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Thread: DIY BMU build

  1. #11
    Join Date: Apr 2008

    Location: Warrington

    Posts: 3,031
    I'm Neil.

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    Quote Originally Posted by Bigman80 View Post
    Right, Rothwell SUT back in with the Vivant and......... No hum, hiss or nasty sounds. SO.....it's the bloody Wizard phonostage.
    Interesting, maybe the Wizard just doesn’t want to see -120V on neutral. This has often been cited as a potential issue with balanced mains.
    Mana Acoustics Racks / Bright Star IsoNodes Decoupling >> Custom Silent Media Server >> Halide Bridge USB (with AQVOX USB power) >> Pedja Rogic's Audial Model S DAC + Pioneer PL-71 turntable / Vista Audio phono-1 mk II / Denon PCL-5 headshell / Reson Reca >> LFD DLS >> LFD PA2M (SE) >> Royd RR3s.

  2. #12
    Join Date: Jan 2013

    Location: Birmingham

    Posts: 3,892
    I'm James.

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    At least your efforts were not in vain! But now you have to do more work on the Wizard!
    VPI Scout 1.1 - Ortofon 2M Black - Croft 25R+ - Croft Series 7 - Spendor SP2

  3. #13
    Join Date: Nov 2015

    Location: Wolverhampton

    Posts: 5,866
    I'm Oliver.

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    Quote Originally Posted by Yomanze View Post
    Interesting, maybe the Wizard just doesn’t want to see -120V on neutral. This has often been cited as a potential issue with balanced mains.
    That's a good point but it wasn't as quiet as the Vivant previously so I think there is definitely a bit of work to do.
    Analogue: Technics SP10 MK2 > Phonomac AT-1010 MK5 tonearm > Ortofon Kontrapunkt b > Wizard Jfet MC Valve Phonostage (Telefunken & Tesla Valves)
    Digital: NONE
    Amplification: Nelson Pass DCB1 & Monarchy Audio SM-70 Class A Amplifier
    Cables: Fisual S-Flex Speaker Cable & SPOTFIRE IC Cables & NEW SPOTFIRE Tonearm cable
    Speakers: Pioneer CS-77A

  4. #14
    Join Date: Nov 2015

    Location: Wolverhampton

    Posts: 5,866
    I'm Oliver.

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    Quote Originally Posted by Jimbo View Post
    At least your efforts were not in vain! But now you have to do more work on the Wizard!
    Yes, Jimbo. Bittersweet but not too much of a worry. Alan has a couple of ideas. Apparently the Vivant is grounded in a different way to the Wizard so we may have an easy fix.
    Analogue: Technics SP10 MK2 > Phonomac AT-1010 MK5 tonearm > Ortofon Kontrapunkt b > Wizard Jfet MC Valve Phonostage (Telefunken & Tesla Valves)
    Digital: NONE
    Amplification: Nelson Pass DCB1 & Monarchy Audio SM-70 Class A Amplifier
    Cables: Fisual S-Flex Speaker Cable & SPOTFIRE IC Cables & NEW SPOTFIRE Tonearm cable
    Speakers: Pioneer CS-77A

  5. #15
    Join Date: Nov 2015

    Location: Wolverhampton

    Posts: 5,866
    I'm Oliver.

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    Last update as I have now exhausted all the combinations I can think of.

    The Wizard makes no change to hum level when plugged in via the BMU or directly into the wall socket.

    The SUT is more prone to hum when connected to the Wizard so my conclusion is that the Transformer in the Wizard is omitting a massive amount of interference.

    I have the SUT next to the Vivant without any issue bit it's almost a meter away from the Wizard before I reduce the hum to similar levels.

    Due to this, I may put the PSU into a separate box and use a long umbilical to the Phonostage.

    Welcome to other suggestions!
    Analogue: Technics SP10 MK2 > Phonomac AT-1010 MK5 tonearm > Ortofon Kontrapunkt b > Wizard Jfet MC Valve Phonostage (Telefunken & Tesla Valves)
    Digital: NONE
    Amplification: Nelson Pass DCB1 & Monarchy Audio SM-70 Class A Amplifier
    Cables: Fisual S-Flex Speaker Cable & SPOTFIRE IC Cables & NEW SPOTFIRE Tonearm cable
    Speakers: Pioneer CS-77A

  6. #16
    Join Date: Nov 2015

    Location: Wolverhampton

    Posts: 5,866
    I'm Oliver.

