Monday, February 19, 2018

Review: Q119 Analog Sequencer

The Q119 from Synthesizers,com is a 24-step analog sequencer. If you haven't used an analog sequencer before and don't know what its purpose is, it's a device that stores a set of control voltage values, and sends them to an output one after the other, under the control of a clock signal. As is the case with many analog sequencers, the “storage” for the control voltages consists of a set of knobs, each of which selects a control voltage within a given range. If you've listened to early Tangerine Dream or any other “Berlin school” electronic music, you've doubtless heard note sequences produced by an analog sequencer connected to the control input of a VCO. Repeating control voltage patterns have a huge variety of other uses, such as controlling filters, switching between different signals via connections to VCAs, and even using the output as an audio signal when the clock rate is high enough.

Like all products, the Q119 is formatted in the MU (Dotcom) format, which means it uses 1/4” jacks for all signal connections, and the standard Dotcom six-pin MTA-100 connector for power. (It does draw from the +5V power; the power supply must supply that voltage in order for the Q119 to function.) At a width of 8U, it is one of the physically largest modules that offers. The panel is divided into three basic sections: The section on the left has the clock controls and the various option switches that change the way the sequencer works. The middle and largest section consists of the 24 step controls, each having a control voltage tuning knob and an LED indicator. The section on the right is the output section, with the row outputs, and the master outputs with their offset and lag controls. Q119 analog sequencer, with a single-width Q128 A-B switch shown next to it for size comparison.

Clock Rate, Start/Stop, and Cycle Controls

Cycle option switches at the top,
clock controls at center,
start/run/stop controls at bottom
In the clock section, the most prominent controls are the oscillator frequency (RATE) knob and the GATE WIDTH knob. The RATE knob and the adjacent RANGE switch control the rate of the internal clock. With the knob full CCW and the RANGE switch on LOW, the slowest available rate is about 3 Hz, which to me is not slow enough. If you want slower, you have to use an external clock, The fastest available rate, with the RANGE switch on HIGH, is about 320 Hz. To the left of this knob is the external clock input and the SOURCE switch. As you might guess, when the SOURCE switch is in EXTERNAL, the internal clock is disconnected and the sequencer is driven by a clock signal received at the external clock input. This input should be a pulse wave (although the sequencer will square it up if it isn't), and the sequencer advances on the leading edge.

When the internal clock is being used, the GATE WIDTH control determines the “on” time of the gate outputs, as a duty cycle percentage (which means that as the frequency gets faster, the gate on time gets shorter). Unfortunately, the one on my Q119 does not work (I bought this unit used); it produces gates that are about 1 ms wide regardless of what I set the knob at. Fortunately, when an external clock is used, the gate on time follows the pulse width of the external clock; the GATE WIDTH control is ignored. This means that if you are driving the Q119 with a VCO that has pulse width modulation, you can change the gate “on” time by adjusting the VCO's pulse width, or better yet, make the gate “on” time voltage controlled by feeding a control voltage to the VCO's pulse width input.

The start/stop controls at the bottom of the clock section consist of four pushbuttons and three associated input jacks (one for each button except SET END). The START button, when pressed, causes the sequencer to start; it then runs continuously (unless the the SINGLE / CONTINUOUS switch is in the SINGLE position), until the STOP button is pressed. The GO button causes the sequencer to run as long as the button is held; when the button is released, it stops. The jacks under the START and STOP buttons accept trigger signals; receiving a signal on one of these jacks has exactly the same effect as pushing the associated button. The jack under the GO button accepts a gate input; the sequencer will run as long as the gate signal is high.  The SET END button, we'll cover in a minute.

How fast will it run?

With an external clock, I tested mine to see how fast it would run, and it made it up to 920 Hz; faster than that, and the sequencer freezes. ('s documentation only says that it will run “up to” 1 Khz.) This means that you can, in effect, use the Q119 as a sort of function generator at low audio rates; at this speed, a full 24-step sequence will cycle at about 38 Hz, and faster if you make the sequence shorter. There is no limit on the slowest rate; you can unplug the cord from the external clock jack, and the sequencer will simply wait until you plug it back in. When the sequencer is stopped, pressing the MANUAL STEP button next to the RATE knob causes the sequencer to advance one step. This is normally used to tune steps when setting up a sequence, but it can be used to “clock” the sequencer manually.

