RF•STOP DC Power Filter

A DAC and its connected power and input signal components require ultra-low noise for best sound. This cannot be overstated.

For DACs with a DC input:

• Replace the factory provided (external brick) switch-mode supply with a compatible 3rd party linear PSU with better regulation and filtering. Look for power supplies with upgraded fuses or improved wiring to further add benefit of additional RF filtering.
• For best performance, use a battery to avoid galvanic contact with AC mains and other AC connected components. Consider LiFePO₄ (LFP) technology for the lowest electrochemical discharge noise and low EMI BMS (battery management system) such as 'DALY' brand.
• Avoid buck-type voltage regulators or integrated digital logic modules in the battery or power supply; these only add RF noise.

RF•STOP™ DC Power Filter is a two-stage design that uses inductors of highly permeable core material for excellent attenuation of common-mode and normal-mode noise up to the critical RF frequency of 500MHz. A maximum current rating of 4A ensure sufficient performance for most DACs.

Normally RF•STOP is located between the power source and DC input to a component, however RF•STOP can also be used to isolate components that are powered by the same DC power source (via a splitter cable). Installing RF•STOP between two component prevents transfer of RF noise between them. Additionally RF•STOP may be used to ensure that a galvanic digital signal input (dual coax) from OPTO•DX or source is properly filtered.

Use 2.1mm or 2.5mm connections for input and output and a well shielded DC power cable such as Gotham GAC-4/1 11301 UltraPro Star Quad. Avoid long cable runs to minimize EMF induced noise via antenna effects; ideally locate RF•STOP close to the component and use ultra-short cables (0.3 meter or 12 inches).