This week, in our non-linear micro-series of "retro-tests," we take a look at that venerable monophonic drum machine, the Roland TR-77. The first product ever designed by the famous Japanese brand, the TR-77 is a remarkable example of simplicity and inventiveness.
In 1972, Roland released three drum machines, the TR-33, the TR-55 and the TR-77, with the later being the first product put out by the Japanese brand. With sounds generated by analog synthesis, no programming possibilities and a single monophonic output, they seem like primitive units today. However, with a little inventiveness and dexterity, they offer surprising possibilities for playing and benefit from controls that were profoundly innovative for their time, and they still come in handy when you want to use them today. And what’s more, they can be modified!
Many famous studios and musicians acquired the TR-77 after its release. If you listen to tracks by Bowie (Art Decade, on Low – apparently the TR-77 employed was his own), Ultravox (Hiroshima, mon amour, on Ha! Ha! Ha!), Gary Numan (I Nearly Married a Human, on Replicas) or on George McRay’s huge disco hit Rock Your Baby — one of the first hit tracks to employ a drum machine — it’s sound is easily recognized.
So, what’s so special about it? Let’s take a closer look…
General presentation of the TR-77
First of all, “TR” stands for “transistor rhythm.” So, logically, there are transistors galore. We’ll note in passing that the machine doesn’t say “TR”, but is actually called Rhythm 77.
On the front panel is a set of controls that can be operated independently or simultaneously to create complex variations within presets, tempi and time divisions.
Some of these controls have the function of accessing said presets, thus the two series of pushbuttons that occupy the majority of the front panel and the rotary selector:
The slide potentiometers and temporary pressure buttons allow you to adjust the playing dynamics, including respective volume of the different channels (apart from the “bongos” or “claves” which cannot be modulated), output sound fade, start and stop by touch control using the chrome bar (we’ll come back to this function, as it can prove very practical for the inventive musician), the slider to fine-tune the tempo and the lever to split the rhythm.
On the rear, there are three 6.35 mm (1/4-inch) jacks: one for high-impedance output, the other for low impedances (it works well with headphones), then the jack for the footswitch for on/off, which, as we’ll see, can also accommodate an external trigger.
Before going deeper into the bowels of the machine, let’s place it in the context of its era.
History of drum machines
When the TR-77 appeared in 1972, several American and Japanese companies were already building drum machines, and had been for some years. In this context, the TR-7, and some of Korg’s latest Minipops (I’m thinking in particular of the 20S), really do appear as the culmination of non-programmable drum machine technology. Because unlike the CR-78, TR-606, 808, and 909, the 77 is not programmable. A control set lets you play preset patterns, which can then be modified live, but it’s impossible to compose a specific pattern yourself in advance. It’s also impossible to play an instrument on its own at the touch of a button unless you set the volume of the other instruments to zero.
The first commercially available example was Wurlitzer’s “Side Man, ” whose impulse generation is organized into rhythmic patterns according to the distribution of contacts on a circular printed circuit on which a motor rotates two contact lamellae. This works a little like a rotary selector that rotates ad infinitum with the aid of a motor and selects, one after the other, sets of channels resembling percussive sounds (by analog synthesis, we’ll return to this principle in the next section).
Another well-known example is Seeburg’s “Prince Rhythm, ” which, when used properly, gives chills.
Next, let’s look at the circuitry.
Technical specifications and innovations
The TR-77 works by analog synthesis, which means that its sounds come from analog circuits, producing short tones whose timbre is made to imitate a known acoustic instrument and which can be combined to create modulations. They are activated by a master oscillator, which, like a clock, produces a precise, regular pulse that serves as the framework for the rhythmic patterns.
- for all “treble” instruments – snare drum, maracas, hi-hat, guiro – a white noise generator is employed, whose sound undergoes envelope processing (faster or slower attack, longer or shorter resonance), and potentially low-pass filter processing, to mimic different fundamental pitches.
- for all “low” or “mid” instruments, where the fundamental is often more perceptible, sine waves whose frequencies are tuned according to the instrument are used, along with envelope processing.
The T output is also connected via two diodes mounted head-to-tail (D5 and 6) to the second part of the circuit. These two diodes, only allowing current to flow in one direction, act as “switches” at the input to the next circuit, enabling one side and then the other of the first stage of the toggle (shown in green in the circuit) to be activated.
This flip-flop is made up of five stages connected in series, which thus form a frequency divider: i.e., from the oscillation frequency supplied by the multivibrator, they create sub-divisions, 32 to be precise, and this is how you end up, from a basic clock, with two bars in 4/4 divided down to the half-note (2 × 16 steps).
