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 print their logo on semiconductor devices: 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.
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 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 which simply marketed them: certainly Mullard made them, and I suspect 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 some, please
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. If you know about Valvo examples, or know how I can obtain some, please
Valvo went on to manufacture the next set of transistors from the Philips group: the OC70 to OC72 AF amplifier types from 1954. Valvo also made the variant shown : OC71A, and added this suffix to a few other types too. I don't know what it signifies, possibly a tighter gain selection. Again I have no original documentation for this so if you know how I can obtain some (or a scan of it), please
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. 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
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, 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.
Valvo went on to issue own-branded versions of the majority of early semiconductor devices in the Philips-group range. It is interesting to try to compare Valvo's range with that of Mullard. The primary Valvo source for comparison that I have readily available is the Valvo-Handbuch "Halbleiterdioden und Transistoren" dated 1962, but I have supplemented it with other data. For Mullard types I used the "Mullard Maintenance Manual" 1961, the "Mullard Designer's Guide" May 1964, and other earlier sources plus Mullard types in my possession. I only compare the germanium series plus a few early silicon types: AA, AC, AD, OA, OC and BCZ. The earliest types OC50/51/10/11/12 were obsolete by the time of the documents I used. (I had to write some software to generate this table because the html coding was so onerous and error-prone).
"OAZ group" comprises OAZ200 to OAZ213 Zener diodes in SO-2 metal-over-glass outline.
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.
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
Obviously, the interesting types are the ones that Mullard (and probably Philips too) did not manufacture:
I don't have any of the Valvo matched pairs (like 2-OA72 or 2-OC30). I am seeking examples of these, by Valvo or Mullard.
Here is the BCZ10 silicon PNP general purpose transistor. The group BCZ10 to BCZ12 shares with the OC200 group and the rather obscure BCY10 to BCY12 the oddity of being the only silicon transistors in the SO-2 metal-over-glass encapsulation.
This BCZ13 is an oddity. It is a silicon PNP transistor intended as an AF amplifier. The only other transistors that use this Philips-group subminiature can are the germanium OC57 to OC59 intended for use in hearing aids. It is not printed VALVO, but the case is very small, and the examples of OC57 to OC59 that I possess are also unbranded.
Here is the OC79 germanium PNP low power AF amplifier/driver.
Here are some unused OC47s in original packaging. I don't have Valvo-branded OC46 or OC80A transistors. I am seeking examples of those.
Here are two Valvo-branded OA9 diodes. I am seeking examples of OA72.
Here's an interesting device: it's the germanium phototransistor OCP70. This is included in the Philips Pocketbook for 1959, but not in my Valvo data books for 1958 and 1960. However, 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 military specifications. This is intriguing, as the type OCP71 seems to have superseded OCP70 rather quickly. I don't have any Valvo OCP71s, although I have a number of Mullard ones.
For completeness, here is an image to show that Valvo made germanium diodes in both of the main Philips-group encapsulations (single-ended and double-ended glass capsules). I don't have any in other outlines, notably the OAZ Zeners in the SO-2 metal-over-glass capsule.