Friends of the 6L6 - Some power tetrodes and pentodes

Comparisons of some Power Tubes

This Table has been compiled from various tube manuals, as well as the highly recommended book Tube Lore I am sure that I have made a few transcription errors, so please go to the original sources for design information. If you can spot a real serious error, please send me an e-mail and I will endevor to fix it.

Tube type Base Filament Transconductance Plate Rating Notes

When RCA introduced the 6L6 Beam Power Pentode in the 1930's, they could not have realized that they were creating a design that would outlive the tube era, and be considered a vital ingredient of rock and roll. The 6L6 is probaly the tube that is most likely to come to mind one one thinks of an audio output tube. Russian, Chinese and eastern european factories still sell tubes that they call 6L6s.

The orginal 6L6 was a metal octal tube, part of the first ever group of metal tubes.

6L6 7AC 6.3V 900ma 6000 19 Metal

6L6G 7AC 6.3V 900ma 19 ST-16 Glass

6L6GA 7AC 6.3V 900ma 19 ST-14 Glass

6L6GB 7AC 6.3V 900ma 19 T-12 Glass

6L6GC 7AC 6.3V 900ma 6000 30 T-12 Glass higher ratings

A number of special purpose or industrial tubes bear a family resemblence to the 6L6

1614 7AC 6.3V 900 ma 21

1621 7S 6.3V 700ma 7.9 Similar to 6F6 for applications requiring continuity of service.

1622 7AC 6.3 V 900ma 13.8 Similar to 6L6 for applications requiring continuity of service.

5881 7AC 6.3 V 900ma 6100 23 For output stages of Hi-Fi Audio

5932 7AC 6.3 V 900ma 6000 21

5992 7AC 6.3 V 600ma 4000 10

6550 7AC 6.3 V 1800ma 11000 42

7408 7AC 6.3 V 450ma 6000 14

7581 7AC 6.3 V 900ma 6000 30

7581-A 7AC 6.3 V 900ma 6600 35

KT66

EL34/6CA7 6.3V 1500ma 11,000 25

Unlike most series of tubes with the same letter designation and numbers, the 12,25,35and 50L6 tubes have lower ratings and a smaller physical size than their big brother the 6L6. The slightly lower heater rating of the 35L6 explains it's somewhat reduced ratings.

12L6 7AC 12.6V 600ma 8000 10

17L6 7AC 16.8V 450ma 8000 10

25L6 7AC 25V 300ma 8200 10 Popular as a computer tube!

1632 7AC 12.6V 600ma 9000 5.5 simlar to 25L6 except for heater and plate ratings. For applications critical as to Uniformity of Characteristics

6046 7AC 25V 300ma 8000 10 Relay Driver 25L6

35L6 7AC 35V 150ma 6100 8.5 Lower ratings due to lower heater power

50L6 7AC 50V 150ma 8000 10 Mainstay of the Octal All American Five.

There were other 6.3V Octal power tubes

6F6 7S 6.3V 700ma 2500 11 Octal Version of Type 42

6G6 7S 6.3V 150ma 2300 2.75

6K6 7S 6.3V 400ma 2300 8.5 Octal Version of a Type 41

6V6 6.3V 450ma 4100 12

6W6 7AC 6.3V 8000 12

6Y6 7AC 6.3V 1250ma 7100 12.5 Low Power applications, low maximum Plate Voltage

6DG6 7S 6.3V 1200ma 8000 10

6EF6 7S 6.3V 900ma 5000 10

6EY6 7AC 6.3V 680ma 4400 11

6EZ5 7AC 6.3V 800ma 4100 12

There were a number of other power tubes with the 7AC or 7S base, many designed for Military or Mobile equipment. Others for Series heater applications.

9EF6 7S 9.4V 600ma 5000 10

12A6 7Ac 7S 12.6V 150ma 3000 7.5 Discontinued before 1959

12B6 7S

12EF6 7S 12.6V 450ma 5000 10

25A6 7S 25V 300ma 2450 5.3 Octal Version of Type 43

25B6 7S 25V 300ma 5000 12.5

26E6 7S 26.5V 300ma 7100 12.5

50C6 50V 150ma 7000 12.5

1631 7AC 12.6V 450ma - 16 Similar to 6L6 except for Heater and plate ratings. For applications critical as to Uniformity of Characteristics

5824 7AC 25V 300ma 5000 12.5

8417 7S 6.3V 1600ma 23,000 35

Minature Power tubes.

Probaly more 50C5 and 50C5A tubes were made than any other power tubes other than the 50L6. Both types were the mainstay of inexpensive tube radios between 1939, and the 1960's. There are several tubes that are closely related to the 50C5.

