Triode Pentode Tubes 27 April 2017 Mike at MDBVentures.com Visit us at http://www.MDBVentures.com - Great prices on great tubes! Triode/Pentode tubes are work-horse tubes used in many different circuits. Below is a list of most of the triode/pentode tubes. Special case custom tubes are not listed. Please note that while I have tried to be sure that the information is reliable, it has been obtained from multiple sources, plus there is the inevitable probability of errors as the information was transferred to this format. A note about the listings. The arrangment format of this listing is by the base type. I selected this format as it is most likely that when looking at the list you are looking for similar tubes that can replace an existing tube that is either no longer available, too expensive, or possibly you just want to try a different tube in an existing circuit. Some tubes have additional versions with different heater voltages but with all the other characteristics remaining the same. The other available tube voltages are shown in the Notes. An "*" after the tube number indicates that the tube heater has a controlled warmup time. This is used in circuits that use series strung heaters to reduce the turn-on current surge. Normally the controlled heater tubes are identified by an "A" appearing as the last letter of the tube number when there is a non-controlled heater version of the same tube. A "+" after the tube number indicates that the tube is available in both the "A" version and the non-A version. If there is not a non-controlled heater version of the tube then the "A" suffix is normally not used. You can use a controlled heater tube in a parallel tube circuit, but it is not recommended to use a non-controlled heater tube in a circuit where a controlled heater tube is used. Doing so can stress the tubes in the circuit and potentially cause heater burn-out due to the turn-on current surges. Note: In some cases there were other additional tweaks made to the tube as a part of the re-design of the tube for the "A" version. Generally though any changes are normally inconsequential to the operation of the tube, otherwise the tube would no longer fit the tube designation number and would have to be assigned a different tube designation number. Triode/pentode tubes are available in most of the tube shapes and sizes, but the greatest proliferation of the tubes appeared with the miniature 9 pin tubes. Mainly because the number of pins allowed the designers to properly bring out the internal connections. Prior to that compromises had to be made with internal connections used instead. Most commonly having the sections share a common cathode connection which limited the design options when using the tube. The 9pin miniature triode/pentode tube found its greatest use during the peak of tube based consumer goods. Especially finding use in TV circuits during the 50s and 60s. Having two components inside one tube