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The VRC7 is a famous Konami expansion chip for the Famicom. Used in the Japan-only video game Lagrange Point, it was a cost reduction on top of the Yamaha YM2413 (OPLL)! Compared to the YM2413, the VRC7 has:
  • 6 channels (instead of 9)
  • No drums mode
  • Custom patch set
The VRC7 is based on the Yamaha YM2413/OPLL, a cost-reduced FM synthesis sound chip derived from the Yamaha YM3812 (OPL2).

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Technical Specifications

  • 6 channels of 2-operator FM synthesis
  • 1 user-definable patch (this patch can be changed throughout the course of the song)
  • 15 pre-defined patches (VRC7-specific) which can all be used at the same time
  • Support for ADSR on both the modulator and the carrier
  • Sine and half-sine based FM synthesis
  • 9 octave note control
  • 4096 different frequencies for channels
  • 16 unique volume levels (NOTE: volume 0 is NOT silent)
  • Modulator and carrier key scaling
  • Built-in hardware vibrato support

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Effects

EffectDescription
10xxChange patch
11xxSet feedback of channel
12xxSet operator 1 level
13xxSet operator 2 level
16xySet multiplier of operator
x: Operator (1 or 2)
y: New MULT value
19xxSet attack of all operators
1AxxSet attack of operator 1
1BxxSet attack of operator 2
50xySet AM of operator
x: Operator (1 or 2, or 0 for all)
y: Whether AM is on
51xySet SL of operator
x: Operator (1 or 2, or 0 for all)
y: Value
52xySet RR of operator
x: Operator (1 or 2, or 0 for all)
y: Value
53xySet VIB of operator
x: Operator (1 or 2, or 0 for all)
y: Whether VIB is on
54xySet KSL of operator
x: Operator (1 or 2, or 0 for all)
y: Value
55xySet EGT of operator
x: Operator (1 or 2, or 0 for all)
y: Whether EGT is on
56xxSet DR of all operators
57xxSet DR of operator 1
58xxSet DR of operator 2
5BxySet KSR of operator
x: Operator (1 or 2, or 0 for all)
y: Whether KSR is on

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Chip Configuration

The following options are available in the Chip Manager window:
  • Clock rate: Sets the rate at which the chip will run
  • Patch set: Changes the chip model, providing different built-in sounds. VRC7 is the default.

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Instrument Editor

This chip uses the FM (OPLL) instrument editor. The VRC7 is part of the OPLL family:
  • Yamaha YM2413 - The original OPLL with 9 channels and drums mode
  • Konami VRC7 - 6 channels, no drums mode, custom patches
  • Yamaha YM2423 - Same as YM2413, different patch set
  • Yamaha YMF281 - Also changes the patch set

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