iFi Audio 6XX Zen Can Signature User Guide

6XX

Thank you for purchasing the CAN Signature 6XX from ZEN series. The CAN Signature 6XX is a balanced headphone amplifier optimized for Sennheiser HD 6XX headphones.

1. Power switch

2. Input channel switch
Input 1: RCA
Input 2: Single-ended 3.5mm
Input 3: Balanced 4.4mm

3. PowerMatch selection: 0dB/6dB/12dB/18dB
We recommend to start from 0dB and then increase the switchable gain level to attain an enjoyable and comfortable level of volume from the headphones.

Warning: at the outset do not use excessive gain, otherwise damage to hearing or connected headphones may ensue. AMR/iFi audio is not responsible for any damage/injury from misuse.

4. Analogue Volume Control
At normal listening levels, the volume control should be around the 12 o’clock position. Increase the gain level to enjoy a higher listening level.

5. Single-ended 6.3mm output
For connecting single-ended 6.3mm headphones. With single-ended 3.5mm headphones, connect with a 3.5mm to 6.3mm adapter.

6. Balanced 4.4mm analogue output
For connecting balanced 4.4mm headphones.

Tip: As the Sennheiser HD 6XX headphones use balanced design, we recommend the 4.4mm balanced output.

7. HD 6XX LED
Headphone corrections optimized for Sennheiser HD 6XX headphones.

8. XSpace® Matrix LED
The Ahgaca® Matrix(on/off) recreates a holographic sound field. It is a pure analogue signal processing circuit designed for listening to headphones as if one was listening to speakers. This addresses the ‘music inside the head’ sensation, which makes for unsettling listening.

Tip: Sonically-hindering DSP is NOT used for HD 6XX nor XSpace® Matrix systems. They use the highest-quality discrete components and operate purely in the analogue domain. Hence all the clarity and resolution of the original music is retained.

9. Settings
This button chooses between:
– Off
– HD 6XX
– XSpace®

10. Balanced 4.4mm analogue input
This is a balanced analogue input.

11. Single-ended 3.5mm analogue input
For connecting single-ended 3.5mm input.

12. RCA analogue input
This is an analogue input.

13. Balanced 4.4mm analogue output
This is an analogue output via 4.4mm > XLR or other balanced interconnects. You could use this for an active speaker.

Tip: As the ZEN CAN Signature 6XX is balanced, this is the recommended output.

14. DC 5V power
Please connect the ZEN CAN Signature 6XX to the enclosed power supply, the super-silent iPower X.The ZEN CAN Signature 6XX must ONLY be powered by 5 volts.

Specifications

Input voltage:| DC 5V/2.5A
AC 100 -240V, 50/60Hz (iFi iPower X included)
---|---
Max Output:|
Balanced:| >15.1V/385 mW (@600 Ohm)

11.0V/1890 mW (@ 64 Ohm)
6.2V/1200 mW (@ 32 Ohm)
S-E:| >7.6V/98 mW (@ 600 Ohm)
7.4V/870 mW (@ 64 Ohm)
7.2V/1600 mW (@ 32 Ohm)
THD &N:|
Balanced:| <0.006%(@ 360 mW/2.4V 16 Ohm)
S-E:| <0.005%(@ 100 mW/1.27V 16 Ohm)
SNR:|
Balanced:| >121dBA (@ 15.20)
S-E:| >120dBA (@ 7.6V)
Max. Input:|
Balanced:| 7.4V RMS
RCA:| 3.8V RMS
3.5mm:| 1.92V RMS
Gain:| 0dB, 6dB, 12dB and 18dB
Frequency Response:| 10Hz – 200kHz (-3dB)
Power consumption:| No Signal          ~5W
Max Signal        ~12W
Dimensions:| 158 x 117 x 35 mm
6.2″ x 4.6″ x 1.4″
Net weight:| 550 g (1.21 lbs)
Warranty period:| 12 months

Specifications are subject to change without notice.

ifi-audio.com

Ver1.1

Quick Set-Up

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Set-Up video

1. Power
2. Power Match
3. Analogue Volume Control
4. SE 6.3mm output
5. BAL 4.4mm output
6. Input Selector

1. SE 3.5mm input
2. RCA input
3. BAL4.4mm line output
4. DC Power SV input
5. BAL4.4mm input

(1) Power (SV only)

