Valvo logo

The German company Valvo was an old and well-established company that made renowned vacuum tubes. Their history is not very well documented on the Web, at least not in English, but a starting point is this page on the German wikipedia (translated by Google), and some more detail is given on this Facebook page.

These reveal that the company was founded in 1924 in Hamburg, and in 1927 became part of the Philips group. Neither article mentions semiconductors in any detail, their focus being on vacuum tubes. However, the relationship between Philips and its subsidiaries Mullard (in England), Valvo (in Germany) and La Radiotechnique (in France) appears to have been quite free. (There was also Amperex in the USA, but this was essentially a sales channel). The subsidiaries had their own research facilities (of course Philips had major laboratories in Eindhoven) and may have been able to develop devices that went on to be manufactured across the group. If you know more about how this worked, please Apparently Valvo was split in the 1980s and sold in 1999.

Valvo did not normally print their logo on semiconductor devices, probably because of space limitations: they just printed the word VALVO in capital letters. I am seeking to buy or trade for germanium transistors and diodes made by Valvo, especially the types 100.O.C, OC10 to OC12, and OC50 to OC51, but also some others. More details are given below.

A possibly difficulty with identifying Valvo devices is that many came in small cartons clearly marked 'Valvo'. However the devices inside may be unbranded. This raises the question of whether they were really manufactured by Valvo, or whether they are Valvo-boxed Philips production.

The primary Valvo data book that I possess is the Valvo-Handbuch 'Halbleiterdioden und Transistoren'. I have copies dated 1958 and 1962. I also have a booklet 'Dioden Transistoren' dated 1960. I'm grateful to Gert who has sent me scans of the contents pages of several 1960s Valvo Taschenbuchs and the semiconductor Handbuch for 1965. I am interested in other original data books or sheets for any of their semiconductor devices.

If you know about them, or have have some devices for sale or trade, please


The earliest transistors made by the Philips group as a whole are described in several places on the Web, although the Philips pages on their company history seem to have disappeared, perhaps because of the change to NXP Semiconductors. On Google, there is a site by Mark Burgess that covers early Philips semiconductors, revealing that their first transistors were the point-contact types OC50 and OC51. It is unclear which manufacturers in the Philips group really made these and whether others simply marketed them: certainly Mullard made them, and I believe that Valvo did too.

I have a number of OC51 transistors that I believe were made by Mullard, and they have no branding. If you know about Valvo examples, or know how I can obtain Valvo OC50 or OC51, please

wanted transistor

The first junction transistors made by the Philips group were the trio OC10 to OC12 in small plastic cuboids. Again it is unclear which manufacturers in the Philips group really made these and which simply marketed them, and again I have some and they are unbranded. I recollect that I saw some claimed to be Valvo production in the Deutsches Museum in Munich. If you know about Valvo examples, or know how I can obtain some, please

OC72 transistor OC71 transistor OC70 transistor

Valvo went on to manufacture the next set of transistors from the Philips group: the OC70 to OC72 AF amplifier types from 1954. My two OC70s are sealed in their original cartons and I don't want to open them. I would like to find a loose one for display purposes. If you know how I can obtain one, please

100.O.C transistor

Another puzzle exists around the creation of Europe's first power transistor, the type 100.O.C. Mark Burgess states that this was 'released by Valvo in October 1954' and became the wider Philips group type OC15. In the USA it was marketed as the 2N115. I have the example shown: it bears no branding and all the printing on it is in English, including 'Semicond. Lab. Development Sample'. Consequently, I'm unconvinced that Valvo made this. I have no original Philips-group documentation for either 100.O.C. or OC15: it might help resolve the question. If you know how I can obtain some (or a scan of it), please

Valvo OC16 transistor

The first commercial power transistor in Europe was the OC16, in a stud package, released about 1956. It can be found branded Mullard and Valvo (shown), as well as unbranded, which I take as indicating Philips production in the Netherlands.

