1. You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
    Dismiss Notice
Dismiss Notice
This forum does not allow a single user to have more than one username. If anyone wants to change their username contact an admin and it will be done. Multiple accounts belonging to the same member will be deleted without warning.

Looking for amplifier options for SSB (10-12)m

Discussion in 'Amplifiers' started by Chris120, Jan 13, 2021.

  1. AudioShockwav

    AudioShockwav Extraterrestrial Admin
    Staff Member

    Apr 6, 2005
    Likes Received:
    The 811 was built to be the cheapest HF amp as the number one priority.
    And that's from the man that designed it.
    As for AM mode with the 811
    May this image be forever burned into your memory.



    Attached Files:

    Shadetree Mechanic likes this.

  2. Dr_DX

    Dr_DX Well-Known Member

    Jan 29, 2006
    Likes Received:
    FYI - For what its worth, Amprepairguy (KB1SEL), won't even work on a 811 amp unless the owner is willing to convert it to a 572b. The Chinese 811's have such a poor vacuum, it's not worth the money or effort to repair them.

    He is pretty well respected by a lot of folks when it comes to tube amps.
  3. Mr Fix it

    Mr Fix it Well-Known Member

    Dec 7, 2012
    Likes Received:
    Has to do with the way the Chinese construct them . They are so poorly made that plate to filament arcs are not uncommon .

    I have repaired hundreds of al-811 and al-811h amplifiers produced by Ameritron.

    9.9 times out of 10 the cause for need of repair is due to a 811 tube flashing.

    Once the customer switches over to 572b tubes, no more issues. Even though they are also of China origin

    The emission life of a China 811 or China 572b is far less than a old rca 811 or cetron 572b. But it is what it is.

    I re hi pot all new tubes when I purchase them, I used to see countless plate to grid short failures right out of the box on new 811 tubes.

    Even with a pre tested, good set in hand installed and working in a amplifier, issues would occur during shipping to a customers qth. After they re installed and tried to fire amp up.

    This is with amp packed in one box , tubes in another box both shipped separate via FedEx.
    #33 Mr Fix it, May 26, 2021
    Last edited: May 26, 2021
  4. Chris120

    Chris120 Member

    Oct 14, 2018
    Likes Received:
    I ended up going with an Icom 7300 and an Ameritron AL-80B. I'm happy!
  5. Shockwave

    Shockwave Sr. Member

    Sep 19, 2009
    Likes Received:
    If you run AM, run away from today's 811A's. It's not just that they melt when trying to produce the highly inefficient carrier, the melting causes them to short out. This almost always causes amplifier damage and in some cases can back up into the receiver, severely damaging it.

    They haven't made a real 811A tube in 40 years. Just pull up a Google image of an old RCA 811A tube and right away you'll notice all manufacturers have deleted 12 horizontal radiator fins, in favor of two vertical ones.

    The original 12 fins not only provided much better mechanical stability, they also removed heat from the critical center area of the anodes. For reliable AM or FM operation, 811A tubes must be switched out with 572B's.

    The only reason the six pieces of metal were removed, that were bent to make the 12 fins, is because that required two extra steps. The fins had to be made on another machine and then spot welded to the anode. They eliminated those two steps in order to sell you a supremely junkie tube.

    On the other hand, the anode inside the 572B tube is approximately five times thicker and made of graphite material which will not melt. Having the same pin out and inter electrode capacitance, makes it a direct drop-in replacement for the 811A.
  6. Tokin

    Tokin The Man With No Shoes

    Oct 31, 2019
    Likes Received:
    S&W357 likes this.

    SIX-SHOOTER Sr. Member

    Oct 2, 2010
    Likes Received:
    Anyone that can Read the Specs can figure it out & my last statement said TWO Ameritron amplifiers work on 6 meters.They are BOTH Solid State amplifiers so No Tube amplifiers manufactured by Ameritron work on 6 Meters.Is that clear enough that you can understand it? {:>)

    Ranch55, 9C1Driver and Tokin like this.

Share This Page

  • About Us

    The WorldwideDX Radio Forum was originally established in 2001. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. We are working every day to make sure our community is the best Radio Hobbyist's site.
  • Like us on Facebook

  • Premium VIP Member

    The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. Care to buy us a beer? We'd really appreciate it!

    Donate to us!