EL34

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EL34

An EL34 vacuum tube
manufactured by Mullard

Classification:

Pentode

Service:

class-A
amplifier, class-AB
amplifier, class-B
amplifier, (audio amplifiers)

Height:

4.44 in (113 mm)

Diameter:

1.5 in (38 mm)

Cathode

Cathode type:

Indirectly heated

Heater voltage:

6.3

Heater current:

1.5 A

Anode

Max dissipation Watts:

25

Max voltage:

800

Typical class-A
amplifier operation

Amplification factor:

11

Anode voltage:

265V

Anode current:

100mA

Screen voltage:

250V

Bias voltage:

-13,5V

Anode resistance:

2k Ohms

Typical class-AB
amplifier operation
(Values are for two tubes)

Power output:

55W

Anode resistance:
(anode to anode)

3,4k Ohms

Anode voltage:

420V

Anode current:

2*120mA

Screen voltage:

375V

Bias voltage:

-38V

Reference

Tung-Sol 6CA7 (EL34 Substitute) Vacuum Tube Logic Book 2nd Edition,
1994, page 151

The EL34 is a thermionic valve or vacuum
tube of the power pentode
type. It has an international octal
base (indicated by the '3' in the part number) and is found mainly in the final
output stages of audio amplification circuits and
was designed to be suitable as a series regulator by virtue of its high
permissible voltage between heater and cathode and other parameters. The
American RETMA
tube designation number for this tube is 6CA7. The Russian analog is
6P27S (Cyrillic: 6П27C).

Contents

1 Specifications

2 Application

3 Replacement

4 Similar tubes

5 See also

6 References

7 External
links

Specifications[edit]

In common with all 'E' prefix tubes, using the Mullard-Philips
tube designation, the EL34 has a heater voltage of 6.3V. According to the
data sheets found in old vacuum tube reference manuals, a pair of EL34s with
800V plate voltage can produce 90 watts output in class AB1 in
push–pull configuration. However, this configuration is rarely found. One
application of this type was in "Australian Sound" public address amplifiers
commonly used in government schools in Australia in the 1950s, using four EL34s
for ~200 watts. More commonly found is a pair of EL34s running class AB1 in push–pull
around 375–450V plate voltage and producing 50 watts output (if fixed bias is
used), while a quad of EL34s running class AB1 in push–pull
typically run anywhere from 425 to 500V plate voltage and produces 100 watts
output. This configuration is typically found in guitar amplifiers.

Current production JJ E34L, blue glass edition

The EL34 is a pentode, while the 6L6, which delivers a similar range of power
output, is a beam
tetrode which RCA referred to as a beam power
tube. Although power pentodes and beam tetrodes have some differences in
their principles of operation (the beam forming plates of the beam tetrode or
fifth electrode (3rd grid) of the pentode, both serving to hinder the return of
unabsorbed electrons from the anode (or plate) to the 4th electrode (2nd grid))
and have some internal construction differences, they are functionally closely
equivalent. Unlike the 6L6, (EIA base 7AC) the EL34 has
its grid 3 connection brought out to a separate Pin (Pin 1) (EIA base 8ET) and
its heater draws 1.5 Amps compared to the 0.9 Amp heater in the 6L6. However,
Sylvania (and possibly GE) marketed a tube as 6CA7 which was not only in a
markedly different 'fat boy' envelope, but used a beam forming plate much like a
6L6. Examining the mica spacer on the top of the tube will confirm the lack of a
suppressor grid. Although these tubes have similar (but not identical)
characteristics, they are made very differently.

Matched EL34 vacuum tubes by Russian manufacturer Svetlana

The EL34 was introduced in 1953 by Mullard
and its parent company Philips
and, although no longer made by them, is manufactured by JJ
Electronic, Shuguang, Svetlana and Reflector
(Sovtek, Electro-Harmonix, Tung-Sol and
some brands), amongst others. Some firms make a related tube called an E34L
which is rated to require a higher grid
bias voltage, but which may be interchangeable in some equipment.

Application[edit]

The EL34 was widely used in higher-powered audio amplifiers of the 1960s and
1970s, such as the very popular Dynaco
Stereo
70 and the Leak TL25(mono) and Stereo 60, and
is also widely used in high-end guitar amplifiers because it is characterized by
greater distortion (considered
desirable in this application) at lower power than other octal tubes[citation
needed] such as 6L6,
KT88 or 6550. The EL34 is found in many
British guitar amps and is associated with the "British Tone" (Marshall, Hiwatt, Orange) as
compared to the 6L6 which is generally associated with the "American Tone" (Fender/Mesa
Boogie, and the earlier classic Marshall "Plexi" amps used the KT 66, a beam
tetrode similar to the 6L6, as well).

Replacement[edit]

6CA7

Similar tubes[edit]

KT77

6P27S
(6П27С)

See also[edit]

EL84

Pentode

6V6

6L6

5881

KT66

KT88

6550

Beam tetrode

List
of vacuum tubes

References[edit]

Technical specifications.

EL34 Philips Metal Base

Valvo GMBH, Valvo Taschenbuch 1958.

RCA, RCA Receiving Tube Manual RC26, 1968.

JJ Electronics EL34 and E34L data sheet (PDF)

EL34 EI Yugoslavia

External links[edit]

Duncan's Amps TDSL.

Reviews
of EL34 tubes.

Tube
Data Archive, thousands of tube data sheets

Retrieved from "https://en.wikipedia.org/w/index.php?title=EL34&oldid=670944891"

Categories:

Vacuum
tubes

Guitar
amplification tubes

Hidden categories:

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This page was last modified on 11 July 2015, at
08:31.

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