VOLTMETER and DISPLAY CONTROLS
RST
- Reset. Use this button to reset the voltmeter software in the off chance that a malfunction
occurs.
MODE
- This button selects between the default needle meter and numerical displays
I/O
- Display ON/OFF button. Save power when not in use by turning off the display.
DIRECT VOLTMETER INPUT
Signals can be measured unaffected by the signal processor using this jack. The signal present
here is buffered and hard wired to the adjacent THRU jack to the right of this input.
NORMAL OUTPUT and THRU/MULTIPLE
The jack lOUT is the post processor output. This output is buffered and normaled to the
THRU jack and acts as a +OUT multiple. However, using the DIRECT VM INPUT jack will break the
multiple as indicated on the panel. If a jack was connected in the THRU output, the new signal
inserted into VM will now be present on that jack.
INVERTED OUTPUT
This output provides and inverted version of the post processor output. Please note that the
information on the display is indicative of the +OUT only; unless you self patch the -OUT into the
VM input.
8
9
10
11
Compact Utility
Finally - a compact utility that addresses your needs. GND CTRL was designed to fill a gaping hole or should we say an - overfilled hole in
the utility world. Until now, utility modules were designed with rarely more than one basic function. This often required filling up
limited rack space with attenuators, multiples and inverters -taking up space needed for that new VCO or VCF - and still, without any
convenient way to measure or even scale CVs.
Even more frustrating is that all that redundancy of function in one module is hardly necessary in a small system or for typical small to
medium sized patches. GND CTRL takes the best of utilities and couples them with the convenience of a built in voltmeter and preset
scaling unit in a compact and space saving 8hp. There is no doubt GND CTRL will make patching easier and more efficient while saving
panel resources.
Voltage Bridging
The growing variety of analog and microprocessor driven modules in Euro is great, but given the lack of standards, not all modules
produce or accept the same range of control voltages. GND CTRL’s gain presets address this issue and provide an easy way to interface
modules while getting the best range and response. Common voltages produced and utilized by the majority of Eurorack audio/video
modules are unipolar; 0.5V, 0-1V, 0-5V, 0-10V and b/-2.5V and +/-5V. The Presets address these conversion ratios. With the
visual aid of the voltmeter along with the Manual Attenuator and DC bias make this task a simple one. Dead spots and compatibility
issues are history.
Bridging External Devices
GND CTRL can be used to boost line level signals for use in the modular environment and similarly to attenuate modular signals for
monitoring level sensitive devices.
DC Voltage Source
Use the DC Bias to produce an adjustable bipolar DC voltage source. Mix the signal with modulators or use as a trigger voltage source for
pressure sensitive resistors and voltage source for boosting CV range. The currently displayed voltage is available at the +OUT and THRU
outputs as well as an inverted version at the -OUT output.
Know Your Voltages!
Knowing precise voltage levels in a patch is far more accurate than remembering a knob’s position. We all know just how subtle settings
can be.
Not only that but this knowledge provides a much deeper understanding of modular synthesis and what is happening in your patches.
PRESET
FUNCTION
SUGGESTED USE
.1 Divide by 10 Video & Ext Bridging
Attenuation
.2
Divide by 5 Video & CV Bridging
Attenuation
.5
Divide by 2 CV Scaling, 10V to 5V
5V to 2.5V
1
Unity No Gain
2
Multiply by 2 CV Scaling, 5V to 10V
2.5V to 5V
5
Multiply by 5 CV Scaling, 1V to 5V
Boost Low/Ext Signals
10
Multiply by 10 CV Scaling, 1V to 10V
Boost Low/Ext Signals
IMPORTANT!
Do not attempt to jumper the 6 pin header on the back of the GND CTRL PCB!
This is for possible future voltmeter firmware updates. There are no
easter eggs or secret settings beyond the possibility of a “SURPRISE, YOU FRIED YOUR MODULE!” smoke fest. You will also void any possibilty of a free repair.
That being said, we are here to help if you ever have any problems with our modules! If you are curious and have questions just ask :)
The number one cause of damage are reversed or misaligned power connections. Always abide by the -12V aligned with the RED stripe rule for SSF modules.
We do tolerate mistakes as all our modules are reverse polarity protected but do please pay attention because not all modules have this feature!
Thank you for your purchase and as always - ENJOY!
CALIBRATION PROCEDURE
The calibration should be performed exactly as follows:
Using an accurate multi-meter to three decimal places.
And a stable voltage source.
1.) Start up GC and the multi-meter.
2.) Patch the voltage source to a attenuator and then
to the AUX input of GC.
3.) Patch a cable from the THRU output on GC to the
multi-meter probe leads.
4.) Using the multimeter, set the voltage from your
voltage source to 5.35 or close to that - just a value to
two decimal places that is close to 5V but not 5V exactly!
5.) Set the stabilizer pot to about 9 O'clock
6.) Using the PCB trimmer and taking the measurement
off the MAX reading - set GC MAX reading to exactly
what you get off the multi-meter to two decimal places
- as close as possible.
7.) Using the attenuator on your voltage source, cycle
through voltages from 0 to 10V and make sure that the
reading is within 10-15mV across the board or as close
to that as is possible . The reading will slightly skew
increasingly off the mark as you tend away from 5V in
both directions. But doing it this way gives the best all
round performance.
