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Thread: FS: Onix OA21 amplifier (Modified)

  1. #1
    Join Date: Apr 2011

    Location: cheltenham

    Posts: 561
    I'm matt.

    Default FS: Onix OA21 amplifier (Modified)

    I've owned this amp longer than any piece of kit and i'm honestly in two minds about selling it. What I would Ideally like is to sell it to someone who would give me first refusal if they ever decided to sell. I'm more than happy for people to come and listen first (you wont be disappointed)
    Vocals are lovely and clean, and project well. Treble is smooth and detailed, and bass is tight and deep. It sounds very similar to my modified Quad 306, so in that respect, there's no reason to keep it. I'm keeping the 306 because it's easier to work on and I can experiment with passive preamps.


    Volume pot was replaced with a Noble - As used In the Avondale Grad 1 preamp - NLA unfortunately.

    Main smoothing capacitors - Panasonic UP series 4700uf 63v - Chosen for their high ripple current rating - Also NLA, and also unfortunate.

    Bridge rectifier replaced with LQA30T300 Q-Speed soft recovery diodes.

    Relays replaced for service/longevity reasons

    T0-3 Transistors heatsink thermally bonded to the case with Noctua NT-H1 thermal compound (better heat transfer than the usual stuff).

    Coupling capacitors replaced with Nichicon FW (standard for audio) These are by far the best sounding coupling caps I've tried In the Onix and i've tried a lot.
    Vishay Sprague Tantalex 150D are in the feedback position. Chosen because they are, or were used in the Avondale NCC200 power amplifier and sound better than anything else i've tried. In the past I tried Elna Silmic (Too smooth/soft) - Nichicon Muse KZ (thin and harsh In the upper midrange), Polypropylene (various), polyester and Russian K52-2 Silver Tantalum all gave a similar sound to Nichicon Muse KZ.

    Transistors in the long-tailed-pair are matched (HFE and VBE) and thermally bonded. This lowered the DC offset from about 20 to 25mv down to about 5 to 10mv (See here for details - http://paul-kemble.tripod.com/sound7e.html)

    Bias set to 18mv (as it should be)

    Most of the resistors are replaced with Vishay Dale RN60 apart from the sensitive feedback loop area, where i've used standard MRS25 metal films (RN60 sound a touch soft here)

    The negatives - No phono card Is fitted, and the external power supply Input socket was removed (only needed if you were planning on adding a Soap power supply). They were removed when trying out various mods but the shed leaked and they must of got thrown out with a load of electrical equipment that went rusty

    There are a few scratches and a small dent on one side as can be seen in the pictures.

    Looking for 250 plus 15 p&p

    Pics to follow...

  2. #2
    Join Date: Apr 2011

    Location: cheltenham

    Posts: 561
    I'm matt.

    Default










  3. #3
    Join Date: Apr 2011

    Location: cheltenham

    Posts: 561
    I'm matt.

    Default

    Forgot to post the internal picture:


  4. #4
    Join Date: Apr 2016

    Location: Bishops Stortford

    Posts: 833
    I'm Chris.

    Default

    Coming from Brighton, I remember this back in the day as a pretty impressive performer (in std form) and easily matched up to the cheaper Naim and Linn amps
    SW1X Universal Music Server UMS I Signature with Power Supply Unit PSU I Signature
    SW1X USB I Signature
    SW1X DAC III Special
    SW1X Open Baffle Speakers containing both vintage and modern alnico drivers and paper cones. All silver wired and crossover-less where possible - 4" vintage Siemens Klangfilm tweeters, 8" SEAS exotic W8 midrange drivers and vintage 15" Altec VOTT 416 bass drivers
    DRD 45 single ended, 45 triode, monoblocks,
    Silver mains cables, interconnects and speaker cables by SW1X

  5. #5
    Join Date: Apr 2011

    Location: cheltenham

    Posts: 561
    I'm matt.

    Default

    Quote Originally Posted by bumpy View Post
    Coming from Brighton, I remember this back in the day as a pretty impressive performer (in std form) and easily matched up to the cheaper Naim and Linn amps
    I much prefered the Onix to my old Naim 102 pre, Hicap and 180 power, let alone my Nait 1.

  6. #6
    Join Date: Dec 2011

    Location: sussex

    Posts: 289
    I'm phil.

    Default

    I’m still using a complete onix system, just had the pre amp serviced by tony and sounding sublime, still never had anything that makes me consider swapping it
    Modded td160 super Thorens ol encounter arm hana sl cart, angle audio studio pro mc virtual battery phono amp with separate psi, Onix pre and mono amps, Onix CD player, Onix BWD and soap tuner. B&W dm2 speakers or super pencil 12 speakers, atlas cables, seperate mains power supply with earth spike.

  7. #7
    Join Date: Jan 2016

    Location: Argyll and Bute

    Posts: 252
    I'm Colin.

    Default

    This was my first proper amp bought from a dealer in Edinburgh , loved it just great performer

    Colin

  8. #8
    Join Date: Apr 2011

    Location: cheltenham

    Posts: 561
    I'm matt.

    Default

    Price drop - 200 plus 15 p&p

  9. #9
    Join Date: Apr 2011

    Location: cheltenham

    Posts: 561
    I'm matt.

    Default

    Now 180 plus 15 p&p

  10. #10
    Join Date: Apr 2011

    Location: cheltenham

    Posts: 561
    I'm matt.

    Default

    SOLD

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