11C5 7CV 11.6V 450ma 5,800 4.5

12C5 7CV 12.6V 600ma 7,500 6.0

17C5 7CV 16.8V 450ma 7,500 6.0

25C5 7CV 25V 300ma 7,500 6.0

35B5 7BZ 35V 150ma 5,800 4.5 Reduced ratings due to lower Heater power - Identical to 35C5 except for terminal layout

35C5 7CV 35V 150ma 5,800 4.5 Reduced ratings due to lower Heater power

50B5 7BZ 50V 150ma 7,500 6.0 Identical to 50C5 except for terminal layout

50C5 7CV 50V 150ma 7,500 6.0 Revised layout helps in meeting requirments for UL listing of series string radios.

The 7BZ base was also used in the 6AQ5 Family, which was popular for Mobile radio use.

6AQ5 7BZ 6.3V 450ma 4,100 12

6005 7BZ 6.3V 450ma 4,400 12

12AQ5 7BZ 12.6V 225ma 3,700 12

The 50EH5 and related tubes have a much higher gain than the 50C5. Some radios with the *EH5 do not have a audio preamplifier. Phonographs can use the 50EH5 driven directly from a piezo phono cartridge.

6EH5 7CV 6.3V 1200ma 14,600 5.5

12EH5 7CV 12.6V 600ma 14,600 5.5

25EH5 7CV 25V 300ma 14,300 5.5

35EH5 7CV 35V 150ma 12,000 5.0

50EH5 7CV 50V 150ma 14,600 5.0

60EH5 7CV

12FX5 7CV 12.6V 450ma 13,500 5.5

19FX5 7CV 18.9V 300ma 13,500 5.5

60FX5 7CV 60.0V 100ma 13,500 5.5

Other tubes with a 7CV base

4GZ5 7CV

6AS5 7CV 6.3V 800ma 5,600 5.5

12AS5 7CV 12.6V 400ma 5,600 5.5

6CA5 7CV 6.3V 1200ma 8,100 5.0

12CA5 7CV 12.6V 600ma 8,100 5.0

17CA5 7CV 16.8V 450ma 8,100 5.0

25CA5 7CV 25V 300ma 8,100 5.0

50CA5 7CV 50V 150ma 8,100 5.0

12CN5 7CV 12.6V 450ma 3,800 n/a RF pentode, not really a power tube.

6CV5 7CV 6,3V 1200ma 7,500 7.0

12CV5 7CV 12.6V 600ma 7,500 7.0

17CV5 (or CU5?) 7CV 16.8V 450ma 7,500 7.0

12DM5 7CV 12.6V 450ma 7,500 5.5

12ED5 7CV 12.6V 450ma 8.100 6.25

32ET5 7CV 32V 100ma 5,500 5.4

25F5 7CV 25V 150ma 5,800 4.5

25F5A 7CV 25V 150ma 6,400 5.5

50FA5 7CV 50V 100ma 5,800 5.2

50FK5 7CV 50V 100ma 12,800 5.0

40FR5 7CV 40V 100ma 6,000 5.2

34GD5 7CV 34V 100ma 5,700 5.0

6GH5 7CV 6.3V 380ma 8400 4.8

6GZ5 7CV 6.3V 380ma 8,400 4.8

12R5 7CV 12.6V 600ma 7,000 4.5

17R5 7CV 16.8V 450ma 7,000 4.5

A very popular Hi-Fi tube is the 6BQ5/EL84. This is a nine pin minature.

6BQ5/EL84 9CV 6.3V 760ma 11,300 12

8BQ5 9CV 8V 600ma 11,300 12

10BQ5 9CV 10.6V 450ma 11,300 12

7189 9CV 6.3V 760ma 11,300 12

7189A 9CV 6.3V 760ma 11,300 13.2

Other tubes with a 9CV base

6CW5/EL86 9CV 6.3V 760ma 11,000 14

8CW5/XL86 9CV 8V 600ma 11,000 12

10CW5/LL86 9CV 10.6V 450ma 11,000 12

15CW5/PL84 9CV 15V 300ma 11,000 12

32CW5 9CV

45b5 9CV 45V 100ma 8,800 14

8327 9CV 6.3V 760ma 13.2 Class C

6CZ5 9HN 6.3V 450ma 4,800 12 Sometimes recomended as a replacement for a 6973, although it would require re-wiring the socket.

6973 9Eu 6.3V 450ma 4,800 12 RCA promoted this as a good tube for HiFi equipment, it is also used in Projectors and Juke Boxes, it is getting hard to find.

6GC5 9Eu 6.3V 1200ma 8,000 12 High filament current limits this as a 6973 sub.

7061 9Eu 13.5V 210ma 4200 9

12AB5 9EU 12.6V 200ma 4100 12

6197 9BV 6.3V 650ma 10,000 7.5 Computer Power Amp.

I do have a long term goal to develop another table with a comparison of twin and tripple triodes like the 12AX7 and the 6SN7. No promises about when I will have a chance to do it however.

