The Original grounded grid triode was introduced in the early 1960s. This tube is no longer being manufactured. The power dissipation is 400 Watts.
EIMAC 3-500Z
The later version of the 3-400Z has larger fins for the increased power dissipation of 500 Watts. The body is slightly larger and it requires minor changes, to fit where the 3-400s were used. It requires a heat dissipating connector.
3-500ZG
The Graphite anode version of 3-500Z. The anode dissipation is approximately 600 Watts, and additional air flow may be required. The Graphite anode provides a more rugged tube. Produced by Eimac, RF Parts Company (prc), Taylor, Amperex (3-500Z/8802), etc.
3-500C
Generic Chinese Graphite tube.
Comparison of 3-500Z Manufacturers
EIMAC
Eimac was the original designer of 3-500Z line, and is generally considered the "standard" for comparison. Eimac no longer produces 3-500Z or other glass tubes.
AMPEREX
Amperex is an excellent graphite anode tube of quality equal to Eimac 3-500ZG. Late production was made in France. It is marked 3-500Z /8802.
RF PARTS
The "RFP" line is the best quality graphite anode tube in the Eimac® format. Virtually an exact copy of the Eimac 3-500ZG in both mechanical and electrical characteristics. It easily represents the best value for the price. All tubes receive 100% RF Parts testing. This tube was made in China for RF Parts Company and meets our standards of excellence.
TAYLOR
The Taylor tube is virtually the same quality graphite anode tube in the Eimac® format. It is an exact copy of the Eimac 3-500ZG in both mechanical and electrical characteristics. It easily represents the best value for the price. All tubes receive 100% RF Parts testing. This tube was made in China for RF Parts Company and meets "Taylor Tubes" standards of excellence.
3-500ZG Taylor
First Quality Tube at a Competitive Price
These tubes carry 1 Year Limited Warranty against manufacturing defects and workmanship.
3-500ZG RFP
"RFP" line is the best quality graphite anode tube in the Eimac® format. Virtually an exact copy of the Eimac 3-500ZG in both mechanical and electrical characteristics. RF PARTS 3-500ZG easily represents the best value for the price. All tubes receive 100% RF PARTS testing.
These tubes carry 1 Year Limited Warranty against manufacturing defects and workmanship.
3-500ZG Amperex
Graphite anode tube of superior quality equal to Eimac 3-500ZG. Made in France, and marked 3-500Z/8802.
These tubes carry 1 Year Limited Warranty (against manufacturing defects and workmanship) through RF PARTS.