Reference manual

TIJN 50 is a filter and drive effect. Two filters, each one a model of a different circuit, fed hot enough that the filter's own saturation is the distortion, with the cutoff able to move at audio rate. There is no separate distortion stage, because a filter driven twenty decibels too hard is a better sound than a clean filter followed by a waveshaper. It opens as a wire: both filters wide open, no resonance, no drive, no iron, so putting it on a track changes nothing until you do.

Happy 50th

MARTIJN ENGBRENGHOF

Half a century on this earth, and a good chunk of it spent chasing the hardest kicks and the dirtiest basslines Dutch soil ever produced.

Long before “producer” was a job title people put on LinkedIn, you were in the booth writing, arranging and pressing records under more names than most people have had hot dinners: E. Engbrenghoff, M. Engbrenghof, Engbrengoff, take your pick, the vinyl never quite agreed on the spelling but it always agreed on the sound.

E-Rick & Tactic tearing up Thunderdome with “Hardcore Rules The World.”

Raw, relentless, and built to be played way too loud.

Fifty years old and still, somehow, the same guy who’d rather argue about a snare sample than small talk about the weather. That’s not a small thing. That’s a life spent caring about the right things.

Martijn, we’ve been friends for more than 25 years now, and something tells me the next 25 will look a lot like the last: us, old and grey, sitting behind the geraniums, still complaining about badly recorded music.

Here’s to you, brother.

ITS YOUR BOY RON

What it is

TIJN 50 is a filter and drive effect. Two filters, each one a model of a different circuit, fed hot enough that the filter's own saturation is the distortion, with the cutoff able to move at audio rate.

There is no separate distortion stage. A filter driven twenty decibels too hard, limiting on its own resonance path, is a better sound than a clean filter followed by a waveshaper, and it is the reason the models had to be nonlinear before any of this was worth building.

It opens as a wire. Both filters sit wide open with no resonance, no drive and no iron, so putting it on a track changes nothing until you do.

THE SHORT VERSION

The panel

One screen with a fixed shape. Nothing moves when you change anything, so you always look in the same place for the same thing.

The signal runs left to right and the plate darkens as it goes: three Void fields cut out of the yellow, numbered one, two and three, then the output back on the plate itself.

WHAT THE COLOURS MEAN

The colour rides the pointer, on the black cap, and never the travel arc: the arc crosses the yellow plate, where a yellow arc would not be there at all.

THE BLACK BAR

How a control works

The plate in the middle of the panel is a display. At rest it reads TIJN. Touch a control and it reads that control, then goes back to its own name after four seconds.

When the matrix is moving a control, its knob grows a second, thinner pointer at the value the filter is actually using, with a bar between that and where your hand left it.

Your first five minutes

Put it on a drum loop. Press the preset name in the black bar, open Kick, and step through with the arrows until something sounds right.

Then turn one thing. FREQ 1 is the cutoff of the first filter; RESO next to it is how hard it rings. Take RESO past about nine tenths and the filter starts to oscillate on its own, which is a tone you can tune with FREQ.

DRIVE is how hard the filter is fed. It does not have its own distortion: what you hear is the circuit running out of room, so the character changes with the circuit you have chosen and with how much resonance there is.

FOLLOW, in the modulation row, opens the cutoff with the level of what comes in. On a kick that means the filter opens on every hit without a single automation point.

When you want it to scream: FM DEPTH with the rate somewhere in the hundreds. Turn oversampling to 4x when you do.

The five circuits

These are not five settings of one filter. Each one is modelled from its own schematic or data sheet, and the differences were measured rather than chosen.

MEASURED, TWO OCTAVES BELOW THE CUTOFF

Fourteen decibels between the two ladders alone.

Resonance and oscillation

Every circuit oscillates near the top of its resonance control, and not all of them at the same place. Past that point the filter is making its own tone and FREQ is tuning it.

MEASURED, WHERE THE TONE STOPS DECAYING

The five knobs are levelled against each other, which took two measurements. Below a peak of twelve decibels nothing is touched at all, so the difference in weight and thinning between the circuits survives exactly as it was measured. Above that the peak is held, so changing circuit changes the character and not how loud the plug-in is.

The SEM's resonance is mapped point by point onto the 2044's, so the control travels evenly the whole way and RESO at a given position means the same thing on every circuit. One label, one meaning.

LO HI, and the two slots

LO·HI only does anything when that slot is on SEM. It runs the filter continuously from lowpass, through a notch in the middle, to highpass, which is the fader the original had.

SERIAL sends the first filter into the second. PAR runs both from the same input and adds them, which is how you get two resonant peaks at once, or a band split with one slot low and the other high.

The numbered disc at the head of each field switches that stage off. Lit is on, a hairline ring is off. A filter that is off passes its input straight through, but it keeps running underneath, so switching it back on does not click.

Drive and iron

DRIVE is the gain into the filters, up to forty decibels, in whole steps. The output compensates for most of it but not all: a box that gets a little louder as it is driven is a box people reach for, and taking all of it back makes the control feel dead.

Switching stage one off bypasses the drive and its compensation together, so the switch is a switch and not a level control.

IRON

A transformer at each end, in the category of a discrete transformer-coupled preamp. It is not a waveshaper, and the difference is the whole point.

The flux in a transformer's core is the INTEGRAL of the voltage across the winding, and saturation is a property of the flux. The same level therefore makes twenty times more flux at 50 Hz than at 1 kHz, so iron colours the bottom and leaves the top alone. It is why a preamp's distortion figure is always quoted below a hundred hertz: that is the hard part.

The magnetising current that the core draws once it saturates runs back through the source and pulls the winding voltage down, and less voltage is less flux. That loop is closed here rather than assumed, which is why the bottom end gets quieter as the iron works instead of louder.

MEASURED, AT FULL AMOUNT, FULL SCALE IN

There is a second harmonic as well, flat at about -36 dB across the whole band, and that is deliberately not the core: iron with no DC on it is symmetric. The flat part is the single-ended gain stage between the two windings, and it is most of what people mean by warmth.

THE RANGE OF THE CONTROL

Those figures are the knob at its end with a full-scale sine on it, which is the hardest thing anybody can ask of a transformer. The control covers everything below that, and it moves with how hard you hit it as much as with where you set it. Total distortion at 50 Hz, against input level: 23 percent at 0 dBFS, 14 at -6, 3.5 at -12, and two tenths of a percent at -18. At 200 Hz and above it stays under 2 percent wherever the knob is.

One control, two jobs. Where most material sits it is weight on the bottom and nothing at all on the top, which is what a transformer is for and what a waveshaper cannot do, having no core to integrate into. Wound up on something loud and low it stops being a colour and becomes the effect, and that is the point: this is a box built to be driven too hard, and the iron was given the range to go there with it.

At zero the stage returns the sample unchanged, bit for bit.

Follow and release

FOLLOW opens both cutoffs with the level of what comes in, up to six octaves. RELEASE is how fast it closes again. The rise is always fast, because that is what makes a box follow a drum instead of chattering at it.

RELEASE reaches zero, and zero means what it says: the follower drops the instant the signal does. Around a hundred and twenty milliseconds is where most material sits.

IT IS NOT A LEVEL CONTROL

Opening a lowpass upward only adds whatever the material had up there, so how much louder it gets is a property of the signal rather than of the setting. Measured over six octaves of opening: white noise rises about two and a half decibels an octave, pink noise about a third of a decibel, and a kick drum slightly falls.

The output takes back the middle case, which is what music approximates. Turn FOLLOW from nothing to its maximum on a mix and the level stays inside a decibel or two. On a kick it stays inside two.

It is deliberately not set for the white noise case. Taking two and a half decibels an octave back would drop music by fourteen decibels as the filter opened. On genuinely broadband material, hats and cymbals and noise sweeps, the box does still get louder as the follower opens, and that is a filter opening, which is what you asked it for.

FM and oversampling

FM DEPTH moves the cutoff, up to five octaves, at the rate set next to it. Below about twenty hertz that is a wobble. In the hundreds it is a different instrument: the filter starts generating sidebands of its own, metallic and rude, and that is the sound this whole category is bought for.

FM SOURCE chooses between a sine of its own and the incoming signal, which turns the box into something that argues with the material rather than decorating it.

OVERSAMPLING

Moving a cutoff at audio rate makes sidebands on purpose, and the ones that land above half the sample rate fold back down into the middle of the music at frequencies that have nothing to do with the note being played.

This was measured rather than assumed. With the FM off, the drive and the filters' own saturation fold back at -115 dB or quieter on four of the five circuits at every setting: oversampling is not needed for that at all.

WITH THE CUTOFF MOVED AT AUDIO RATE, BELOW 18 KHZ

Which is what the three settings are for. 1x leaves the oversampling out altogether, and with the FM off that is all it needs. 2x is the default and covers everything up to and including deep FM, which is where it should stay. 4x is there for deep FM with the resonance high, and buys another twenty decibels for it.

Oversampling costs latency, and the number of samples is printed at the right of the black bar. The host is told, so nothing moves out of time.

The LFOs and the matrix

Four slots. Each one takes a source, a destination and an amount from minus one to plus one. An amount of one is the full swing printed on the panel, so a number in the table and a number on a knob mean the same thing.

THE CLOCK

A row whose source is an LFO prints that LFO's clock next to its name: LFO 1 · 1/8 when it is locked to the tempo, LFO 2 · 0.25 when it is free. Press the same cell and the menu offers the sources and, underneath them, that LFO's clock: free running, or any note value from four bars down to a thirty-second.

The clock belongs to the LFO, not to the row, so two rows using LFO 1 share it.

A modulated control shows it: the knob grows a second, thinner pointer at the value the filter is actually using.

Output, wet and iron

There is a soft knee at the very end that does nothing at all until it has to. Drive, resonance and audio-rate FM can each add level on their own, and all three at once can add more than any table predicts, so the last thing in the chain is a ceiling that appears only when something reaches it. Below that it is not in the signal path at all.

The bank

Fifty-six presets in nine groups, in the black bar: back, forward, the name, save. The name is also the menu.

A dot appears beside the name the moment a control moves, so the label never claims to be something it is not.

A factory preset stores only what it changes, and loading one puts everything back to its default first. No preset can inherit a setting from the one you played before it.

YOUR OWN

SAVE asks for a name and a group. Your presets are one file each in your user folder, so they survive a reinstall and can be copied to another machine by hand. They store the whole state, because what they are for is getting back exactly what you had.

The preset menu will open that folder for you, and will delete one of yours but never one of the factory bank's.

MIDI learn

Right-click any control on the panel: learn, forget this controller, back to its default, or forget every controller. Choose learn and move a fader; the next controller message that arrives is bound to it.

The map is not part of a preset. It lives beside your presets, so a controller you set up once works for every preset, every session and every instance.

It is stored by the name of the control rather than by a number, so a control added in a later version cannot silently move your fader onto something else.

MIDI is accepted for this and for nothing else.

Every control

STAGE 1

STAGE 2, THE FIRST FILTER

STAGE 3, THE SECOND FILTER

OUT

MOVEMENT

THE TOP BAR

THE LFOS

THE MATRIX

Latency, and what is known

The host is told, and the dry path is delayed to match exactly: measured sample for sample at all three settings.

WHERE THE NUMBERS HOLD

The levelling between the circuits is measured at a cutoff of one kilohertz and holds within a decibel from 120 Hz to 6 kHz on four of the five. The Moog moves 3.3 dB across that span, which is the ladder's own gain changing with where it is tuned, and it is left exactly as it is: flattening it would flatten out part of what makes that circuit that circuit.

The follower's level compensation is set for musical material, where it holds inside two decibels on a mix or a kick. On broadband noise the box opens further, by about eight decibels over the full six octaves, because there the filter really is letting that much more through. One number cannot serve both, and music is the one it serves. See FOLLOW AND RELEASE.

Below 18 kHz, 4x is up to twenty-three decibels quieter than 2x on the circuit that asks the most of it. Counted right to the top of the band the two measure alike, because the last decimation stage's transition band sits between 24 and 28 kHz and folds into 20 to 24 kHz, at the very edge of hearing.

Where your files are

The preset menu opens the preset folder for you, so none of these paths have to be typed anywhere.