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RCM In A Rack

Yamaha TG77 Tone Generator

Article from Sound On Sound, January 1991

Yamaha's flagship workstation, the SY77, has now given birth to a new top-of-the-range expander, the TG77. Martin Russ conducts the examination.

When I reviewed the Yamaha SY77 FM/sample playback synthesizer/workstation in early 1990, I was struck by the number of buttons and LEDs which covered its front panel. Unlike many of today's instruments, it did not look as if converting the SY77 to a rack unit was going to be at all straightforward — especially given the additional problems posed by the three tiers of stacked PCBs squeezed inside the SY77! So the appearance of a prototype TG77 at the APRS exhibition in mid '90 was quite surprising, both in terms of timing and what is included on the front panel!

In this review I will concentrate on the additional features which make the TG77 rather more than just a simple conversion of a synthesizer to a rack mount format. The sequencer and disk drive are not present in the TG77, so for storage and recall of large numbers of sounds, you will need either a computer-based librarian program, or indeed an SY77. See the January and February 1990 issues of Sound On Sound for more information on Yamaha's RCM synthesis.


The SY77 is big, black and heavy. The TG77 is big (about the same size as an Akai S1000), black and considerably lighter (only 10kg), but apart from the large backlit blue LCD, almost everything else about the outside is different. The small buttons on the SY77 have become SPX900/1000 style sculptured squares, the volume control sliders have been replaced by a concentric rotary control, and the alpha dial has vanished completely. Most of the LEDs which lit the SY77 up so nicely in the dark have been omitted, although things like Element Indication have been moved to the LCD display, where your eyes are directed for most of the time when editing anyway, so this might be an improvement as well as an economy.

From left to right, the top of the front panel contains Mode selection buttons: Voice, Multi and Utility. Underneath these are three control buttons: Edit/Compare, Copy, and Effect Bypass. The final button in this area is the Memory selector button, which is in a rather strange position well away from the Bank and Number buttons on the far right. The mains switch is a neat, recessed push-on/push-off device, with power indication given by the LCD and the red LEDs in the Mode switches. The Effect Bypass switch has the fourth and final LED on the front panel.

The volume control consists of a small and fiddly pair of concentric rotary knobs, which I found rather awkward to use. These do not actually control the volume of the left and right channels as you might expect — instead, the two knobs control the output of two assignable groups of sounds, each of which is already in stereo. Because of the way that the internal effects processor is arranged, Output 1 tends to be the 'wet' output and Output 2 the 'dry' output, so what looks like a volume control is actually more like a quadraphonic effects mix control. The rear panel outputs reflect this, with two sets of stereo outputs and eight individual assignable outs. 12 outputs for a 16-part multi-timbral instrument provides a good compromise, between not enough and too many outputs, which should suit most users. There is also a stereo headphones output which carries a mix of the two main stereo groups, located on the front panel (a distinct improvement on the SY77's rear panel position.)

The LCD display dominates the front of the TG77 — the 3U height of the rack mounting case is probably a product of having to accomodate the display and its associated soft key function buttons. The TG77 improves on the SY77's user interface by making more use of soft-keys, although there still seems to be a reluctance to abandon the one button/one function approach. Perhaps the next generation of instruments will move even closer to a display with which one interacts, instead of one which just shows what is happening...

The omission of an alpha dial is probably a conscious design decision, since dials on rack mount devices have a tendency to get altered too easily — by accident; when people brush past them, or through intentional fiddling. The vertical data slider is much more resistant to inadvertent change. The two data card slots are reasonably out of the way of most button-pressing and slider-moving. Two blocks of 12 buttons take the total number of buttons on the front panel to 31 (almost exactly half the number of buttons on the SY77) — the right-hand block is the numeric keypad, whilst the other contains the cursor keys, page movement, bank select, and the (rather awkward to use) element/operator editing control buttons. I would have preferred to see less emphasis on neat blocks and more on functional groupings here. Apart from the 12 1/4" audio output jacks, the rear panel has the usual MIDI In, Out and Thru sockets and a captive mains lead. The placing of the LCD contrast control on the back panel makes even less sense than the positioning of the SY77's headphone socket — how are you supposed to alter the TG77's LCD contrast when the unit is in a rack?

Build quality is up to Yamaha's usual high standard, with solid steel construction extending to even the steel rack mount ears, which are hidden beneath the anodised aluminium of the front panel.


The TG77's voice structure and storage facilities are exactly the same as those of the SY77. There are four sets of 64 Voices: Internal RAM, Card ROM/RAM, and two banks of Presets in ROM. Each of these Voices can consist of up to 4 Elements, and there are 16 RAM and 16 Preset Multis which are 16-part multi-timbral configurations of several Voices. The waveforms and drum sounds used in the sounds are exactly the same as on the SY77 — I would actually have preferred a different set of drum sounds, with the same instrument waveforms. The internal effects processor contains four separate blocks, two of which produce modulation effects, with the other two for reverb-based treatments. See SY77 review for more details.

The internal sounds draw on a wide range of programming experience on the SY77 — I know this because Preset 'P1-A09: SP.Padfaze' is a voice I programmed for the SY77, originally called 'PhasePad'. It has always been one of my ambitions to have one of my sounds adopted by Yamaha (and how many reviewers do you know of who are good enough at programming to actually get their sounds adopted by the manufacturer? — Ed). The results of increasing familiarity with RCM are readily apparent in the Presets. The SY77's instrumental emulations have largely been replaced by timbres which have a quality which is both 'real' and 'synthetic' at the same time. The depth of control and flexibility which is inherent in RCM means that the range of sounds is quite stunning, and applicable to a wide range of genres. The built in demos show this (as they should, I suppose), with everything from MOR organ pieces to house and jazz, via orchestral, ballroom dancing and soap opera themes. During demo play, there are several display modes that tell you a little about what's going on inside the machine. You can look at activity on MIDI channels, notes played, a keyboard display, Voice name display, and an elapsed time indication. The Auto mode even changes the display automatically every few seconds, cycling through all the options. The channel display could be useful when using the TG77 as an expander, but at least in this software version the facility is only available during demo play. The audio quality of the TG77 is excellent, with the zipper noise on the Pan function almost inaudible, even on bass voices where it can sometimes be obtrusive — in this respect the TG77 is perhaps slightly better than the SY77. However, I am not sure where the advertised 22-bit DACs are hidden — I could only find three 16-bit Burr-Brown PCM 56s on the audio PCB.


Unlike the SY77, the TG77 gives you control over the voice assignment of the 32 note maximum polyphony when you are using Multis. You can select either Dynamic Voice Assignment (DVA) or Static Voice Assignment (SVA). The latter allows you to determine how many notes or elements are allocated to each Voice (and thus each MIDI channel). There is also much more information on how things are working — special displays show you an editable summary of how the Individual Outputs are used, and there is a display of the mode of each voice (AWM, AFM, AWM & AFM etc) so that you can decide how to allocate voices efficiently. If only the SY77 had useful displays like this! Voice mode also has an addition which is simple but very useful, involving only a minor change to the way that voices are named. All the voices are now in the format TYPE-MODE-NAME, where the three parts give different sorts of information about the voice: 'Type' denotes the sort of sound (ST for strings, BR for brass etc). The 'Mode' character shows the type and number of elements used:

. = 1AFM or 1AWM
: = 2AWM or 2AFM
: = 1AFM & 1AWM
* = 2AFM & 2AWM

This leaves seven characters for the name itself. Overall this is such an useful improvement that I am considering renaming all my own SY77 voices...


MIDI-wise, the TD77 performs well. MIDI Volume and pitch bend messages worked correctly in Multi mode. Bank Change messages are not implemented, but you can assign MIDI Controllers to control eight internal parameters. The TG77 proved capable of coping with very high density multi-channel MIDI note and controller information. Delays and note-stealing only became apparent with a very heavy data stream, such as that from a ridiculously dense hi-hat pattern: repeated 1/768ths with random pauses at 250 bpm! The AWM waveforms are stored in ROM, so samples cannot be downloaded via the MIDI Sample Dump Standard. I found no problems in using the TG77 with master keyboards which send the All Notes Off MIDI message — this message can interfere with the Sustain pedal function in some other Yamaha products, most notably early versions of the EMT10.


The TG77 is an excellent successor to the TX802 as the flagship of Yamaha's tone generator range. The powerful mix of Advanced FM, sample replay and digital filtering give the TG77 a huge range of usable sounds, and the user friendly interface makes using it much easier than some of its minimalist competitors. For anyone with a master keyboard and sequencer, it represents a superb way of getting RCM synthesis without the burden of the SY77's workstation approach. Beware: 16 channels of RCM multi-timbrality in one box is very addictive!