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    Quick update,

    I've had the BMU up against a Tacima 6 way power conditioner today.

    The Tacima would've solved my noisy mains problem for £30 and had I known about it earlier I probably would've never built the BMU. it's a cracking bit of kit but there is a compromise, in my system, the soundstage narrowed a touch and the HF didn't stay as natural.

    The BMU seems to have little in the way of compromise other than the mechanical buzzing of the toroidal TF. Which is pissing me right off 🤣

    A better quality TF will obviously fix this but it'll have to wait.

    The BMU is a big winner here, I love it. Shame it's buzzing but I'm now a mains quality convert. It's well worth getting one if you're just plugging in to the ring main directly like I was.

    Thanks to Shaman for convincing me with tales of his *** BMU. A much welcome addition to my system.

    Thanks to Alan for donating the BT unit and your continued assistance
    Analogue: Technics SP10 MK2 > Phonomac AT-1010 MK5 tonearm > Ortofon Kontrapunkt b > Wizard Jfet MC Valve Phonostage (Telefunken & Tesla Valves)
    Digital: NONE
    Amplification: Nelson Pass DCB1 & Monarchy Audio SM-70 Class A Amplifier
    Cables: Fisual S-Flex Speaker Cable & SPOTFIRE IC Cables & NEW SPOTFIRE Tonearm cable
    Speakers: Pioneer CS-77A

  7. #17
    Join Date: Mar 2014

    Location: Herefordshire

    Posts: 92
    I'm Alex.

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    Some of the hum will be the case resonating with the transformer. Start with getting some 10mm thick neoprene foam and put it on the top and bottom of the transformer. That will help de couple the transformer mechanically from the case.

    Then get some "Dead mat" sound deadening sheets and stick it to the inside of the case walls, base and top. You will have a well isolated case sound wise and will cut down the buzzing to be ignorable when listening.

  8. #18
    Join Date: Nov 2015

    Location: Wolverhampton

    Posts: 5,866
    I'm Oliver.

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    Quote Originally Posted by Blueflash View Post
    Some of the hum will be the case resonating with the transformer. Start with getting some 10mm thick neoprene foam and put it on the top and bottom of the transformer. That will help de couple the transformer mechanically from the case.

    Then get some "Dead mat" sound deadening sheets and stick it to the inside of the case walls, base and top. You will have a well isolated case sound wise and will cut down the buzzing to be ignorable when listening.
    Thanks!!

    Good ideas.
    Analogue: Technics SP10 MK2 > Phonomac AT-1010 MK5 tonearm > Ortofon Kontrapunkt b > Wizard Jfet MC Valve Phonostage (Telefunken & Tesla Valves)
    Digital: NONE
    Amplification: Nelson Pass DCB1 & Monarchy Audio SM-70 Class A Amplifier
    Cables: Fisual S-Flex Speaker Cable & SPOTFIRE IC Cables & NEW SPOTFIRE Tonearm cable
    Speakers: Pioneer CS-77A

  9. #19
    Join Date: Aug 2008

    Location: Suffolk, UK

    Posts: 1,250
    I'm Paul.

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    Yes, some mechanical isolation on the transformer. Also is the transformer potted? If not you can place it on some mylar sheet or acetate heat laminator pocket and pump in some epoxy resin into the hole in the transformer. You will need to drill a hole for the fixing bolt.
    ~Paul~

  10. #20
    Join Date: Mar 2017

    Location: Liverpool

    Posts: 276
    I'm Sandro.

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    ground%20lift.gif
    What is the transformer size ?

    DC Blocker ? twist wires ? earth Bus ? (single wires from start point to one single point)
    Earth lift ?

    PS the Firebotle Vivant look really Gorgeous who is in charge for dusting and Polishing ?

    Seriously where das he get those enclosures? I would really like one

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