Libero
pasqua49GUIDE TO EL34guide to EL34 6CA7.htm

Guide to the EL34 / 6CA7  

by

Pasquale Russo

(6.th Edition - February 2015)

   

 

 (365 pages – over 300 color pictures)

Available on-line in PDF format

email

 

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 EL34’s 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) don’t 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)

 

  • Introduction

 

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

  • Methods for tube designations

 

Mullard-Philips ……………………………………………………………………………………………………………….

34

RETMA ……………………………………………………………………………………………………………………………

35

GEC ………………………………………………………………………………………………………………………………..

36

  • Tetrodes – Beam Tetrodes – Pentodes

 

The Tetrode ……………………………………………………………………………………………………………………

37

The Beam Tetrode …………………………………………………………………………………………………………

40

The Pentode …………………………………………………………………………………………………………………..

43

  • The harmonic and the intermodulation distortion

45

  • Valve Characteristic curves

47

Va/Ia Characteristic curve …………………………………………………………………………………………….

47

Plate Characteristics Mutual Characteristics …………………………………………………………………

48

Amplification factor,Transconductance,Plate conductance,Plate resistance,Load line..

49

  • The EL34’s datasheets

51

  • Tube structure

53

Base ………………………………………………………………………………………………………………………………

54

Plate ………………………………………………………………………………………………………………………………

57

Getter …………………………………………………………………………………………………………………………….

59

Top and bottom spacers ……………………………………………………………………………………………….

63

Glass envelope ……………………………………………………………………………………………………………….

64

  • EL34s manufactured by the Philips Group

 

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

  • EL34 manufactured by Telefunken (West Germany)

 

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

  • EL34 manufactured in East Germany    

 

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

  • Other European EL34s

 

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 (1960’s) .............................................................

Tesla EL34 2.nd version (1970’s-1980’s) ..................................................

Tesla EL34 3.th version (1990’s) .............................................................

Tesla EL34 4.th version (late 1980’s – 1990’s) ..........................................

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

  • EL34 made in Russia

 

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

  • EL34 made in Japan

 

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 (1960’s) ...........................................................................

235

·                                 Mid version (late 1960’s) .......................................................................

236

·                                 Late version (1970’s-1980’s) ..................................................................

237

Summary 6CA7 / EL34s made in Japan ..............................................................

238

  • 6CA7 made in USA

 

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

  • 6CA7 made outside USA

 

Lindal 6CA7 (Korea) ………………………………………………………………………………………………………

257

E.I. 6CA7 Big Bottle  ……………………………………………………………………………………………………..

259

Electro-Harmonix 6CA7 …………………………………………………………………………………………………

260

Summary of 6CA7s made outside USA ………………………………………………………………………..

261

  • Close or identical to EL34

 

CV1741 by Mullard ………………………………………………………………………………………………………..

263

EL34G by Sovtek …………………………………………………………………………………………………………..

266

EL34WXT by Sovtek ………………………………………………………………………………………………………

267

EL34EH by Electro-Harmonix ………………………………………………………………………………………..

268

  • Different ratings or performance

 

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

  • EL34 made in China

 

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

  • Other EL34/6CA7s

 

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

  • Famous Tube Reissue

Mullard EL34 reissue ……………………………………………………………………………………………………..

Tung-Sol EL34B ……………………………………………………………………………………………………………..

Genalex Gold Lion KT77 reissue …………………………………………………………………………………..

  • Unknown tubes ……………………………………………………………………………………

 

346

351

353

355

Alphabetical index

356

References

362

 

 

 

 

 

   Below you may see a brief overview :

 

 

EL34s

manufactured by

the Philips Group

 

 THE PHILIPS GROUP

Philips, Mullard, Valvo, Amperex 

Koninklijke Philips Electronics N.V. (Royal Philips Electronics N.V.), usually known as Philips,  was founded in 1891 by Gerard Philips, a maternal cousin of Karl Marx, in Eindhoven, the Netherlands. Its first products were light bulbs and other electro-technical equipment. Its first factory remains as a museum. In the 1920s, the company started to manufacture other products, such as vacuum tubes. In 1927 they acquired the British vacuum tube manufacturers Mullard and in 1932 the German tube manufacturer Valvo, both of which became subsidiaries. In 1955 or so they acquired Amperex, originally located in Brooklyn, New York. Amperex was a long established manufacturer of transmitting tubes when they were acquired by the Dutch firm. Philips continued to improve and enlarge the transmitting plant in New York, but also used the Amperex name to distribute their new line of Dutch made tubes, to feed the booming U.S. Hi-Fi market.

The most important Philips Group’s Factories and their codes:

Eindhoven

Holland

Philips

1 – 2 – 3 - 6 -7- 8

Heerlen

Holland

Philips

 

Sittard

Holland

Philips

+ X  Y

Blackburn

G.B.

Mullard

B

Hamburg

Germany

Valvo

D

Munich

Germany

Siemens & Halske

≠

Brussels

Belgium

M.B.L.E. (Mazda)

L


  

THE EARLY EL34

(EINDHOVEN: 1954 - 55)

This is an EL60 with an octal socket adapter. The valve is easy identified by:

·         Extended  base

·         No hole in guide pin

·         Metal collar

·         Round plate

·         Flat ring getter

·         KE  Code on the metal collar (the old Philips code for EL34 metal).

 

Hits production begins in 1954 in EINDHOVEN (NL) and ends in 1955. This type, today extremely rare and  highly appreciated for its sonic qualities, is named too Royal Dutch EL34 or Tall Feet seven.

The code on the metal collar is formed by five symbols. The first, the third and the fourth are identical in all tubes. The second and the fifth, instead, can vary. Thus the basic code is : 5 (x) (first line)  KE (x) (second line). (see Philips Codes for EL34s metal based)

 

............ omitted ........... 

 

 

 

The second EL34 metal base

  (EINDHOVEN: 1954-1957)

 

This version may be identified by:

·         Black base

·         Folded and welded plate

·         SYN or SYO Code 

·         Hole in guide pin (generally)

 

  The valve was made in Eindhoven from 1954 to 1957. The code may be different:

5 (x)  (first line)

5 (x)(x)  (first line)

SYN   (second line)

SYO   (second line)

 

 ............ omitted ........... 

 

 

The Third  EL34 metal base

 (EINDHOVEN: 1956)

 

The valve can be identified by:

·         Lighter brown base

·         Crimped plate

·         Two piece disc getter

·         SY1 Code 

·         Hole in guide pin

 

 

 

Many thanks to :

 (http://www.tube-classics.de/TC/Tubes/Valvo%20EL34/EL34.htm)

(http://www.jogis-roehrenbude.de/)

 

 

The new edition of the Guide is available periodically on eBay or soon  emailing me.   (pasqua49@libero.it)

  

  Home