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Thread: Arcadia 7W PSE 2A3 Power Amplifier Upgrade

  1. #1
    Join Date: Nov 2011

    Location: Manchester, UK

    Posts: 266
    I'm Simon.

    Default Arcadia 7W PSE 2A3 Power Amplifier Upgrade

    Recently in for some major upgrades was one of the original SJS Arcadia 7W PSE 2A3 amplifiers, originally built back in 1998.

    Following the terminal exit of the main power transformer the opportunity was taken to upgrade and almost rebuild it.

    The main power transformer was replaced by an external dual mono PSU, containing 6 mains transformers; two for the HT to the 2A3 power valves, two for the HT to the 6072A-5687 input/driver stage, and two for the negative bias supply for the grids of the 2A3s.





    EZ81 rectifiers, choke input and first smoothing cap for the input/driver stage power supply are inside the PSU case



    Four umbilical cables connect the psu to the audio chassis





    Independent left and right mains switches, with remote switching controlled form the audio chassis




    Removal of the power transformer from the audio chassis allowed for a pair of larger chokes to be fitted for the 2A3 HT supply, each channel has NOS GZ37 choke input supply and Elna Cerafine HT caps in the HT, and NOS Mullard EZ81 and choke input supply for the bias supply



    Inside there was a major component refresh and upgrade; tantalum resistors, Hovland Musicaps, lots of Black Gates, Jensen 4 pole HT caps, Kemet bias supply caps and silver wiring





    Not looking to shabby for it's age, and now fit and ready to go



    SJS Arcadia Line Level Pre-amplifiers, Headphone amps, MM Phono Stages and SET Power amps - service, repairs, upgrades.
    Designed and hand-built in England.

  2. #2
    Join Date: Mar 2008

    Location: Galashiels

    Posts: 13,669
    I'm inthescottishmafia.

    Default

    Very nice!
    “Music has always been a matter of energy to me, a question of fuel. Sentimental people call it inspiration, but what they really mean is fuel. I have always needed fuel. I am a serious consumer. On some nights I still believe that a car with the gas needle on empty can run about fifty more miles if you have the right music very loud on the radio”

    Hunter S Thompson

  3. #3
    Join Date: Nov 2011

    Location: Manchester, UK

    Posts: 266
    I'm Simon.

    Default

    Dropbox changes did for all the images in the original post, so I thought it may be worth updating all the links and putting the photos back in

    At the end of 2015 one of the original SJS Arcadia 7W PSE 2A3 amplifiers, originally built back in 1998, came in for a major service and upgrade.

    Following the terminal exit of the main power transformer the opportunity was taken to upgrade and almost rebuild it.

    The main power transformer was replaced by an external dual mono PSU, containing 6 mains transformers; two for the HT to the 2A3 power valves, two for the HT to the 6072A-5687 input/driver stage, and two for the negative bias supply for the grids of the 2A3s.





    EZ81 rectifiers, choke input and first smoothing cap for the input/driver stage power supply are inside the PSU case



    Four umbilical cables connect the psu to the audio chassis





    Independent left and right mains switches, with remote switching controlled form the audio chassis



    Removal of the power transformer from the audio chassis allowed for a pair of larger chokes to be fitted for the 2A3 HT supply, each channel has NOS GZ37 choke input supply and Elna Cerafine HT caps in the HT, and NOS Mullard EZ81 and choke input supply for the bias supply



    Inside there was a major component refresh and upgrade; tantalum resistors, Hovland Musicaps, lots of Black Gates, Jensen 4 pole HT caps, Kemet bias supply caps and silver wiring





    Not looking to shabby for it's age, and now fit and ready to go



    SJS Arcadia Line Level Pre-amplifiers, Headphone amps, MM Phono Stages and SET Power amps - service, repairs, upgrades.
    Designed and hand-built in England.

  4. #4
    Join Date: Nov 2008

    Location: Banbury, Oxfordshire/Panteg is where my late father was born

    Posts: 4,382
    I'm Chris.

    Default

    They look stunning, lovely quality amplifier.
    Chris

    We've gone on holiday by mistake !

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