Cycle options

The four switches across the top select various options for the sequencer's operation. The MODE switch, I'll cover in the next section where we go over the step controls. The voltage range OUTPUTS switch sets the minimum and maximum range of the step tuning knobs. When the switch is in the -5 / +5 mode, turning a step knob full CCW causes tha step to output -5V, and full CW outputs +5V; the 12 o'clock position outputs 0V. When the switch is in the 0 / +5 mode, full CCW on the step knob outputs 0V. (The 12 o'clock position doesn't output 2.5V; I'll say more about this later.)

When the CYCLE switch is in the SINGLE position, the sequencer always stops on the last step in the sequence. To make it run again, a START operation has to be performed again. In the CONTINUOUS position, as you might expect, the sequencer runs in a continuous loop until you stop it. (Note that when the “hidden” random mode is selected, this switch is ignored; the sequencer always runs continuously until stopped.). The SEQUENCE switch, when in the UP/DOWN position, causes the sequencer to reverse direction when it reaches the last step in the sequence, and again when it gets back to step 1. If the configured length of the sequence is 6 steps, then after step 6 the next steps will be 5, 4, and so on, back to 1. At that point it will again change direction and count through 2, 3, etc. When the up/down mode is selected, and the CYCLE switch is in the SINGLE position, the sequencer stops when it returns to step 1.

The SET END button serves two purposes. Its primary function is to allow you to set the desired length of a sequence. This is done by pressing the SET END button once and releasing it; the LED for either step 1 or the current end step will begin to flash rapidly. Repeatedly press the SET END button to advance the end step (you have to do it quickly); when it reaches the step you want, stop pressing the button. After a second or two, the flashing will stop, and then that step will be the final step in the sequence. This is effective for all sequence modes -- up, up/down, and random. Note that when you switch the sequencer to 3x8 mode, it will automatically set step 8 as the end step. When you switch back to 1x24 mode, step 8 will remain the end step, and you will have to use SET END to reset it to a longer sequence if you want. (Or cycle the power.)

The SET END button is used with the MANUAL STEP button to select two "hidden" modes of the sequencer. The normal start mode is the "reset" mode; in this mode, any time the sequencer starts, it first resets to step 1. Pressing MANUAL STEP while pressing and holding SET END selects the "continue" mode. In this mode, when the sequencer starts, it resumes with the step after the one it stopped on. Doing the opposite of that – pressing SET END while pressing and holding MANUAL STEP -- sets the cycle mode to the random mode. In this mode, each time the sequencer advances, it selects a step at random. Although I haven't attempted to do an analysis of the distribution, it seems to be pretty uniform. One thing to note is that the code presents the same step from being selected twice in a row. This is a nice feature when generating random notes; in a random-note sequence, it tends to be jarring to the listener to hear the same note sound twice. The CYCLE and SEQUENCE switches have no effect when the random mode is engaged; the sequencer runs continuously until stopped. Either of these hidden modes may be disengaged by repeating the button sequence for that mode, or by cycling the power. 

Step Controls

The heart of the Q119 is in the 24 step blocks, which are organized in three rows of 8 steps each. Each step block consists of a single knob, which is used to select the output voltage for that step, and a red LED that indicates when the block is active. To improve finger room for the knobs, the odd-numbered steps have the knob on top and the LED on bottom, while the even-numbered steps are the reverse. This results in a rather amusing pattern of lights moving in a zig-zag when the sequencer is running, which some performers object to, but I think it actually improves recognition of which step is active. The LEDs also function with the SET END button in selecting which step is to be the last step in the sequence. Changing the setting of a knob will be reflected immediately in the output if the sequencer is on that step (the step's LED is lit), whether running or stopped.

Q119 step controls and LEDs, with row outputs on the right.

The organization of the step blocks into three rows is not merely a visual presentation. The Q119 has two operating modes, known as “1x24” and “3x8”, and selected by the MODE switch. In the 1x24 mode, the sequencer drives a single sequence of up to 24 steps long, using the three rows in series. When the sequence runs, it will proceed across the top row until it reaches step 8, then resume on the second row at step 9, going to 16 and then jumping to the third row at step 17. At step 24, it jumps back to the first row and step 1. In the 3x8 mode, the sequencer drives the three rows in parallel, producing three sets of control voltages at the three BANK outputs. The first step is steps 1/9/17, then it proceeds to 2/10/18, and so on, up to 8/16/24, at which point it returns to 1/9/17. The LEDs for the proper steps in each row will light simultaneously, as opposed to the 1x24 mode, in which only one LED is lit at a time. (In either mode, the SET END button can be used to make the sequence shorter than the maximum, if desired.)

Control voltages

The control voltage knobs are not linear with respect to output voltage. With the OUTPUTS switch in the -5/+5 position, one might expect that the zero position (12 o'clock) is 0 volts, and each major hash mark is a difference of one volt. The first statement is true, but the second is not. From 0 to +1 on the indexing is a difference of about 0.6V. The steps get larger moving further away from the zero position, finally reaching plus or minus 5V at the +5 and -5 positions respectively. With the OUTPUTS switch in the 0/+5 position, something similar happens: the full CCW position (-5 in the indexing) is 0V; -4 is about 0.3V, -3 is about 0.7V, and so on. In both modes, the steps get larger as you move farther away from 0V. This is something of a benefit if you can use the ADD offset control (further down) so that you can keep most of the steps near the 0V position, which makes it easier to make fine adjustments. However, it is confusing if you expect to be able to look at the indexing and dial up a desired voltage; that isn't straightforward. If you need a specific voltage, it is best to check it with a voltmeter. If you are running the output into a VCO and trying to tune notes, it is usually better to either let the sequence run and tune it by ear, or if that doesn't work for you, single-step the sequencer with the MANUAL STEP button and check each note against a tuner. 
Output section, with row (bank)
outputs on the left, and the master
outputs on the right.


The output section contains the master outputs, a set of row outputs for each row (labeled BANK 1/2/3), a knob for adding lag (portamento), and a knob and jack for adding an offset voltage to the master output. The master output is usually used when the sequencer is operating in the 1x24 configuration. The master OUTPUT jack outputs the voltage from the currently active step. The GATE jack outputs a gate which rises when the sequencer advances to the next step, and falls some time after, as determined by the GATE WIDTH knob in the control section (or the pulse width of the external clock, if an external clock is being used). The LED next to the GATE jack lights when the gate is active. If the MODE switch is in the 3x8 mode, the master OUTPUT jack will have the sum of the active steps from each row. This isn't usually what you want, but it does have creative possibilities. Note that the OUTPUT jack is active all of the time, including when the sequencer is stopped. The GATE output remains low when the sequencer is stopped.

The row output jacks are active when the corresponding row is active. When the sequencer is in the 3x8 configuration, the top-row OUTPUT jack outputs the voltage selected from the currently active step in that row, and the other two row OUTPUT jacks perform the same function for their rows. All of the GATE jacks pulse together in this mode. In the 1x24 mode, the row output jacks are only active for the row that contains the currently active step. When the current step is not in that row, the OUTPUT jack outputs the minimum voltage (0V or -5V depending on the OUTPUTS switch setting), and the GATE jack remains low.

Master output modifiers

The GLIDE and ADD knobs only effect the control voltage master output. The GLIDE is a conventional lag processor that acts on the control voltage output. The ADD knob adds an offset voltage to whatever voltage is present at the master output; this has a number of obvious uses, such as transposing sequenced notes, or bringing them in tune with another instrument. If a cable is plugged into the ADD INPUT jack, that is also added to the master output.  To sum it up, the voltage at the master output consists of:
  •  The current step control voltage (or the sum of the three steps, in the 3x8 mode)
  •  The ADD knob voltage
  •  The signal present at the ADD INPUT jack

Interaction with another sequencer

The DONE OUTPUT jack sends a trigger signal at the time that the sequencer advances from the last step back to step 1 (or would have, except for the CYCLE switch being in the ONCE position). This allows you to operate two (or more!) Q119s in a round-robin fashion, by setting their cycle switches to ONCE, and then patching the DONE output of one into the START input of the next. When the first one finishes, it will start the second one, etc. By careful adding of the outputs, you can create sequences of 48 or more steps. (You could take the master OUTPUT jack of one Q119 to the ADD INPUT of the next one to combine the control voltages, but you'd need some external module to combine the gates.)

