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.

ZEN CAN Signature 6XX
ZEN CAN Signature 6XX
ZEN CAN Signature 6XX from iFi audio
ZEN CAN Signature 6XX from iFi audio
Signature tailoring by iFi

The ZEN CAN Signature 6XX analogue headphone amplifier takes sonic tailoring to the next level with ActivEQ.

Level-up

The original ZEN CAN, our all-analogue headphone amplifier, boasted the ability to drive tough headphone loads, a balanced circuit design, vanishingly low levels of distortion and versatile sonic tailoring.

The ZEN CAN Signature 6XX takes this to another level. It further improves the sound quality with enhanced circuit design, whilst maintaining the versatile features of the ‘regular’ version and adding something special – a custom EQ setting precisely tailored across the entire frequency response curve to make the most of a popular headphone model.

ZEN CAN Signature 6XX from iFi audio

ActivEQ

This new feature, called ActivEQ, combines active and passive components to create a specific EQ curve to suit a particular pair of headphones, performed in the analogue domain without a hint of additional noise or distortion.

The ZEN CAN Signature 6XX, features ActivEQ for the ‘MassDrop x Sennheiser HD 6XX’ – a popular pair of high-quality headphones with more than 120,000 sold to date, based on the Sennheiser HD 650 and created exclusively for Drop.com.

These headphones are renowned for the quality of their midrange performance but exhibit some quirks in the bass and treble regions, which can be seen in frequency response measurements.

EQ. Activated.

When the ‘HD 6XX’ button is pressed, the ZEN CAN Signature 6XX calibrates its signal to complement the headphone’s response characteristics right across the frequency range, thus tailoring its performance to precisely fit the HD 6XX like a made-to-measure suit. In particular, the 7kHz treble and bass below 500Hz is gently elevated.

What’s more, the benefits of this ActivEQ curve are equally applicable to the Sennheiser HD 650, which shares the same characteristics. It also has an effect on other Sennheiser models – take a look here.

This feature can be switched on or off. Without ActivEQ engaged, the ZEN CAN Signature 6XX’s performance is adroitly balanced to make the most of all manner of headphones and in-ear monitors.

ZEN CAN Signature 6XX from iFi audio

No pain, just gain.

The ZEN CAN Signature 6XX features four gain settings in six dB steps – 0dB, 6dB, 12dB and 18db.

This enables the amp to precisely suit the connected headphones. Unity gain (0dB) is useful to ensure low noise with sensitive in-ear monitors, while the higher gain settings make the most of tougher headphone loads, delivering excellent dynamic headroom.

XSpace

This analogue processing mode compensates for the ‘in-head localisation’ effect that can occur when using headphones to listen to music that was mixed using a pair of speakers.

It widens the headphone soundstage to deliver a more spacious and speaker-like experience.

ZEN CAN Signature 6XX from iFi audio

Balance of power

The ZEN CAN Signature 6XX’s circuitry is a balanced, symmetrical dual-mono design – a topology usually reserved for high-end headphone amps – with a number of key elements trickled down from the discrete Class A circuitry developed for iFi’s flagship headphone amplifier, the Pro iCAN.

Key components have been upgraded to enhance performance in line with the improvements made to the ZEN CAN Signature 6XX, including the use of Panasonic OS-CON and Elna Silmic II capacitors.

Driving force

The amp offers prodigious drive capability, delivering 1600mW (7.2V) into 32 ohms from the single-ended output, with 15V+ available to loads of 300 ohms or more through the balanced output, ensuring it takes even current-hungry planar headphones in its stride.

Delivering ultra-low distortion, rich sonic detail, engaging dynamics and the ability to drive all manner of headphones with ease, the ZEN CAN Signature 6XX is a truly a driving force to be reckoned with.

Stay connected

The ZEN CAN Signature 6XX offers stereo RCA and 3.5mm single-ended inputs, plus a balanced 4.4mm Pentaconn input. A 4.4mm balanced output is also provided, to connect to power amps equipped with a balanced input.

It provides a pair of headphone outputs – a 6.3mm output for headphones that have a standard single-ended connector (compatible with all headphones) and a 4.4mm Pentaconn balanced output for headphones offering balanced connection.

