Gilbert Yeung FCF Capacitor Packs

What is an FCF?

The FCF (Fab Cap Fanute) capacitor packs from Angela - Gilbert Yeung are specially constructed banks of capacitors to greatly increase the power reserve of the output stage of an audio component. The size and composition of the capacitors is specific to the model of FCF, or the voltage requirements of your device, and have been carefully selected over years of A/B testing for the best performance and what it does for the sound. 

FCF Jack

Many models of components from Gilbert Yeung come preinstalled with an FCF jack for a plug and play upgrade option. To use FCF, simply plug the pack into the rear mounted jack with the device off, then power on the device. FCF contains an integrated high current soft start circuit to safely power up the large reservoir of energy. Once the indicator is at full brightness and the relays have engaged, FCF has fully charged and is bonded to the power supply.

FCF specifically connects to the output stage of your power supply, meaning that this is a modification that can be done to other equipment should they be of the proper quality and performance. This can range from vintage receivers, power amplifiers, or even new components from other manufacturers. This service is provided by the QUARK service and modification shop here in Illinois USA, and will require a separate purchase of a capacitor pack. If you are interested in this service please visit the link here, or send me a message to see if this modification will work for you.

Pictured is an FCF jack installed into a Parasound A21 power amplifier.

 

The Sound and A/B Testing 

Each FCF pack is burned in for a period of time after completion, but the pack will still need some time for the capacitors to fully settle and it is normal to note some changes in the sound as this happens. 

Once you have connected the FCF pack through the associated jack and turned the component on, wait for the pack to fully charge. Once it is charged you can instantly A/B the difference that it makes in your system by disconnecting the FCF pack from the device, and plugging it back in. Depending on the size of the pack there is a 3-5 minute window of time that you can plug the capacitor pack back into the component for instant A/B comparison, otherwise you will need to power off the device again as to not create a spark upon reinsertion. 

The capacitor packs add a new level of dimensionality and palpability to the soundstage and imaging. Similarly to using an amplifier with abundant headroom, a capacitor pack gives your component that headroom and immediate power that is not capable from the wall alone, and allows the circuit to perform unhindered. The soundstage blends in behind the speakers and gives more weight to the center image, allowing you to pinpoint finite details and locations of instruments easier. Unplugging the pack you can immediately notice these effects start to collapse as if you were walking away from the stage, plug the capacitor pack back in and it all comes back into focus. While instant A/B is a fun exercise, you will find it hard to not have it in your system once you have heard it.

The Science 

Adding a capacitor pack does much more than just increase the internal reservoir of DC power. All conductors are 14 gauge copper for high current capability ensuring that regardless of the load your amplifier sees, the power supply will not sag, and it will always have more than enough power than it needs on demand for increased dynamics and stability through musical transients. The greater the amount of capacitance, the lower the input resistance of the individual electronic components trying to pull from it, providing something that no power cable or audiophile fuse or tweak can. Even better is that this can be instantly compared back and forth for the pronounced effect that it has.