Building DIY synthesizers and effects units to recreate the music of the gods: late-90s goa trance
Thanks to my dad’s good taste in music, my childhood had a killer soundtrack: classic rock, 70s folk music, and 80s new wave. At home or in the car, a constant rotation of The Beatles, Cream, Simon and Garfunkel, Talking Heads, and The Human League. Things were off to a good start.
Then in 1995, I encountered something completely different - techno:
I had never heard music like this: blatantly artificial sounds at a blazingly-fast BPM. I was hooked. In retrospect, 80s new wave was drenched in synthesizers, but they were always used alongside human voice. Techno completely eliminated the human element and leaned fully into synthesized sounds.
After Mortal Kombat came years of uninspired techno remixes, and then around 1999 it happened again - I heard something completely different. Music from another dimension:
I got the chills. This did not sound like music made by humans - this was the music of the gods. Through accident of birth, I had discovered the briefly-lived (1994-1999) genre of goa trance right at its peak. I soaked up every song I could get my hands on. Nothing before (or after) has excited me as much as the otherworldly sounds and compositions I encountered in those years. And while there were many bangers, nothing surpassed the brilliance of Simon Posford as Hallucinogen.
Like most things I become obsessed with, I eventually overdid it and had to take a decade(s)-long break. That break ended one summer night in 2015 when I was inexplicably reminded of my time with the music of the gods. Surely the genre had developed and matured in the 15 years I had been away from it, increasing in complexity and strangeness! I got excited and went digging. What I found was extremely disappointing.
Goa trance had died out shortly after I stopped listening to it, evolving into the more commercially-palatable (and in my opinion, formulaic, uninspired, and sonically uninteresting) psytrance which is still produced today. I found almost no songs from 2000-onwards which gave me the same feeling that goa trance did: the feeling that I was listening to music from another dimension.
If I wanted to hear new music with those sounds and feelings, I would need to make it myself.
Clearly there was something about late-90s goa trance that resonated with me in a way that no other music has. I want to understand what made this music unique and how it was made. And once I understand it, I want to recreate it.
The process to achieve this will be:
A thorough history of goa trance has already been written, so we can shift our attention to identifying (what I consider to be) the defining characteristics of the genre. We will start with classics from the 1994-1999 period, and then move on to the (rare!) songs from the decades after which capture the same feel.
For me (and many others) the king of goa trance was Simon Posford. His two albums as Hallucinogen define the sound I am obsessed with:
That sound I am obsessed with:
His signature is unmistakable, and it can be heard in all of his collaborations and remixes from the era (some examples):
Cosmosis (Bill Halsey with Jeremy Van Kampen) had a similar feel:
So did Koxbox:
And early Astral Projection:
Other prolific artists of the era had a lower hit rate for me, but produced their own classics (e.g. Etnica, more Etnica, Pleidians, Green Nuns of the Revolution, UX, Man with No Name, Infected Mushroom).
In addition to the bigger acts, a number of one-hit wonders managed to hit the sweet spot.
These were the songs which defined the sound I refer to as “the music of the gods”. All of these artists either stopped producing music in the early 2000s, or their style morphed into something different. (e.g. Simon Posford’s music slowed down considerably as he pioneered the psybient genre as Shpongle. Infected Mushroom developed a unique blend of psytrance and progressive metal.)
Goa trance ended by the early 2000s (coincidentally just after I stopped listening), replaced by the more melodic and less sonically complex psytrance which continues to this day.
When I revisited goa trance in 2015, I was very excited to see how the genre had developed in the intervening years. Goa trance was a groundbreaking genre for its time, pushing (relatively) primitive hardware and software to its limit (and often beyond!) Modern production techniques like sidechain compression, frequency carving, and multiband compression have brought cleaner, punchier mixes to electronic music: aggressive leads over crystal clear basslines and drumlines with none of the “muddiness” of the earlier releases. From an instrumental perspective, highly-refined wavetable synthesizers and granular synthesis techniques have unlocked entirely new sounds, and aftertouch keyboards offer new methods of expression (beyond the knobs and sliders of the 90s).
I was shocked to discover that despite all of these advancements, almost nobody had been making goa trance since the golden years.
Cosmosis briefly revisited the genre with two songs that fit squarely in the classic goa trance genre:
And a few artists have produced tracks I consider worthy:
I am not alone in thinking that goa trance deserved further development: the release of Ethereal - Anima Mundi in late 2003 marked the start of a goa trance “revival” genre: neogoa / “new school goa”. Suntrip Records formed in late 2004 to focus on this new genre, with releases by Filteria and Goasia, among others. A similar goa trance revival genre appeared in 2008, with the artist Agneton releasing the first nitzhogoa album - this time a cross between nitzhonot and classic goa trance.
Both of these genres claim to be what I was looking for: an evolved form of goa trance guided by modern techniques. Although the music does retain the key components of goa trance (i.e. choice of scales, reliance on melodies, exotic sounds), it does not (in my opinion) achieve the goal - the music has deviated too far from its predecessor in too many respects. The tempo is too fast, the melodies are too saccharine, the (overused) voice samples (already a problem with classic goa trance) are distractingly cheesy, and the clarity/punchiness provided by the modern production techniques is drowned out by an overabundance of layers. To me the music sounds like a self-aware parody of classic goa trance.
Despite my dislike of neogoa/nitzhonot, it has birthed two albums which are so ridiculously over-the-top that they deserve a listen for fans of classic goa trance:
These albums suffer from all the complaints made earlier, but lean so heavily into them that it becomes charming. Goa trance made me grin and ask myself “what the hell is this, and who made it??” - these two albums achieve the same effect.
After a thorough survey of the relevant corners of the internet (e.g. psytrance forums in various languages, chronologies, lists(https://psytranceguide.com/), and obscure release sites) I had accepted that goa trance reached its peak with Simon Posford. He defined the genre, and then perfected it a rare combination. It seemed to me that in the decades since Simon’s involvement in goa trance ended, nobody was either willing or able to continue the work he started. I thought all hope was lost. And then I stumbled upon Artha:
There it is. The unmistakable voice of God (read: Simon Posford). But this was more than just an imitation of Hallucinogen, this was the next step I was hoping for. Crisp modern production, catchy melodies, complex sounds, with some new ideas mixed in.
Artha is a producer from Poland and has been making goa trance since the early days (1997). His initial work as Timer was contemporaneous with Hallucinogen - built using trackers (specifically: protracker and digibooster) on an Amiga. Through years of experimenting (eventually switching to the obscure DAW Buzz), and with steady feedback from goa trance fans in the community, Artha produced enough tracks for both an EP (Fluori Dolby) and an LP (Influencing Dreams).
Together, these releases are (in my opinion) the worthy successors to Hallucinogen. Artha released one more album (Dream Telepathy) six years later, but (as usual, it seems) the style changed and it just does not have the same magic. (I’ve noticed this pattern for many artists: the initial release is the culmination of decade(s) of ideation, refinement, and experimentation. Subsequent follow-ups are inevitably put together without the benefit of that initial bounty of time and creativity.)
Now that we have mapped out the family tree of goa trance (by my reckoning), we can analyze the music to determine what makes it unique and interesting.
After an obsessive amount of listening and analyzing, the formula for classic goa trance becomes clear.
Tempo and Meter
Songs are fast with a driving kick drum:
Scales
The three notes which define the goa trance sound are the root (1), a semitone above the root (b2), and a whole note below the root (b7). Most goa trance hooks are variations of [1, b2, b7] with visits to 4, 5, b6.
To facilitate this, songs are built on Indian, Middle-Eastern, and Gypsy scales:
Pitch-bends are used liberally and emphasize the intervals unique to these scales. Although Dorian #4 does not contain b2, it may be borrowed and incorporated in a pitch bend.
Bassline
Songs feature a pedal point bassline (repetition of a single note) consisting of:
For dramatic effect, the following techniques are commonly used:
The bassline and the kick never overlap, this is achieved via note placement and not sidechaining. The following three patterns are the foundation of almost all goa trance basslines:
The note and note length can vary, but the pattern is always centered on the root note.
