Amp cooling questions

Discussion in 'Amateur Radio Amplifiers' started by N4EYZ, Jan 18, 2016.

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  1. KA9JLM

    KA9JLM Ham Member QRZ Page

    That would be the easiest.

    You could use one of these to set the fan speed that you want.

    Good Luck.
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Beautifully built. Tank components more robust than an SB-200. Don't know how gutsy the power supply is, but if it's gutsy enough this should easily do 700W PEP output.
  3. KA9JLM

    KA9JLM Ham Member QRZ Page

    It is nice.

    It should be enclosed. I seen no safety to keep you from killing yourself.

    The Deck is overkill for 2X572Bs. I would guess he was a AM operator.

    Pictures of the Power supply would be nice.

    It is a keeper for sure. You can draw a schematic if needed. :)
  4. KM1H

    KM1H Ham Member QRZ Page

    The someones name is Carl and I prefer that to someone and the resistor info is in Post #5.

    Nice looking amp.

    That fan is overkill for SSB/CW and may already be slowed down. The 572B at 2500V only needs a little air movement to keep the seal temperatures in spec and the tiny phonograph motor and blade in the Heath SB-200 did it quite well and couldnt even be heard.

    aka Someone
    KA9JLM likes this.
  5. W8JX

    W8JX Ham Member QRZ Page

    The SB200 was also able to take advantage of convection cooling as tubes were horizontal with fan below them AND heat rises which increases fans airflow. With a vertical mounting and horizontal cooling you need more air flow.
  6. N4EYZ

    N4EYZ Ham Member QRZ Page

    Thanks for the positive comments! I wish I had the skill and knowledge this fella possessed as he was pretty well known for his abilities. I do have an equipment rack and at some point I plan to install it there. I think WB2WIK was a bit concerned about the knob placement especially the possibility of inadvertently changing the band switch while tuning up. I can see his point but this band switch (knob) takes a fair bit of effort so at least in this case I doubt I'll be changing bands by accident
  7. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Good, just be careful.

    Turning (or even trying to turn) a bandswitch while transmitting is what destroys bandswitches more than anything else...and those can be very pricey nowadays.
  8. KM1H

    KM1H Ham Member QRZ Page

    Nope again, all you need in either position is some small air flow at 600-700W out. The Heath HA-10 used a small fan for 4 vertical 811A's running the same power.

    Tubes such as the 813, 4-125A, required just a small fan with tubes vertical at the same power levels and with a lower plate dissipation. I ran a 4 x 813 amp for decades at 1500W with a reduced speed muffin fan.

    The amp in question has unimpeded airflow making it a KISS for cooling.
  9. W8JX

    W8JX Ham Member QRZ Page

    I guess you failed physics. Forced air cooling from below is more efficient because heated air rises increasing airflow vs on a horizontal plane where there is no natural current. I have a old JD tractor that uses Thermo Siphon cooling. It has no water pump and as water in block is heated it like air rises and flows into radiator top tank and as it cools is stinks and creates a flow through block. Works for water and air.
  10. KM1H

    KM1H Ham Member QRZ Page

    I guess you failed reading comprehension while I aced physics at several levels.
    K8PG and K5PHW like this.

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