Index | Blog | Contributors | Contact Us
hificritic.com
  • Home
  • Blog
  • Subscriptions
  • Issues
    • Current Issue
    • Current Issue Excerpts
    • Back Issues >
      • 2021 - 2022
      • 2019 - 2020
      • 2017 - 2018
      • 2015 - 2016
      • 2014 - 2013
      • 2012 - 2011
      • 2010 - 2009
      • 2008 - 2007
    • Back Issue Excerpts >
      • 2022 Excerpts >
        • Vol 16 No 3 Excerpts
        • Vol 16 No 2 Excerpts
        • Vol 16 No 1 Excerpts
      • 2021 Excerpts >
        • Vol 15 No 4 Excerpts
        • Vol 15 No 3 Excerpts
        • Vol 15 No 2 Excerpts
        • Vol 15 No 1 Excerpts
      • 2020 Excerpts >
        • Vol 14 No 4 Excerpts
        • Vol 14 No 3 Excerpts
        • Vol 14 No 2 Excerpts
        • Vol 14 No 1 Excerpts
      • 2019 Excerpts >
        • Vol 13 No 4 Excerpts
        • Vol 13 No 3 Excerpts
        • Vol 13 No 2 Excerpts
        • Vol 13 No 1 Excerpts
      • 2018 Excerpts >
        • Vol 12 No 4 Excerpts
        • Vol 12 No 3 Excerpts
        • Vol 12 No 2 Excerpts
        • Vol 12 No 1 Excerpts
      • 2017 Excerpts >
        • Vol 11 No 4 Excerpts
        • Vol 11 No 3 Excerpts
        • Vol 11 No 2 Excerpts
        • Vol 11 No 1 Excerpts
      • 2016 Excerpts >
        • Vol 10 No 4 Excerpts
        • Vol 10 No 3 Excerpts
        • Vol 10 No 2 Excerpts
        • Vol 10 No 1 Excerpts
      • Excerpts 2007 - 2015
    • Sample Issue (Download)
    • Annual HIFICRITIC Indexes
  • Reviews
    • Hardware Reviews
    • Sound Classics
    • Review Classics
  • Recommendations
    • HIFICRITIC Awards
    • Colloms Sound Quality Ratings >
      • Ratings Explained
      • Digital Audio
      • Integrated Amplifiers
      • Power Amplifiers
      • Preamplifiers and Phono Stages
      • Loudspeaker Cables
      • Interconnect Cables
  • Feedback
    • Leave Feedback
    • Feedback 2009 to present >
      • Feedback 2015-2016
      • Feedback 2013-2014
      • Feedback 2011-2012
      • Feedback 2009-2010
    • Contact us

Audio Note makes a DAC – yes, the converter itself

29/10/2015

0 Comments

 
​Located at Partridge Green West Sussex, near Brighton UK  Audio Note comprises a sprawling collection of three adjacent, connected industrial units covering warehousing, manufacturing, research and development with a turnover in the low millions Sterling. The organisation has grown like topsy over recent years and is continuing to expand despite its core technologies being primarily based on historic, valve-tubed electronics with top class audio transformers of their own manufacture. 
Picture
​The pictured output transformer is absolutely huge, this is the ULTRA 211 SE output transformer, 15 kOhm primary and split secondaries to allow bi-wiring, all silver wired with 55% nickel C-cores, weighing around 18 kilograms each.

​While their heart is undoubtedly in reproducing analogue audio, where the signal may begin with their own hand made moving coil cartridges, they do not fear digital audio by any means and make fine DACs and  CD players including state of the art examples at well over £300,000.  £1,000,000  audio systems may be readily assembled with a choice selection of top AN components. Nevertheless several designs are quite competitively priced eg a TT1 turntable with Audio Note moving magnet cartridge, and a ‘Zero’ all valve integrated amplifier. In fact for about £5,000 you can buy an Audio Note audio system, a large pair of speakers, valve amplification and a valve equipped CD player. 
Picture
Founder Peter Qvortrup has a stock of these amazing Psvane 212 triodes and is determined to build a limited edition SE power amplifier with them. Their original application was driving a high power loudhailer on an aircraft carrier to instruct pilots of fighters and helicopters  on the flight deck while under power.