element helped to keep circuit costs down. During the 60s especially the number of tube types in the 9 pin miniature increased significantly as the TV manufacturers started to use specifically designed tubes for the circuits to reduce the costs by minimizing the needed support circuitry for the tube. This was particularly important in the early color TVs where the number of tubes and circuits required to decode and present the color picture were double or tripple that of the black and white TVs. So cost reduction of the circuits became even more important. Note: This table looks best using a fixed size smaller font on a desktop computer with a screen wide enough to show all the information on each line (about 160 characters wide). -------- Miniature Triode/Pentode Tubes -------------------------- -------------- Pentode ---------------------------- -------------- Triode --------------- Tube Base Filament Grid Plate Screen Rp Gm MaxVp Grid Plate Rp Gm Mu MaxVp Notes 6AX8 9AE 6.3V 0.45A 120K 300V 10mA 110V 3.5mA 400,000 4,800 300V 56K 150V 18mA 5000 8500 40x 300V 6BL8 9AE 6.3V 0.45A -2.0V 170V 10mA 170V 2.8mA 400,000 6,200 250V -2.0V 100V 14mA 4000 5000 20x 250V (also 4BL8) 6EA8* 9AE 6.3V 0.45 -1.0V 125V 12mA 125V 4.0mA 200,000 6,400 330V 56K 150V 18mA 5000 8500 40x 330V (also 5EA8, 9EA8, 19EA8) 6EH8* 9AE 6.3V 0.45A -1.0V 125V 12mA 125V 4.0mA 170,000 6,000 300V -1.0V 125V 13.5mA ---- 7500 40x 300V 0V 100V ---- 70V ----- ------- 6,500 300V 6GH8+ 9AE 6.3V 0.45A -1.0V 125V 12mA 125V 4.0mA 200,000 7,500 350V -1.0V 125V 13.5mA 5400 8500 46x 330V (also 5GH8, 9GH8) 6GJ8* 9AE 6.3V 0.60A -1.0V 125V 12mA 125V 4.5mA 150,000 7,500 330V -1.0V 125V 11.5mA 5400 15000 40x 330V 6HL8* 9AE 6.3V 0.60A -1.0V 125V 12mA 125V 4.5mA 150,000 10,000 330V -1.0V 125V 12.5mA 5000 7000 40x 330V 6KD8 9AE 6.3V 0.40A -1.0V 125V 9.5mA 110V 3.5mA 200,000 5,000 330V -1.0V 125V 13.5mA ---- 7500 40x 330V (also 5KD8) 6LM8+ 9AE 6.3V 0.45A -2.0V 125V 12mA 125V 4.0mA 150,000 6,000 350V -1.0V 125V 13.5mA 5400 8500 46x 330v 6LN8* 9AE 6.3V 0.45A -2.0V 170V 10mA 170V 2.8mA 400,000 6,200 250V -2.0V 100V 14mA 4000 5000 20x 250V 6MQ8 9AE 6.3V 0.535A 62K 125V 12mA 125V 4.5mA 150,000 10,000 330V 56K 150V 18mA 5000 5000 40x 330V (also 5MQ8) 6MU8* 9AE 6.3V 0.60A 150K 150V 19mA 150V 4.2mA 165,000 9,000 330V -1.0V 125V 115mA 5800 6000 35x 330V (also 8MU8) 6U8+ 9AE 6.3V 0.45A -1.0V 125V 9.5mA 110V 3.5mA 200,000 5,000 330V -1.0V 125V 13.5mA ---- 7500 40x 330V (also 5U8, 9U8) 6678 9AE 6.3V 0.45A 68K 250V 10mA 110V 3.5mA 400,000 5,200 330V 56K 150V 18mA 5000 8500 40x 330V (special 6U8) 7059 9AE 13.5V 0.195A 68K 250V 10mA 110V 3.5mA 400,000 5,200 300V 56K 150V 18mA 4700 8500 40x 300V 7687 9AE 6.3V 0.50A 62K 220V 10mA 130V 3.4mA 500,000 5,800 330V -8.5V 215V 7.5mA 7200 2500 18x 250V 7731 9AE 6.3V 0.45A 68K 250V 10mA 110V 3.5mA 400,000 5,200 330V 56K 150V 18mA 5000 8500 40x 330V 8445 9AE 6.75V 0.44A -2.0V 170V 10mA 170V 2.5mA 400,000 6,200 330V -1.0V 100V 12.5mA ---- 