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Normal operating color for a Type 80 rectifier tube?

Discussion in '"Boat Anchor" & Classic Equipment' started by N8YX, Sep 22, 2020.

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  1. KA9JLM

    KA9JLM Ham Member QRZ Page

    They operate with AC on them. They should be non-polarized, Or connect 2 polarized in series (+--+) to make them non-polarized.
  2. KP4SX

    KP4SX Premium Subscriber QRZ Page

    No. Its a common power supply configuration. Just observe polarity!
    There's DC coming off the filament of the tube which is in practice the cathode. Plenty of AC ripple just as if it were a silicon diode.
    N2EY likes this.
  3. KA9JLM

    KA9JLM Ham Member QRZ Page

    Exactly, That is why they use non-polarized caps in the original design.

    Will it work with polarized, Yes. How good for how long, Unknown.
  4. KP4SX

    KP4SX Premium Subscriber QRZ Page

    90% of these radios used polarized caps. The only ones I have seen using NPs were in the late 20's/very early 30s before electrolytics took hold. And most of them were 2 or 4 mfd.
    Its a common everyday half-wave rectifier!
  5. K1APJ

    K1APJ XML Subscriber QRZ Page


    1. It is NOT a voltage doubler.
    2. It does NOT need NP caps.
    3. It is NOT a half wave rectifier

    It is a full-wave rectifier with the choke in the negative side. Bias for the output stage is tapped off ahead of the choke (that point, being closer to the transformer center tap, is more negative than ground, which is connected downstream of the choke.)
    Last edited: Sep 24, 2020
    KP4SX, N2EY, WA1GXC and 1 other person like this.
  6. WR2E

    WR2E Ham Member QRZ Page

    Wouldn't that be more rightly called "pulsating DC" ? It's not changing polarity, right?
  7. WR2E

    WR2E Ham Member QRZ Page

    I didn't think so either.

    I'm a bit confused about the placement of the cap between the +HV and the CT though.
  8. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    Comment: It boggles my mind that anyone would put power on a 90 year old radio without checking every single component first.
    "Live Dangerously!" ;)

    For those of us not familiar with the DeWald 610LW consumer radio:
    -6 Tubes
    -Longwave, BCB, Shortwave

    KA9JLM likes this.
  9. K1APJ

    K1APJ XML Subscriber QRZ Page

    N9LCD likes this.
  10. KD2ACO

    KD2ACO Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    Yup squared.

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