There exists also a more primitive version of the OC16 with leads emerging from the top. It is shown on my Mullard page. This is always unbranded in my experience but if you know of a Valvo-branded one, please

As I stated above, the oldest Valvo databook that I possess is 'Halbleiter - Dioden Transistoren' dated 1958. It lists the following types:

  • OA5 germanium gold-bonded diode
  • OA7 germanium gold-bonded diode
  • OA31 germanium high-current junction diode
  • OA70 germanium diode
  • OA72 germanium diode
  • 2-OA72 germanium diode pair
  • OA79 germanium diode
  • 2-OA79 germanium diode pair
  • OA73 germanium diode
Valvo OA5 diode Valvo OA7 diode
  • OA81 germanium diode
  • OA85 germanium diode
  • OA86 germanium diode
  • OA87 germanium diode
  • OA91 germanium diode
  • OA95 germanium diode
  • OA200 silicon diode
  • OA202 silicon diode
Valvo OA81 diode Valvo OA85 diode Valvo OA86 diode
  • OC16 germanium power transistor
  • 2-OC16 germanium power transistor pair
  • OC30 germanium power transistor
  • 2-OC30 germanium power transistor pair
Valvo OC16 transistor Valvo OC30 transistor
  • OC44 germanium transistor
  • OC45 germanium transistor
  • OC65 germanium transistor
  • OC66 germanium transistor
Valvo OC44 transistor Valvo OC45 transistor
  • OC70 germanium transistor
  • OC71 germanium transistor
  • OC72 germanium transistor
  • 2-OC72 germanium transistor pair
Valvo OC71 transistor Valvo OC72 transistor
  • OC76 germanium transistor
  • OC77 germanium transistor
Valvo OC76 transistor Valvo OC77 transistor

I would be most interested to see earlier (pre-1958) Valvo databooks or sheets, either originals or scanned images. I would also like to obtain examples of interesting Valvo-branded types missing from my collection, particularly OA31, OA72, OA87, OC65 and OC66. If you know how I can obtain some, please

The 'Dioden Transistoren' booklet from 1960 adds more types:

  • BA100 silicon all-purpose miniature diode
  • OA9 germanium gold-bonded diode
  • OA47 germanium gold-bonded diode
  • OAZ200 - OAZ207 silicon Zener diode
  • OC22 germanium power transistor
  • OC23 germanium power transistor
  • OC24 germanium power transistor
  • OC26 germanium power transistor
  • 2-OC26 germanium power transistor pair
  • OC28 germanium power transistor
  • OC29 germanium power transistor
Valvo OA9 diode
  • OC35 germanium power transistor
  • OC36 germanium power transistor
  • OC46 germanium switching transistor
  • OC47 germanium switching transistor
  • OC57 germanium subminiature transistor
  • OC58 germanium subminiature transistor
  • OC59 germanium subminiature transistor
  • OC60 germanium subminiature transistor
Valvo OC35 transistor Valvo OC36 transistor Valvo OC47 transistors
  • OC74 germanium output transistor
  • 2-OC74 germanium output transistor pair
  • OC75 germanium AF transistor
  • OC79 germanium output transistor
  • OC80 germanium switching transistor
Valvo OC74 transistor Valvo OC75 transistor Valvo OC79 transistor Valvo OC80 transistor
  • OC139 germanium NPN switching transistor
  • OC140 germanium NPN switching transistor
  • OC141 germanium NPN switching transistor
  • OC169 germanium RF transistor
  • OC170 germanium RF transistor
  • OC171 germanium RF transistor
Valvo OC140 transistor Valvo OC169 transistor
  • OC200 silicon transistor
  • OC201 silicon transistor
Valvo OC201 transistor

I would like to obtain examples of interesting Valvo-branded types missing from my collection, particularly OC46, OC57 to OC60, OC80, OC139 and OC141. If you know how I can obtain some, please

The Handbuch 1962 edition adds even more types, most now using Pro-Electron nomenclature:

  • AAZ12 germanium gold-bonded diode
  • AAZ13 germanium gold-bonded diode
  • AAZ15 germanium gold-bonded diode
  • AAZ17 germanium gold-bonded diode
  • AC107 germanium transistor
Valvo AC107 transistor
  • ADZ11 germanium power transistor
  • ADZ12 germanium power transistor
Valvo ADZ12 transistor
  • AF102 germanium RF transistor
  • AF114 germanium RF transistor
  • AF115 germanium RF transistor
  • AF116 germanium RF transistor
  • AF117 germanium RF transistor
  • AF118 germanium RF transistor
Valvo AF102 transistor Valvo AF116 transistor
  • AF124 germanium RF transistor
  • AF125 germanium RF transistor
  • AF126 germanium RF transistor
  • AF127 germanium RF transistor
  • AFZ12 germanium RF transistor
  • ASY26 germanium switching transistor
  • ASY27 germanium switching transistor
  • ASZ15 germanium power switching transistor
  • ASZ16 germanium power switching transistor
  • ASZ17 germanium power switching transistor
  • ASZ18 germanium power switching transistor
  • ASZ23 germanium switching transistor
  • AUY10 germanium power RF transistor
  • BA102 silicon miniature diode
  • BA109 silicon miniature diode
  • BCY10 silicon PNP AF transistor
  • BCY11 silicon PNP AF transistor
  • BCY12 silicon PNP AF transistor
Valvo BCY12 transistor
  • BCZ10 silicon PNP AF transistor
  • BCZ11 silicon PNP AF transistor
  • BCZ12 silicon PNP AF transistor
  • BY100 silicon power diode
  • BYY15 silicon power diode
  • BYY22 silicon power diode
  • BYZ14 silicon power diode
  • BZZ10 - BZZ13 silicon miniature Zener diode
Valvo BCZ10 transistor Valvo BCZ11 transistor
  • OA90 germanium miniature diode
  • OAZ208 - OAZ213 silicon Zener diode
  • OC80A germanium transistor
  • OC122 germanium RF transistor
  • OC123 germanium RF transistor
Valvo OC80A transistor

I would like to obtain examples of interesting Valvo-branded types missing from my collection, particularly BCY10, BCY11, BCZ12, OC122 and OC123. If you know how I can obtain some, please

I have a copy of the contents page of the Handbuch for 1964 and it includes many more Pro-Electron types. The most interesting to me are those that still use the older idiosyncratic outlines:

  • ASY31 germanium PNP switching transistor
  • ASY32 germanium PNP switching transistor
Valvo ASY32 transistor

I would like to obtain an example of ASY31 which seems to be rather rare. If you know how I can obtain one, please

It is interesting to compare Valvo's early range with that of Mullard. I maintain computer files that list all the types contained in my reference data books, both paper and electronic. I wrote some java software to generate this table by reading and processing my files for Valvo and Mullard. I only processed types starting with OA or OC, plus LDR and ORP. I added entries for types that I know to exist even though my databooks do not list them, this includes the early types OC10/11/12/50/51 for Valvo, which I strongly suspect do exist although I have no proof.

Type Valvo Mullard        Type Valvo Mullard        Type Valvo Mullard        Type Valvo Mullard        Type Valvo Mullard
2-OA72 OA91 OAZ246 OC57 OC123
2-OA79 OA95 OAZ247 OC58 OC139
2-OC16 OA200 OC10 OC59 OC140
2-OC20 OA202 OC11 OC60 OC141
2-OC26 OA210 OC12 OC65 OC169
2-OC28 OA211 OC16 OC66 OC170
2-OC29 OA214 OC16R OC70 OC171
2-OC30 OA250 OC16T OC71 OC200
2-OC35 OA251 OC19 OC71A OC201
2-OC36 OA252 OC20 OC72 OC202
2-OC72 OAP12 OC22 OC73 OC203
2-OC74 OAZ200 OC23 OC74 OC204
LDR03 OAZ201 OC24 OC75 OC205
LDR04 OAZ202 OC25 OC75A OC206
OA5 OAZ203 OC26 OC76 OC207
OA6 OAZ204 OC28 OC77 OCP70
OA7 OAZ205 OC29 OC78 OCP71
OA9 OAZ206 OC30 OC78D ORP10
OA10 OAZ207 OC30A OC79 ORP11
OA31 OAZ208 OC30B OC80 ORP12
OA47 OAZ209 OC35 OC80A ORP13
OA70 OAZ210 OC36 OC81 ORP14
OA71 OAZ211 OC41 OC81D ORP30
OA72 OAZ212 OC42 OC81DM ORP50
OA73 OAZ213 OC43 OC81M ORP60
OA79 OAZ240 OC44 OC82 ORP61
OA81 OAZ241 OC45 OC82D ORP62
OA85 OAZ242 OC46 OC82DM ORP63
OA86 OAZ243 OC47 OC83 ORP69
OA87 OAZ244 OC50 OC84 ORP90
OA90 OAZ245 OC51 OC122