Interaction with other modules

Some performers who use an analog sequencer to produce note sequences find it easier to set up the sequencer when they can run the outputs through a quantizer. offers a quantizer, the Q171, which has features designed to make it complementary to its sequencers. In particular, it has three quantization channels, so that you can quantize all three rows when using the 3x8 mode, and it has gate inputs to force quantization to only occur on the note gates, which can help avoid the “dithering” problem (where the quantizer jumps back and forth between adjacent notes). However, other quantizers could certainly be used. 

Output selector switches, such as the Q962, have potential uses with the Q119.  The DONE OUTPUT can possibly be used to cycle between different bus selections or outputs, for various purposes.


It seems a bit unfair to describe the Q119 as an “entry level” sequencer, since it is a quite capable module. It is not as full featured as, say, the Moon Modular 569, the GRP R24, or's own Q960. Then again, it also costs a lot less than those others; the direct-sale price of $560 USD is a bargain in the world of analog sequencers, which generally tend to be expensive. (Moon's direct-sale export price, excluding VAT, for the 569 is E1258.77, which at the exchange write on this date, 7 Feb 2018, works out to $1545.41 USD.) The main thing that those sequencers have that the Q119 lacks is flexibility; they typically have features like individual gate outputs for each step and reset trigger inputs. Then again, they sometimes require either additional aid modules or fancy patching to perform functions that the Q119 has built in. So yes, the Q119 is a good choice for someone who has no experience with analog sequencing and wants to get practice with it, but it's a module that will continue to be useful in your case even after you purchase one of the higher-end sequencers.

Demonstration videos

This first video is a basic demonstration of the Q119's different cycle modes.  The 1x24 and 3x8 modes are demonstrated at different speeds, with up, up/down and random sequencing, and the single and continuous cycle options.  The use of the SET END button is also demonstrated.

This second video illustrates using the Q119 in the 1x24 mode, with a sequence length of 14 steps, to generate an approximation of a familiar Synergy sequence (the one from which this blog takes its name). Driven by a pulse wave from a Q106 VCO in LFO mode, it is modulating another Q106, whose triangle output is going into an MOTM-440 OTA filter. Envelope is from a Q170 Envelope++, and it is controlling a Q109? VCA. Note that this actual patch is only an approximation of the original, for demonstration purposes.  Please excuse the rough tuning; I don't have a quantizer and I didn't spend a lot of time on tuning the notes. Nonetheless, if you listen to much Synergy, you should recognize it.  I use an external clock and gradually speed up the sequence, in the same manner as the original.  Just before the end, I take it up to a faster speed than Larry Fast's old Moog 960 was capable of, just to show off the Q119 a bit.

You will notice something at the start of the video: there seems to be a "skip" at the very start of sequence, between the first and second notes.  This is due to the fact that I'm using an external clock in this video.  (When I reach to something above the top of the picture, I'm reaching for the requency control of the Q106 that is serving as the clock source.)  The Q119 syncs its own clock when it is instructed to start, but it has no way of making an external clock sync to it.  So when I start the sequencer, it starts at some random point in the external clock's cycle.  If this is part way through the cycle, then the first step will be short, time-wise, and that is what you hear here: the first step occurs on the START button press, and then the next step occurs on the next clock transition, but I hit START at some point in the middle of the clock cycle, so the interval between the first step and the second step was short.  If I had wanted that interval to be precise, I could have watched the LED on the Q106 and pressed START at the start of the cycle.  Or I could have fed an external trigger source to the Q119's START jack, and to the Q106's hard sync input.  

This third video illustrates using the sequencer in 3x8 mode. What is happening here is that the top row is being used to modulate a Q106, whose sawtooth wave is going into an SSL 1310 digital delay that is being modulated by an LFO. (There is no filter in the patch.) The bottom row is being used to generate a gate signal – turning the knob up causes the gate to be “on” on that step, and turning the knob down causes it to be “off”, so that that step does not sound. As the sequence plays, I play with the bottom row to make different notes in the sequence sound.