(2) Input

1. RCA
2. SE 3.5mm
3. BAL 4.4mm

(3) Output

1. SE 6.3mm
2. BAL 4.4mm

1. BAL4.4mm

(4) PowerMatch

0dB
6dB
12dB
18dB

(5) Modes

ZEN CAN Signature Lowdown

6XX

SPECIAL BY DESIGN

• ActivEQ is an exact match with the HD 6XX headphone
• End-to-end True Differential balanced circuitry
• Premium parts selection drawn from the £3000 Pro range

FEATURES

• Adjustable gain to match other headphones
• XSpace analogue headphone spatialiser
• 4.4mm balanced output

ACTIVEQ

HD 6XX

• Spectacular balanced midrange

But…

• Bass under 100Hz is rolled off
• Upper treble is a little attenuated
• Upper presence region has significant ‘hole’ in frequency response

ActivEQ

• EQ curve precisely correct
• Active & passive components
• Performed in the analogue domain
• Magical midrange preserved
• SNR and Distorion unnaffected

HEADPHONE MATCH | Sennheiser HD 6XX

1. Improved Bass
2. Ideal Curve
3. Improved Treble
4. The ideal curve was determined by measurements in addition to listener feedback
5. Blue line: ZEN CAN Signature 6XX + Sennheiser HD 6XX
   Red line: Sennheiser HD 6XX

• Works with other Sennheiser headphones

HEADPHONE MATCH

• ActivEQ can be switched off, making it compatible with all headphones

Frequency Response 20Hz to 20KHz

1. Improved Bass
2. Ideal Curve
3. Improved Treble
4. The ideal curve was determined by measurements in addition to listener feedback
5. Blue line: ZEN CAN Signature 6XX + Sennheiser HD 6XX
   Red line: Sennheiser HD 6XX

Super Dupont Resonantor modification     Source: Inner Fidelity measurements    With 6XX setting ON

The ideal curve was determined by measurements in addition to listeners’ feedback.

PRO SERIES | HIGH-END CIRCUIT DESIGN

• Class A output stage from the Pro range
• Drives 15V / 750mW into 300 ohms
• <0.0066% distortion

SUPERIOR DESIGN AND COMPONENTS

1. Excellent noise reduction capability and frequency characteristics

2. Elna Silmic II capacitors

3. Balanced circuit

4. For audio use with extremely low distortion

5. Advanced trench technology MOSFET as muting switch hence when not in use doesn’t affect the sound.

6. Low noise/distortion OV2637A (0.0001%) Performance quals/surpasses many high-end headphone amplifiers

7. Tokyo Cosmos Electric potentiometer

8. Thin Film Resistors
   Power noise & distortion than metal/carbon film

9. Black military spec PCB

CONNECTIONS

1. **Power input DC 5V***

2. Balanced Output
   4.4mm to XLR**

3. RCA Input

4. Single-Ended Input
   3.5mm

5. Balanced Input
   4.4mm connection to ZEN DAC Signature

1. SE HP – 6.3mm
2. Balanced HP – 4.4mm

*Do not use a power supply higher than 5V
**Do not connect your headphones to this port

SPECIFICATIONS

INPUTS

RCA:| 3.5 (SE), 4.4mm (BAL))
Headphone output:| 6.35 mm, 4.4 mm
Gain:| 0 dB, 6 dB,12 dB,18 dB adjust
THD+N (A-Weighting):| 0.0066% (BAL), 0.0058% (SE)
Maximum output power (16 ohms)| 3.0 V / 600 mW (BAL), 4.0 V / 1000 mW (SE)
---|---
Maximum output power (300 ohms)| 5.1 V / 756 mW (BAL), 7.6 V / 196 mW (SE)
Maximum output power (600 ohms)| 15.2 V / 385 mW (BAL), 7.6 V / 98 mW (SE)
SNR:| 122 dB (BAL)
---|---
Dynamic range:| -122 dB (BAL)
Frequency response| (-3dB): 10 Hz – 200 kHz
Function Button:| HD6XX adaption and/or XSpace; Bypass
IMD:| 0.01%
Maximum power consumption:| 13 W / 2.6A
---|---
Dimensions:| 4.6 x 3.9 x 1.2 in (11.7 x 10 x 3 cm)
Weight:| 1.87 Ibs (0.85 kg)
Zout (headphone out)| 0.25 ohms (SE), 0.5 ohms (BAL)
---|---
Zout(balanced line out)| 200 ohms

ABOUT iFi

iFi audio is the sister company of AGL and is headquartered in Southport, UK. It owns the hifi brand Abbingdon Music Research (AMR). They respectively design and manufacture portable and desktop ‘ultrafidelity’ audio products and high-end audio ‘homebased’ components. The combined in-house hardware and software development team enables iFi audio and AMR to bring to market advanced audio products.

