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Dentron Clipperton L

Discussion in 'Amateur Radio Amplifiers' started by KN4VCT, Aug 14, 2019.

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  1. KE0ZU

    KE0ZU Ham Member QRZ Page

    NOT TO WORRY, I have the original placard carefully wrapped, and safely tucked away in a velvet lined case.:D
  2. N2ZD

    N2ZD Ham Member QRZ Page

    Wow! Everyone’s all over the place. Stop telling the new guy to stick his hands in the amp. BE VERY CAREFUL, that thing will make you dead real fast!!
    Anyway, I had that amp. You won’t see full power for a few reasons, none of which are very important as full power isn’t necessary.

    Firstly if it’s not on 220 most 110 lines will sag and give you less power.
    Secondly an Icom 7100 will fold back on a slight hint of a high swr and drive that amp with less than max input.
    Thirdly, a 7100 rarely makes 100 watts ever, most make 80-90
    Max. I said most..

    All of this will cut into your bottom line.

    If you look carefully, the original Dentron “blockbusters” have been replaced with later caps so someone went thru the amp already. It looks like from the pics that the diodes have been replaced with more robust ones.
    Anyway, the tuned input is hogwash. Get a tuner and make the radio see 1:1 or so into the amp and don’t bother with boards or other nonsense to tune the input. Wasted time for little or no additional s unit gain.
    I have a TL-922A (without 10m) activated and two sb-220’s and many more amps and all of them make substantially less power on 10m, it doesn’t matter because 10m at a stock 100 watts you’ll kick ass when the band is cooperative so don’t sweat it as it’s the nature of the beast.

    Anyway, if you get it to make 400 watts or more on 10m, it’s working fine. A typical dentron with 4x 572b’s will make 1000 or more on 20m with the plate meter pegged to the right of its working right. Providing all of the input needs are met.

    Tune it for max output, lowest swr into and out of the amp. Keep your flackking hands out of it until you respect it and your life and then drop the input power to the amp until you see 600 watts out of it and watch it last you a lifetime.

    Regards Richy N2ZD
  3. K4RT

    K4RT Ham Member QRZ Page


    I think you got yourself a nice amp. If you operate the amplifier per the instructions in the manual I would expect it to provide years of reliable service.

    I had a Clipperton L for about 25 years and it was a very reliable amplifier. I was the second owner and I put many hours on it chasing DX, contesting, and rag-chewing on CW, SSB, and RTTY. I never had any problems with the 572 tubes, which I believe were the original tubes. Mine was wired for 110 VAC. As I recall I never ran the plate current above 600 mA, which may be specified in the manual. I did replace the cooling fan with one that ran quieter and the amp required minor maintenance now and then.

    N2ZD makes a good point about safety around high voltage. If you need to lift the top cover, learn how to ensure that the HV capacitors are discharged and always make that's your first step.

    Keep us posted.

    Brad K4RT
  4. KN4VCT

    KN4VCT Ham Member QRZ Page

    Thanks everyone for all the advice! One question though, the power cord on this amp is shot, how deep do I have to dig to replace it?
  5. KN4VCT

    KN4VCT Ham Member QRZ Page

    Also I just ran a 220 circuit to the radio room today
    W1TRY likes this.
  6. K4RT

    K4RT Ham Member QRZ Page

    You should be able to find what you need at a local hardware store or larger store like Lowe's or Home Depot. Make sure you buy a cord with proper current rating for your amp, preferably somewhat higher than what the amp draws to ensure a safe margin. For 110V I have bought 3-wire line cords that have a factory plug at one end and tinned wires at the other. For 220V you may or may not have to install the plug yourself. It's been a while but I believe the Clipperton manual includes the specs and wiring instructions for 110 and 220 you should follow.
  7. KN4VCT

    KN4VCT Ham Member QRZ Page

    Ok I actually have a pre made 220v cord, made for dryer's etc. This cord is made for a 30 amp plug. But I was just wondering if I need to unsolder a bunch of stuff to get to the connection? Here is the cord by the way, it's like that all the way through too.

    Attached Files:

  8. W1QJ

    W1QJ Ham Member QRZ Page

    A dryer cord is made with #10 wire, way to big. Original is #16 SJ cord, use the right stuff, even #14 is ok. But #10 is over kill and harder to work with.
    W2VW, WA4SIX and W1TRY like this.
  9. WA4SIX

    WA4SIX Ham Member QRZ Page

    Changing voltage cord & taps should be right in the manual.
    I have read several threads this morning. You do have the manual, right?
    I have never had one, but the connections might be in a separate chamber in the back or bottom of the rig.

  10. K4RT

    K4RT Ham Member QRZ Page

    Agree with QJ and QQ.

    The cord in your photo should definitely be replaced before using the amp. Does that cord connect a terminal block to the transformer primary winding?

    QQ makes a good point about voltages. You can't be too careful. I'll assume that you know how to ensure that the HV capacitors are discharged before working inside the cabinet. But if not, ask.

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