7000 43x 330V 6X8+ 9AK 6.3V 0.3A -1.0V 125V 9mA 125V 2.2mA 300,000 5,500 275V -1.0V 125V 12mA 6000 6500 40x 275V (also 5X8, 9X8, 19X8) 6AN8+ 9DA 6.3V 0.45A 56K 125V 12mA 125V 3.8mA 170,000 7,800 330V -3.0V 150V 50mA 4700 4500 21x 330V (also 5AN8) 10C8 9DA 10.5V 0.3A 100K 135V 11.5mA 135V 3.2mA 190,000 8,000 300V 390K 250V 7.3mA 12000 4400 53x 300V 12CT8 9DA 12.6V 0.3A 82K 200V 15mA 125V 3.4mA 150,000 7,000 300V 150K 150V 9mA 8200 4900 40x 300V 7060 9DA 13.5V 0.3A 82K 200V 15mA 250V 3.5mA 400,000 5,200 300V 150K 150V 9mA 8200 4900 40X 300V 7258 9DA 13.5V 0.21A 56K 125V 12mA 125V 3.5mA 170,000 7,800 330V -3.0V 150V 15mA 4700 4500 21x 330V 8489 9DA 6.3V 0.45A -1.0V 125V 12mA 125V 3.8mA 170,000 7,000 330V -3.0V 150V 15mA 4700 4500 21x 330V 6JW8 9DC 6.3V 0.43A -1.0V 100V 6.0mA 100V 1.7mA ------- 5,500 250V -2.0V 200V 3.5mA ---- 3500 70x 250V 6KE8 9DC 6.3V 0.40A 33K 125V 10mA 125V 2.8MA 125,000 12,000 280V 68K 125V 13mA 5000 8000 40x 280V 6LX8* 9DC 6.3V 0.45A -1.0V 100V 6.0mA 100V 1.7mA ------- 5,500 250V -2.0V 200V 3.5mA ---- 3500 70x 250V 6MG8 9DC 6.3V 0.45A -2.0V 170V 10mA 170V 2.8mA 400,000 6,200 330V 56K 150V 18mA 5000 8500 40x 330V 6AU8+ 9DX 6.3V 0.60A 82K 200V 15mA 125V 3.4mA 150,000 7,000 300V 150K 150V 9mA 8200 4900 40x 300V (also 8AU8, 12AU8) 0V 40V 28mA 125V 10mA ------- ----- 330V 6AW8+ 9DX 6.3V 0.60A 180K 200V 13mA 150V 3.5mA 400,000 9,000 300V -2.0V 200V 4.0mA 17500 4000 70x 330V (also 8AW8) 0V 65V 46mA 150V 15mA ------- ----- 330V 6BA8+ 9DX 6.3V 0.60A 180K 200V 13mA 150V 3.5mA 400,000 9,000 300V -8.0V 200V 8.0mA 6700 2700 18x 300V (also 8BA8) 0V 65V 42mA 150V 12.5mA ------ ----- 300V 6BH8* 9DX 6.3V 0.60A 82K 200V 15mA 125V 3.4mA 150,000 7,000 300V -5.0V 150V 9.5mA 5150 3300 17x 300V (also 8BH8) 6CX8 9DX 6.3V 0.75A 68K 200V 24mA 125V 5.4mA 70,000 10,000 330V 150K 150V 9.2mA 8700 4600 40x 330V (also 8CX8) 0V 40V 40mA 125V 15.5mA ------ ------ 330V 6EB8 9DX 6.3V 0.75A 68K 200V 25mA 125V 7.0mA 75,000 12,500 330V -2.0V 250V 2.0mA 37000 2700 100x 330V (also 8EB8, 10EB8) 6GN8 9DX 6.3V 0.75A 100K 200V 25mA 150V 5.5mA 60,000 11,500 330V -2.0V 250V 2.0mA 37000 2700 100x 330V (also 8GN8, 10GN8) 6HF8 9DX 6.3V 0.75A 68K 200V 25mA 125V 7.0mA 75,000 12,500 330V -2.0V 200V 4.0mA 17500 4000 70x 330V (also 10HF8) 0V 45V 40mA 125V 15mA ------- ------ 330V 6JE8 9DX 6.3V 0.78A 82K 250V 22mA 170V 4.0mA 140,000 12,000 330V -2.0V 200V 4.5mA 16600 4200 70x 300V (also 8JE8, 11JE8) 6JL8 9DX 6.3V 0.75A -3.5V 300V 25mA 150V 5.0mA 60,000 11,500 330V 150K 150V 10mA 7500 4700 35x 330V (also 6JL8) 6JV8* 9DX 6.3V 0.60A -1.0V 125V 22mA 125V 4.0mA 100,000 11,500 330V -2.0V 200V 4.0mA 17500 4000 70x 330V (also 8JV8) 0V 40V 28mA 125V 9.0mA ------- ------ 330V 6KR8+ 9DX 6.3V 0.75A 82K 200V 19.5mA 100V 3.0mA 60,000 20,000 330V 68K 125V 15mA 4400 10400 46x 330V (also 8KR8, 10KR8) 0V 35V 54mA 100V 13.5mA ------ ------ 330V 6KS8+ 9DX 6.3V 0.60A 150K 150V 20mA 150V 4.5mA 150,000 9,500 330V -2.0V 200V 4.0mA 17500 4000 70x 330V (also 8KS8) 0V 