|
Preface to the sixth edition
Considering the increasing scarcity of vintage EL34s and the growing interest for similar tubes made in the golden age, I totally revised the chapter about the ancestors of the EL34, describing widely valves such as AL5/375, EL5/375, 4688, 4689,4699, EL35, EL60 and EL61, today highly sought by tube-fans.
New details and pictures were added to EL34s famous versions, like Philips metal base D-D getter (a real surprise, for me at least) or Philips coin base (made probably by Valvo).
I considered also the unsolved question about Brimar EL34, i.e. if they really made an own version or simply relabelled valves manufactured by others.
Completely revised the chapter about RFT EL34s, because during their large production were introduced many variations, for instance in getter and plate design.
Still within the European production, I treated even other Companies, like Haltron, Ultron and Polam, trying to establish if they were only simple tube importers.
About 6CA7, were introduced the Lindal version made in Korea and another great beam tetrode, Toshiba 6GB8, well known by the experts, slightly different for its ratings and still today very interesting.
More details regarding Japanese and Chinese production further clarify the argument.
This new edition consists of 365 pages and many new color pictures were added. I hope that these new searches can be useful for the reader. As usual, I invite anyone who finds mistakes or has further information to let me know.
February 2, 2015 Pasquale Russo
Preface to the fifth edition
Just one year after the previous edition, I felt the need to draw up a new version of my Guide, because many new data I obtained thanks to researches, deeper studies or observations and also from reports of friends and readers. Moreover, in some cases it was necessary to modify some inaccurate information or make clearer several aspects.
In short, I had a further confirmation of what was huge the topic to deal with.
It was necessary, for instance, re-write the chapter on the Philips date-codes or on Sylvania 6CA7 versions.
New chapters like RFT quality marks, Matsushita or NEC 6CA7 versions, Shuguang fat bottle 6CA7 versions, or Guiguang EL34s were added.
The more recent Chinese production and the famous tube reissues, like Mullard EL34 reissue or Tung-Sol EL34B are now included in the Guide.
The pages of this new edition are 332 instead of 291 of the previous edition, and many new color pictures and tables were added.
I am aware that also this new version cannot be considered definitive and I invite those who wish it to contact me for advice or new information. Finally, as usual, I hope that the reader will excuse my shortcomings of language, resulting from my imperfect knowledge of the English.
December 16, 2013
Preface to the fourth edition
Further research and information collected over the time encouraged me to a new revision, in order to better focusing some aspects, add new aspects and sometimes fix mistakes. So in the guide are increased the pages (291 instead of 249) and the pictures (over 270).I revisited almost all chapters and, when it has been possible, I replaced some pictures with better.
Tesla and Amperex chapters, for instance, are now fully modified, introducing new versions and, for Tesla tubes, further information on date-codes. Moreover Japanese Matsushita and Hitachi are enhanced with new images and information.
The large Chinese production that still increases nowadays at high speed but trying, in my opinion, to achieve better results over the time, moved me to modify and add new chapters, for instance Psavane 6CA7s and EL34s.
I am aware that, cause the enormous amount of production for EL34/6CA7 tubes, it is impossible for anyone elaborate an exhaustive Guide, but each new attempt is always fascinating for me.
I renew my apologies for my English and I hope that the reader will appreciate my efforts. I will grateful to anyone who want provide further information or criticism.
December 2012
Preface to the third edition
The enormous quantity of materials regarding the EL34 and 6CA7 still today does not allow and maybe will never allow a full presentation on this subject.
Almost every day I discovered new unknown aspects and sometimes apparent contradictions to my previous elaborate. Thus I felt the need of further searches and deepening.
Moreover, in my previous edition I perhaps neglected the more recent elaborations, like the Chinese versions, which have today a great importance both for quantity and quality of the manufacturing.
The major aim of my Guide is to help the reader to know the main characteristics of every version, facilitating his identification but too supplying essential references on history, chronology, evolution of each model. Thus, many chapters was revisited and enriched, as for instance TFK pre-series, Siemens and Tesla EL34s, GE 6CA7s, Matsushita and Nec 6CA7s, etc.
Furthermore, new chapters was written, like history and plants of RFT, RFT versions, RFT and TGL codes, Tesla date-codes, Tungsram EL34s, Sovtek EL34G, EL34G+ and EL34WXT, Chinese tube history and factories, Chinese EL34s, US labelled EL34/6CA7s, etc. So, this new edition is over 240 pages instead of 190 of the previous edition.
