MCRU Linear Power Supply for Cambridge Audio DacMagic 100

MCRU and Longdog Audio have sold 100’s of our specially developed fully regulated linear power supplies. They provide a constant output voltage to replace the switch mode power supply bundled with most electronics. Cheap and noisy the SMPS does nothing for sound quality and can actually be detrimental to your hifi system sound quality, proven by customer feedback.

We have tested these extensively and the regulated design does indeed improve the sound. We have 3 designs on offer, a standard option, a Second option with Kimber Kable and Furutech options and finally the flagship option including upgraded fuse, cable, and mains lead.

All three upgrade options are based on our award winning two case design details behind the design are below, if you want the best possible performance from your streamer these power supplies are a must. If your streamer is powered by a wall wart power brick pictured below we can supply our regulated design instead.

The power supplies are made to suit your country, 100V, 120V, 230V and come supplied with a power cord as standard with the appropriate plug on UK, EU, USA, AUS etc.

Specifications

OPTION ONE – STANDARD MODEL – BASIC MAINS LEAD £240

OPTION TWO – KIMBER DC KABLE – FURUTECH GOLD PLATED IEC INLET – AMR GOLD PLATED FUSE – SUPRA LORAD MAINS LEAD TO SUIT YOUR COUNTRY £335

OPTION THREE – PURE SILVER DC CABLE – FURUTECH RHODIUM PLATED IEC INLET – SR ORANGE FUSE – ISOL-8 WAVE MAINS LEAD TO SUIT YOUR COUNTRY £595

The rational behind our linear power supplies…………………………

When thinking of regulation, it’s worth remembering the Roman god Janus. Who was the god of gateways, and was a two faced god looking in both directions. Likewise a good voltage regulator is required to look in both directions at once. From one direction you have the mains supply, with the ever increasing noise, distortion and random variation that exists on our household mains supply. In the other direction you have the device you are supplying power to. The load will be asking constantly varying current, and the job of the regulator will be to ignore the varying load and to supply a rock steady voltage that ignores the changing load.

To ask a single regulator to perform both tasks means that it can not do either as well as it could. We don’t ask our regulators to be two faced, we split the two functions into two separate regulators and put them both where they can do the best job.

The first regulator is close to the mains supply, its job is to take the incoming mains and convert it into a low(ish) noise DC supply, and to isolate the mess that is our household power lines from what follows. In most power supplies on the market, the output of the first stage would be directly connected to the load device, and that would certainly be an improvement over the supplies that most manufactures provide. But we can do better by adding the other face of Janus to the system.

The second regulator is supplied with a clean low noise supply, and its job is to handle the changing demands of the load. To do that, it needs to be as close to the load as possible. So we remove the second regulator from the main box, and place it close to the load, both electrically and physically, that removes it from the noise and interference of the mains supply, and allows it to spend its time looking towards the load. Typical commercial voltage regulator chips are general purpose devices, but are not quiet enough for the task on hand, so the second regulator uses a bespoke regulator based on a low noise multi stage filtered voltage reference, a low noise error amplifier and a high current low resistance mosfet. To allow it to handle the changing load it also needs to supply current on demand, so all the remaining space in the second regulator is filled with low impedance capacitors to act as a local energy source.

Using the two stages of regulator, we achieve a noise floor equal or better than most battery supplies, and a effective source resistance of the order of 0.02 ohm (and the short cable run to the load avoids increasing this valve by adding copper where its not needed, and the use of a discrete regulator design allows that tiny value to be maintained way above frequency any audio device operates at.