There are some interesting differences visible in the above table:

If you know that any of the above is incorrect, (which is quite possible...), please

This table is a similar comparison for the early pro-Electron-named types. I list the germanium ones (starting with 'A') plus the silicon types BCY10 - BCY12 and BCZ10 - BCZ12 which are found in the SO-2 metal-over-glass outline, plus BC13 and BCZ14 which use a rare miniature encapsulation.

Type Valvo Mullard        Type Valvo Mullard        Type Valvo Mullard        Type Valvo Mullard        Type Valvo Mullard
AA119 AC172 AD161 AF180 ASZ18
AA129 AC176 AD162 AF181 ASZ20
AAY11 AC176K ADY26 AF185 ASZ21
AAY12 AC187 ADZ11 AF186 ASZ23
AAZ12 AC187K ADZ12 AFY19 ATZ10
AAZ13 AC188 AF102 AFZ11 AU101
AAZ15 AC188K AF114 AFZ12 AU103
AAZ17 ACY17 AF115 ASY26 AUY10
AAZ18 ACY18 AF116 ASY27 BCY10
AC107 ACY19 AF117 ASY28 BCY11
AC125 ACY20 AF118 ASY29 BCY12
AC126 ACY21 AF124 ASY31 BCZ10
AC127 ACY22 AF125 ASY32 BCZ11
AC128 AD136 AF126 ASY67 BCZ12
AC128K AD139 AF127 ASZ15 BCZ13
AC130 AD140 AF178 ASZ16 BCZ14
AC132 AD149 AF179 ASZ17

Again there are differences between the two product sets shown in the above table:

Here are some interesting types in the Valvo range, but not in Mullard's as far as I know:

Valvo wanted transistor
  • According to the superb radiomuseum site Valvo made a germanium diode type OA74, in fact they show an image of one and state that it was made by 'other Philips related manufacturers'. It also turns up elsewhere in Web searches. Nevertheless it is not found in any early Valvo or Mullard databook that I have seen, although it is listed in the 1963 CV Register as a 'prototype or possible substitute' for CV425. If you know where I can get any branded examples (Valvo or Mullard), please
Valvo OC75A transistor Valvo OC71A transistor
  • Here are the Valvo types OC71A and OC75A. These suffixed versions do not appear in the Valvo databooks I have seen, if you know where I can get data for these, please
Valvo OCP70 phototransistor
  • Here's an interesting device: it's the germanium phototransistor OCP70. All the examples I have seen are unbranded except these ones. The rightmost one is printed VALVO. It also bears a stylised crown containing the letters BWB and a number, seen on the middle one. This stands for 'Bundesamt fuer Wehrtechnik und Beschaffung' which translates as 'Federal Office of Defense Technology and Procurement'. I have some that are not marked VALVO, instead they just have the BWB mark and a capital V, seen on the leftmost one, which stands for 'Verteidigungsgeraetenormen' or 'Defense equipment standards'. This means that these devices meet German military specifications.
Valvo wanted transistor
Valvo BCZ13 silicon transistor