For further information, please contact
comms@ifi-audio.com
+44 (0) 1704 543 858

Volume Pots vs Volume ICs

October 2021
Volume Pots
comms@ifi-audio.com
+44 (0)1704 543 858
www.ifi-audio.com

Above: ZEN CAN

Volume Pot vs Volume IC

There has been a bit of discussion around the merits of physical volume control pots vs volume control ICs lately, in both the press and from a customer’s viewpoint.

It’s swings and roundabouts, of course! There are some things a volume pot is good at and others not so good. The good point would be sound quality. Not so good would be low-level channel tracking.

My background fiddling with circuits and volume controls is extensive and started when I heard a difference in the sound quality of a pot when I was about 16 at the Melbourne Audio Club. Quite a few DIY audiophiles’ consensus at the club was that a volume pot has superior sound quality over an IC volume control. They (and I) have listened to a lot of volume pots over the years.

Hidden behind the facade of prestige is the desire to match the sound to their system, which highlights the fact that there are tonal differences between pots. One of the pots that had (and still has) a good set of attributes was the 9mm type as found in the ZEN CAN and other iFi units. My own experiments have taken me to fiddle with IC volume controls as well, and I have quite a few different ones in the IC drawer.

Both volume pots and IC pots have their quirks.

– Volume pots are able be loaded down with the circuit they’re driving without adding much extra distortion, and so are more transparent from the fact they don’t need an extra amplifier stage, be it valve, discrete SS or IC op amp.
– IC volume controls can’t be loaded down heavily with the following circuit as they produce a lot of extra distortion, necessitating the use of an extra buffer stage, with its own attendant sonic colouration. The IC pot consists of resistors that are connected to with the use of Mosfet switches, themselves adding distortion and nonlinear capacitance.

Generally, though, IC volume controls have superior channel tracking and repeatable volume control settings, and they change the level setting as the signal crosses through 0v so that no clicks are heard. That’s why they are used in modern studio equipment and some hi-fi components, where their noiseless and easily implemented, compact and cost-effective operation is appreciated. Their family sound is slightly soft and a little more artificial than a physical volume control, and high attenuation can see them in their least sonically favourable light. Having said that though, given a transparent subsequent stage to drive they can be very good, and the IC volume control with high quality class A buffer in the AMR DP-777 is a good example.

There are quite a few different ways to change the volume these days. Transformer volume controls have the best signal-to-noise ratio, light- dependent resistors have nice sonics but poor tracking and worsening distortion at high attenuation levels.

Switched resistors have precision and sound quality on their side but can be expensive. The approach taken by the AMR AM-77 amplifier is microprocessor- controlled relays and resistors and is very transparent, with repeatable settings.

A digital-only system can have a purely digital volume control, but good ones can be expensive and must by design rely on the good linearity of the DAC chip and buffer stage for best sound quality.

For the ZEN CAN, a 9mm analogue pot was chosen as it provides a good measure of real transparency beyond its price point. The iFi Pro iDSD and Pro CAN still use a volume control pot, but a physically larger type that has good tracking between the channels.

Also, you don’t get the feel of turning a knob with an IC volume control either. It’s more physically intuitive to turn a knob, and you can change volume much more quickly.

Addendum
Here are some measurements to show some difference between the 9mm pot and a typical volume control IC.

Volume IC at -6dB with buffer.
The distortion is moderate.

The 9mm 50k volume pot at half resistance, equivalent to the volume IC at -6dB.

You can see the distortion is minimal and approaches the limits of the Audio Precision (AP) which is impressive.

Here is the AP by itself with no volume control, measuring itself.

The distortion is about the same as that with the volume control!
Noise floor is lower.

Just for comparison, here is the volume IC with no buffer and 100k loading.

Any loading increases distortion markedly, necessitating use of a buffer.

iFi is the sister-brand of Abbingdon Music Research (AMR) and is headquartered in Southport, UK. The two brands respectively design and manufacture portable, desktop and lifestyle audio products and high-end hi-fi components. Combined in-house hardware and software development teams and a ‘music first’ approach enable iFi and AMR to create advanced audio products that deliver new levels of design, functionality and performance at their respective price points. Since i Fi’s formation in 2012, its products have earned many awards around the world, helping it to become one of the fastest-growing brands in its field.

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