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amplifier comparison


ill never be able to afford either . but its my understanding on tube amps that for similar power the fewer tubes there are the less likely/frequently repairs/replacement are needed .
 
depends whats driving it, the 3cx3000a7 needs 400+ watts to achieve 6000w (realistically 7600w) out where as the 500z's need 150 or so to reach 4,000w out.

the 3cx3000a7 would be my choise, its actually made for rf output. its not a tv sweep tube from the 50's.

got 8 grand burning a hole in your pocket? i have about 350 reasons i would not want it though. thats about what the big fkr weigh's and the basment has a pretty narrow stairway.
 
Both amps are capable of the same power if the power supply can make it. Eight regular 3-500Z tubes have a total plate dissipation of 4KW just like the single 3CX3000A7. The 3-500Z amplifier will actually require more drive then the 3CX3000A7 for the same output. The gain or amplification factor for a 3-500Z is only 130 while the 3CX3000A7 has an amplification factor of 160. No way around it, the 3-500Z's are going to require more drive especially if they are graphite.

The 3CX3000A7 will run more efficiently with it's higher plate voltage and not having all the stray capacitance of running 8 tubes. The 3CX3000A7 is far more reliable then eight 3-500Z's because of it's external anode and the fact the single tube can handle the entire power delivered from the supply. With the 3-500Z's you always have to worry about how matched the tubes are so one doesn't hog more of the drive power and start the chain reaction of constantly blowing the strongest one up.
 
im curious why do you say the 3cx3000 is poorly designed.The layout was designed by the same engineer who designed almost all of the henry amps.

His name is dennis and he lives in georgia.The only thing i did was add extra capacitence to the load tuner and a vacuum output relay.Atleast in this picture.

The 8 tube 3-500z amp was made by a hack by the name of david rock he live in ks.
 
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I wouldn't want either, both are very poorly designed.
- 'Doc

You have to remember they are CB boxes. Just putting that many 3-500Z's together is a mistake. Nevermind that RF relay or even cooling system with the blower. You can tell that 3CX3000A7 wasn't built for 11 meters by Henry either. The tank coil is right up on the metal front panel not beneficial to the "Q" of the circuit. Soldering the flat strap directly to the terminal on the ceramic vacuum relay is a no no. That can easily cause the ceramic to crack. Once you're past the load tuner, you essentially have a 50 ohm path to the antenna and don't have high current. Since most of the current is dumped to ground through the load caps, one should use a suitable flexible braid to the fragile relay. Now that I look at them both without bias, W5LZ has a valid point. I guess it would be like choosing between the lesser of two evils.
 

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