Step up Xformer Question - Amp

Discussion in 'Amateur Radio Amplifiers' started by KK4YDR, Dec 19, 2015.

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  1. KM1H

    KM1H Ham Member QRZ Page

    The dryer outlet is very popular with hams and forget about that POS AL-811H, especially at anything over 500-600W.

    I dont like the AL-82, 3600 is too much HV for Chinese tubes which like to arc when outgassing...that takes out a lot of other parts that the glitch resistor doesnt protect anyway.

    You have 2 choices the 80B or 1500.

    Carl
     
  2. KK4YDR

    KK4YDR Ham Member QRZ Page

    Thanks for the feedback. I am really pointing towards the 1500 anyeays. Those tubes are nice and stout.
     
  3. K4VLF

    K4VLF Ham Member QRZ Page

    I am still impressed with a AL-80B I installed a year ago (running 120 VAC).
     
  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    The 80B can run quite well on a 120V outlet if it's the only thing being powered by that outlet.

    But the AL-1500 has no provision for 120V power at all. It's 240V all the way and doesn't use series primaries like the 80B and the smaller amps do.

    The 'dryer outlet' idea has merit, if you have a 240V electric dryer outlet. If you have a gas dryer, that outlet may not exist. Check it out and see.
     
  5. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    The 1500 is a good amp, and has just one tube that should last a lifetime.
     
  6. KH2G

    KH2G Guest

    I use a "Y" cord on the dryer and it works well. 120 Volts draws more current watt for watt so I always recommend the 240V when at all available. Enjoy 73 Dick KH2G
     
  7. KK4YDR

    KK4YDR Ham Member QRZ Page

    Thank you guys very much for the feedback. That is what I was looking for. It seems the Y cord and extension is what I need to do. And when I need to run high power QRO I can just grab the cord and run it to my amplifier. I guess a 25' extension cable will be more than enough.
     
  8. AC8AC

    AC8AC Ham Member QRZ Page

    ive often said the same thing i own one . i got it cheap due to a band switch failure .. will it do legal limit sure dont mean it should i alc it back to 1200

    once and a wile ill key it for a wile to get the anodes hot but i dont trust the band switch much . if i find legal limit necessary i just use my home brew 3cpx1500 amp legal limit with air to spare

    but the 3-500 is my favorite tube to use on a daily basis
     
  9. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    8877 is the best high powered 'amateur radio level' tube there is, and I doubt it's likely anything will come along to replace it. 3CX3000A7 is even better, but bigger and requires more filament power.

    Ironically, for those who don't mind a somewhat higher electric bill and have the room, the 3000A7 is a wonderful choice because they can be found cheaper than 8877s for some reason. ASI locally to me builds all their 'smaller' amps, ones in the 1kW to 5 kW range, with 3000A7s. I did ask Charlie why he does that, and it was purely a financial thing...he can get 3000A7s cheaper than 8877s. And hams can't blow them up.
     
  10. REASTON

    REASTON QRZ Member

    A 3cx3000a7 is a very nice tube and an incredibly inefficient tube at low output power, like 40% efficiency at 1500 watts. And that only pertains to the plate power consumption. Add in a 52 amp filament requirement and I suspect the money saved over an 8877 will be easily offset by very high power bills over the life of the tube.

    If I were to build or buy a tube amp today, which I will never do again, I would use an 8877 or I wouldn't build or buy a tube amp. The last remaining tubes available today are slim pickings. SS works for me and has for 2 decades solely without the use of tubes. Tubes were nice in their day but their day has gone. Hams will probably be scrounging for tubes until the last one left on earth dies.
     
    Last edited: Dec 20, 2015

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