What is the name of this component?

Discussion in 'Shock Brother's DIY Amps' started by itsGiusto, Oct 23, 2019.

  1. itsGiusto

    itsGiusto Tele-Meister

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    Ceriatone amps have bias-probe sockets that you can plug the needle-like DMM probe-style into.
    See the red jacks in this picture:

    [​IMG]

    I'd like to buy some more of these sockets so I can add a way to measure plate voltage of the power tubes. But what are these components called? I can't seem to find them, cause I don't know their name.
     
  2. Edvin

    Edvin TDPRI Member

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    Banana connector?
     
  3. Mouth

    Mouth Tele-Holic

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    Delete
     
  4. gusfinley

    gusfinley Tele-Holic

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  5. gusfinley

    gusfinley Tele-Holic

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    I like to install these across one ohm resistors in my plate circuit - this gives a conversion of 1mV = 1mA of plate current.

    If you also install a potentiometer on the chassis then you can set your bias without having to remove the amp from the head cabinet - just remove the backpanel.
     
    Last edited: Oct 23, 2019
    magic smoke likes this.
  6. Teleguy61

    Teleguy61 Friend of Leo's

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  7. Bill Moore

    Bill Moore Tele-Afflicted

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    I used them for my DR build, but you still need to measure the voltage to figure the bias! (I have a ring terminal on a short wire.)
    DR-33.JPG
     
  8. magic smoke

    magic smoke Tele-Meister

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  9. itsGiusto

    itsGiusto Tele-Meister

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    Yeah, that's what I'm after. Ceriatone amps have the bias pot on the top side of the chassis. They recommend just plugging in 410v as the plate voltage, but of course, that won't be truly accurate, unless you actually measure the voltage.

    Though now that I think about it, it could be highly highly dangerous to expose the plate voltages to the outside of the amp. What if I'm carrying it after unplugging it, the filter caps haven't discharged, and my fingers slip. I could get a terrible shock. I might have to scrap this idea.
     
  10. gusfinley

    gusfinley Tele-Holic

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    Fear not!

    Unless you have fingers with 2mm diameter protrusions of appreciable length, you shouldn't be able to accidentally touch the recessed conductors in the tip jacks.

    If you do have little ones that like to insert objects in random places that might be a concern.

    I also like to add bleeder resistors across my filter caps to drain the caps when the amp is off.
     
  11. Wyatt

    Wyatt Tele-Afflicted

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    That's why they don't so it. It's just the bias current being measured at the tip jacks. Generally, I measure the plate voltage once, mark it, and that's good enough to ballpark for any future installs. If I have to go back into the chassis, I'll check the measurement (plate voltage does change as you bias). But the difference in dissipation for +/– 25VDC (which is relatively massive) is probably ≥ 3%, so I consider the difference in +/– 10VDC inconsequential.
     
    Last edited: Oct 23, 2019
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