- Latest addition to the studio is a customised Studio-22 modular
synthesizer from synthesizers.com
(aka dotcom), so this section documents progress & mods... with a
few warnings for newbies like me! More info on modular synths can be
found in this forum.
One advantage over conventional synths is that the oscillators (and noise
sources) are permanently running. I'd not fully appreciated this before,
but it means you don't need any external gear to get sounds out of it.
With previous synths & sound modules, you usually end up repeatedly
pressing keys on a keyboard (or running a sequencer) while you tweak the
knobs, but with the modular the sounds are there all the time - in fact
you have to go out of your way to shut them up!
Note there's no
output level control on these oscillators so
don't plug a PA or headphones directly into them unless you have some
external control over the volume. You can patch them via a module with a
gain control such as an amplifier or mixer module, but either way watch
those levels; 10v peak-to-peak signals can do a lot of damage!
So if you want instant drones, patch one or more oscillators to the amp,
and try different pitches and waveforms. If you want a regular pulse to
check out the envelope generators & filters, switch the sample &
hold module to 'internal'; its gate input socket becomes a pulse output
whose speed is controlled by the sample rate knob. There's endless
possibilities even without connecting an external keyboard or sequencer.
This basic test
shows my first lash-up after switch-on.
Synthesizers.com supply individual modules, cabinets and accessories as
well as a range of complete plug & play 'studio' systems. The
standard Studio-22 comprises a walnut cabinet pre-filled with a
selection of 18 modules, blanking plates, an internal PSU and a set of
1/4" jack-to-jack patch cables, but you can customise the package
contents as required. Either ask for price quotes via email or use their
downloadable SynthInvent tool to design your own system with immediate
feedback on cost.
Module widths are measured in multiples of 'Moog units' or MU, e.g. the
Q108 VCA module is 1 unit wide, the Q106 VCO is 2 units wide. The
Studio-22 cabinet, as its name suggests, has space for 22 units at the
front and 4 at the back.
The 18 default modules are mounted with 17 at the front, leaving one
unit free, and one at the back, leaving 3 units free.
You can free up one more unit at the front by moving the Q101 power
on/off module to the back, but you'll need access to the switch unless
you use an external mains on/off switch.
You can reduce costs by replacing the Q101 & Q102 power modules
with the combined Q137 module (mounted either at the front or the back),
the trade-off being less power sockets for chaining to other units.
Costs can also be reduced by choosing the MDF cabinet, or leaving it out
altogether if you can source your own. Ditto for the patch cables, but I
found reducing the no. of shipping boxes had very little affect on the USA
to UK postage costs.
My final choice was to use the Q137 as described above and mounted at
the back, freeing up enough space at the front to add the 2-unit wide
Q150 'Moog-like' ladder filter. I excluded the patch cables as I wanted
to make my own, and this saving helped to justify the walnut cabinet.
The latter took a lot of conscience-wrestling but it really is the icing
on the cake! Including a cabinet also meant the whole system came
ready-assembled & tested so it was just a case of 'plug in and
N.B. the mains voltage selector switch had been left in the 110v
position so check this before plugging in!
Modules from other vendors can be mixed with dotcom modules, but see
forums for advice on power connections/adapters and physical dimensions.
Saving money by making your own can be a good idea... a few lengths of
unbalanced screened cable, a handful of 1/4" mono jack plugs, a soldering
iron... but be warned - not all cables are the same!
Some cables marketed as 'instrument' cables have a conductive coating
around the inner core for draining away static electricity to reduce
crackles when the cable is flexed, e.g. for guitarists moving on stage.
This conductivity has no effect on normal audio signals but if used for
control voltages (CV), the resistance may
cause the voltage to
drop slightly, although this depends on how well the CV driver can cope
with loading. If the voltage is being used to control pitch, this could
throw the synth out of tune.
Coincidentally, the Q104 MIDI-to-CV module had a fault (subsequently fixed
free of charge) which made it very susceptible to loading, so these
anti-static instrument cables were no use initially. A fully working Q104
can drive many loads without voltage sag so instrument cable may
have been ok, but either way I ended up replacing the patch leads with
standard twin-core microphone cable with one core unused.
The pre-formed cables from synthesizers.com are colour coded according to
length, but a functional colour scheme may be more useful for following
the flow of a patch. There doesn't seem to be a standard for this, so I
copied one of the other synth vendors and used black for audio, red for
control, blue for gates and yellow for anything else such as triggers
On the other hand, you could just leave them all the same colour as one of
the advantages with voltage control is that control & audio voltages
can be interchanged; e.g. you can control the pitch of one oscillator with
the audio output of another, or even itself; so the function of a patch
cable may be ambiguous anyway.
- If you're after those
nostalgic sequenced patterns of Tangerine Dream, Kraftwerk, Jean Michel
Jarre etc. be warned - these synths are essentially monophonic, so
creating lots of overlapping sequences in a live environment comes at a
price. There's no problem if you overdub layers during recording,
but for live perfomances you may need more modules or additional synths.
A typical 'voice' in a subtractive synth like this uses a VCO as a note
pitch source, and a triggered or gated VCF/EG/VCA combination to control
its envelope, so the no. of concurrent voices depends on the no. of
sources and whether or not you want independent triggering for each one.
This customised Studio-22 system has 3 VCOs and 2 VCF/EG/VCA sets, so this
limits you to 2 independent voices. There are various compromises &
work-rounds such as mixing all 3 VCOs into a single EG/VCA giving 3
independent pitches but with a shared trigger, etc. Modules can also be
used in non-conventional ways to emulate other modules, e.g. a VCF in
self-resonating mode can act as a VCO; see forums for other ideas.
a simple 2-voice example using Sequetron to sequence multiple patterns
live via MIDI
. The supporting PC
only has MIDI interfaces so these need converting to the various CVs (e.g.
pitch, gate, trigger, velocity) to drive the synth; one converter is
required for each voice.
I only had a single channel Q104, and there was no room for another module
so an external device from Kenton was used for the 2nd voice. Multiple
channel converters are also available from both vendors; the Q174 from
synthesizers.com is a 2-channel module with the same 1-MU width as the
Q104 (it only became available a few months after my purchase - Murphy's
a couple of external sound generators (also driven via MIDI) to increase
the no. of voices for live sequencing/playing.
- Some experiments
driving the synth via CV
of MIDI. This video
shows a Doepfer MAQ 16/3 sequencer driving the 3 VCOs independently with
their mixed outputs connected to a single EG & VCA, giving 3 simple
voices. Twiddling the MAQ knobs came up with a nice pattern so it was
tweaked and transferred to a Doepfer Schaltwerk. The MAQ CV outputs were
then free to control a VCF frequency both directly and via an EG module,
resulting in this video
Another 2 voice video
showing Sequetron recording and controlling the synth via MIDI,
with a brief taster of the hard/soft clipping option in the Q109 VCF.
Feb-2014 - Sampling is another
way of increasing polyphony. It retains the modular's sound at the
expense of hands-on control, although the sampler can be fed back
through the modular to regain some of this. Capturing the sounds/patches
can be tedious depending on your sampler's automation capabilities; this
series of videos show how the
Sample Aid tool can help. A test session comprising a 21-note,
19-velocity multisample is available for E-MU samplers E-MU
4B FAT-format (approx 65MB); contact me for portable .sfz/.wav
The dotcom modules are fairly easy to modify - there are no
surface-mount components and all panel controls & LEDs are connected
to the PCB via push-on connectors. The simplest DIY mods (if you are not
averse to drilling the front panels) are to add toggle switches to the
internal PCB jumpers which already exist on some modules.
The jumper links are shown in the data sheets supplied with each module
and provide various configuration options, e.g. the Q106 VCO module has
two 1v/octave frequency inputs which are normally configured as
independent inputs, but a jumper allows them to be linked together. This
is useful if you want to drive multiple VCOs with the same pitch control
signal - you would normally have to use a split cable or connect
them via a Multiples module, but when the inputs are linked you can
simply daisy-chain them together. Adding a switch allows you to change
this option at any time without having to power off the synth, remove
the module and change the jumper. Some other jumper options are shown
The toggle switches can be connected to the jumper pins via push-on
connectors (recommended for ease of maintenance) or soldered.
Synthesizers.com can supply switches pre-wired to push-on connectors so
if you're likely to need these, order them at the same time to save
All module PCBs are mounted parallel to the front panel using stand-off
pillars, so for single switch mods some DIYers have avoided drilling by
removing one of these and using the hole for the switch. If you do
decide to drill the panel, it is recommended to remove the PCB and all
controls first to prevent swarf getting lodged and causing shorts later.
Either way, there is limited space behind the panels so the layout may
have to be a compromise... and be aware that toggle switches vary in
size so the old saying applies: 'measure twice, cut once'! Here's
my DIY results:-
The left-hand SPDT switch toggles the two 1v/oct sockets from being
independent inputs (default) to being linked together for daisy-chaining.
The right-hand SPST switch is meant to toggle the output voltage swing
between -5v...+5v (default) & 0...10v, but is redundant on my setup as
it only works with the Q141 Oscillator Aid module - rtfm doh!
The left-hand photo shows a SPDT on-off-on switch which gives medium
(default), short & long time constants. Note this 3-way option also
requires some PCB track cuts and soldering. A much simpler option is
possible with just a SPST switch and no PCB mods giving 2 time constants:
default or long.
The right-hand photo shows a SPST switch which toggles the output voltage
swing between 0...5v (default) & -5v...+5v.
This SPST switch turns the automatic level control on & off (default).
This SPST switch toggles the clipping between soft (default) & hard.
This DPDT switch toggles between linear & exponential (default)
response. Using a simple switch limits the linear response to the Up
direction only (the downwards slew time is zero), but there is a PCB mod
which overcomes this (see web).
The top-left SPDT switch toggles the Gain control range between -5v...
& 0v... (default), the top-right SPST switch toggles the Control 'off'
level between -5v & 0v (default), and the bottom-right SPST switch
toggles the Control signal range between ...10v & ...5v (default).
In hindsight, the top-right switch would be better if placed to the left
of the Control knob - a case of not thinking it through properly!
Not a mod, but a recommendation to label the existing switch to clarify
its operation to avoid accidents - connecting outputs to outputs may
To be continued...