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Thread: 6B4G Monoblocks with Hashimoto Transformers

  1. #1
    Join Date: Oct 2016

    Location: London

    Posts: 313
    I'm David.

    Default 2A3 / 6B4G Monoblocks with Hashimoto Transformers

    These amps started in life as some Audio Innovations The First Monos. They were produced by the factory built in AI 800 stereo chassis. Someone got hold of them and added a choke input GZ37 rectified power supply and converted the phase splitter from ECC82 to 5687 operation. The trouble was they got in a frightful pickle in implementing an earth lift system, as well as the heater supply. Worst of all, the chassis was not earthed at all, potentially exposing the user to dangerous voltages. The amp hummed like hell, but did show good promise for sound quality.

    The amps have now been totally rebuilt with Hashimoto tranformers and chokes. Heating is all DC regulated. The amps now sound amazing, and run completely silently even on my 96DB speakers. Just as well really as the owner will be using them to drive his £4k headphones!

    [IMG][/IMG]

    [IMG][/IMG]

    They also measure incredibly well with those Hashimoto transformers as these photos of 1 and 10khz square waves show
    [IMG][/IMG]
    [IMG][/IMG]
    Last edited by AD Audio; 08-10-2020 at 12:40. Reason: title better

  2. #2
    Join Date: Jan 2008

    Location: Norfolk, UK

    Posts: 6,209
    I'm BigBobJoylove.

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    Very nice indeed David! They look lovely, I'm sure they sound it too.

    Having had no experience with valve amps, what's the reason for having an earth lift system?

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  3. #3
    Join Date: Mar 2008

    Location: Galashiels

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    I'm inthescottishmafia.

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    Be these are lovely. Always liked a decent 2a3.
    “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

  4. #4
    Join Date: Jan 2013

    Location: Bristol

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    I'm Justin.

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    Huh? I thought 6B4G was an octal 6A3.

  5. #5
    Join Date: Mar 2008

    Location: Galashiels

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    I'm inthescottishmafia.

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    Yep. Still the same as a 2a3 though, aside from filament voltage.
    “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

  6. #6
    Join Date: Mar 2016

    Location: Barnet, london UK

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    I'm Adam.

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    Great work again David
    "lack of passion is fatal"


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  7. #7
    Join Date: Jan 2013

    Location: Bristol

    Posts: 6,843
    I'm Justin.

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    Quote Originally Posted by Ali Tait View Post
    Yep. Still the same as a 2a3 though, aside from filament voltage.
    I ordered a Russian equivalent to 6B4G with an octal to UX4 adapter last week just because they are mega cheap. Will put them in the Lampizator to see what they are like. Not expecting much but you never know.

  8. #8
    Join Date: Oct 2016

    Location: London

    Posts: 313
    I'm David.

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    Quote Originally Posted by Filterlab View Post
    Very nice indeed David! They look lovely, I'm sure they sound it too.

    Having had no experience with valve amps, what's the reason for having an earth lift system?
    The earth lift system stops any earth loops happening when you connect ancillary equipment. Works incredibly well and can reduce the noise floor too

  9. #9
    Join Date: Oct 2016

    Location: London

    Posts: 313
    I'm David.

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    Quote Originally Posted by User211 View Post
    I ordered a Russian equivalent to 6B4G with an octal to UX4 adapter last week just because they are mega cheap. Will put them in the Lampizator to see what they are like. Not expecting much but you never know.
    Let us know how those valves are. I will be building another pair of these in due course

  10. #10
    Join Date: Mar 2008

    Location: Galashiels

    Posts: 13,669
    I'm inthescottishmafia.

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    Quote Originally Posted by User211 View Post
    I ordered a Russian equivalent to 6B4G with an octal to UX4 adapter last week just because they are mega cheap. Will put them in the Lampizator to see what they are like. Not expecting much but you never know.
    Nice, let us know what they are like. 6C4C is it?
    “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

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