Alesis MIDIVerb 4 (1986)
18-bit dual-channel effects processor with MIDI control, introduced as an affordable alternative to high-end reverb units.
Overview
The Alesis MIDIVerb 4 is a dual-channel parallel effects processor introduced in 1986. It was the first 16-bit professional effects unit priced under $1000, targeting home studios, small studios, and PA systems. Marketed at £395 RRP, it offered 63 factory preset reverb effects including gated and reverse types, with instant recall via front panel or MIDI. The unit features true stereo parallel processing, Auto Level Sensing™, and a simple interface with rubber touch-pads and a two-digit LED display.
Specifications
| Bit Depth | 18-bit ADC/DAC |
| Internal Processing | 24 bit |
| Channels | 2 |
| Inputs | (2) 1/4" (stereo or summed mono) |
| Outputs | (2) 1/4" (mono or stereo) |
| MIDI Ports | MIDI In, MIDI Thru |
| Presets | 63 factory (0–62), 128 user |
| Simultaneous Effects | 3 |
| Maximum Delay Time | 1,300 ms |
| Pitch Shift Range | ±1 octave |
| Decay Time Range | 0.2 to 20 seconds |
| Dynamic Range | 90dB |
| Bandwidth | 20Hz–20kHz |
| Operating Level | -10dB line level |
| Input Impedance | 50KΩ |
| Power Supply | 9V AC adaptor (external) |
| Dimensions | 8¼ x 8¼ x 1½ inches |
Design
The MIDIVerb uses a single double-sided PCB with all ICs in sockets, featuring an 8031 microprocessor and a DSP chip. It runs on RISC architecture and includes an Xicor X2444P NVRAM chip with 32 bytes of memory. Early units used LF354 op-amps, later replaced with quieter TL084 chips. The case is black molded plastic with blue and white markings, and controls are laid flat rather than forward-facing. A factory modification increased the 8031 clock speed from 8 to 12 MHz using a new crystal and timing capacitor.
Context
Priced at £399, the MIDIVerb competed with high-end units like the Yamaha R1000 but targeted budget-conscious users. It made digital reverb technology accessible to lower-end markets and was followed later in 1986 by the Microverb, a non-MIDI version with a 16-bit A/D converter. Reviewers noted its quiet operation, effective effects, and impressive sound for its size and cost.
Market
Common issues include failing voltage regulators, oscillator crystals, and shorted 0.1mfd capacitors. The reset circuit is considered unreliable, and front panel pots—especially the MIX control—wear with heavy use. Repairs typically involve recapping the power supply and replacing regulators. Broken units sold for as low as £30 in 2020.
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