Back to the tube page

I enjoy the weather arround here!

please visit my other pages...

- -

There are three Skating FAQ Files on my Web Site

Welcome to

Karen Bryden's

My Thoughts on

Listing Last updated June 10/2001 by cmacd

back to my Index page

This page is running on the server
at in
Ottawa Ontario Canada.

Tube type	Base	Filament	Transconductance	Plate Rating	Notes
When RCA introduced the 6L6 Beam Power Pentode in the 1930's, they could not have realized that they were creating a design that would outlive the tube era, and be considered a vital ingredient of rock and roll. The 6L6 is probaly the tube that is most likely to come to mind one one thinks of an audio output tube. Russian, Chinese and eastern european factories still sell tubes that they call 6L6s. The orginal 6L6 was a metal octal tube, part of the first ever group of metal tubes.
6L6	7AC	6.3V 900ma	6000	19	Metal
6L6G	7AC	6.3V 900ma		19	ST-16 Glass
6L6GA	7AC	6.3V 900ma		19	ST-14 Glass
6L6GB	7AC	6.3V 900ma		19	T-12 Glass
6L6GC	7AC	6.3V 900ma	6000	30	T-12 Glass higher ratings
A number of special purpose or industrial tubes bear a family resemblence to the 6L6
1614	7AC	6.3V 900 ma		21
1621	7S	6.3V 700ma		7.9	Similar to 6F6 for applications requiring continuity of service.
1622	7AC	6.3 V 900ma		13.8	Similar to 6L6 for applications requiring continuity of service.
5881	7AC	6.3 V 900ma	6100	23	For output stages of Hi-Fi Audio
5932	7AC	6.3 V 900ma	6000	21
5992	7AC	6.3 V 600ma	4000	10
6550	7AC	6.3 V 1800ma	11000	42
7408	7AC	6.3 V 450ma	6000	14
7581	7AC	6.3 V 900ma	6000	30
7581-A	7AC	6.3 V 900ma	6600	35
KT66
EL34/6CA7		6.3V 1500ma	11,000	25
Unlike most series of tubes with the same letter designation and numbers, the 12,25,35and 50L6 tubes have lower ratings and a smaller physical size than their big brother the 6L6. The slightly lower heater rating of the 35L6 explains it's somewhat reduced ratings.
12L6	7AC	12.6V 600ma	8000	10
17L6	7AC	16.8V 450ma	8000	10
25L6	7AC	25V 300ma	8200	10	Popular as a computer tube!
1632	7AC	12.6V 600ma	9000	5.5	simlar to 25L6 except for heater and plate ratings. For applications critical as to Uniformity of Characteristics
6046	7AC	25V 300ma	8000	10	Relay Driver 25L6
35L6	7AC	35V 150ma	6100	8.5	Lower ratings due to lower heater power
50L6	7AC	50V 150ma	8000	10	Mainstay of the Octal All American Five.

There were other 6.3V Octal power tubes
6F6	7S	6.3V 700ma	2500	11	Octal Version of Type 42
6G6	7S	6.3V 150ma	2300	2.75
6K6	7S	6.3V 400ma	2300	8.5	Octal Version of a Type 41
6V6		6.3V 450ma	4100	12
6W6	7AC	6.3V	8000	12
6Y6	7AC	6.3V 1250ma	7100	12.5	Low Power applications, low maximum Plate Voltage
6DG6	7S	6.3V 1200ma	8000	10
6EF6	7S	6.3V 900ma	5000	10
6EY6	7AC	6.3V 680ma	4400	11
6EZ5	7AC	6.3V 800ma	4100	12

There were a number of other power tubes with the 7AC or 7S base, many designed for Military or Mobile equipment. Others for Series heater applications.

9EF6	7S	9.4V 600ma	5000	10
12A6	7Ac 7S	12.6V 150ma	3000	7.5	Discontinued before 1959
12B6	7S
12EF6	7S	12.6V 450ma	5000	10
25A6	7S	25V 300ma	2450	5.3	Octal Version of Type 43
25B6	7S	25V 300ma	5000	12.5
26E6	7S	26.5V 300ma	7100	12.5
50C6		50V 150ma	7000	12.5
1631	7AC	12.6V 450ma	-	16	Similar to 6L6 except for Heater and plate ratings. For applications critical as to Uniformity of Characteristics
5824	7AC	25V 300ma	5000	12.5
8417	7S	6.3V 1600ma	23,000	35
Minature Power tubes.
Probaly more 50C5 and 50C5A tubes were made than any other power tubes other than the 50L6. Both types were the mainstay of inexpensive tube radios between 1939, and the 1960's. There are several tubes that are closely related to the 50C5.
11C5	7CV	11.6V 450ma	5,800	4.5
12C5	7CV	12.6V 600ma	7,500	6.0
17C5	7CV	16.8V 450ma	7,500	6.0
25C5	7CV	25V 300ma	7,500	6.0
35B5	7BZ	35V 150ma	5,800	4.5	Reduced ratings due to lower Heater power - Identical to 35C5 except for terminal layout
35C5	7CV	35V 150ma	5,800	4.5	Reduced ratings due to lower Heater power
50B5	7BZ	50V 150ma	7,500	6.0	Identical to 50C5 except for terminal layout
50C5	7CV	50V 150ma	7,500	6.0	Revised layout helps in meeting requirments for UL listing of series string radios.
The 7BZ base was also used in the 6AQ5 Family, which was popular for Mobile radio use.
6AQ5	7BZ	6.3V 450ma	4,100	12
6005	7BZ	6.3V 450ma	4,400	12

