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Thread: Maddog's Lamington Jr Amplifier build diary

  1. #61
    Mentor Marcel's Avatar
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    Quote Originally Posted by dave.king1 View Post
    Talking of the megger and other wonders of electrickery I remembered this bit of wisdom from first year in college

    Ten Commandments of Electrical Safety
    (1) Beware of the lightning that lurks in an undischarged capacitor lest it cause thee to be bounced upon thy backside in a most ungainly manner.

    (2) Cause thou the switch that supplies large quantities of juice to be opened and thusly tagged, so thy days may be long on this earthly vale of tears.

    (3) Prove to thyself that all circuits that radiateth and upon which thou worketh are grounded lest they lift thee to high-frequency potential and cause thee to radiate also.

    (4) Take care thou useth the proper method when thou taketh the measure of high-voltage circuits so that thou doth not incinerate both thee and the meter, for verily though thou hast no account number and can be easily replaced, the meter doth have one and as a consequence bringeth much woe upon the supply department.

    (5)Tarry thee not amongst those who engage in intentional shocks for they are surely non-believers and are not long for this world.

    (6) Take care thou tampereth not with interlocks and safety devices, for this incureth the wrath of thy seniors and bringeth the fury of the safety officer down upon thy head and shoulders.

    (7) Work thee not on energized equipment, for if thou doeth, thy mates will surely be buying lunch without thee and thy space at the table will be filled by another.

    (8) Verily, verily I say unto thee, never service high-voltage equipment alone, for electric cooking is a slothful process, and thou might sizzle in thy own fat for hours on end before thy Maker sees fit to end thy misery and drag thee into His fold.

    (9) Trifle thee not with radioactive tubes and substances lest thou commence to glow in the dark like a lightning bug.

    (10) Commit thee to memory the works of the prophets, which are written in the instruction books, which giveth the straight info and which consoleth thee, and thou cannot make mistakes.
    And yet we so often see those with young and mindless abandon test and fail at each of the above commandments..... the old have adhered without fail...

  2. #62
    GAStronomist DrNomis_44's Avatar
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    In an ideal world, the resistance of insulation material would measure infinite, but as we all know in the real-world 1+1 rarely ever equals 2, most materials used for insulation measure up to a few giga-ohms, that's 1000,000,000 ohms, or a thousand-million ohms, in addition to that, most insulation materials have what's called the Dielectric-Strength, this is a measure of how much voltage the material can withstand before the voltage gets too great and causes a puncture in the material that allows the voltage to leak through it.

    Marcel may be able to elaborate on that.

  3. #63
    Mentor Marcel's Avatar
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    Nah, I think you pretty much covered it Doc... If anyone is curious I'm sure they know how to use Google...

  4. #64
    Quote Originally Posted by Marcel View Post
    Back in high school we had a few wind up Megger's of different sizes....a very basic instrument that had a crank handle to make it work which often got used by the nasty kids to zap unsuspecting victims....
    In the first two years of my apprenticeship everyone used to use a megger to charge capacitors and throw at each other to catch. The the great fun nazis from safety and HR put a very quick stop to it. Used to hurt like buggery but was funny as

  5. #65
    Member Andy123's Avatar
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    Just wondering if these amps are in any way customisable?
    The website mentions it has 2 controls but doesn't say what they are - I'm guessing volume and tone?
    How hard would it be to put something like this together with separate treble/middle/bass knobs?

  6. #66
    GAStronomist Simon Barden's Avatar
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    You'd need a new design to work to, as you'l invariably need another preamp valve to go with the tone stack, so the power supplies need to be a bit beefier.

  7. #67
    Overlord of Music dave.king1's Avatar
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    The 15W Lamington has the extra controls you are looking for at a not massively extra cost, but you will be starting with mains voltages not a power pack.

    https://www.valveheaven.com/diy-amp-kits/diy-amp-kit/

    Marcel or Doc may have a more suitable circuit for your needs

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