Cookie-Cutter ‘Sub-Sonic Filter’

Tom Evans who makes very nice phono stages made the following astute comment:

A rumble filter simply adds to the bass cut making your already “cut” records sound bass light. Plus, it “time-steps” the bass in relation to the higher frequencies (where our hearing is most sensitive) so much so it can confuse the ear into believing the bass is playing out of tempo.

iFi solution:

Since the very first iPHONO launched in 2012, we have used our own in-house ‘Subsonic Filter’. It made it into the iPHONO2 and the iPHONO3 and now, the ZEN Phono which is the very first time this filter is seen in such an affordable price level.

As there is only minimal vertical modulation remaining at very low frequencies with an an actual cut LP that is playable, we know that “vertical modulation” at low frequencies must be warp.

So we designed a filter to take advantage of this.

This is not artificial but real knowledge. By understanding fully how LPs are cut and replayed,  it is possible to filter record warp strongly without at the same time attenuating low bass or adding group delay.

DC Blocker
DC Blocker
DC Blocker from iFi audio
The amplifier is the heart of your system.

If you have a mechanical hum, deploy the DC Blocker.

Got big amplifier. Bye bye mechanical hum.

Many large amplifiers have a really annoying mechanical hum (emitted from the toroidal transformer itself).

You can hear it when you place your ear close or next to the chassis.

This is caused by a small amount of DC voltage in the mains which makes its way through to the mains transformer, it will become ‘saturated’ and start to hum like a trooper.

The DC Blocker is a clever device that you place at the IEC (at the rear power inlet) and as its name implies, it stops DC from getting into the amplifier. It therefore eliminates amplifier transformer hum.

Cute. Clever.

All the benefits of cutting out annoying hum with no drawbacks.

  • Intelligently stops any DC voltage from the mains to eliminate transformer hum
  • EMI shielding is retained
  • Equipment safety is unaffected
DC Blocker from iFi audio

Behind every good component is a DC Blocker.

The bigger the amplifier, usually, the larger the toroidal which is susceptible to residual DC voltage. JUst add the DC Blocker at the IEC to stop DC from getting in.

  • 90-240V
  • Maximum rating >10A, continuous current rating 7A
  • Small size, universal application, won’t block any other connectors, sockets, or cables

ZERO DC Block technology – stops DC from getting into your amplifier and eliminates amplifier transformer hum.

High-performance glass passivated semiconductor.  High-case dielectric strength of 1500VRMS. UL listed.  Flame resistant IEC socket/connecter/chassis (Fireproof polymers UL94-V0).

EMI shielding is retained.

The DC Blocker removes such DC and eliminates such mechanical transformer hum, makes the transformer operate at the optimum environment. With the DC Blocker, there is 0 DC pass through.

Support

ZERO DC Block technologyBlocks incoming DC – up to 1,200mV
Voltage rating90 – 240 volts
Maximum current rating> 10A
Continuous current rating7A
Universal IECHospital-grade IEC connectors
Dimensions68 x 37 x 32 mm / 2.7” x 1.5” x 1.3”
Weight63g / 2.2oz

Reviews

Works well for me.

Very happy with the blocker, it has eliminated the intermittent hum I was getting on my Audiolab 6000A

(Click name to read original review)
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