Farad power supplies is a spin-off company by principal designer of Pink Faun equipment, Mattijs de Vries, designed and build in The Netherlands.
Farad power supplies incorporate the latest of capacitor technology, EDLC super capacitors. The Farad power supply is available in one version: a 3A output (1-3F capacity). A 12A (15-50F capacity) version is currently on the test bank.
All supplies have an IEC power input and gold plated GX16-4 output for flexible power cable choice, high induction double shielded power transformer, schottky rectifiers, a choke power supply buffering, and a first stabilization charging the super capacitor bank to create a dynamic battery alike source. From this source the output voltage is stabilized by a fast transient, low noise regulator and post filtered with ultra low ESR polymer and reversed shape high voltage ceramic capacitors. All is mounted in an aluminum enclosure on a high quality gold plated PCB with star ground and star power supply configuration. Farad power supplies are fully protected against short circuit, over- and under voltage, reversed voltage, over temperature and surge currents.
Farad power supplies bring great improvement in any system, not only when replacing a SMPS, but also when replacing linear power supplies.
Farad power supplies have a factory fixed output voltage ranging from 3.3V to 19Vdc on request. They can be delivered suitable for 100-120V and 220-240Vac, 50-60Hz primary input voltage. Price is € 439,-. (December 2018). Higher quality shielded cable with gold plated receiving side connector additional 59 euro, or an even higher quality cable for € 129,-. Please note: all prices ex VAT.
On the subject of Forums... We have chosen not to participate in discussions on forums. In our opinion everybody has a point and all designers have to make decisions based on their best practice. We did do a lot of listening tests and measurements to come to the final end design of our power supplies, all choices were made based on that and our 20 years of experience in designing them. In the below Q+A we try to explain some of the choices we made. We invite everybody to listen and judge for themselves, not to make choices based on opinions by others, mostly with their own interests. If you have any questions, please contact us directly. Thanks!
Q & A
What are super capacitors?
EDLC Super capacitors, also called ultra-capacitors or booster capacitors are the latest development in capacitor technology. They are based on a porous carbon material with very high surface area and very small layer distances, resulting in very high charge density. Super capacitors combine a very high capacitance with high pulse power capability and low ESR values. In short they act like batteries without their disadvantages.
Why do you use super capacitors?
Where typical large electrolytic capacitors have typical values up to 10.000uF, or 0.01F, even our 3A super cap supplies have a capacitance over 1F meaning 100 times more energy storage! Super capacitors can deliver high pulse currents and have low ESR, resulting in a very stable and clean, battery like, power input for the final low noise linear regulator. The better and more stable this input, the better the final result.
Is it true that supercaps have a short lifespan?
See the manufacturer curves for the capacitors we use in our designs. All capacitors in our designs will be below 80% of the rated voltage. Even at full load continuously the caps temperature will stay below 50 degrees. In practice the supply will be 40 degrees maximum at normal use (below 2A average). So lifetime expectancy according to the manufacturers curves will be worst case over 10 years, in practice more like 20 years.
Why do your supplies only have one fixed output voltage?
The power dissipation of a linear regulator is dependent on the ingoing and outgoing voltage and current. Therefore the only way to make the output flexible is to make the input voltage flexible or by using switching power regulators, as many other brands do. Both of these ways are very sub-optimal designs. Since we are aiming to be the absolute reference in linear regulated power supplies, we specifically choose to go for rigid, but fully optimized fixed output voltage in our power supplies.
Why are you using the super capacitor power bank as smoothing capacitors and do you not switch between one bank while loading the other?
There are several reasons why we do not do this. First it means extra switching electronics in the supply lines, second it means that you are using only half of capacity of the super caps at a time. Third and maybe most important, it means that the final regulator does not get a constant voltage at its input, meaning different voltage drop, and therefore slowly varying power dissipation and temperatures all the time. This influences the output characteristics of the regulator, and the output power quality. Because in our supplies we use a choke smoothing and pre-regulation before the supercapacitor banks, noise residue will be minimal and also the necessity for switching.
What is the importance of star grounding and star configuration power supply?
When two electrical points are connected to each other, the connection between them never is perfect and will always have inductance, capacitance and resistance. When current is drawn through this connection (whether it is wire, PCB trace or point to point), a voltage will be induced, adding noise to the signal. The presence of these problems can be heard when disconnecting interlinks between devices as loud plops, squeezing and buzzing. Although almost always present, it is not normal and a good system does not have these noises.
By starring ground lanes and power lanes, the distance of the connecting lines will be reduced to zero inside the device and thus also the induced noises. A supply can measure really good on a test bench, but when not properly starred, it will give a lot of additional noise in a system.
Why do you not use power line filtering?
A good power supply is in fact just a power line filter. We use specially custom wound shielded high inductance toroidal transformers. By adding chokes and fast filtering capacitors around it, we already have better initial power input, without adding additional components in the signal chain, keeping things more simple and better.
What protection do the Farad power supplies have?
Most commercial linear and SMPS power supplies will give out full voltage when their final regulator, or parts around it break down. This will almost certainly result in heavy damage of the device to which is connected to it. Farad power supplies are not only protected against the usual things like shorts, over-temperature and over-current, but also have a microprocessor controlled crow bar protection against over-voltage. In short this means the supply will short itself and blow its own fuses when a dangerous too high output voltage is detected, so the load will never be damaged.
Farad 12 v against standard switched supply: Substantial more easy sound and soundstage, more involvement, more PRAT.
Farad 5v on the iFi Dac: Even more relaxed sound, higher involvement, more initmate sound, more PRAT, higher transparancy in soundstage."
Why do you use gold plated 4 pin GX16 output connectors?
Output impedance of a power supply is really important. A total output impedance of 100 mOhms (typical in many commercial power supply systems), already gives a voltage drop of 300mV when the load changes from 0 to 3A. This means bad regulation, and off course needs to be as minimal as possible. Output impedance is made up by the regulator, the PCB traces, connector and cables. We choose a low impedance, high transient, low noise output regulator. On the PCB we use power planes, so wide organic shaped traces. We do not like to use barrel (or alike low level quality) connectors, since they have high contact resistance, typically in the order of 30 mOhms. Instead we use the gold plated GX16 4-pin connector, gold plated GX16 connectors have a typical contact resistance of 3 mOhms, and with two pins parallel this is even halved, giving much lower total output impedance.
Why do you use an output connector and not a solid attached cable?
We know the importance of cable swapping, it can make a big difference in the final quality of a system. For our DC output wire we standardly use 4 strands of 0.5 mm2 tin plated copper. Tin plated copper has a long quality lifespan and does not have the sonical disadvantages of silver(plated) wires. The cable impedance is an important factor in the quality of a power supply. The total of 1 mm2 wire area (equal to 17 AWG) we use means only 16 mOhms per meter (8 mOhms per 50 cm). For example a 22 AWG (widely used in power supplies) wire has a resistance is 52 mOhms per meter, running up to 84 mOhms per meter for a 24 AWG wire. Also two thinner wires parallel sound better than one wire of the same thickness. We also deliver a higher quality cable at additional costs. This wire is shielded and also had gold plated connector at the receiver side.