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Yamaha FX770

Guitar Effects Processor By Paul White
Published November 1994

Not only does this digital processor produce a wide range of convincing guitar tones, it can also double as a general‑purpose studio effects unit. Paul White dusts off his axe and plugs in.

Ever since the original SPX90, Yamaha have been forging a reputation for good‑sounding effects that are easy to use — something that can't be said 'hand on heart' of everything Yamaha have ever designed. Though it was felt by many that the company's digital guitar pre‑amps fell short of being convincing, Yamaha continued undaunted in their quest for the ultimate 16‑bit, super‑clean, hi‑fi digital distortion. The culmination of their efforts is the FX770 which, I'm pleased to report, delivers a very wide range of convincing guitar tones, from jazz to rock, both live and in the studio.

The 1U rackmounting FX770 is a digital processor specifically geared to the needs of the guitar player. Up to nine effect blocks can be selected for simultaneous operation, including a choice of amp simulation types for DI recording, and real‑time parameter control of Wah Wah and volume is possible using conventional volume pedals, in addition to the now mandatory real‑time MIDI parameter control. The 16‑bit, 44.1kHz sampling input stage delivers a frequency response from 20Hz to 20kHz with an overall dynamic range of 85dB — which, in subjective terms, means that the FX770 is very quiet and you can have your effects as bright‑sounding as you like.

Though the majority of effects on offer are based on resoundingly familiar concepts, there's still plenty of flexibility to be had, with seven different types of preamp simulation, three wah wah variations, loads of modulation, delay, reverb and pitch shifting effects, as well as panning, rotary speaker emulations, compressor/limiter and ducking delay. And at the end of the line you can choose from nine guitar‑amp simulation options. There's also an analogue insert point (just in case you feel a burning need to add yet another effect!) which comes before the amp simulator. Though the way in which the effects blocks are chained together is nominally organised for you, there are options to reorganise various parts of the chain — wah wah before or after the preamp stage, or modulation before or after the reverb, for example. The Block diagram shown in Figure 1, taken from the user manual, shows this arrangement very clearly.


I must confess to being rather unexcited by the styling of the FX770's front panel, which is finished in black with a dull gold legend. This, combined with knobs that look as though they've recently been liberated from a '50s toaster, conspire to give the unit a retro look that doesn't quite work for me. However, the array of buttons, backlit LCD window and LED numeric readout is classic Yamaha, as is the operating system, which can be largely sussed without any need to open the manual.

Because the FX770 is a guitar‑specific device, the single, mono input is on the front panel and is high impedance, so that it will not load passive guitar pickups. An input level control matches the guitar level to the analogue‑to‑digital (A‑to‑D) converter, while green and red LEDs monitor signal present and overload respectively. A meter switch on the rear panel switches the metering from the input signal to the insert return, which is a nice practical touch.

There are four rotary controls on the front panel of the FX770, one of which is an analogue Presence control which comes after the output D‑to‑A converter. This is purely 'flying finger' automated; its setting isn't included as part of a patch. When DI'ing some of the brighter overdrive sounds, backing off the Presence control helps smooth out the sound, while the more jangly, clean patches benefit from a high Presence setting. The Output Level control is located immediately to the right, and this also appears to be analogue, which is a good thing; digital level controls tend to sacrifice resolution, and hence sound quality, at lower settings.

In the display section, the numeric window shows the currently selected patch number from 0 to 99. As there are 100 preset patches and 100 user patches, two status LEDs next to the display show which bank is currently selected. The two‑line LCD window displays the patch name and the usual parameter information when editing or setting up the various Utility functions, such as the MIDI parameters.

Each of the nine effects groups has its own selection button, accompanied by a green LED which lights when the effects block is selected, making it easy to see at a glance which effects comprise the current patch. The remaining eight buttons handle the Play, Edit, cursor and Utility functions, including Bypass, though a Data entry knob is also included, which provides a quick way of getting around the patches, as well as being used to change parameter values. The AC power switch is not illuminated, but as the rest of the front panel glows like a Christmas tree, this might be considered a positive move for energy conservation rather than an omission!