Structure
Songs are typically 7 to 9 minutes in length and follow the pattern of trance music in general:
Goa trance is highly melodic, which makes the tracks memorable. A melodic theme is developed at the beginning of the song, and in the second third of the song the theme comes back with something different (e.g. a change in timbre, or the lead is gated). The final part of the song brings back the theme in a higher octave or develops it into a second part.
Melodies often have the structure of rock guitar riffs being played with a keyboard (i.e. monophonic hammering of notes in the scale, centered around the root note).
Timbre
The essential sound of goa trance is the swept resonant filter. A harmonically rich signal (e.g. a sawtooth, square, or pulse wave) is fed through a low-pass filter with high resonance, and the cutoff frequency of the filter is played expressively. The filter cutoff knob is the instrument.
Simon Posford sweeping the low-pass filter cutoff of a distorted Roland SH-101 lead in “Hallucinogen - Deranger”:
As you sweep a resonant low-pass filter over a harmonically rich, pitched sound, the filter’s resonant peak amplifies whichever partials it passes (typically the note’s harmonics) so that the timbre changes while staying tied to the pitch. This is why goa trance melodies can feel wide and varied despite consisting mostly of three notes: [1, b2, b7].
This technique of “playing the cutoff knob” originates in acid music, and is a result of quirks in the design of the Roland TB-303 bass synthesizer (to be discussed in detail later).
For leads, bass, and pads, the sounds are built on square, saw, or pulse wave oscillators.
For otherworldly spacey sounds, sine wave oscillators are used (due to pure sine waves being rare in nature).
Sine wave oscillator (with a swept low-pass filter cutoff) in “The Deviant - S.T.C.”:
Formant sounds are common, again inherited from acid music (under certain settings, the filter of the Roland TB-303 approximates a mammalian vocal-tract formant).
Layered formant sounds in “Snake Thing - Shango”:
Tangent: the Nord Lead synthesizers were released in the mid-90s with a multi-mode filter. As their popularity grew, artists moved past the low-pass filter of previous instruments and the sound changed as the genre evolved into modern psytrance.
Although powerful trackers (e.g. Impulse, ProTracker) and primitive DAWs (e.g. Cubase) were available in the 90s, goa trance was primarily created using a live-mixing technique:
Artists would play the mixing desk like an instrument: as their loops were running on their instruments they would fade between tracks, tweak effects knobs, play with EQ settings, re-route effects channels, and build up a track on-the-fly.
Thanks to a 2007 interview from a rare DVD, we have video of Simon Posford utilizing this technique (which he pioneered), working on the song “Strangled Cat” (likely the last Hallucinogen track):
Two synthesizers are fundamental to the goa trance sound: the Roland TB-303, and the Roland SH-101.
The Roland TB-303 is a (failed) monophonic bass guitar synthesizer that was discontinued in 1984 due to sounding nothing like a bass guitar. By the early 90s they were available cheap on the second-hand market, so producers began experimenting with them.
Two design features changed the music world forever:
Pushing these features of the instrument beyond their intended use yields interesting results (enough to kickstart an entire genre).
Since the goal was to simulate plucked bass guitar strings, the envelope generators in the TB-303 are fast-attack with decay only. One envelope is adjustable and is applied to the filter (VCF) cutoff, the other is fixed and applied to the amplifier (VCA).
The internal sequencer allows you to accent any note in the pattern. This does three things:
This is achieved in the circuit (in part) by charging and discharging a small capacitor. And this leads to another unintended consequence: if you continue to stack accented notes, the capacitor does not have time to fully discharge, and it charges more and more with each accented note - the filter cutoff gradually sweeps upward, and the famous rising scream results. Adding distortion makes the effect even more gnarly.
The rising scream of distorted TB-303 accent notes in “Mindfield - Let’s Get Stoned and Watch The Freaks”:
For those artists who couldn’t get their hands on a TB-303, the Novation Bass Station was a comparable (and cheaper) synthesizer capable of recreating the unique sounds of the TB-303 with some work.
The Roland SH-101 is a full-blown monophonic analog synthesizer, capable of much more than the bass sounds of the TB-303 (although it is capable of accurately emulating those sounds thanks to its equally famous resonant low-pass filter).
