g-storm electro pro vcf eurorack filter demo

please support the channel: impurfekt.bandcamp.com/

the pro vcf from g-storm electro is a clone of the 3320-based curtis filter. this filter was used on the sequential circuits pro-one, elka synthex, fairlight cmi, ppg wave 2 and a variety of other classic synthesizers, samplers and drum machines. in this case the circuit has been expanded to feature 2-pole and 4-pole low pass modes.

i'm familiar with modern iterations of the curtis filter from a variety of dave smith synthesizers and his dsm01 eurorack curtis filter (reviewed here: • dave smith instruments curtis eurorac... ). I've not used a vintage version however so i was keen to give the pro vcf a try.

having used the pro vcf for a few months i'd say it has a different character from the curtis filters i'm more familiar with. the pro vcf sounds more open and vintage to my ears. it's not as dark and crunchy. it excels at sounds which benefit from a bit of air (flute sounds for example). overall it feels brighter and softer than a modern curtis filter.

the option between 2-pole and 4-pole is appreciated. 2-pole mode works great for pads and soft, organic sounds. while 4-pole mode is perfect for dark, heavy sounds. it's a great sound design filter with a very recognizable flavor. when driving the filter you'll notice added smudge and a different resonance response. note that adding resonance will reduce the overall volume; which is typical for this filter circuit.

i really appreciate the amount of cv control and inputs on the pro vcf. with two cutoff cv inputs and one resonance cv input you can modulate the heck out of this thing. having two audio inputs with separate attenuators lets it double as a mixer as well.

as usual with g-storm electro, the build quality is excellent. the knobs are well-placed, move smoothly and feel sturdy. labeling is clear and well-placed. overall it has a vintage design that hearkens to the original pro-one synthesizer. while i purchased the aluminum version, it also comes in black (which i might have to swap for).

my only critique with this filter is the installation. i found the screw holes to be a tight fit. so much so that rotating screws into my eurorack caused the filter to shift in whatever direction my screws rotated in. so my screws kept missing the right hole. slightly larger screw holes would be much appreciated.

overall this filter is an easy choice. the sound is vintage and recognizable. it's very well designed. it's built well and priced right. i highly recommend the pro vcf for anyone looking for a solid, vintage workhorse of a filter.

complete specifications:
inputs - 2 audio, 3 cv
outputs - 1 mono
current – 10mA +12v, 11 -12v, 0mA+5v
depth - 22mm
width - 8hp

timestamps:
filter sweeps (2-pole) 0:46
filter sweeps (4-pole) 3:07
filter drive 4:58
saw bass 7:25
s&h pwm 9:43
tri melody 12:22

patch notes:
studio electronics slim o thru g-storm electro pro vcf thru doepfer a-188-1

sequencing/tracking/mixing - steinberg cubase

disclaimer: featured equipment was purchased out of pocket for music production purposes