Franc Audio Accessories Ceramic Disc Isolators

Hardware Review

Franc Audio Accessories Ceramic Disc Isolators
Friday, November 12, 2021
isolation feet
Jason Kennedy

Vibrations; can’t live with them, can’t hear anything without them. In order to turn an electric signal into sound a loudspeaker has to vibrate, likewise a stylus is vibrated by the the side of a vinyl groove and this produces a (tiny) electrical signal. In an ideal world these would be the only things that vibrate in an audio system however, in reality, the vibrations produced loudspeakers get into components and affect the way that they perform. Stopping vibration from getting into the floor by replacing spikes with spring isolation helps a lot but even then it’s possible to hear differences in support systems for amplifiers, DACs, CD players you name it. Turntables, which are designed to measure vibration, are naturally very sensitive to what they sit on but a small amount of experimentation will reveal that most components are affected by external vibration.

Franc Audio Accessories are made in Poland by Paweł Skulimowski with the aim of restricting the flow of vibration into both components and loudspeakers, he makes a small but well finished range of Ceramic Disc Isolators in a variety of sizes. The basic system is as the name indicates, one or three ceramic balls are used between metal plates that have either a smooth plastic coated top surface or a spike locating hole. It’s a variation on the ball and cup type isolators made by a variety of brands with some degree of movement between the top and the base of each foot.

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Fat feet

I tried four different sets of Franc feet starting with the least expensive Ceramic Disc TH, this is 32mm high with a central spike locating hole in its top surface and sits on a 48mm diameter base that’s loosely attached but does not come away. In sets of three this foot is good for components up to 100kg in weight, so loudspeakers are clearly an option. Next up is the Ceramic Disc Classic that is higher at 45mm and larger in diameter, it has a separate top cap with a smooth surface and removing it reveals a small ceramic ball in the middle of a carbon fibre trident, these are good for up to 150kg on three feet.

The Ceramic Disc Slim Foot contains three ceramic balls in a damped enclosure that stands 25mm high and has a spike receptor hole which can also take an M6 bolt for direct fixing to a loudspeaker. This foot can support up to 200kg in a set of four. Its big boned brother, the Fat foot “is best for heavy and extra heavy stuff” apparently, this is taller at 45mm and has the same threaded hole in the top but is designed to cope with components weighing up to 320kg if you use four, how you get them under such a behemoth is another question.

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TH feet

Sound quality
First up were the Slim feet under a pair of Eggleston Emma Evolution speakers which produced fuller bass and a bigger image thanks to better resolution of reverb and this resulted in a more open, live presentation. They also take a little bit of edge off the sound, but manage to do this whilst retaining image focus and reducing perceived distortion which is a neat trick.

Swapping in the Fat feet results in a calmer, more precise sound that’s more involving. On a string quartet the reverb is cleaner and there’s more space between the notes, suggesting lower noise and resulting in better timing, in short making the music more enjoyable.

Putting three Classic feet under a heavy Moor Amps Angel 6 power amplifier, which was already on a spring isolated rack, also relaxed the sound and allowed more low level detail to come through which made the music more nuanced. This helped to deliver impressive depth of image from an old Michelle Shocked album with its double bass and acoustic guitars gaining increased tonal depth in the process. Putting the TH feet under a Rega Planar 10’s three feet was also beneficial, making it sound more relaxed than it did on the glass shelf of a rack that incorporates damped spring isolation. I have to conclude that glass is not a great surface for a low mass turntable like this Rega. The Franc feet were beneficial to a greater degree than elsewhere and given the price of three TH feet represented the best value upgrade I’ve yet encountered for this turntable. They allowed it to deliver Joni Mitchell’s voice with increased subtlety and apparent dynamic range, the big bass note on Overture to Cotton Avenue (Don Juan’s Reckless Daughter) was gorgeous in its tone and depth of image. That said the mid and top seemed to benefit the most. Replacing the TH with Classic feet here increased the sense of 3D imaging significantly, producing tactile bass that was both cleaner and more substantial than the TH could achieve.

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Classic feet

With an iFi Pro iDSD DAC using three TH feet increased note decay and image scale again, relaxing the sound and obviously improving timing. Keith Jarrett’s piano sounded harder and flatter without the feet and gained nuance and ease with them in place. The result was very similar to the power amp in truth with low level detail clearly benefiting from a lower noise floor which in turn reinforces all the quieter sounds that combine to produce a more convincing overall picture.

I went back to a different pair of speakers later on, trying the Slim feet under PMC twenty5.26i floorstanders. This was also a positive move despite the degree of isolation that is built into the base of this speaker. They became calmer and more tonally rich with distinctly better timing, the Grateful Dead getting their boogie back in clear-cut fashion thanks to more easily discernible interplay between musicians and less hash in the high energy sound of this band’s Europe ’72live album. Putting in the Fat feet did the same again but to a greater degree, they clearly offer better isolation and allow the speakers to deliver more of the inspiration in the music and thus make it more involving. 

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Slim feet

Going back to the DAC I tried the three Classic feet which seemed like overkill given compact nature of the iFi and the size of these feet but they worked better than TH feet. Especially in the presentation of inner detail while there was a lot going on in the music, essentially revealing the quieter sounds that are usually masked by more dominant elements. This means that complex or intense pieces make more musical sense and require less effort to appreciate, which is useful for those whose tastes stray into more adventurous terrain.

The Franc Ceramic Isolators clearly help all manner of equipment to deliver higher resolution, higher fidelity to the music signal and that is what we are all after. The price seems appropriate for the quality of build and finish and I would happily have left them under my gear if that gear didn’t have to be chopped and changed so often. For those with more permanent systems these feet are highly recommended.

Specifications: 

Ceramic Disc Slim Foot
Type: Loudspeaker isolation feet.
Material: Plastic, ceramic and aluminium.
Isolates from: Not specified.
Speaker weight range: Set of 3: 0-150kg, Set of 4: 0-200kg.
Speaker base size: Any.
Dimensions (HxDia): 25mm x 59mm.
Weight: 139g

Ceramic Disc Fat Foot
Type: Loudspeaker isolation feet.
Material: Plastic, ceramic and aluminium.
Isolates from: Not specified.
Speaker weight range: Set of 3: 0-240kg, Set of 4: 0-320kg.
Speaker base size: Any.
Dimensions (HxDia): 45mm x 68mm.
Weight: 

Ceramic Disc TH Foot
Type: Component isolation feet.
Material: Plastic, ceramic and aluminium.
Isolates from: Not specified.
Component weight range: Up to 100kg on three feet.
Component size: Any.
Dimensions (HxDia): 32mm x 48mm.
Weight: 131g

Ceramic Disc Classic Foot
Type: Component isolation feet.
Material: Plastic, ceramic and aluminium.
Isolates from: Not specified.
Component weight range: Up to 120kg on four feet.
Component size: Any.
Dimensions (HxDia): 45mm x 68mm.
Weight: 276g

Warrnty: 5 years

Price: 
TH Foot: Set of 3: £180, Set of 4: £240
Classic Foot: Set of 3: £630
Slim Foot: Set of 3: £390, Set of 4: £520
Fat Foot: Set of 3: £540, Set of 4: £720
Manufacturer Details: 

Franc Audio Accessories

www.f-franc.com

Distributor Details: 

Kog Audio
T +44(0)24 7722 0650
www.kogaudio.com