The back of the unit is largely occupied by sockets; there are jacks for two footswitches, two foot controllers (Wah and Volume), stereo outputs and insert send and return, plus a pair of DINs for MIDI In and Out. A small slide switch toggles the MIDI Out socket between Thru and Out operation. No footswitches or control pedals are provided, though virtually any standard model may be used — Yamaha recommend their own FC5 footswitch, which may be used for Bypass/Tuner (a handy guitar tuner is available in Bypass mode) in socket 1 or as Bank or Program select in socket 2. Socket 2 may also be used as an Effect Trigger input. A small rotary control is used to set the Effect Return level which, as mentioned, may be metered via the front panel LEDs.

Driver's Impression

There are three modes of operation: Play, Edit and Utility.

Play mode is used during performance; pressing the Play button toggles between the Preset and User programmes, as well as getting you into Play mode in the first place. Patches may be stepped through using the cursor buttons or, rather more quickly, by using the Data Entry knob; MIDI program changes from the outside world may also be used to switch patches. When you're in Play mode, individual effect blocks may be toggled on or off using their respective dedicated buttons, though no changes will be made permanent unless they are deliberately saved in one of the user memories.

Edit mode provides access to the individual effect parameters; after pressing Edit, selecting an effect type button brings up the first page of parameters for that effect, while the effect status LED flashes to show you which effect you're editing. The cursor button is used to move to the left or right on the screen and the Data Entry knob changes parameter values — all very standard and very straightforward. Editing options include Patch Select, Noise Gate, Patch Naming, the position of the volume pedal in the signal chain (see Figure 1), Footswitch 1 assignment, Controller 1&2 assignment, and Effect Copy. It also appears to be possible to edit effects blocks that are not included in the current patch. As is customary, any new edits are lost when a new patch is selected, unless they're first saved in one of the User Memories.

Utility mode provides access to the MIDI setup of the FX770 and to the various assignable functions, such as MIDI controller sources and destinations. Two MIDI parameters may be controlled simultaneously. There's also the option to create and store up to seven different MIDI patch assignment tables, which is about six more than I'd ever need! SysEx data dumps may also be initiated from this page, where you can choose to dump the entire memory, the System (Utility) parameters only, specified Programs, or Bank (MIDI program assignment table).

On balance, the FX770 provides a sensible mix of flexibility and ease of use.

For live performance, footswitch 2 may be programmed to cycle round a user‑selectable number of patches, starting at any patch number, and the footswitch may also be used to enter a 'tap tempo'‑type delay value or to set tempo in the modulation block (Pan and Tremolo). As you might imagine, there are further layers of fine detail that there just isn't space to go into here, but I think I've covered most of the important points.

Player's Perspective

Having reviewed some of Yamaha's very early attempts at digital tube‑amp emulation, I was very keen to see what improvement the years had brought, and though I still don't feel the DI'd sound is entirely true to the vintage valve combo, it is still very good indeed — and infinitely more flexible than a battered old combo with only one good sound. If I had to draw a comparison, I'd say that the kind of guitar sounds you get are not dissimilar to those produced by a Zoom unit, even though the technologies used are rather different. In other words, what you get is a highly produced result that sounds as though it's already been recorded in a studio and subjected to the full machinations of modern‑day production.

The overdrive sounds are adjustable from a gentle blues whine to a full‑throated thrash metal shred, and because every combination of pre‑amp and amp/speaker simulator type gives a different result, there are plenty of permutations to explore. Because the pre‑amp includes a three‑band, fully parametric equaliser, there's no lack of control when it comes to customising your sounds, but as the manual rightly warns, it's very easy to go over the top and mangle a sound almost beyond recognition. As with Zoom products, the amp/speaker simulators tend to be heavily coloured, making the sound almost larger than life, but the real surprise is the influence of the Presence control, which adds dramatically to the flexibility of this processor. For example, if you get too carried away setting up a bright overdrive sound, the result can be unnaturally edgy, but using the Presence knob, this can be brought back under control very quickly. Similarly, a glassy rhythm sound can be made to positively gleam by cranking the Presence up. Internal noise‑gating is available to keep the hiss level down, but much of the credit must go to the design of the processor itself, because very little noise is evident even when you're using very bright or considerably overdriven sounds.

