Isol-8 SubStation F3 Axis black

ISOL-8 SubStation F3 Axis: six filtered outlets and DC blocking

A deep, steady hum coming from the amplifier, even with the volume turned down, is rarely caused by interconnect cables. The culprit is often a DC component on the mains, which makes the transformer vibrate. This version of the SubStation F3 blocks this component at the unit’s input, then distributes power to six filtered outlets, with separate circuits for sources and amplifiers. It is hand-assembled in England.

Why a transformer starts to vibrate

A toroidal transformer works properly as long as the voltage it receives is a symmetrical sine wave. Some household appliances, through the way they draw power, add a slight DC voltage to this sine wave. The transformer’s magnetic core then partially saturates, its windings vibrate and the amplifier hums. The noise is mechanical, coming from the chassis rather than the speakers, and it can change depending on which appliances are switched on elsewhere in the house.

ISOL-8’s Axis circuit sits at the input of the SubStation F3 Axis, before the entire distribution stage. It blocks the DC component and lets alternating current pass through. All six outlets benefit, including those for sources: a preamplifier or player with a toroidal transformer is affected just as an amplifier is.

Six outlets and two types of filtering

Once the DC component has been removed, power reaches two groups of outlets. The source outlets pass through a multistage Transmodal filter, and ISOL-8 limits cross-contamination: noise that a DAC or a network player feeds back into the mains does not directly reach the device plugged in next to it. These low- and medium-current outlets support 6 A in total.

The high-current outlets use a variant of the Transmodal filter with very low series resistance. At times, an amplifier demands far more current than its average consumption, during a drum attack or a sustained bass note, and this filtering does not restrict those demands. All the outlets share a continuous 15 A rating.

The Transmodal filter acts on differential-mode interference, between live and neutral, and common-mode interference, between these conductors and earth. The protective earth has its own choke, wound by ISOL-8. Surge protection and a resettable circuit breaker complete the system.

Power inlet and construction

Three inlet options are available when ordering: IEC C14 (10 A), IEC C20 (20 A) or Neutrik powerCON. The C14 is sufficient for a system drawing less than 10 A in total, approximately 2,300 W at 230 V. With a power-hungry amplifier, the C20 or powerCON make the unit’s full 15 A available. ISOL-8 IsoLink Vertex and Vector power cords are available with these terminations.

The 450 × 375 × 132 mm enclosure features a 10 mm machined aluminium front panel, in silver or black. Inside, the chokes are wound by ISOL-8, the capacitors are polypropylene and the wiring is silver-plated copper with PTFE insulation. Assembly is carried out by hand in Worcestershire.

Technical specifications

Type and range

• Type: passive mains conditioner with DC blocking
• Range: SubStation F

Filtering and protection

• DC blocking: integrated Axis ISOL-8 circuit, upstream of the outlets
• Filtering: multistage Transmodal, common-mode and differential-mode
• Cross-contamination control between connected devices
• High-current outlets: Transmodal topology with very low series resistance
• Earth circuit filtering: ISOL-8 wound inductor
• Surge protection
• Protection: resettable circuit breaker

Connections and power supply

• Number of outlets: 6
  • Outlets for low / medium-current sources
  • High-current outlets for amplifiers
• Choice of mains inlet: IEC C14 (10 A), IEC C20 (20 A), Neutrik powerCON NAC3MPXXA
• Total continuous current: 15 A maximum shared across all outlets
  • With C14 inlet: 10 A
• Continuous current for low / medium-current outlets: 6 A maximum in total
• Supply voltage:
  • European version: 220–240 V AC
  • 120 V version: 100–127 V AC
• Frequency: 50 / 60 Hz

Construction and finishes

• Components: inductors wound by ISOL-8, polypropylene capacitors, silver-plated copper wiring with polytetrafluoroethylene (PTFE) insulation
• Front panel: 10 mm thick machined aluminium
• Finishes: silver or black
• Manufacturing: hand-assembled in Worcestershire (England)

Dimensions and weight

• Dimensions (W × D × H): 450 × 375 × 132 mm
  • Depth excluding connectors
• Packaged dimensions: 555 × 500 × 300 mm
• Weight: 10 kg, to be confirmed for the Axis version
  • With packaging: 13.2 kg, to be confirmed for the Axis version