65V 60mA 150V 20mA ------- ------ 330V 6KV8 9DX 6.3V 0.775A 68K 200V 20mA 125V 3.5mA 75,000 23,000 300V -2.0V 200V 4.0mA 17500 4000 70x 300V (also 11KV8) 82K 125V 16.5mA 125V 3.1mA 55,000 21,000 300V 6LF8* 9DX 6.3V 0.60A -2.5V 100V 20mA 150V 5.0mA 200,000 11,000 330V -2.0V 200V 4.0mA 17500 4000 70x 330V 0V 75V 50mA 150V 12mA ------- ------ 330V 6LQ8 9DX 6.3V 0.775A 82K 125V 16.5mA 125V 3.1mA 55,000 21,000 300V 68K 125V 15mA 4400 10400 46x 300V (also 11LQ8) 10LW8 9DX 10.5V 0.45A 82K 200V 16.5mA 100V 2.8mA 60,000 19,000 330V -2.0V 200V 2.6mA 18700 4000 75x 200V 6LY8 9DX 6.3V 0.75A 82K 200V 19.5mA 100V 3.0mA 60,000 20,000 330V -2.0V 250V 1.0mA 59000 1700 100x 330V (also 10LY8) 0V 35V 54mA 100V 13.5mA ------ ------ 330V 6MV8* 9DX 6.3V 0.60A -1.0V 125V 13mA 125V 4.0mA 150,000 9,000 400V -2.0V 250V 2.5mA 25000 3600 100x 330V 7716 9DX 13.6V 0.35A 68K 200V 24mA 125V 5.2mA 70,000 10,000 330V -1.0V 125V 1.5mA 35000 2900 102x 330V 5AV8* 9DZ 4.7V 0.6A 180K 200K 9.5mA 150V 2.8mA 300,000 6,200 300V -6.0V 200V 13mA 5750 3300 19x 300V 5B8* 9EC 4.7V 0.6A 180K 200V 9.5mA 150V 2.8mA 300,000 6,200 300V -6.0V 200V 13mA 5750 3300 19x 300V (screen grid tied to triode cathode) 6AZ8 9ED 6.3V 0.45A 180K 200V 9.5mA 150V 3.0mA 300,000 6,000 300V -6.0V 200V 13mA 5750 3300 19x 300V 6BE8+ 9EG 6.3V 0.45A 68K 250V 10mA 110V 3.5mA 400,000 5,200 300V 56K 150V 18mA 5000 8500 40x 300V (also 5BE8) 5DH8* 9EG 5.2V 0.6A 56K 125V 16mA 125V 3.8mA 150,000 8,600 300V 390K 250V 7.3mA 12000 4400 53x 300V 6BM8 9EX 6.3V 0.78A -16V 200V 35mA 200V 7.0mA 20,000 6,400 600V 0V 100V 3.5mA ----- 2500 70x 300V (also 11BM8, 50BM8) -6.0V 100V 26mA 100V 5.0mA 15,000 6,800 600V 6FY8 9EX 6.3V 1.20A -13.5V 125V 50mA 125V 10mA ------- 7,500 150V -1.5V 125V 2.5mA ----- 2500 --- 150V (also 12FY8, 25FY8, 50FY8) 16A8 9EX 16V 0.3A -16V 200V 35mA 200V 7.0mA 20,000 2,500 250V 0V 100V 3.5mA ----- 2500 70x 250V 6BR8+ 9FA 6.3V 0.45A 68K 250V 10mA 110V 3.5mA 400,000 5,200 300V 56K 150V 18mA 5000 8500 40x 300V (also 5BR8) 6FV8+ 9FA 6.3V 0.45A -1.0V 125V 12mA 125V 4.0mA 200,000 6,500 330V -1.0V 125V 14mA 5000 8000 40X 330V (also 5FV8) 6JN8* 9FA 6.3V 0.45A -1.0V 125V 12mA 125V 4.0mA 200,000 7,500 300V -1.0V 125V 13.5mA 5400 8500 46x 300V (also 12JN8, 19JN8) 6MB8 9FA 6.3V 0.40A 33K 125V 10mA 125V 2.8mA 125,000 12,000 280V 68K 125V 13mA 5000 8000 40x 280V (also 5MB8) 12EC8 9FA 12.6V 0.225A 0V 12.6V 0.66mA 12.6V 0.28mA 750,000 2,000 16V 0V 12.6V 2.4mA 6000 4700 25x 16V 19HV8 9FA 18.9V 0.15A -1.0V 125V 12mA 125V 4.0mA 200,000 6,500 330V -1.0V 100V 0.8mA 54000 1300 70x 330V 8446 9FA 6.75V 0.44A -2.0V 170V 10mA 170V 2.5mA 400,000 6,200 330V -1.0V 100V 12.5mA ----- 7000 43x 330V 6CH8 9FT 6.3V 0.45A 220K 200V 9.5mA 150V 2.8mA 300,000 6,200 300V -6.0V 200V 13mA 5750 3300 19x 300V 6CL8* 9FX 6.3V 0.45A -1.0V 125V 12mA 125V 4.0mA 120,000 6,000 330V -1.0V 125V 14mA 5000 8000 40x 330V (also 5CL8, 9CL8, 19CL8) 6CM8* 9FZ 6.3V 0.45A 180K 200V 9.5mA 150V 2.8mA 600,000 6,200 300V -2.0V 250V 1.8mA 50000 2000 100x 300V (also 5CM8) 6CS8* 9FZ 6.3V 0.45A 56K 125V 13mA 125V 3.0mA 300,000 7,700 330V -2.0V 125V 12mA 5500 4000 22x 330V 6KZ8* 9FZ 6.3V 0.45A -1.0V 125V 12mA 125V 4.0mA 200,000 7,500 330V -1.0V 125V 13.5mA 5400 8500 46x 330V (also 5KZ8, 9KZ8) 6CQ8* 9GE 6.3V 0.45A -1.0V 125V 12mA 125V 4.2mA 140,000 5,800 330V 56K 125V 15mA 5000 8000 40x 330V (also 5CQ8) 6CG8+ 9GF 6.3V 0.45A -1.0V 125V 9.0mA 125V 2.2mA 300,000 5,500 275V -1.0V 125V 12mA 6000 6500 40x 275V (also 5CG8, 9CG8) 6FG7 9GF 6.3V 0.45A -1.0V 125V 11mA 125V 4.0mA 180,000 6,000 330V -1.0V 125V 13mA 5700 7500 43x 330V (also 5FG7) 0V 100V ----- 100V ----- ------- 7,400 330V 6GD7 9GF 6.3V 0.38A 82K 170V 10mA 150V 3.3mA 350,000 12,000 250V -1.0V 125V 15mA 4700 10000 47x 125V 6LJ8 9GF 6.3V 0.4A 33K 125V 12mA 125V 3.5mA 125,000 13,000 280V 68K 125V 13mA 5000 8000 40x 280V (also 4LJ8, 5LJ8) 5GS7 9GF 5.4V 0.45A -1.2V 170V 10mA 150V 3.3mA 350,000 12,000 250V -3.0V 100V 14mA ---- 5500 17x 125V (also 4GS7, 7GS7) 6CU8* 9GM 6.3V 0.45A 56K 125V 12mA 125V 3.8mA 170,000 7,800 330V -1.0V 125V 17mA 4100 5800 24x 330V 6CR8* 9GJ 6.3V 0.45A 56K 125V 13mA 125V 3.0mA 300,000 7,700 330V -2.0V 125V 12mA 5500 4000 22x 330V (also 5CR8) 6DX8 9HX 6.3V 0.72A -3.4V 220V 18mA 220V 3.0mA 150,000 10,000 300V -1.7V 200V 3.0mA ---- 4000 65x 300V (also 10DX8) 15DQ8 9HZ 15V 0.3A -2.9V 200V 18mA 200V 3.0mA 130,000 10,400 250V -1.7V 200V 3.0mA ---- 4000 65x 250V 6DZ8 9JE 6.3V 0.9A 180K 145V 45mA 120V 6.8mA ------- 7,500 150V 1500K 120V 0.8mA ---- 1400 100x 150V (also 9DZ8, 12DZ8, 18DZ8, 35DZ8) 6EU8* 9JF 6.3V 0.45A -1.0A 125V 12mA 125V 4.0mA 80,000 6,400 330V 56K 150V 18mA 5000 8500 40x 330V (also 5EU8) 7199 9JT 6.3V 0.45A 62K 220V 12.5mA 130V 3.5mA 400,000 7,000 330V -8.5V 215V 9.0mA 8100 2100 17X 330V 1000K 100V 1.1mA 50V 0.35mA 1,000,000 1,500 330V 6GV7 9KN 6.3V 0.35A -1.5V 125V 10mA 125V 3.1mA 25,000 7,500 250V -3.0V 100V 14mA ---- 5500 17x 250V (also 7GV7) 12FR8 9KU 12.6V 0.32A 0V 12V 1.9mA 12V 0.7mA 400,000 2,700 16V 0V 12.6V 1.0mA ---- 1200 10x 16V 6GE8 9LC 6.3V 0.9A -2.0V 150V 5.5mA 150V 1.7mA 340,000 3,200 330V -21V 150V 35mA 1080 5000 5.4x 275V 7734 9LC 6.3V 0.9A -2.0V 150V 5.5mA 150V 1.7mA 340,000 3,200 330V -21V 150V 35mA 1080 5000 5.4x 275V 6GV8 9LY 6.3V 0.9A -15V 170V 41mA 170V 2.7mA 25,000 7,500 250V -0.8V 100V 5mA 7600 6500 50x 250V (also 9GV8, 18GV8) 11MS8 9LY 11.6V 0.45A -10V 120V 50mA 110V 3.0mA 13,000 8,500 250V 0V 100V 10mA 9000 7000 63x 250V 19KG8 9LY 18.9V 0.15A -1.0V 125V 12mA 125V 4.0mA 200,000 7,500 300V -1.0V 125V 13.5mA 5400 8500 46x 300V 6GW8 9LZ 6.3V 0.7A -7.0V 250V 36mA 250V 5.5mA 45,000 10,000 300V -1.7V 250V 1.2mA 62500 1600 100x 300V 4FS7 9MP 4.6V 0.6A -1.2V 170V 10mA 150V 3.3mA 350,000 12,000 250V -3.0V 100V 14mA 3100 5500 17x 125V 6HG8 9MP 6.3V 0.34A -1.2V 170V 10mA 150V 3.3mA 350,000 12,000 250V -3.0V 100V 14mA 3100 5500 17x 125V (also 4HG8, 5HG8, 7HG8, 8HG8) 6JC8* 9PA 6.3V 0.45A -1.0V 125V 9mA 125V 2.2mA 300,000 5,500 275V -1.0V 125V 12mA 6000 6500 40x 275V 8102 9PJ 13.5V 0.23A -1.0V 125V 12mA 125V 4.0mA 200,000 7,500 330V -1.0V 125V 13.5V 5400 8500 46x 330V 6KA8* 9PV 6.3V 0.6A 180K 150V 4.0mA 100V 2.8mA 100,000 4,400 300V -2.0V 200V 4mA 17500 4400 70x 300V (also 8KA8) 6GJ7 9QA 6.3V 0.41A -1.2V 170V 10mA 120V 3.0mA 350,000 11,000 275V -3.0V 100V 15mA ---- 9000 20x 140V (also 4GJ7, 5GJ7, 8GJ7) 6GX7 9QA 6.3V 0.4A -1.0V 125V 8.0mA 125V 2.5mA 200,000 11,000 275V -1.0V 125V 13mA 4700 8500 40x 275V (also 4GX7, 5GX7, 8GX7) 6HB7 9QA 6.3V 0.45A -1.0V 125V 12mA 125V 4.0mA 200,000 6,400 330V 56K 150V 18mA 5000 8500 40x 330V (also 5HB7) 6HD7 9QA 6.3V 0.45A -1.0V 125V 12mA 125V 3.5mA ------- 7,500 275V 100K 100V 14mA 4880 8200 40x 275V 6HJ7 9QA 6.3V 0.45A -1.0V 125V 9.5mA 125V 2.3mA ------- 12,300 275V 100K 100V 14mA 4880 8200 40x 275V 6KT8 9QP 6.3V 0.6A -1.0V 125V 12mA 125V 4.5mA 150,000 10,000 330V -2.0V 250V 1.8mA 31500 3200 100x 330V 6LC8* 9QY 6.3V 0.6A 180K 150V 4.0mA 100V 2.8mA 100,000 4,400 300V -2.0V 200V 4.0mA 17500 4000 70x 300V (also 8LC8) 8A8 9DC 8.4V 0.3A -2.0V 170V 10mA 170V 2.8mA 400,000 6,200 259V -2.0V 100V 14mA ----- 5000 20x 250V (also 9A8, 17A8) ----------- Compactron Novar and 9T9 Triode/Pentode Tubes -------------- -------------- Pentode ---------------------------- ---------- Triode -------- Tube Base Filament Grid Plate Screen Rp Gm MaxVp Grid Plate Rp Gm Mu MaxVp Notes 6JT8 9DX 6.3V 0.725A 82K 200V 17mA 100V 3.5mA 50,000 20,000 330V -2.0V 250V 1.5mA 37000 2700 100x 330V (also 8JT8, 10JT8) (9T9 Compactron/miniature) 0V 35V 50mA 100V 17mA ------- ------ 330V 6HZ8 9DX 6.3V 1.125A 100K 250V 20mA 170V 6.0mA 140,000 12,600 330V -2.0V 200V 3.5mA 17500 4000 70x 300V (9T9 Compactron) 6LB8 9DX 6.3V 0.725A 82K 200V 17mA 100V 3.5mA 50,000 20,000 330V 68K 125V 13mA 6000 5000 30x 330V (also 10LB8) (9T9 Compactron) 0V 50V 55mA 100V 18mA ------ ------ 330V 6HC8 9EX 6.3V 1.20A -18V 250V 30mA 250V 3.0mA 55,000 5,100 350V -3.0V 250V 1.4mA 34000 2000 68x 330V (also 17HC8) (9T9 Compactron) 0V 60V 180mA 250V 30mA ------ ----- 350V 6KY8+ 9QT 6.3V 1.1A -10V 135V 39mA 120V 3.0mA 18,000 8,400 300V -3.0V 250V 1.4mA 40000 1600 64x 330V (also 15KY8) (Novar/Compactron) 0V 50V 170mA 120V 20mA ------ ----- 300V 15MX8* 9QT 15V 0.45A -10V 135V 39mA 120V 3.0mA 18,000 8,400 300V -3.0V 250V 1.4V 40000 1600 64x 330V (Novar/Compactron) 0V 50V 170mA 120V 20mA ------ ----- 300V 17LD8* 9QT 16.8V 0.45A -8.0V 120V 46mA 110V 4.0mA 11,700 7,100 250V -5.0V 150V 3.3mA 11300 1900 21.5x 250V (Novar/Compactron) 0V 45V 122mA 110V 17mA ------ ----- 250V 6LR8* 9QT 6.3V 1.5A -10V 135V 56mA 120V 3.0mA 12,000 9,300 400V -4.0V 250V 2.3mA 16000 3600 58x 400V (also 21LR8, 31LR8) (Novar/Compactron) 6JZ8+ 12DZ 6.3V 1.2A -8.0V 120V 46mA 110V 3.5mA 11,700 7,100 250V -5.0V 150V 5.5mA 8500 2350 20x 250V (also 13JZ8, 17JZ8, 24JZ8, 25JZ8) (Compactron) 6LU8+ 12DZ 6.3V 1.5A -10V 135V 56mA 120V 3.0mA 12,000 9,300 400V -4.0V 250V 2.3mA 16000 3600 58x 400V (also 16LU8, 21LU8) (Compactron) 6MF8 12DZ 6.3V 1.4A -20V 250V 50mA 250V 3.5mA 5,000 4,100 400V -4.0V 250V 2.6mA 14000 4100 58x 400V (also 15MF8) (Compactron) 6MY8 12DZ 6.3V 1.45A -10V 135V 56mA 120V 3.0mA 12,000 9,300 330V -4.0V 250V 2.3mA 16000 3600 58x 400V (also 16MY8, 21MY8) (Compactron) 6T9 12FN 6.3V 0.93A -8.0V 250V 35mA 250V 2.5mA 100,000 6,500 275V -2.0V 250V 1.5mA 45000 2100 95x 300V (Compactron) 6AG9 12HE 6.3V 0.82A 56K 250V 28mA 150V 5.6mA 40,000 30,000 330V 350K 150V 0.2mA 8500 4600 39x 330V (Compactron) 6AL9 12HE 6.3V 0.82A 56K 250V 28mA 250V 5.6mA 40,000 30,000 330V 270K 200V 7.6mA 9200 6300 59x 330V (also 8AL9) (Compactron) 6AH9 12HJ 6.3V 0.9A 122K 250V 25mA 150V 6.0mA 55,000 21,000 400V -9.0V 250V 8.0mA 7300 2750 20x 330V (also 9AH9) (Compactron) 56R9 12EN 42V/14V 0.15A -8.0V 120V 49mA 11OV 4.0mA 10,000 7,500 150V 1.5K 100V 0.6mA 55500 1800 100x 150V (Compactron) ------------ Octal Triode/Pentode Tubes ----------------------- -------------- Pentode ---------------------------- ---------- Triode -------- Tube Base Filament Grid Plate Screen Rp Gm MaxVp Grid Plate Rp Gm Mu MaxVp Notes 6P7 7U 6.3V 0.3A -3.0V 250V 6.5mA 100V 1.5mA 850,000 1,100 250V -3.0V 100V 3.5mA 16000 500 8.0x 100V (octal) 1D8 8AJ/8AW 1.4DC 0.1A -9V 90V 5.0mA 90V 1.0mA 200,000 925 110V 0V 90V 1.1mA 43500 575 25x 250V (octal) 25D8 8AF 25V 0.15A -3.0V 100V 8.5mA 100V 2.7mA 200,000 1,900 100V -1.0V 100V 0.5mA 91000 1100 --- 100V (octal) 1B8 8AF/8AW 1.4DC 0.1A -6.0V 90V 6.3mA 90V 1.4mA ------- 1,150 110V 0V 90V 0.15mA 240000 275 --- 110V (octal) 3A8 8AS 2.8/1.4DC 0.05/0.1A 0V 90V 1.5mA 90V 0.5mA 800,000 750 110V 0V 90V 1.5mA 800000 750 --- 110V (octal) 6AD7 8AY 6.3V 0.85A -16.5V 250V 34mA 250V 6.5mA 80,000 2,500 285V -16.5V 250V 34mA 80000 2500 --- 375V (octal) 12B8 8T 12.6V 0.3A -3.0V 90V 7.0mA 90V 2.0mA 200,000 1,800 90V 0V 90V 2.8mA 37000 2400 96x 90V (also 25B8) (octal) 15A8 8GS 15V 0.6A -7.5V 110V 45mA 110V 4.0mA 13,000 7,300 300V -30V 225V 25mA 1600 3800 6.0x 300V (octal) -------------- Misc Triode/Pentode Tubes (10pin miniature/subminiature/preoctal/Loktal) ------------ -------------- Pentode ---------------------------- ---------- Triode -------- Tube Base Filament Grid Plate Screen Rp Gm MaxVp Grid Plate Rp Gm Mu MaxVp Notes 19Q9* 10H 18.9V 0.15A -1.0V 125V 12mA 125V 4.0mA 200,000 6,500 330V -1.0V 125V 14mA 5000 8000 40x 330V (10pin miniature) 6U9 10K 6.3V 0.41A -1.4V 160V 13mA 110V 5.0mA ------- 12,000 250V -2.0V 100V 14mA ---- 5000 17x 250V (also 5U9, 8U9) (10pin miniature) 6X9 10K 6.3V 0.41A -1.7V 160V 13mA 135V 5.0mA ------- 14,000 250V -1.0V 170V 8.5mA ---- 4800 55x 250V (also 5X9, 8X9) (10pin miniature) 6F7 7E 6.3V 0.3A -3.0V 250V 6.5mA 100V 1.5mA 850,000 1,100 250V -3.0V 100V 3.5mA 16000 500 8.0x 100V (preoctal) 7GS7 9GF 7.6V 0.3A -1.2V 170V 10mA 150V 3.3mA 350,000 12,000 250V -3.0V 100V 14mA ---- 5500 17x 125V (loktal) 7GV7 9KN 7.4V 0.3A 180K 250V 10mA 150V 3.2mA 800,000 4,000 300V -3.0V 100V 14mA ---- 5500 17x 250X (loktal) 7HG8 9MP 7.2V 0.3A -1.2V 170V 10mA 150V 3.3mA 350,000 12,000 250V -3.0V 100V 14mA ---- 3100 17x 125V (loktal) Notes: Items with "---" indicate that the information was not available. *=heater warm up time controlled +="A" and "non-A" versions available (A=controlled heater warmup time) Tubes with controlled heater warmup time are generally intended for series strung tube heaters. They can also be used in non-series strung heater circuits. Non-heater controlled tubes are normally only used in parallel heater circuits. Why controlled heaters? In the early days, tube heater power was provided by a transformer that reduced the line voltage to the desired heater voltage or in portable radios an "A" battery for the heater. As the number of tubes needed for devices increased, especially with the advent of TVs and the demand for lower cost radios and TVs, the circuit engineers looked for ways to reduce costs. One way was to get rid of the transformer and drive the circuits directly from the line voltage to achieve that required wiring the tube heaters in series. The problem with wiring tube heaters in series is that during the power-on phase as the heaters are going from the low cold resistance to the normal operating temperature where the resistance increases (and thus the current through the heater decreases), there can be excessive current surges that can damage the tube heaters. This is especially the case when there are tube heaters with different voltages in the circuit. If one tube heats up more rapidly than the other tubes, then it will increase its resistance faster. That can cause the voltage across the tube to go higher than the tube is rated which can stress the heater. Also by reducing the voltage available to the other tube heaters, it means that they will take longer to warm up. In addition to the stress this causes, having different tubes getting up to operating temperature at different times can cause instabilities or even potentially cause harm to the circuits. To deal with this problem, the tube engineers installed special heater controls in the tubes. The heater control is a small section of heater that can rapidly increase in resistance for a short period of time to reduce the current through the tube until the main heater can get up to operating temperature. This allowed all the tubes in the circuit to warm up in a more consistent time period to reduce the problems that would otherwise occur. The trade off is that another second or so was added to the time for the tubes to warm up to operating temperature. For most people though this effect was not noticable. You can usually tell when a tube heater has a controlled warm up because when you first apply power you will see it get brighter momentarily, then dim back down. If you are not aware of what is going on, it can seem alarming and may even seem like there is something wrong with the tube. However, there is nothing wrong. It is just the tube heater control doing its job.