Taylor 572B

Discussion in 'Ham Radio Discussions' started by AG4RT, Jan 7, 2021.

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  1. AG4RT

    AG4RT Platinum Subscriber Platinum Subscriber QRZ Page

    They were $80 5 years ago and $90 today. Maybe due to a combination of inflation and increased import taxes.

    I don't know either. I doubt the Chinese do any matching, so it's something RF parts is doing. Maybe if I have time I'll see if they mention what they do on their website.

    I don't have anything that uses 811s, so no.
    Last edited: Jan 13, 2021
  2. W4NNF

    W4NNF XML Subscriber QRZ Page

    I should have been more clear I was speaking of the collective you..."if somebody wants to replace 811s with 572s." I also question the need for matched tubes in many amps. Anyhow...100 bucks a pop closes the idea out for me. :)
    W0FS and AG4RT like this.
  3. WA2CWA

    WA2CWA Ham Member QRZ Page

    In push-pull audio amplifier circuits, matched output tubes is good initially. But over time, tubes can age at different rates, so the "matched tubes" thing can fall apart.
    In linear amplifier circuits where tubes are run in parallel, I see no advantage for the tubes to be matched.
    W0FS and WA5VGO like this.
  4. WA9SVD

    WA9SVD Ham Member QRZ Page

    You obviously aren't using your 8911A amp properly.:mad: Where do you get off NOT overdriving it, NOT getting a few extra watts out, and NOT taking long periods of time to tune up???:confused:

    OK, sarcasm off. If treated properly (perhaps even gently) 811A's in an amp should have a long life; if abused, they WILL fail quickly. But it seems "proper" operation is more the exception, rather than the rule. But is a few dozen extra Watts output REALLY going to make a difference? (If it does, perhaps an 811A amp is the wrong choice to begin with.)
    VK2WP and W4NNF like this.
  5. W4NNF

    W4NNF XML Subscriber QRZ Page

    Yes...but. The sad fact is that even if you baby them, the Chinese 811as will occasionally fail. I had one flash over some time back. Not a huge deal. Replace it and replace that meter protection diode and keep on trucking.

    The secret to these amps? Consider the AL811h, which is what I have, a nice 600 watt amp. Stick with 50 watts of drive or thereabouts, and make sure you've got the tune settings recorded so you rarely have to do anything but touchup with 2 - 3 seconds of key down. :)

    As far as tube abuse, I learned my lesson way back when in the days of sweep tube finals. Daddy got real tired of me begging 6LQ6es off him and sat me down for a good, long talk about final tuning one afternoon. :D
    VK2WP, KA4DPO and WZ7U like this.
  6. WA9SVD

    WA9SVD Ham Member QRZ Page

    The problem (well, one of them) is some people think the AL-811a is an 800 Watt amp. (or that they can squeeze 800 Watts out of it.) That keeps the 811A manufacturers VERY happy.:( Add overdrive, and you can almost guarantee a regular (and frequent) tube replacement schedule. Using 572's just hides improper operation for a while.
    W0FS, VK2WP, KA4DPO and 1 other person like this.
  7. KA4DPO

    KA4DPO Platinum Subscriber Platinum Subscriber QRZ Page

    Absolutely, same goes for the SB200 and the 30L1, folks who didn't know any better thought they were KW amps, not even close.
    W0FS and WA9SVD like this.
  8. WA9SVD

    WA9SVD Ham Member QRZ Page

    My SB200 (IF I ever get to use it; I currently have no 240 V line...) will run a pair of 572'a @ 5-600 Watts MAXIMUM. Even IF the 572's are more robust, the power supply isn't really meant for more than 600 Watts.
    KA4DPO and W4NNF like this.

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