+ Reply to Thread
Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 22

Thread: Bucking Transformer for Little Dot mk ii

  1. #11
    RothwellAudio Guest

    Default

    Better safe than sorry.

  2. #12
    Join Date: Apr 2017

    Location: Manningtree, Essex

    Posts: 1,722
    I'm Tony.

    Default

    Well, it's looking like a pretty consistent 244-245 at the moment! Will check a few more times later.


    Sent from my iPhone using Tapatalk
    A mainly digital setup with a musical amplifier and endearing 1970's speakers. A CD player that hardly ever gets used and a turntable that is good enough to remind my how enjoyable my old vinyl is. Some cables and things.

  3. #13
    Join Date: Oct 2012

    Location: The Black Country

    Posts: 6,089
    I'm Alan.

    Default

    No surprise to me.

    Looks like you'll be needing a transformer then.

  4. #14
    Join Date: Apr 2017

    Location: Manningtree, Essex

    Posts: 1,722
    I'm Tony.

    Default

    Quote Originally Posted by Firebottle View Post
    No surprise to me.

    Looks like you'll be needing a transformer then.
    Looks like the safest bet Alan. Grant suggested 24VA?


    Sent from my iPhone using Tapatalk
    A mainly digital setup with a musical amplifier and endearing 1970's speakers. A CD player that hardly ever gets used and a turntable that is good enough to remind my how enjoyable my old vinyl is. Some cables and things.

  5. #15
    Join Date: Apr 2017

    Location: Manningtree, Essex

    Posts: 1,722
    I'm Tony.

    Default

    Measured it again this morning from the surge suppressor that the headphone amp is plugged into and the reading was a constant 242V.
    A mainly digital setup with a musical amplifier and endearing 1970's speakers. A CD player that hardly ever gets used and a turntable that is good enough to remind my how enjoyable my old vinyl is. Some cables and things.

  6. #16
    RothwellAudio Guest

    Default

    That's about 11% over the specified voltage for the amp, but personally I still wouldn't want an external transformer if I could avoid it. I would measure the voltage across the capacitors in the amp to check they're ok first. Anything to avoid extra boxes - and expense

  7. #17
    Join Date: Oct 2012

    Location: The Black Country

    Posts: 6,089
    I'm Alan.

    Default

    Sounds like the OP isn't confident about mooching around inside the amp, but I agree that doing measurements to confirm the overvoltage (or not) is the best course of action.
    If the valve heaters are running at +11% then that's going to be around 7V, not something i'd like to do for any extended time.

    I modified a Chinese preamp that was rated for 220V, when I measured the valve heater voltage is was well over 7V with UK mains, so I fitted a bucking transformer internally.

    Having just looked at internal shots of the Little Dot there isn't any room to fit an extra transformer internally.

    I've just read that someone fitted extra low value resistors to combat the excess heater voltage as shown on this photo:

    Last edited by Firebottle; 05-07-2017 at 09:15. Reason: Internal comment

  8. #18
    RothwellAudio Guest

    Default

    Quote Originally Posted by Firebottle View Post
    I've just read that someone fitted extra low value resistors to combat the excess heater voltage as shown on this photo
    Yes, I was going to mention the possibility of dropping the voltage with resistors but didn't want to get too technical for the OP.

  9. #19
    Join Date: Feb 2013

    Location: W Lothian

    Posts: 99,005
    I'm Grant.

    Default

    if those get hot they are going to damage the board. think a 230v regen would be best overall. a bit pricier but will help everything and its not going to encroach on any design.. only a 5% increase in voltage should be fine
    Regards,
    Grant .... ؠ ......Don't be such a big girl's blouse

    I've said it before and I'll say it again: democracy simply-doesn't-work
    .... ..... ...... ...... ................... ..... ..... ..... ..... .....
    FIIO K7 BT, M11 PLUS, BTR7, KA5 - OPPO BDP-103D - PANASONIC UB450 - PANASONIC 4K ULTRA HD TV - PIXEL 6 - AVANTREE LR BLUETOOTH - 2* X600 SOUNDCORE - HEADPHONES INCLUDE, FIIO, NURAPHONES', FOCAL, OPPO, BOSE, CAMBRIDGE, BOWER & WILKINS, DEVIALET, MARSHALL, SONY, MITCHELL & JOHNSTON - 2*ZBOOK'S- MERCURY BD ROM, ROON, QOBUZ, TIDAL, PLEX, CYBERLINK, JRIVER - MULTI HDD'S -

    Oh my god! There's nothing wrong with the bidet is there?

    “Nothing discloses real character like the use of power. It is easy for the weak to be gentle. Most people can bear adversity. But if you wish to know what a man really is, give him power. This is the supreme test. It is the glory of Lincoln that, having almost absolute power, he never abused it, except on the side of mercy".

    “You see these dictators on their pedestals, surrounded by the bayonets of their soldiers and the truncheons of their police ... yet in their hearts there is unspoken fear. They are afraid of words and thoughts: words spoken abroad, thoughts stirring at home -- all the more powerful because forbidden -- terrify them. A little mouse of thought appears in the room, and even the mightiest potentates are thrown into panic.”

    "You don't have free will. You have the appearance of free will.”

    “There's a war out there, old friend. A world war. And it's not about who's got the most bullets. It's about who controls the information. What we see and hear, how we work, what we think... it's all about the information!”


    ***SMILE, BE HAPPY***

  10. #20
    Join Date: Apr 2017

    Location: Manningtree, Essex

    Posts: 1,722
    I'm Tony.

    Default

    Thanks all for your input on this, there's no substitute for the experience of people who have dealt with stuff every day!

    I'm generally ok with condensing what I need out of a ton of technical information but my background is software and I have little exposure to electronics other than swapping components and rebuilding computers.

    I'm inclined to go with Grant's suggestion of a 230v regen on the basis that it will cover everything, including any future purchases. Any preferred suppliers or devices I should be considering?

    I was looking at this site a little earlier https://airlinktransformers.com/cate...d-power-supply
    A mainly digital setup with a musical amplifier and endearing 1970's speakers. A CD player that hardly ever gets used and a turntable that is good enough to remind my how enjoyable my old vinyl is. Some cables and things.

+ Reply to Thread
Page 2 of 3 FirstFirst 123 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •