Best 3-500z Anode Cooler

Discussion in 'Amateur Radio Amplifiers' started by N8FVJ, Dec 28, 2019.

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  1. N8FVJ

    N8FVJ Ham Member QRZ Page

    I seen many variations in 3-500z anode coolers. Some are small diameter stacked disc and others larger disc. Some have as little as two discs and others many more. And one is a large cast aluminum cooler with fins. Which provides best cooling? Also, I read the Eimac 3-500z requires less anode cooling vs the graphite plate 3-500zg.
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I don't know that one requires more or less than the other, but the anode pin heat sink is to keep the glass/metal (kovar) seal cool. It can't actually cool the anode itself.

    I use the ones with a few "disc"-like protrusions and they seem to work fine with the slightest trickle of air going past them; these are standard Eimac heat dissipating anode caps that have been on the market for at least 60 years, probably longer.
    W1BR likes this.
  3. VA3DXV

    VA3DXV Ham Member QRZ Page

    whatever has the most surface area arranged in a way that allows the best conductive cooling

    I kinda like these

  4. N2EY

    N2EY Premium Subscriber QRZ Page

    I would prefer the one on the left.
  5. VA3DXV

    VA3DXV Ham Member QRZ Page

    The one the video was about... yes!
    N2EY likes this.
  6. WG7X

    WG7X Platinum Subscriber Platinum Subscriber QRZ Page

    Is anyone concerned about the watt meter sitting up there above the un-shielded anodes?

    Or is it just me?
    K4AGO, N8VIL and K7TRF like this.
  7. K7TRF

    K7TRF Premium Subscriber QRZ Page

    Yup, that jumped right out at me as well. The watt meter itself propped up there might be fine but it implies you might reach in there to touch a button on the meter or otherwise get too close to the B+ .... ouch!
  8. N2CG

    N2CG Premium Subscriber QRZ Page

    These high efficiency 3-500Z plate caps were made by a machine shop located near Maion, Ohio operated by two brothers Bob NT8W and Fred N8BX if my memory serves me correctly. They also made other ham radio related accessory products and all their products were high quality.

    I don't know if that YouTube video is still valid because their Website "" is no longer acessable.

    I wish all a Healthy, Prosperous, and Happy New Year!

    73, George N2CG
    N2EY likes this.
  9. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Overdoing the anode pin coolers won't make the anodes any cooler.

    The anodes have to get hot to work, and cool by radiation, not conduction (in 3-500Z types). The "cooler" is there for the pin seal only, and the old Eimac heat dissipating anode caps work fine and were always recommended in all the Eimac app notes.
    KK4RSV likes this.
  10. K1REX

    K1REX Ham Member QRZ Page

    I have the N8BX plate caps and need to remove them to swap out the 3-550Zs. Does anyone happen to know the hex-wrench size for removing the plate caps? I've tried all the hex's I have on the shack, and find they are either just too small in size, or just too large. Any info/help wold be greatly appreciated. Tnx!! Stephen, K1REX

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