Fénix I/O page
At this page you find some info concerning the Fénix. If you are not sure please contact me by mail.
This section covers connecting the Fenix to other devices. Some signal conversion or gain change may be needed:
- Midi-signal to CV's and gates.
- Level adjustment of an audio signal that feeds into an amplifier.
- Converting audio signals to control voltages.
In unbalanced connections, there are two signals to connect devices: Signal and ground. These are usually both in the connector. Fenix banana-patch cords use only the signal, so they are not suitable for connecting to other devices.
There are also balanced audio connections. These have +signal, -signal and a ground lead. Since the Fenix doesn't use balanced connections, we will not cover these. Most professional recording studio's use balanced cables for critical and low-level connections. The Fenix has very high output levels to keep a good signal to noise ratio. Please keep this in mind while connecting it to a mixer.
Improper ground connections may be the cause of ground loops resulting in hum. This is why the first section deals with grounding.
This section also covers Midi interface and audio interfacing.
Ground is used everywhere in any audio setup. Ideally, the ground should be the same throughout the setup.
The ground is used as reference by power supplies and audio connections. If several devices are interconnected using (shielded) grounded cables and the PSU is mains-grounded, you may have a ground loop. This can result in current flowing between devices like PSU and audio input which may cause the typical 50 or 60 Hz hum.
In the picture below, a ground loop is caused by connecting a Fenix to two mains-grounded devices. The loop is closed by the ground-wire of the mains network.
It is not always easy to provide a solution for ground loops.
One possible way is to decouple the signals using 1:1 transformers, but this is an expensive approach. To prevent the risk of ground loops whenever you change your setup it makes sense to design a ground-setup for your entire setup or studio.
Another common approach is to have all outputs ungrounded and only connect the cable-shields at the input-side. A separate ground-lead on each device leads to a central ground-point. If you choose this method, you'll have to run a ground-lead from each device to the ground-point. This may be a problem if you mix grounded and ungrounded devices in the same setup.
A third way is to feed all grounded devices from a properly grounded outlet, and run a ground-lead from each ungrounded device to the ground-point of one grounded device.
If no mains-grounding is used, it is advisable to not use power-strips with grounded outlets. This may create a ground loop through the power-cables.
Devices that use switched power supplies ( such as most computers) may pose another problem. The grounding is an integral part of the mains-filter. It is advisable to connect these to a grounded outlet.
There is no cut and dry way to deal with grounding, and it is important to realize how easily you can create one. You may have to experiment to find the solution that works best for you.
Connecting Fenix to other devices.
Fenix to Fenix.
If you have more than one Fenix, or other modular systems such as Synton or Serge, you can simply interconnect them using banana patch cords. The only thing you need to do is interconnect the ground of both synths. A ground plug is usually found on the power supply (Serge, Synton) or on the rear of the synth (Fenix).
Beware of ground loops if you interconnect two synths and connect both to other devices such as a mixing console.
Connecting a Fenix to other devices
The Fenix Output-module is used to send audio-signals from the Fenix to a mixer, headphones or amplifier. This is a stereo module that uses the tip and ring of a stereo jack-plug. Always use a stereo Jack-plug for connecting this module or you may short-circuit a Fenix output.
The six "Front to Back Patch" banana sockets on the front panel match six mini-jack sockets on the Fenix rear panel. They are labeled by their likely use, but they can be used for any signal as input or output.
They are passive wire connections, designed for easy access to Midi-interfaces such as the Kenton Pro-2000.
Connect the CV, gate, Aux1 and Aux2 outputs of the Midi interface to the matching inputs on the Fenix rear panel. Refer to part 1 of the Fenix user manual for help. The Aux1 and Aux2 outputs can be programmed to respond to various controllers such as key pressure, velocity or modulation wheel.
You can connect the CV to the CV-1 inputs of the VCO's, the Gate to the envelopes and the modulation sources to the CV-2 inputs of the VCO's and / or VCF.
The "Front to Back Patch" connections can be used for processing audio signals, but you may prefer the dedicated I/O modules. Each of these two modules on the rightmost section of the front panel has a stereo jack input that is summed to mono, processed, amplified and fed to the banana output. You can adjust the gain for various sound levels.