Moving onto the effects proper, few of these hold any real surprises, but all perform flawlessly — with the inevitable exception of the pitch shifter, which sounds wonderful when used to create detuning effects, but rather less so when used to generate octaves. The Pitch, Modulation, Delay and Reverb blocks all produce stereo outputs, and the sense of stereo width achieved by some of the effect combinations is dramatic. There isn't much leeway for reconfiguring the effects, but somehow this doesn't seem to detract from the range of available sounds at all. I was particularly impressed by the modulation‑based effects; combining traditional chorus with pitch detuning makes some truly beautiful, shimmering sounds possible. The maximum delay time appears to be 670mS in all delay modes, and the inclusion of ducking delay is rather nice, as it means that the delay level can be kept down until you stop playing, at which point it automatically swells up to fill the gap.

I've never been a great fan of built‑in wah wah devices, but I must admit the FX770's wah wah soon had me regurgitating the usual riffs and cliches. It actually sounds quite authentic, the only minor niggle being that you need to use an insert Y‑lead connected to both the input and output of your volume pedal to make it operate. The other pedal option is for volume control, and here there's a choice of putting it right at the end of the signal chain or directly before the delay‑based effects blocks. The latter is more natural, as when you fade out the guitar, the delays and reverbs are left to die away naturally.

Though the FX770 is a dedicated guitar unit, because the various effects blocks can be switched in or out of circuit, you can also use it as a general‑purpose effects processor, simply by disabling the pre‑amp and speaker/amp simulator stages. There aren't as many reverb options as you'd get in a dedicated studio unit (just three room sizes and a spring emulation), but the key parameters are all editable, including pre‑delay time, HF damping and overall decay up to a maximum of four seconds. True gated reverb effects may also be achieved by setting in a Gate Level parameter value which, in effect, puts a gate block directly after the reverb output.


On balance, the FX770 provides a sensible mix of flexibility and ease of use. There are units on the market with far more flexible programming systems, but they can get very complicated to use, and at the end of the day it's arguable whether the effects you can achieve are any more original‑sounding. There are no algorithms to worry about — all you have to decide is whether or not to make the minor revisions to the order of the effect chain that the software allows.

For the studio owner who also plays a lot of guitar, the FX770 would be a good choice because it can also be pressed into service as a general‑purpose studio effect if required. The operational concept of this unit is very similar to Zoom processors (though Zoom use their own proprietary analogue pre‑amp stages), and anyone in the market for such a device would be well advised to audition them side by side. This isn't journalist‑speak for "I think one of them is better than the other but I'm not going to say which!" — it's simply an acknowledgement that each has its own character. And when it comes to something as subjective as tonal character — especially where guitar players are concerned — there's no substitute for trying the thing out with your own guitar.

Pre‑Amp & Amp Types


  • Type 1: Distortion 1
  • Type 2: Distortion 2
  • Type 3: Distortion 3
  • Type 4: Overdrive 1
  • Type 5: Overdrive 2
  • Type 6: Crunch
  • Type 7: Clean


  • STK‑M1: simulates a typical vintage stack amp sound.
  • STK‑M2: three‑stage stack amp sound.
  • THRASH: thrash metal sound.
  • MIDBOOST: with characterful mid range.
  • CMB‑PG: simulates Yamaha PG1 preamp.
  • CMB‑VR: simulates the VR6000.
  • CMB‑DX: vintage combo amp with the rear of the cabinet open and the speaker exposed.
  • CMB‑TWN: typical American combo amp sound.
  • MINIAMP: mini amp sound with an output of 10W or less.

FX770 Features

  • Three types of compressor/limiter.
  • Three types of wah with various control sources.
  • Seven pre‑amp types.
  • External effects loop with two selectable insert points.
  • Volume and wah can be controlled by FC7 Foot Controller or any connected volume pedal.
  • Real‑time parameter control using MIDI Control changes.
  • Amp simulator to reproduce the sound characteristics of various speakers.
  • Pitch effects including Stereo Pitch Shift and Pitch Chorus.
  • Modulation effects.
  • Reverb (Spring, Small and Medium Room, Hall).


  • Very easy to use.
  • Great range of really good sounds.
  • Sensible real‑time control options.
  • Enough hidden depths to stop the more advanced user becoming bored.
  • No external PSU.


  • Pitch shifter glitchy when used to create large shifts.


A very flexible, yet intuitive processor capable of creating a surprising range of both clean and overdriven guitar sounds. Works well as a DI method of getting an 'instant' produced guitar sound and also doubles as a general‑purpose studio effect unit.