News U4

The S213 is a multislope, multimode voltage controlled filter that has the ability to smoothly morph from low pass to high pass modes in three different ways as a side effect of the slope (roll-off) chosen.
12db/oct slope: The filter will morph from low pass to notch to high pass. This is similar to how the Oberheim(TM) SEM filter works.
24db/oct slope: The filter will morph from low pass to peak to high pass.
36db/oct slope: The filter will morph from low pass to notch inside peak to high pass.
Knob/CV control is available for most of the parameters which are mostly self explanatory. Separate inputs for low pass (In LP) and high pass (In HP) is provided. In LP is normaled to In HP*.
The S213 is equipped with dedicated overdrive Knob/CV controls. The Soft/Fold switch affects the type of overdrive used. Soft will give a familiar but still aggressive flavor when the resonance is cranked up. Fold is a rather unique and and extremely aggressive mode, specially with high drive and resonance.
As with most filter overdrive. The overdrive amount is more or less sensitive to the loudness of the input signal. A good input signal would be from -1V to 1V (0dbFS), so connecting the filter directly to an oscillator and placing the Lev knob at 12:00 o’clock and tweaking the Lev from there is a good idea. However, if the input signal is low, the Drive controls will automatically try to lift the gain to compensate. Still if the input signal is really too low, the filter may not get to saturation level, and hence no overdrive will occur!!. On the flip side, if the input loudness was too high, the filter may be over driven even when the Drive is at minimum, this can specially happen when resonance is very high.
Usage ideas
1.Try to modulating the filter cutoff (Frq CV) and the Morph CV with the same CV source. You’ll some interesting effects there.
2. In 36db mode, put the morph at 12:00 o’clock. using high resonance, modulate the cutoff with some base to mid range input audio. It gives a rather unique and hollow flavor.
*If In HP is not connected, it will take its input from In LP.

Notice that you can obviously combine different shapes, so say you can Exp attack and Log decay and release and so on.
Individual EOA (End of Attack), EOD (End of Decay), EOS (End of Sustain) and EOR (End of Release) trigger/gate outputs are provided. Notice that these are not just triggers but also gates that will sustain until the end of the next period. For example, EOA will start at the end of attack and end at the end of decay. EOD will start at the end of decay and end at the end of sustain, and so on. Also individual LEDs are available for visual feedback that will indicate in which period the ADSR is currently in.
A rather unique feature RTZ (Return To Zero) is provided. Enabled by a switch, this mode will dictate what happens when the Gate In goes high while the release period hasn’t ended yet (i.e. when you press a key while note is still playing). When RTZ is OFF, the module will start a new attack but the output will pickup from it’s current voltage and continue the attack. This can be used for smooth results. When RTZ is ON, the module will start a new attack but the output will go immediately to zero voltage before it continues the attack. This is good for punchy results. The RTZ knob can be used to decide how long the RTZ function takes to return to zero voltage**.
The Gateless switch, when put ON makes the S525 insensitive to Gate In gate length. This means that A, D, R periods will continue their full time regardless if the Gate In went to low voltage or not. But ofcourse, if Gate In goes low and then high again, then a new attack will be triggers normally. This mode is good for producing plucky and bell sounds that don’t depend on how long or how short the musician kept pressing on the key.
The LFO switch lets the S525 retrigger itself once the release period has ended. The gate length used is the latest length it received from Gate In. This length with the release time is what dictates the LFO speed. Note that RTZ mode does not have any effect when LFO mode is ON, because the module will never be retriggered until the release period has finished and already reached zero voltage.
Finally there is a Retrig In patch point. This will retrigger the S525 whenever there is a transition from low to high voltage on the patch point. Note that the retriggering only happens while the Gate In is high, even if Gateless mode is ON.
*Other hardware modules usually provide one switch for the whole module.
**Always start with RTZ knob set to minimum to avoid unexpected results. Then change from there.

Herald Bode and later Robert Moog has created the first analog frequency shifters in around 1964 and latter. Recent years along with the digital tide has shown a rise of a rather different shifter type called pitch shifters, which are now common on digital form for achieving auto tuning or playing samples.
The crucial difference between a pitch shifter and a frequency shifter is that a pitch shifter maintains the harmonic relation within the frequency components of a sound, thus the result stays in tune but is shifted by a musical pitch as if the same sound was played in that pitch. While a frequency shifter changes the harmonic relations, leading to none harmonic and hence completely different sounds, which is what the S620 is designed to do.
The SE620 features smooth manual shifting via it’s large shift knob as well as shift CV. The range of the shift can be controlled with the Wide/Narrow switch. Wide goes 16Khz up or down while narrow goes 1.5Khz up or down. Notice that you can exceed those limits with CV.
There are 3 modes of operation flipped with a switch. Normal, is strictly frequency shifting with no additional effects or artifacts. TZ (Through Zero) allows the harmonics to reflect back into audible range when they go bellow zero frequency (negative), the effect is mostly heard while DOWN shifting. M (Mirror) mode allows negative frequency harmonics to pass through zero and become audible positive frequency harmonics, the effect is mostly heard while UP shifting.
A feedback loop with insert effect patch points is also provided. This is where the power of frequency shifting gets multiplied. Try placing delay lines or an effect of your choice. The feedback knob controls the amount of the wet signal sent through the send patch point. When Fb CV is patched, the knob becomes an attenuator for it. Be careful here as this is an internal feedback loop so it can quickly overload the module if the insert effect is amplifying. Try lower feedback on the knob first then increase slowly. When the send/recv are not connected, send will be normaled to recv*.
beside the out patch point, there is a +90° out. This is a side effect of the complex math behind frequency shifting, It is the same as out but with every harmonic in the spectrum phase shifted by about 90°. Notice that the phase shifts hear are not specific to a certain one frequency but relative to each harmonic frequency. The +90° out can be used for the following:
-As a spacializer to provide depth in stereo. Simply connect the out to say the left channel and the +90° out to the right channel and hear how it differs from the single out patched to both channels.