I hope the readers will appreciate my effort, continuing to supply me advises and criticisms. Only on this matter will be possible a knowledge always better of this glorious chapter of the audio power pentode.
I am trying to improve my English but my age (I am 60) dont make it easy. So I trust the reader will excuse my mistakes.
January 2010 Pasquale Russo
Preface to the Second Edition
The flattering success obtained in the first edition and recommendations of the readers, encouraged me to elaborate a review, trying to improve some special aspects. I changed many photographs and in some cases I have deepened technical questions. I hope that these improvements will make the Guide more useful.
January 2009 Pasquale Russo
Preface to the First Edition
I spent many years collecting and using the EL34s.
Finally I became convinced that it was extremely worth trying to put order in
the enormous literature on this great vacuum tube, which still enjoys
deserved
success and fame throughout all the world. I decided
then to write this technical guide on the EL34s and 6CA7s, which lists the
history and theoretical assumptions about these valves, its models and versions
that have occurred over time, and too the comparisons
between hits various types.
In my discussion I deliberately ignored any value
estimation, concentrating on technical and structural aspects of each model. I
am persuaded that everyone can and must forms its own opinion, based on its
personal needs and tastes.
I also tried to be as concise as possible, focusing on
the characteristics and key aspects of each model. When it was possible, I have
always mentioned the source of reference, for reasons of fairness and too to
give the opportunity to learn more topics. The text is enriched by many pictures
(over 200) and some tables for training purposes.
I believe that my work will be useful for everyone who
needs interest on these tubes for hobbies or for working.
Although I am Italian, I prefer using the English
language, in order to reach the largest possible number of people. The reader
will then excuse my grammar errors and my imperfections of language, due to my
insufficient knowledge of the English. Moreover my work does not have absolutely
literary pretensions but it want only be an useful tool of technical guidance.
Whatever criticism and advice you will want give me will be welcome.
December 2007
Pasquale Russo
|
CONTENTS
(365 pages over 300 color pictures)
|
|
|
|
The predecessors of EL34 :AL5/375,4688,4689,4689K,4699,EL35,EL60,EL61
|
11 |
|
Predecessors Synoptic Table
..
A new 25W audio output pentode (An advert from Mullard Ltd. for EL34 1952)
|
28
30 |
|
|
|
|
Mullard-Philips
. |
34 |
|
RETMA
|
35 |
|
GEC
.. |
36 |
|
|
|
|
The Tetrode
|
37 |
|
The Beam Tetrode
|
40 |
|
The Pentode
.. |
43 |
|
|
45 |
|
|
47 |
|
Va/Ia Characteristic curve
. |
47 |
|
Plate Characteristics Mutual Characteristics
|
48 |
|
Amplification factor,Transconductance,Plate conductance,Plate resistance,Load line.. |
49 |
|
|
51 |
|
|
53 |
|
Base
|
54 |
|
Plate
|
57 |
|
Getter
. |
59 |
|
Top and bottom spacers
. |
63 |
|
Glass envelope
. |
64 |
|
|
|
|
The Philips Group
.. |
67 |
|
The birth of the EL34
. |
67 |
|
The early EL34
.. |
70 |
|
The first EL34 metal base
. |
71 |
|
The second EL34 metal base
. |
72 |
|
The third EL34 metal base
.. |
73 |
|
The fourth EL34 metal base
|
74 |
|
EL34 metal base made in Germany
. |
75 |
|
EL34 metal base D-D getter
... |
76 |
|
Summary of Philips EL34s metal based
. |
77 |
|
Notes about Philips codes KE and SY
.. |
78 |
|
Philips EL34s no metal based ............................................................................ |
82 |
|
Mullard story .................................................................................................. |
83 |
|
· Blackburn (1958-1961)
.. |
86 |
|
· Mullard Xf1 sub-versions
.. |
87 |
|
· Blackburn (1962-1968)
.. |
91 |
|
· Blackburn (1969-1970)
.. |
92 |
|
· Blackburn (1971-1973)
.. |
93 |
|
· Blackburn (1973-1975)
.. |
94 |
|
· Blackburn (1976-1980)
.. |
95 |
|
· Sittard (1975-1960)
|
96 |
|
· Brussels (1960-1962)
. |
97 |
|
· EL34 glass (or coin) base (by Valvo ???)
|
98 |
|
Summary of Philips EL34s no metal based
. |
99 |
|
Brimar EL34
. |
100 |
|
· Amperex metal base
.
