User Guide
Thank you for purchasing the AJH Synth Ring SM module, which like all AJH Synth Modules, has
been designed and handbuilt in the UK from the very highest quality components. We hope that
it will help and inspire you towards creating some great music and soundscapes! It has the follow-
ing features:
A Ring Modulator core with a very unique and warm sounding four quadrant multiplier that
includes three inputs, X, Y & Z. It is a vintage design based entirely on a discrete transistor core,
and includes an extra, resonant Z modulator input. It also has a frequency doubling switch; from a
single triangle or sine wave input an 1 output is generated.
Two independent Sub Bass generators with very fast tracking, creating -1 Octave and -2 Octaves
from the X input. These are not simple square wave subs, they generate shaped waveforms that
vary from a trapezoid wave with rounded edges at lower frequencies to sine like waveforms at
higher frequencies and are useful up to 1kHz. They have a much lower harmonic content than
square wave subs, designed to have more power and sit much better in a mix.
A five input DC coupled mixer based on the discrete transistor CP3 modular design dating back to
the early 1970’s. The outputs of the ring modulator, X and Y inputs and Sub Bass outputs are
routed to the mixer by default – plugging a patch cable into any of the mixer inputs defeats this
normalising and allows it to be used as a regular 5 channel mixer for both audio and control
voltages.
A clipping / distortion module – input 5 of the mixer is considerably “hotter” than the other four
mixer channels and will clip the signal as soon as it hits threshold level. If a DC bias voltage is
added the signal is shifted and this allows positive or negative asymmetric clipping of the wave-
form
Module width is 14 HP of EuroRack space and it is compatible with standard Euro Rack cases. The
height of the panel is 128.5mm, and depth is 24mm, or 34mm with the power cable attached.
There are four mounting holes at the corners of the module and we provide 4 of M3 rack fixing
screws, along with a Eurorack compatible power cable. Current consumption is 55mA from the
+12V supply rail and 50mA from the -12V supply rail.
All AJHSynth modules are covered by a one year guarantee against manufacturing defects.
Notes:
It is important that the power supply ribbon cable is connected correctly, see the “Power Cable Orienta-
tion” section for more details. Also, we recommend that a high quality, low noise Eurorack power
supply is used with this modules, some switched mode PSU’s generate high levels of line ripple which
may cause undesirable audio noise on the output.
Ring Modulator - Dual Sub Bass - Mixer
www.ajhsynth.com
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