With a mixer for blending waveforms (saw, square, pulse), a sub-oscillator, a routable LFO, and multiple ways to modulate various parameters (including a bender and optional mod-wheel!), it was responsible for many of the most famous lead sounds in goa trance.
Although its internal sequencer did not have the accent feature of the TB-303, it did offer portamento (glides) which (combined with creative use of the various knobs and sliders) enabled similarly “slippery” melodies.
The crunchiest distorted SH-101 lead in all of goa trance from “Hallucinogen - Orphic Thrench”:
For percussion, again a Roland instrument carries the genre: the Roland TR-909.
The TR-909 kick dominates goa trance. For hi-hats, the TR-909 was the go-to for both open and closed. But owning a TR-909 was not a necessity: usually the stock TR-909 sounds were sampled so they could be tuned, enveloped, and layered.
In terms of samplers, three companies were dominant: Kurzweil (Simon Posford used the K2000 ROMpler), Akai (S-series, used by Total Eclipse and Green Nuns of the Revolution), and E-mu (Emulator IV and ESI series).
These samplers were also used as sources for any sounds which were not synthesized (e.g. didgeridoo, human voices, or sounds ripped from other tracks).
(Sampling of kicks was not the only option for those without a TR-909, the SH-101 is able to create a similar (but cleaner) kick sound: by disabling all oscillators and using only the noise generator as the source, tuning the filter resonance to its max, setting the filter cutoff to its lowest, and applying a fast envelope.)
The Korg MS-20 monosynth was known for its versatile filters: two resonant filters in series (one high-pass, the other low-pass), each of which could be independently modulated. Modulating two filter cutoffs in relation to each other is a simple technique used to create formant sounds, which feature prominently in goa trance.
The versatility didn’t stop there: the MS-20 offered an external signal processor (ESP) which allowed users to plug in any instrument of their choosing and run it through the filter chain (or even use the audio as a modulation source elsewhere in the signal path).
The Roland Juno 106 was popular for leads, and (thanks to its 6-voice polyphony and famous chorus effect): chords and pads.
Introduced near the end of the genre, the Nord Lead 1 and 2 were versatile and affordable polysynths with a powerful filter, and became popular for leads, chords, and pads.
Some instruments were less popular, but used heavily by Simon Posford - the OSCar:
And the Korg Arp 2600:
In goa trance, the effects are where the magic happens. Almost every sound on every track has been run through an effect (usually many), and the effects are often being applied in unintended ways.
The simplest effect is distortion (or overdrive). By amplifying an audio signal beyond the limits of the amplifier, the signal becomes clipped:
This clipping (either hard or soft) adds a grittiness/bite to the input sound. Passing a saw wave through distortion produces the crunchy sound found on nearly every goa trance track. (Overdrive is a milder version of distortion, which preserves more of the original tone.)
This effect was originally achieved by pushing large amplifier cabinets past their limits, but eventually dedicated distortion units (typically in the form of a guitar effects pedal) were created, offering an adjustable clipping threshold along with other parameters (typically tone and volume).
Two distortion pedals feature prominently in goa trance. The ProCo RAT:
And the Ibanez Tube Screamer:
Differences in circuit topology lead to the distinct sounds of these units:
Another ubiquitous effect is a much more complex one: reverb. In goa trance, reverb is usually achieved digitally (with each effects vendor offering unique algorithms), with occasional use of the analog spring reverb found in guitar amps. The Eventide H3000 series was used for digital reverb by Simon Posford and Astral Projection, among others:
Shimmering reverb combined with gating for a psychedelic effect in “Trance Africa Express - Sheyba”:
Feedback delay is another effect which features prominently in goa trance. This effect is the result of looping a diminished version of a sound through a delay (3/16s was common) and feeding the delayed signal back through the delay unit. The stereo version of this effect (known as “ping-pong delay”) is even more psychedelic, with each repeat alternating between the left and right channel.