· Amperex no metal base
.
· Amperex by Matsushita
. |
101
102
106 |
|
Summary of Amperex EL34s
. |
108 |
|
Notes about Philips Xf code and Xf0 code
|
109 |
|
Valvo story
. |
122 |
|
|
|
|
Telefunken story
|
115 |
|
First EL34 metal based
.. |
117 |
|
Second EL34 metal based
|
118 |
|
First no metal version
. |
119 |
|
Second no metal version
.. |
120 |
|
Third no metal version
|
121 |
|
Fourth no metal version
. |
122 |
|
Fifth no metal version
. |
123 |
|
Glass base version
. |
124 |
|
TFK EL34 with two slant ring getters
. |
125 |
|
Summary of TFK EL34s - Notes about Telefunken EL34 codes
. |
129 |
|
TFK EL34s made by Mullard
. |
134 |
|
|
|
|
The story of RFT
. |
138 |
|
EL34s manufactured by RFT
|
143 |
|
RFT EL34s no dimple top (early versions)
.. |
147 |
|
RFT EL34s dimple top (late versions)
. |
148 |
|
RFT EL34s quality marks
.
Summary RFT EL34s
. |
150
151 |
|
Notes on TGL codes
. |
151 |
|
Notes on RFT date-codes
|
152 |
|
RSD EL34s
.. |
155 |
|
Differences between TFK made in W.G. and in E.G.
|
157 |
|
|
|
|
Siemens & Halske story
|
161 |
|
EL34 Siemens made by Philips
. |
162 |
|
EL34 Siemens made by Telefunken (W.G.)
.. |
164 |
|
EL34 Siemens made by RFT (E.G.)
|
165 |
|
EL34 Siemens made by E.I.
EL34 Siemens made by J.J.
|
166
167 |
|
E.I. EL34 - E.I. 6CA7 ..................................................................................... |
168 |
|
Tesla EL34s - Tesla story ...............................................................................
Tesla EL34s versions .......................................................................................
Summary Tesla EL34s versions .........................................................................
Tesla EL34 1.th version (1960s) .............................................................
Tesla EL34 2.nd version (1970s-1980s) ..................................................
Tesla EL34 3.th version (1990s) .............................................................
Tesla EL34 4.th version (late 1980s 1990s) .......................................... |
170
171
173
177
178
179
180 |
|
Tesla E34L .................................................................................................... |
181 |
|
Teslovak E34L ................................................................................................ |
181 |
|
Notes on Tesla codes .......................................................................................
Teslovak E34LS .............................................................................................. |
182
187 |
|
JJ EL34 E34L ............................................................................................... |
188 |
|
Tungsram EL34s - Tungsram story..................................................................... |
190 |
|
Tungsram EL34 by Mullard .....................................................................
Tungsram EL34 by Tesla ........................................................................
Tungsram EL34 by RFT .......................................................................... |
191
193
194 |
|
Haltron EL34s ................................................................................................. |
195 |
|
Hultron EL34s ................................................................................................ |
197 |
|
Polam(p) EL34s .............................................................................................. |
198 |
|
Summary of other European EL34s
.. |
199 |
|
|
|
|
Svetlana Story
. |
201 |
|
Svetlana S logo (prior to 2003)
.. |
202 |
|
· Svetlana black base .............................................................................. |
203 |
|
· Svetlana clear top ................................................................................. |
204 |
|
· Svetlana brown base ............................................................................. |
205 |
|
· Svetlana S logo date-codes .................................................................. |
206 |
|
Svetlana C winged logo ................................................................................. |
206 |
|
Svetlana S logo (post-2003) .......................................................................... |
212 |
|
Sovtek EL34s ................................................................................................. |
215 |
|
· Sovtek EL34G ....................................................................................... |
215 |
|
· Sovtek EL34G + - Sovtek EL34WXT |
216 |
|
Electro-Harmonix EL34s
.. |
218 |
|
Summary of EL34s made in Russia
.. |
219 |
|
|
|
|
Matsushita EL34s ............................................................................................ |
221 |
|
Metal base version ................................................................................ |
222 |
|
Disc getter version ................................................................................ |
223 |
|
D-D getter version ................................................................................ |
224 |
|
Single ring getter version
. |
225 |
|
2-ring getter version
. |
226 |
|
Amperex EL34 by Matsushita
|
227 |
|
Variants in Matsushita EL34s
...