12AQ5	7BZ	12.6V 225ma	3,700	12




The 50EH5 and related tubes have a much higher gain than the 50C5. Some radios with the *EH5 do not have a audio preamplifier. Phonographs can use the 50EH5 driven directly from a piezo phono cartridge.
6EH5	7CV	6.3V 1200ma	14,600	5.5
12EH5	7CV	12.6V 600ma	14,600	5.5
25EH5	7CV	25V 300ma	14,300	5.5
35EH5	7CV	35V 150ma	12,000	5.0

50EH5	7CV	50V 150ma	14,600	5.0
60EH5	7CV

12FX5	7CV	12.6V 450ma	13,500	5.5
19FX5	7CV	18.9V 300ma	13,500	5.5
60FX5	7CV	60.0V 100ma	13,500	5.5

Other tubes with a 7CV base

4GZ5	7CV
6AS5	7CV	6.3V 800ma	5,600	5.5
12AS5	7CV	12.6V 400ma	5,600	5.5
6CA5	7CV	6.3V 1200ma	8,100	5.0
12CA5	7CV	12.6V 600ma	8,100	5.0
17CA5	7CV	16.8V 450ma	8,100	5.0
25CA5	7CV	25V 300ma	8,100	5.0
50CA5	7CV	50V 150ma	8,100	5.0
12CN5	7CV	12.6V 450ma	3,800	n/a	RF pentode, not really a power tube.
6CV5	7CV	6,3V 1200ma	7,500	7.0
12CV5	7CV	12.6V 600ma	7,500	7.0
17CV5 (or CU5?)	7CV	16.8V 450ma	7,500	7.0
12DM5	7CV	12.6V 450ma	7,500	5.5
12ED5	7CV	12.6V 450ma	8.100	6.25
32ET5	7CV	32V 100ma	5,500	5.4
25F5	7CV	25V 150ma	5,800	4.5
25F5A	7CV	25V 150ma	6,400	5.5
50FA5	7CV	50V 100ma	5,800	5.2
50FK5	7CV	50V 100ma	12,800	5.0
40FR5	7CV	40V 100ma	6,000	5.2
34GD5	7CV	34V 100ma	5,700	5.0
6GH5	7CV	6.3V 380ma	8400	4.8
6GZ5	7CV	6.3V 380ma	8,400	4.8
12R5	7CV	12.6V 600ma	7,000	4.5
17R5	7CV	16.8V 450ma	7,000	4.5

A very popular Hi-Fi tube is the 6BQ5/EL84. This is a nine pin minature.
6BQ5/EL84	9CV	6.3V 760ma	11,300	12
8BQ5	9CV	8V 600ma	11,300	12
10BQ5	9CV	10.6V 450ma	11,300	12
7189	9CV	6.3V 760ma	11,300	12
7189A	9CV	6.3V 760ma	11,300	13.2
Other tubes with a 9CV base
6CW5/EL86	9CV	6.3V 760ma	11,000	14
8CW5/XL86	9CV	8V 600ma	11,000	12
10CW5/LL86	9CV	10.6V 450ma	11,000	12
15CW5/PL84	9CV	15V 300ma	11,000	12
32CW5	9CV
45b5	9CV	45V 100ma	8,800	14
8327	9CV	6.3V 760ma		13.2	Class C

6CZ5	9HN	6.3V 450ma	4,800	12	Sometimes recomended as a replacement for a 6973, although it would require re-wiring the socket.
6973	9Eu	6.3V 450ma	4,800	12	RCA promoted this as a good tube for HiFi equipment, it is also used in Projectors and Juke Boxes, it is getting hard to find.
6GC5	9Eu	6.3V 1200ma	8,000	12	High filament current limits this as a 6973 sub.
7061	9Eu	13.5V 210ma	4200	9
12AB5	9EU	12.6V 200ma	4100	12

6197	9BV	6.3V 650ma	10,000	7.5	Computer Power Amp.