Units which could achieve these effects include the Ensoniq DP/2 and the Alesis Quadraverb:
Feedback delay in “Etnica - Astral Way”:
Phasers and flangers were used for sweeping psychedelic effects. Popular units included the previously-mentioned Ensoniq DP/2 and Alexis Quadraverb, as well as the Ensoniq DP/4:
Flanging effect on the lead in “Psychopod - Universal Mind”:
Gating was another popular effect, used for both psychedelic and rhythmic effects. A noise gate, originally intended to mute noisy guitar circuits when not being played, was repurposed to repeatedly interrupt (“gate”) instruments and other audio signals in creative ways, as a form of tremelo. A popular unit was the Drawmer DS201:
Gating of female vocals for a psychedelic effect in “Hallucinogen - Angelic Particles”:
Rhythmic gating in “Slinky Wizard - Wizard”:
Pitch-shifting was used to push instruments and other audio signals into octaves outside their typical range. On top of that, modulating the pitch-shift was used to creative effect (similar to the “playing the cutoff knob” technique used with resonant filters). The previously-mentioned Eventide H3000 series was a popular unit, as well as the Eventide DSP4000:
Pitch-shifted throat-singing in “Toï Doï - Spiral Dive”:
This leads to the one effect which, to me, defines goa trance. It is the sound that initially drew my ear in, and sent me down the path of learning sound synthesis. I call it “the croak”.
Many of the sounds of goa trance were inspired by the psychedelic experiences of the artists - they would experiment with effects to recreate the sounds and feelings they encountered. The success of their efforts is apparent:
My first exposure to goa trance was similar. As a child I had a recurring nightmare where a young boy (presumably myself) was trapped in the bottom of an infinitely-deep square-shaped cell. The boy was sitting in the corner, crying as the “camera” viewed him from above. The walls of the cell had fibrous connective tissues (like achilles tendons) stretching from one side to the other, all the way up. As the camera pulled back, the connective tissues would contract and make a deep, rubbery stretching sound - like a bullfrog croaking. That sound haunted me.
So when I first heard Hallucinogen, I got the chills:
The croak in “Hallucinogen - Space Pussy”:
The croak in “Ozric Tentacles - Pteranodon (Hallucinogen remix)”:
That was exactly the sound from my childhood nightmares. Hearing it still gives me chills.
Creating the effect is quite simple: take the lowest pitch saw wave you can get from a synthesizer, feed it through a pitch-shifter, then through a low-pass filter, and add distortion. Like most effects in goa trance, a “playing the cutoff knob” technique is what makes things special: as you lower the pitch on the pitch-shifter, simultaneously raise the filter cutoff. Adding reverb makes it even better.
We can see this technique demonstrated by Erez Eisen of Infected Mushroom:
Although Infected Mushroom quickly developed their own unique (and wildly successful) style, it was the sounds of Hallucinogen that initially influenced them. As is always the case in goa trance: all roads lead to Simon Posford.
Now that we know what equipment is needed, we can begin the next logical step: creating all of it from scratch.
As one of the most admired synthesizers of all-time, there are countless clones and emulations of the TB-303 - but the dream would be to perfectly reproduce the original circuitry. Thanks to the work of LadyAda of AdaFruit Industries, the original TB-303 circuit has been thoroughly reverse-engineered, documented, and released under an open-source license as the x0xb0x.
Unsurprisingly, some of the components used in the original circuit are no longer produced. The most important of these is the voltage controlled amplifier (VCA) chip (the Roland BA662A OTA). Luckily, since the late 2010s Coolaudio has worked with external fabs to create functional clones of out-of-production chips from classic vintage synthesizers. Their clone of the BA662A is the readily-available V662A.
The other discontinued components can be obtained as NOS (new old stock) from marketplaces such as eBay:
The matched pairs of transistors requires us to purchase multiple copies of each, and test their gain (via the process detailed here). We need pairs with nearly equal gains.
We purchase the x0xb0x circuit boards, enclosure, front panel, and all of the vintage components. But before building, we should explore the decades of improvements/modifications made by dedicated TB-303 owners - known as the Devil Fish modifications.
From the long list of options, we will implement the following:
After many long hours of soldering, we have our completed TB-303 replica (with mods):
But a TB-303 is only half of the equation, it needs distortion to be complete.
Thanks to the relative simplicity of their analog circuitry, there is a thriving DIY effects pedal scene in the electric guitar community. Almost all of the famous effects units from the 50s through the 90s have been reverse-engineered and had their circuits released as stripboard layouts.