An increasing number of high-quality headphones and in-ear monitors either come so equipped or give the option of detaching the cable and upgrading to a 4.4mm Pentaconn connector, and this output makes the most of them (it is particularly recommended for high-impedance headphones).

Dynamic Duo

The ZEN CAN Signature 6XX works well with the ZEN DAC Signature. Products can be bought separately but a ‘ZEN Signature Set’ is now available. This comprises both ZEN Signature units plus a high-performance 4.4mm Pentaconn cable (worth £69 when purchased separately) to connect them together.

When used in tandem, the two ZEN Signatures make a fantastic, desktop-sized headphone system for both digital and analogue sources, further extending the reputation of iFi’s ZEN Series for delivering exceptional performance and versatility at remarkable prices.

Majestic measurements

ZEN CAN Signature 6XX: 1,600mW
Laptop Headphone: 30mW

52x

more headphone power

A fully-discrete and balanced amplifier audio circuit. The full symmetric dual-mono headphone amplifier with gold-plated 4.4mm balanced connection. Premium engineering is more expensive but lowers the noise floor to a whisper-quiet levels.

Check out the tech note for the details.

As with many other iFi audio products, we’ve incorporated a custom OV Series operational-amplifier. This top-notch component contributes to the extremely low noise, low distortion (0.0001%) and wide bandwidth.

Panasonic OS-CON caps totaling 5,410uF give very-low Equivalent Series Resistance (ESR), excellent noise reduction capability and frequency response characteristics. In addition, OS-CONs have a long-life span and its ESR changes little even at low temperatures since the electrolyte is solid.

They are not often found in products costing <US$1000.

A Tokyo Cosmos Electric Co. (TOCOS) multi-track potentiometer is used. This has close channel matching tolerance for optimal performance in quiet listening (low positions of pot).

Switching between settings has been engineered to ensure sonic transparency with advanced trench technology MOSFET is used as a muting switch.

This FET-based switching is handled by a micro-controller, which only ‘wakes up’ when the user changes a setting, thus eradicating any sonically deleterious interference.

TDK C0G (Class 1 ceramic) capacitors offer high stability and low losses for resonant circuit applications.

Getting ever closer to the theoretical ideal of pure, frequency-constant capacitance, these capacitors reduce capacitor-induced distortion to vanishingly low levels.

They are pricey but are a perfect addition to our products.

We use ELNA Japan Silmic II capacitors for the power supplies.

The primary constituent of the newly developed dielectric is silk fibre. This material was believed as unfathomable as an aluminium electrolytic capacitor. The new material beats silk fibre and mixes it with Manila hemp fibre to provide the dielectric to an aluminium electrolytic capacitor used for high-grade music. The result is second-to-none superior acoustic properties and excellent linearity.

Support

Specifications

InputsRCA
Headphone output
Gain
THD+N (A-Weighting)
3.5 (SE), 4.4mm (BAL))
6.35 mm, 4.4 mm
0 dB, 6 dB,12 dB,18 dB adjust
0.0066% (BAL), 0.0058% (SE)
Output Impedance (HP)BAL
SE
<2 Ohms
<1 Ohm
ZOUTBalanced line out
200 ohms
SNR122 dB (BAL)
Dynamic range-122 dB (BAL)
Frequency response(-3dB): 10 Hz – 200 kHz
Function ButtonHD6XX adaption and/or XSpace; Bypass
IMD0.01%
PowerMaximum output power (16 ohms)
Maximum output power (300 ohms)
Maximum output power (600 ohms)
Maximum power consumption
3.0 V / 600 mW (BAL), 4.0 V / 1000 mW (SE)
5.1 V / 756 mW (BAL), 7.6 V / 196 mW (SE)
15.2 V / 385 mW (BAL), 7.6 V / 98 mW (SE)
13 W / 2.6A
Dimensions160(w) x 117(d) x 35(h) mm
6.3" x 4.6" x 1.4"
Weight1.87 Ibs (0.85 kg)

Reviews

ZEN Signature Set (6XX) – “HD 6XX Headphones…. There may be no better way to enjoy them.”

“Do you own the Massdrop x Sennheiser HD 6XX headphones? If so, you need to hear them with the iFi ZEN Signature Set ($599) from iFi Audio. I’d usually wait until the conclusion to make a big statement like that, but I started with it in case you only read one sentence of this review.”

(Click name to read original review)
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