow loading times