Although there are differences in the circuits of different distortion pedals, the nature of the clipping (e.g. hard clipping, soft clipping) is often dictated by the diodes which are used. Building up a stockpile of NOS discontinued diodes will give us the most accurate recreation of the classic effects:
The ProCo RAT is the obvious place to start. As one of the most-analyzed effects pedal circuits, there are a few common mods we will add: the Ruetz tone mod (replacing a fixed resistor with a variable resistor, to adjust the tone of the distortion), and the addition of diode-switching (to easily compare the effect of different resistors on the nature of the clipping).
We start by modifying an existing layout:
Then design a perfboard layout:
We end up with our customized ProCo RAT:
The ProCo RAT 2 is worth making for the sake of comparison. The design is almost identical, with changes only to the clipping diodes and opamp.
The Ibanez TS9 Tube Screamer comes next:
And while we are at it, another classic unit is the MXR Distortion+:
Phasing is a surprisingly simple effect: a dry signal is passed through a series of all-pass filters which introduce frequency-dependent phase shifts without adjusting the magnitude of the signal. The phase-shifted signal is mixed with the dry signal, and through destructive interference (where the phase-shifted signal is 180 degrees out-of-phase) certain frequencies are eliminated from the signal. Those frequencies shift with time, giving the phasing effect.
We start with the Ross Phaser:
Then the Electro Harmonix Small Stone:
Flanging is a more complicated effect: the result of a time-shifted signal being mixed with the dry signal. Achieving this requires delay, which requires some form of “memory” - usually in the form of a delay line implemented in a BBD (bucket-brigade device.
The Flangelicious is a circuit built around a 1024-stage BBD (the MN3207):
Tremolo is achieved by modulating the signal amplitude, with the creativity coming from the rate of modulation and the waveform used as a modulation source. The Twin Peaks “Tap Tempo” Tremolo provides a lot of customization:
As mentioned above, delay effects require some form of “memory”. BBDs max out at 250ms of delay (after 4096 stages!), but the feedback delay used in goa trance requires multiple seconds of delay. We are left with no choice but to pursue a digital design utilizing SRAM.
The DigiDelay suits our needs, with up to 4 seconds of delay and controllable feedback:
Having to build a number of full-blown analog synthesizers would be tedious work, especially since much of what contributes to a synthesizer’s unique sound are its filter (VCF) and amplifier (VCA) designs. A modular design, where the VCA and VCF are seperated from a master software-controllable control board (handling everything else: power, osillators (VCO), etc.), would be ideal.
The Shruthi is exactly what we are looking for. An open-source hybrid digital/analog monosynth, it consists of a digital control board providing the main oscillators and sub-oscillator, and interchangeable analog “filterboards” containing everything else. A dedicated fanbase has developed and many filterboards (both official and unofficial) are available, recreating the designs of many classic monosynths.
Getting the PCBs made is simple enough but some of the more obscure filterboards depend upon discontinued chips, so we will need to track down new-old-stock (NOS) as well as functional clones:
All the designs are through-hole which makes soldering a breeze. We start by making the filterboards recreating the most-common monosynths used in goa trance.
Roland-inspired diode ladder: “SMR4 MkII”
Korg MS-20: “Yellow Magic (LP2+Delay)”
Korg-style diode-ring Sallen-Key topology: “Three Rings Circuits Dual SKF”
While we are at it, we continue with some other classic synths (not typically used in goa trance, but worth experimenting with).
Moog-style transistor ladder: “TO-LAD-4tr”
Oberheim Xpander-style pole-mixing: “4-Pole Mission”
Yamaha CS-80: “Old Crow’s CS-80”
And some rarer synths.
Formanta Polivoks with overdrive and FM feedback: “Polivoks”
Steiner-Parker Synthacon multimodal filter: “Shruthacon”
EDP Wasp: “Wespe”
And for completeness, a few unique filter designs which may be useful.
