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Third Rock Music Center


Yamaha G50 Guitar to MIDI converter in good condition

available at

Low in-store inventory, may be subject to change.

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Guitar to Midi Converter
3 Modes 
13 pin Divided Pickup input
guitar 1/4" input for Mono Mode
For questions or help ordering, call: (513) 843-5739

G50 Design

Housed in an innocuous black, 1U?high rackmounting case, the Yamaha G50 is simply an interface between a guitar fitted with a G1D split pickup system and an external MIDI sound module — there's no on?board synth here, as there is with Roland's GR1 or GR09. If the split pickup looks familiar, that's because it was designed specifically to be interchangeable with Roland's GK2 pickup unit; presumably the idea is that existing Roland users will find be more tempted to change horses if they don't have to invest in a new pickup. It is possible to use the Yamaha G50 without a split pickup, but in this mode the conversion is purely monophonic and the success (or otherwise) of the process depends to a large extent on how cleanly you can play.

Looked at simply, the G50 receives information from each of the six sections of the split pickup, analyses the pitch, then translates this to MIDI note, velocity and pitch?bend information. However, analysing the pitch of a guitar string is difficult because of the rich harmonic structure of a plucked guitar note. Furthermore, until the noise of the pick against the string has passed, there is no pitch to track, and even when the note has steadied, the process of extracting the pitch takes a finite amount of time. The usual outcome of this process is inaccurate pitch recognition and a noticeable delay, especially on the lower strings.

Current systems attempt to address these problems by using fast digital analysis algorithms to make a quick guess at the pitch, then as the note stabilises, constantly updating the pitch data. If this is done fast enough, the tracking gives the illusion of being both instantaneous and accurate. Though no specific details on how the Yamaha system works have been released, it has been mentioned that advanced neural net technology (computers that learn) was used at the design stage to help the system differentiate between intentional notes and misinterpreted harmonics or noise.

The G50 provides memory locations for 128 user programs, though as the unit contains no sounds, you might be forgiven for wondering why it needs any at all. The idea is that you can set up different picking sensitivities for different songs, make use of split functions, which place different sounds on different strings, or save custom settings for the new picking position feature, which allows the sound to change depending on how close to the bridge you pick. A program can also contain a MIDI patch change, so that the appropriate sound is called up automatically.

User Interface

Though its primary use will probably be with a 6?string guitar, the G50 will also work with a 4?string bass, providing that the bass is fitted with a suitable divided pickup. A switch on the rear panel selects guitar or bass operation. Sharing the rear panel are the MIDI In and Out sockets, a Sustain/Hold pedal socket, a direct output for the regular guitar pickup, and an input for the obligatory (and exceedingly irritating), external power supply. I don't mind separate power supplies too much on dedicated studio gear, but I would hope that Yamaha have enough confidence in the G50 to expect some people to use it live — and flimsy push?in power connectors are in no way compatible with my experience of the live performance environment!

Aside from the G1D pickup input, and the jack for a regular guitar input, the front panel has only eight buttons, an LED display, and a power switch. There's also a printed parameter crib sheet on the front and top panels, which saves having to constantly refer to the manual. Editing is via the usual menu system, with parameter select and value buttons doing most of the work.

Operationally, the G50 has three distinct MIDI modes:

  • Multi?Channel Mode: in this mode, any six consecutive MIDI channels (excluding channel 10, which is reserved for drums), can be selected, and each guitar string transmits data on its own MIDI channel to an external multitimbral synth set to polyphonic mode. All the strings can thus play different sounds, if required, and because the mode is polyphonic, fretting a new note on a string won't kill off the sustain of the previously?sounded note on that string. However, because the strings are on different channels, independent pitch?bending is possible. This mode may also be used with synths that support Mono mode (one voice per MIDI channel), though playing a new note on the same string will obviously cut off the note that was previously playing. The Oberheim Matrix 1000 is a good choice for using in this context, as it has a dedicated guitar mode, which places each of its six voices on consecutive MIDI channels.
  • Single?Channel Mode: in this mode, polyphonic operation is possible, but because MIDI pitch?bend information affects all notes played on the same channel, the ability to bend individual guitar strings by different amounts is lost. Pitch?bend data is derived from the last note played, and if the note is bent by more than a semitone, it will jump to the next semitone up. Though this sounds rather restricting, it's a viable way to work if you have a non?multitimbral sound module that doesn't support Mono mode. It's also useful for monophonic tone generators such as the Yamaha VL series.
  • Mono mode: this is selected automatically if the regular guitar input is used instead of the divided pickup. In this mode, all the data is transmitted on one MIDI channel and only one note can be played at a time. In addition to the regular user programs, the G50 contains three further preset programs specifically for use with generic General MIDI devices, Yamaha's own MU50, MU80, VL7m or VL1m (version 2).