This 32-step grid is then distributed, according to the selections made by the user, to the voices of the sound synthesis circuit (we’ll come back to this). This distribution (some pulses being sent only to one instrument, some to several at the same time, some being mutated, others not, to create a recognizable rhythmic pattern). This distribution takes place through a diode matrix:
I won’t go into detail about how such a circuit works (though it’s simple, almost primitive). Let’s just say, for example, that it achieves the following:
This gives me a good reason to let you hear what these rhythmic patterns sound like…
Sound
Let’s first review the basic presets, i.e., in order:
- 01_ROCK’N ROLL 100:07
- 02_ROCK’N ROLL 200:07
- 03_SLOW ROCK00:05
- 04_BALLAD00:05
- 05_WESTERN00:07
- 06_6_8 MARCH00:05
- 07_JAZZ WALTZ00:05
- 08_WALTZ00:05
Added to this is the set of “Latin” presets, controllable via the pushbuttons on the left side:
- 01_RHUMBA00:07
- 02_BEGUINE00:07
- 03_CHA-CHA00:07
- 04_MAMBO00:07
- 05_SAMBA 100:06
- 06_SAMBA 200:07
- 07_BOSSA NOVA00:07
- 08_BAION00:07
- 09_BOLERO00:08
- 10-TANGO00:13
To understand the effects of simple combinations, I mixed the preset “Western, ” which is particularly minimal, with the various rhythms controlled by the “2 BEAT” and “4 BEAT” functions and the rotary selector. The effect is made all the more interesting because the combinations take on a polyrhythmic character (4 into 3), which gives them a very particular groove and makes it easy to grasp the variations possible by simply superimposing two voices. It should also be noted that, due to the analog circuit, the precision of this polyrhythm is not perfect, giving it a kind of swing.
First, we hear the preset “WESTERN, ” which is in 6/8, before adding the bass drum on beats 1 and 3 of “2 BEAT, ” then on all beats (in “4 BEAT”), which is where the polyrhythm appears. Next comes the snare drum, first in unison with the bass drum (“BASS & SNARE” mode), then on beats 2 and 3. This is followed by a series of variations, the last of which is produced by the SHUFFLE mode and the simultaneous selection of “2” and “4 BEAT”.
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To conclude, two improvisations:
The first, where I “play” the TR-77 by exploiting various combinations and playing techniques, including multiple selection, pulse splitting, switching from a binary to a ternary measure (to create odd measures or give the feeling of a “stumble” in the rhythm), on/off effect with the touch control (very effective for making drop effects) or with the metronome.
The second where I mixed two TR-77 tracks with two guitar tracks (each instrument being recorded through an MXR Carbon Copy into a tube guitar amp, rated at 40 W, with different levels of gain and distortion):
- 01_MIX05:45
- TR-77 exemple01:09
FAQ: All you need to know about the Roland TR-77 and analog drum machines
1. What is the Roland TR-77
The Roland TR-77 is the first analog drum machine marketed by Roland in 1972. It is monophonic, non-programmable, and produces sounds through analog synthesis circuits.
2. Why is the TR-77 special?
The TR-77 is emblematic, representing Roland’s beginnings in the music industry. Despite its limitations, it offers surprising versatility thanks to its innovative controls and unique sounds.
3. Which famous artists have used the TR-77?
Many legendary artists have incorporated the TR-77 into their tracks:
- David Bowie: Art Decade (album Low).
- Ultravox: Hiroshima Mon Amour (album Ha! Ha! Ha!).
- Gary Numan: I Nearly Married a Human (album Replicas).
- George McCrae: Rock Your Baby, one of the first disco hits to use a drum machine.
4. Is the TR-77 programmable?
No, the TR-77 does not allow you to program rhythm patterns. It uses presets that can be modified in real-time to create customized variations and rhythms.
5. Can the TR-77 still be used today?
Yes! The TR-77 remains a popular choice among analog music enthusiasts. It can be modified for modern uses, and its audio outputs are compatible with current equipment.
6. How the TR-77's analog synthesis works
The TR-77 uses two types of synthesis circuits:
- White noise generators for high-pitched sounds (snare, maracas, hi-hat).
- Sinusoidal oscillators for low or mid-tones (bass drum, bongos).
7. Is it possible to find used TR-77s?
Yes, the TR-77 can be found on platforms like Audiofanzine, which is a reference for vintage audio equipment enthusiasts. Its price varies according to its condition and any modifications.
8. Is the TR-77 comparable to other Roland models?
The TR-77 stands out for its lack of programming, unlike later models, such as the CR-78 or TR-808, which offer more advanced customization options. Nevertheless, it remains a landmark in the evolution of drum machines.
9. Is the TR-77 easy to modify?
Yes, with a bit of knowledge of electronics, it’s possible to add individual outputs for each instrument or integrate modern features, such as MIDI synchronizations.