|
228 |
|
Notes about Matsushita codes
.. |
230 |
|
NEC 6CA7/ EL34 ............................................................................................. |
231 |
|
Disc + ring getter version
. |
232 |
|
Ring getter version ............................................................................... |
233 |
|
Hitachi 6CA7/EL34 .......................................................................................... |
234 |
|
· Early version (1960s) ........................................................................... |
235 |
|
· Mid version (late 1960s) ....................................................................... |
236 |
|
· Late version (1970s-1980s) .................................................................. |
237 |
|
Summary 6CA7 / EL34s made in Japan .............................................................. |
238 |
|
|
|
|
Sylvania 6CA7 - Sylvania 6CA7 versions ..........................................................
45° declined dual top disc getter .............................................................
45° declined dual top disc getter + side ring getter ...................................
One top ring getter ...............................................................................
One top ring getter + side getter ............................................................ |
240
242
243
244
245 |
|
Philips ECG 6CA7s ................................................................................. |
247 |
|
Sylvania date-codes .............................................................................. |
248 |
|
GE 6CA7s ...................................................................................................... |
250 |
|
GE Date-codes .....................................................................................
Sylvania 6Ca7 vs. GE 6CA7 .............................................................................. |
251
254 |
|
Summary of 6CA7s made in USA
. |
255 |
|
|
|
|
Lindal 6CA7 (Korea)
|
257 |
|
E.I. 6CA7 Big Bottle
.. |
259 |
|
Electro-Harmonix 6CA7
|
260 |
|
Summary of 6CA7s made outside USA
.. |
261 |
|
|
|
|
CV1741 by Mullard
.. |
263 |
|
EL34G by Sovtek
.. |
266 |
|
EL34WXT by Sovtek
|
267 |
|
EL34EH by Electro-Harmonix
.. |
268 |
|
|
|
|
KT77 by GEC - GEC story
.. |
270 |
|
C.S. Bull S.Rodda (UK EMI) Beam Tetrode Patent
|
271 |
|
KT77 by GEC made in UK
..
Early version
Late version
..
Genalex KT77 Gold Lion
. |
287
287
288
291 |
|
KT77 by GEC made in China
|
292 |
|
Notes about GEC KT77 date code
|
293 |
|
KT77 by JJ
.. |
294 |
|
E34L by Tesla
|
296 |
|
E34LS by Teslovak-JJ
. |
298 |
|
E34LS for Groove Tubes
. |
300 |
|
6GB8 by Toshiba
|
301 |
|
Black plates + 1 top ring getter version
|
302 |
|
Black plates + 2 top ring getter version
|
303 |
|
Black plates + 2 top ring + 1 side ring getter version
. |
304 |
|
Grey plates version
|
305 |
|
|
|
|
The early Chinese tube industry
|
307 |
|
Shuguang EL34s
|
313 |
|
· Early version
|
313 |
|
· 2.nd version
. |
314 |
|
· 3.th version
.. |
315 |
|
· Late version
. |
316 |
|
Summary Shuguang EL34s
.
Shuguang 6CA7s (Fat bottle) ..
.. |
317
318 |
|
Folded plates version
|
318 |
|
4-stapled plates version
. |
319 |
|
Shuguang Golden Dragon 6CA7/EL34s
.. |
320 |
|
Super TNT EL34mi
|
321 |
|
6CA7-Z
|
321 |
|
Canada Fuller EL34G
.. |
323 |
|
Shuguang Psvane 6CA7-T/EL34s
. |
324 |
|
6CA7-T
|
325 |
|
6CA7-TII
.. |
329 |
|
Psvane EL34
.
Guiguang EL34
.. |
330
332 |
|
|
|
|
National Electronics (NE) 6CA7/EL34s
. |
334 |
|
National Electronics 6CA7 by GE
. |
334 |
|
NE National Electronics 6CA7/EL34 made by RFT
.. |
337 |
|
National Electronics 6CA7/EL34 made in China
..
Early version
Late version
. |
338
338
339 |
|
United Electronics EL34s
. |
340 |
|
Groove Audio Tubes
|
342 |
|
· GT6CA7-GE
.. |
343 |
|
· GTEL34M
|
343 |
|
Mullard EL34 reissue
..
Tung-Sol EL34B
..
Genalex Gold Lion KT77 reissue
..
|
346
351
353
355 |
|
Alphabetical index |
356 |
|
References |
362 |
|
|
|
|
|
|
|
|
|