And until the end of 2013 there was also a healthy kit operation. While kits have finished, Audio Note also do good business with their custom audiophile parts which are used by enthusiast constructors and some other manufacturers in addition to their own production lines. While the famous Rubycon Black Gate used by Audio Note capacitors have ceased production (beware of fakes which now widely available)  Audio Note are working with Rubycon creating new advanced capacitors, and I noted two types of new electrolytic capacitor of same value, size and voltage but one was much heavier, this a very low ESR type with much lower impedance and a higher material density inside.
Picture
A new and stylish tri-motor turntable under development and seen in the research division
​My visit was prompted by a particular development in DAC technology, the research unfolding in over the past year. Experiments with a novel discrete ladder DAC, guided by a belief that selected discrete resistors could sound better than the generally silicon nitride resistive elements used within integrated circuits, led to the design and built of an automatic computerised resistor tester to select from thousands the precise values required to make a DAC of the required precision. 
​The favoured resistor technology would not allow laser trimming as is sometimes done. A prototype NOS discrete DAC has now been built where the zero crossing and array switching issues are now addressed and where the trimming of the last bit is allocated to a precision multi-turn resistor.  It sounded very well indeed with Kegon triode electronics, promising a step beyond the existing Level Five. The latter uses a selected Analogue Devices 18 bit linear DAC. However there is still much work to be done on this new DAC before its eventual release. 
The high precision automatic resistor measurement facility
The computer display showing the extreme accuracy required in selecting values from a particular 1kohm nominal value, accurate to seven places.
The first prototype discreet ladder DAC
The DAC board with those selected 1kOhm audiophile resistors.
0 Comments

Your comment will be posted after it is approved.


Leave a Reply.

    Author

    Martin Colloms has a passion for audio and music and has written for many of the key hi-fi magazines worldwide.

    History

    March 2023
    January 2022
    June 2021
    April 2021
    March 2021
    December 2020
    September 2020
    May 2020
    April 2020
    March 2020
    December 2019
    May 2019
    April 2019
    March 2019
    February 2019
    January 2019
    November 2018
    October 2018
    May 2018
    March 2018
    February 2018
    December 2017
    October 2017
    September 2017
    June 2017
    April 2017
    February 2017
    January 2017
    November 2016
    October 2016
    April 2016
    March 2016
    February 2016
    January 2016
    December 2015
    November 2015
    October 2015
    September 2015
    August 2015
    June 2015
    May 2015
    March 2015
    February 2015
    December 2014
    November 2014
    October 2014
    September 2014
    August 2014
    July 2014
    June 2014
    May 2014
    March 2014
    November 2013
    September 2013
    July 2013
    May 2013
    April 2013
    March 2013
    February 2013
    January 2013
    October 2011
    September 2011
    August 2011
    April 2011
    March 2011
    November 2010

    Categories

    All
    Andrew Everard
    Book Review
    Chris Barber
    Concert
    Conference
    Exhibition
    Festival
    Hardware
    Hearing Loss
    HIFICRITIC Prices
    Launch Event
    Meeting
    Music Downloads
    Music Market
    New Issue
    News
    Paul Messenger
    Press Event
    Recordings
    Show
    Software
    Webinar/seminar
    Yasuko Everard

    RSS Feed

Articles

Features*
Reviews
Hardware 
Music *
Books *

Hardware Reviews**

Digital
Servers
Streamers
Music stores
DACs
CD players
Speakers
Stand mount
Floorstanding
Amplifiers
Power
Preamps
Integrated 
Phono preamps
Cables
Loudspeaker
Interconnect
Digital
Power


Analogue 
Turntables
Tonearms
Cartridges

Music Reviews*

Classical
Pop
Rock
Jazz
Collections

Classics

Sound Classics
Review Classics

Awards

HIFICRITIC Awards

Ratings

Colloms Sound Quality Ratings 
Digital audio
Integrated amplifiers
Power amplifiers
Preamplifiers
Loudspeaker cables
Interconnect cables

Reviews by Year

2020
2014
 
2013 
2012 
2011 
2010 
2009 
2008 
2007

Issues by Year

Current issue
2021 - 2022
2019 - 2020
2017 - 2018
2016 - 2015
2014 – 2013
2012 – 2011
2010 – 2009
2008 – 2007
Annual Indexes

Online Store

Subscriptions
Issues
Hardware Reviews

Contributors

Colin Anderson
Arthur Barton
Chris Binns
Chris Bryant
Harriet Bryant
Jay Clawson​

Martin Colloms
Peter Comeau
Stan Curtis

Greg Drygla​​
Ben Duncan
Andrew Everard
Tony Faulkner
Nigel Finn
Kevin Fiske
Chris Frankland​
Stephen N Harris
Steve Harris​
Andrew Harrison
Jose Victor Henrique​
Jon Honeyball
Keith Howard​
Jason Kennedy
Paul Messenger
Julian Musgrave​
Mark Prendergast
Malcolm Steward
Rafael Todes
Dr Charles Zeilig​

Feedback

What HIFICRITIC readers say
Leave your own feedback
Contact us
* Coming to hificritic.com in the future. **Over 150 more hardware reviews coming to hificritic.com soon. Tell us what you'd like to see. 
hificritic.com
© Copyright 2014-2020 HIFICRITIC Ltd All Rights Reserved | Terms of Use | Privacy and Cookies | Website by Paul Herzlich | Contact Us
Photo used under Creative Commons from wuestenigel
Index | Blog | Contributors | Contact Us
hificritic.com