£1299 inc VAT.

Yamaha-Kemble Music UK, (Contact Details).


  • 16 Note Poly AWM2, 16-bit linear, 32/48 kHz sampling, 113 samples (112 & AFM)
  • 16 Note Poly AFM, 8 operators, 45 algorithms, 17 waveforms (16 & AWM)
  • Real-time Digital Filters (up to 8 per voice)
  • 128 Preset Voices, 64 user memories
  • 16 Preset Multis, 16 user memories
  • 4 separate Effects Processors with 40 Reverb programs and 4 Modulation programs
  • 8 Assignable Outputs
  • 2 Stereo Outputs
  • Data and Waveform Card slots


The Geerdes SY77 SWS (SoftWorkStation) from Germany is an ST librarian and editor package for the SY77, written in GFA Basic, which includes the option of loading a mid-range 24-track sequencer should you want to be able to flick back and forth between editing and sequencing. The program requires a high-resolution mono monitor and 1 megabyte of RAM.

The program starts up in Librarian mode, which is designed to keep track of and maintain the Voices which appear in a Multi. Voices can be stored on disk (up to 1000 in a single bank) and sorted into 128 named groups, making it easy to search for specific types of sounds. A special 'stack' memory acts like a series of edit buffers, where you can temporarily store your edited sounds before permanently storing them as part of a bank. This makes editing much easier because you do not have to constantly worry about losing a previous version of a sound — you can always go back a few editing steps, if you decide that what you had before was better.

For editing purposes, the program compresses the many pages of SY77 LCD displays into just a few highly graphical and iconic ST screens. You interact with the program via the mouse, and there are no keyboard equivalents. There is a randomisation and variation generator, but unfortunately it can only be used with AFM voices.

Changing from one page to another and the redrawing of all the parameter boxes are both rather slow, but once on a page the editing is fast and easy. A small problem with editing the TG77 is that the program does not allow you to turn Operators or Elements on and off — you have to use the SY77 or TG77 front panel switches instead, which interrupts the flow of editing. I could not find an undo function to reverse the last change made, but I assume this is why temporary edit memories are provided.

The optional sequencer, 1st Track, can be called up from the editor simply by pressing the space bar. 1st Track is a straightforward 24-track sequencer with just one main page and no tempo mapping. It does, however, have some very sophisticated event listing, editing and manipulation commands, and you can load and save MIDI files. SY77 owners will probably not want to load and use the sequencer, as the keyboard already has one, but for TG77 owners it could be very handy.

The 85 page ring bound A5 manual has been poorly translated from German (for "menu board" read "menu bar", for example) and it does not really cover the functions in any depth. The program is copy protected by a dongle, and one update was supplied during the review period, which shows that UK support is working.

Overall, SY77 SWS offers similar combined editor/librarian functionality to the long-awaited Steinberg SY77 Synthworks, but the librarian facilities are not as good as those offered by Keynote's excellent Chameleon, and the editing facilities have some omissions and can be quite slow to use. A DX7 to SY77 convertor program is also provided, which works with MIDI dumps and various file formats, and it does a fast and efficient conversion of entire banks of 32 voices at a time to a disk file.

Newtronic, (Contact Details).


There is an enormous range of Voice and Waveform cards available for the SY77 and TG77, both from Yamaha and third party suppliers. There are also plenty of disks for the SY77, again from both Yamaha themselves and from other suppliers. One disk of my sounds (for SY77 only in the current version, but read on...) will shortly be released through SOS Software (see the yellow pages in this magazine) and a second disk is being prepared. I am working on a Public Domain Utility to read SY77 Voice disks with an Atari ST (perfect for TG77 owners).

SOS Software, (Contact Details)
Executive Audio, (Contact Details)
Advanced Media Group, (Contact Details)
Yamaha-Kemble Music UK, (Contact Details) (ask for voice software catalogue)

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Publisher: Sound On Sound - SOS Publications Ltd.
The contents of this magazine are re-published here with the kind permission of SOS Publications Ltd.

The current copyright owner/s of this content may differ from the originally published copyright notice.
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Sound On Sound - Jan 1991

Review by Martin Russ

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