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600 watt HF Linear Amplifier Project

Discussion in 'Homebrew and Kit Projects' started by KD8UYQ, Feb 9, 2017.

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  1. AF6LJ

    AF6LJ Premium Subscriber QRZ Page

    Hi Ripley;
    If you are talking about caps like this... http://www.mouser.com/ds/2/88/MMR series-553002.pdf
    I don't think they are appropriate for the application. Your ceramic disc caps would be better.
    Need to work on the reason why they are failing.
     
  2. KD8UYQ

    KD8UYQ Ham Member QRZ Page

    Hi Sue,

    They are similar to these type of capacitors http://www.mouser.com/ProductDetail...68R4iCgJhg==&gclid=CJ-Jz5263dICFQ-1wAodms4LQg

    Except .1uf 400 volt versions. The only reason those caps fail is when one of my experiments go south and high RF voltages that should be going out the PA board are instead shunted to ground via those unfortunate capacitors.

    Ed, sorry. I didn't answer your question. Yes sir they are 10 ohm resistors in the feedback circuit.

    Ripley
     
    AF6LJ likes this.
  3. AF6LJ

    AF6LJ Premium Subscriber QRZ Page

    I still wouldn't use those, they have a lot of parasitic inductance.
    Your results could be worse.
     
  4. KD8UYQ

    KD8UYQ Ham Member QRZ Page

    Sage advise. I will look into those ATC capacitors that you suggested in an earlier post.

    Ripley
     
    AF6LJ likes this.
  5. AF6LJ

    AF6LJ Premium Subscriber QRZ Page

    Cool..
    They are not cheap but they are very low in parasitic inductance and handle reasonably high RF currents.
     
  6. KG7SWP

    KG7SWP Ham Member QRZ Page

    ATC 1KVs are a different animal than a 1KV disk cap !!!

    Ed
     
  7. KD8UYQ

    KD8UYQ Ham Member QRZ Page

    Hi folks,

    My bride and I were out of town this weekend baby sitting the grand kids while mom (out daughter) was out of town. We helped dad take care of the four boys; 10, 6, and the 2 year old twins.

    While we at their house my long time friend and artisan furniture maker came down from Pittsburgh with the walnut side panels that he glued up for the amplifier cabinet http://www.stevens-woodworks.com/

    PICT0557.JPG

    I had to take a quick peek to see what they would look like up against the side of the cabinet. Carl cut the panels over size for me so that I can trim them down to fit the cabinet exactly.

    PICT0558.JPG

    I like this look a lot.

    After we unpacked I spent the rest of the day and this evening starting to plan out were to mount things.

    PICT0559.JPG

    The LCD display is mounted as is the aluminum sub-chassis that the band selector switch, and band LEDs will be mounted on.

    PICT0561.JPG

    The power supply just slides in from the back and is held in place by two screws that will be hidden by a walnut side panel.

    PICT0560.JPG
    So far so good.

    Ripley
     
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  8. WA7PRC

    WA7PRC Premium Subscriber QRZ Page

    At the world's largest OEM of RF-driven sealed CO2 Lasers, we use A LOT of capacitors from ATC (http://www.atceramics.com/). For bypassing, the ceramics are good choices. When you need temperature-stable, consider porcelain dielectric. The letter suffix refers to the physical size (and voltage & current/ESR rating).
    I like your packaging. :)
     
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  9. AF6LJ

    AF6LJ Premium Subscriber QRZ Page

    I agree his packaging is wonderful.
    Looks great.
     
  10. KD8UYQ

    KD8UYQ Ham Member QRZ Page

    Thank you both for the kind compliments.

    Ripley
     
    AF6LJ likes this.

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