3-500z pay the price, take your chance ?

Discussion in 'Amateur Radio Amplifiers' started by W8ZNX, Sep 29, 2015.

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  1. W8ZNX

    W8ZNX Ham Member QRZ Page


    last spring got Hunter Bandit, last few weeks the power has been dropping off
    60 watts drive 2oo watts out 100 watts drive 200 watts out
    so guess its time for a new pair of 3-500z

    my question
    all the different types / brands (excp. for old stock) are Chinese
    so what is the difference
    are they all coming from the same factory in China

    RF parts prices 3-500ZGprc is 169 bucks, 3-500ZGtay is 184, RF parts brand 3-500ZGrfp $199

    then there is the Machlett brand being sold on Ebay

    and the Amertron 5-500 from DX Eng for $219

    what is your guess as to reason for price difference
    name on bottle and length of warranty?

    mean time thank goodness the stalwart NCL-2000 is still perking away

    still in the stacks
  2. PA5COR

    PA5COR Ham Member QRZ Page

    3 years back I replaced th tube in the Heathkit SB-1000 with a RF Parts 3-500ZG own brand, never looked back working perfct, even sending it to Europe in double packed boxes insured and all.
    Had even a bit more gain as the old (30 year) tube that it replaced.
  3. KK4RSV

    KK4RSV Ham Member QRZ Page

  4. W8ZNX

    W8ZNX Ham Member QRZ Page

    thanks for the tip
    will keep RKR in mind
    yours truly

    just checked 3-500Z from RKR is back order
    same for 811A and 3CX800A7
    Last edited: Sep 29, 2015
    KK4RSV likes this.
  5. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    You might call Merit Arnold at RFP to see what he says, but it "seems" the difference between the three Chinese tubes they sell is the warranty period: Cheapest is 1 year, next is 2 years, most expensive is 3 years.

    It's possible they're all the same tube but the longer warranty ones are tested differently -- I really have no idea. Merit should know.
  6. KE7KPB

    KE7KPB Premium Subscriber QRZ Page

    572Bs, where is a good place to buy a pair?
  7. KC9UDX

    KC9UDX Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    Last time I checked, I could get a pair of 8163s at a reasonable price. Unfortunately I can't check right now.

    Have you tried that route?

    By the way, I hope you have, or plan to, do something about the fan. It's severely underpowered.
    Last edited: Sep 30, 2015
  8. VE7GPG

    VE7GPG Ham Member QRZ Page

    I just got 2 572B from RF Parts - send them an email and ask to be put on the list
  9. W8ZNX

    W8ZNX Ham Member QRZ Page


    last checked only 8163 /3-400 i could find were going for $279 each
    yes the fan is under powered it has been replaced, but may go still go bigger
    thinking about getting some air to the tube pins/socket connections
    remember Bill Orr writing about getting air to 3-500 pins

    its a nice amp, but boy it sure is bare bones
    interlocks! who needs interlocks
    first mod was larger fan, second mod was switch to open antenna change over relay circuit

    next will be a HV relay so high voltage does not simply go on when turned on
    also looking to change out the caps, diodes, ect

    yours truly
    still in the stacks
  10. KC9UDX

    KC9UDX Platinum Subscriber Platinum Subscriber Life Member QRZ Page


    I did a little searching this morning and could not even find a price that good! So, the 3-500 is probably the way to go at this point.


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