Check your ears Yorgos - tempest's vcf leaks sound, that'a a fact.
AMP can create click around 1-4 at attact stage, with 10 at amp attack, sound can't be snappy.
here's what DSI Support says:
''he sound you are hearing is due to low level analog oscillator output leaking through the filter. This is an artifact of the nature of the Tempest's Curtis chip-reliant analog voice architecture and is the expected operation of the synth voice.
The signal to noise ratio of the analog path is ~80db and you may hear the oscillator's bleeding through the filter at very low volumes and/or the noise floor of the synth. I am able to reproduce the results of your video with the Tempest I have here, although by reducing Resonance, Audio Mod, Lowpass Envelope Amount, and Velocity Amount to 0, the issue is much less noticeable. Essentially, in 4-Pole mode, reducing modulation to the filter cuts of much more of the sound. I'm also able to get sub bass tones by increasing Resonance while in 4-Pole mode, which is by design.
Additionally, turning off the analog oscillators will allow you to cut off the sound of the digital oscillators with the lowpass filter. This also allows the creation of kicks and sub bass tones by getting the the filter to self-resonate.''