It is important to decide how you want to process the external sounds. You can:
- Alter a continuous sound with effects such as filter, ring modulation or tremolo.
- Use an external sound to trigger an internal note or event.
- Use a sound to change the properties of an internal sound
I/O input modules
The previous section covered these modules briefly. This is an overview of their functions.
As the amplitude of the external input signal is unknown, it is important to set the level of the gain-controls. The Fenix has two I/O modules, each with its own controls.
1 - The upper I/O is optimized for input signals of varying level such as drum tracks.
2 - The lower I/O generates a gate whenever the input exceeds a threshold level set by the user.
If the overall input sound level changes, you may have to adjust the threshold setting.
1 - The upper I/O has an input gain LED that flashes for every note, and lights constantly if the gain is too high. The gain-control should be adjusted so that the LED is mostly on during loud input sounds. The LED should blink during soft sounds. Very low frequencies may be perceived as series of pulses.
2 - Setting the lower I/O module is done by setting the threshold control in center-position. Then adjust the gain control so that the LED blinks during loud sounds. Adjust the threshold control so that the LED indicates a gate at the right times. Turning the threshold control clockwise yields less gate-pulses.
Some synthesizers including many Moog and Korg analogs use gate signal that is normally high, and drops to zero when a note is played. Sometimes this is called S-Trigger.
There are simple converters for these signals. Should you need to convert such a gate-signal, you can use the Fenix CPR module, combined with the CV-mix 1 module.
Connect the signal to the "-" input of the CPR. Verify that the CPR LED switches off when you play a note. You may use the CV Mixer to attenuate the signal, or to add an offset voltage to the +-input of the CPR if the LED doesn't blink.
Use the CPR output to drive the envelope generators.
If this is part of a fixed setup, you can have your S-Trig device modified so you can liberate the CPR module.
Tracking VCO to other synthesizers
Even though many synths adhere to the one volt per octave standard, it is possible that you experience tracking problems. If all VCO's of a synths do track each other, but are out of tune with other synths, you most likely have one of two problems:
Impedance problems in a CV-interface.
The CV-output of a Midi-interface may not be capable of driving several synths, or several modules within one modular synth.
You can remedy this by feeding the CV to only the Fenix CV mix 2 input and driving all modules from the CV mixer 2 output.
A synth may be perfectly in tune with itself, but not have one volt per octave. This is a common problem in monophonic analog synths that are tuned from their own keyboard.You may find trim pots on the synth to recalibrate.
You can adjust the scaling of a CV by using the Fenix CV mix 2. Connect the external CV to both mixer inputs, and set the CV-2 control to center (0). Feed a VCO CV-1 input from the mixer output. By playing octaves against a fixed reference VCO, you can tune the scale. Then use the mixer output to drive all VCO's and VCF's in the patch.
Most Midi-interfaces allow hardware or software scaling of the outputs.
Alternate Envelope curve
I/O 2 provides an envelope- and a gate-output. The time-constants of this envelope follower are not variable. You can get different rise and fall times by feeding the audio-signal to the slew limiter. For a normal envelope following CV, set the rise-control to zero, and the fall-control to a small value. The more you turn up the fall-control, the slower the CV fades to zero after the sound ends.
If the rise-control is set higher (slower) than the fall-control you will get an inverted envelope curve.
The audio inputs and outputs of the Fenix are provided on 6.3 mm jack-plugs. For connecting the Fenix output jack to a mixer or amp, you may want to buy or make a splitter cable that splits the jack tip to a left output jack, and the ring to a right-output jack. You may also cut off one side of a twin cinch-cable and solder a stereo-jack to the cable. For XLR or other connections, also use twin-cable and separate plugs for left (tip) and right (ring) outputs.
For mono use, a stereo jack-cable is still advisable due to output shorting risks.
The six 3,5 mm mini-jacks on the rear accept commonly available mini-jack patch cords.
You may have to make converter cables for other connections such as Moog plugs or mini-Jack to Jack. You can cut off one connector of a patch cord to create a new converter-patch cord.
Some adapter-leads have a 3,5 mm plug and unshielded twin-wire. This is suitable for connecting CV and gate signals.