Two independent 2-pole state-variable filters (serial/parallel, multimode): “Dual SVF”
Dual 12 dB state-variable low-pass per side (stereo): “LSF-K1 Linear Stereo Filter”
We can take any of the above filterboards and pair it with the digital controlboard to produce our desired monosynth (along with a laser-cut enclosure):
As usual, we explore the modding scene. The Sound Designer Edition is an extensively modified Shruthi + SMR-4 MkII combination which adds many filter control parameters. Naturally we build one of these (and design a basic 3D-printed enclosure) for experimenting with:
Another useful device to build is The Sidekick, which allows any Shruthi filterboard to be used independently as a filter for any audio signal:
The Juno 106 (and its predecessor the Juno 60 - my favorite synth of all time) is a six-voice polysynth where each voice has its own VCA, VCF, and envelopes. Designing and building one of these would be a substantial increase in difficulty over what was done with the single-voice Shruthi. Luckily, this hard work has already been done with the Ambika.
Ambika is essentially six Shruthis combined into one polysynth. Where the Shruthi had modular “filterboards”, the Ambika has modular “voicecards” - containing both an oscillator and filter on each. Almost all of the Shruthi filterboards have been adapted to Ambika voicecards:
If we wanted to adhere strictly to the Juno sound, we would use 6x of the Roland-emulating SMR4 MkII - but for the sake of experimentation we will go with 4x of the SMR4 MkII, 1x of the Polivoks, and 1x of the Tubika transistor ladder.
After ordering the PCBs, gathering the enormous pile of components, and tediously soldering everything together, we have our polysynth:
As usual, we check the modding scene for ideas. One mod of interest is the YAM (Yet Another Mutation) custom firmware which adds a number of new oscillator waveforms and filter control characteristics. Originally designed for the Shruthi, it has been modified to work with Ambika, so we install it and make the necessary hardware modifications.
We are off to a good start with our homebrewed Juno, but it just wouldn’t be a Juno without that famous chorus.
The Juno 106 and 60 sound great dry, but when the chorus is turned on something magical happens:
(watch this for a investigation into what makes the Juno chorus so unique)
Thanks to the hard work of a dedicated hardware hacker, a standalone Juno 60 Chorus unit schematic is available. The secret sauce is the long-discontinued MN3009 bucket brigade device (BBD). Luckily a company named Xvive Audio has resissued the chip.
We once again order PCBs, gather the components, and get to soldering.
Our beautiful Juno 60 Chorus unit is ready (in a custom laser-cut birch plywood enclosure):
The final element which made the Juno 60 magical was its arpeggiator. If you’re familiar with the music of Enya, you’ve heard it in action:
We can add a similar arpeggiator (as well as other sequencing capabilities) to any MIDI-enabled synth via the MIDIpal:
The reverb effects used in goa trance depended on complex (and proprietary) digital algorithms, so we can’t build our own. Eventide units were the go-to for goa trance, so we purchase an Eventide Space:
Pitch-shifting is another complicated digital effect, and Eventide was again the go-to. We purchase the Eventide PitchFactor:
We come to the most important piece of gear: the iconic Roland SH-101 monosynth. My idea was to create the minimum viable SH-101: a single voice with all the characteristics (and controls) of the orignal SH-101, without all the extras (i.e. sequencing, LFO, glide, bender).
It seems possible - the original service schematics are available, as are reference schematics for the major components:
The required chips (Curtis CEM3340 for the VCO, BA662 for the VCA, IR3109 for the VCF) are all available as re-issues or functional clones, which is another hurdle cleared.
However, just as I was about to go down this rabbit hole, Behringer announced their SH-101 clone: the MS-101. It looks, operates, and sounds just like the real SH-101 (so much so that they had to change the name to MS-1 shortly after release!) As satisfying as it would be to cobble together a homebrew SH-101 (and I hope someone does it one day), it is much more satisfying having a near-duplicate clone to play with:
We are finished.
After an obscene amount of research, planning, ordering, and soldering, we have everything needed to create classic goa trance using the original techniques. It will probably comes as no surprise that I have not yet sat down and created a track yet.
Over the years of working on this project I have had the opportunity to re-listen to all of my favorite goa trance tracks and discover many new favorites I had not heard before. Before I begin creating my own tracks, I plan to put together a mix of my favorites as inspiration.