Vintage Germanium Thorn-AEI (Family) Transistors

The early history of British Semiconductor manufacturing is pretty convoluted. There are many different brands which ended up being manufactured by the same company, and some major brands which remained from long gone acquisitions.

Mazda was a brand in Britain from 1911, initially for light bulbs, eventually transferring to the Thorn company. Thorn acquired the Brimar brand when STC's Valve (Tube) and CRT business was acquired in 1960.

Thorn Electrical Industries then created a JV in 1961 with AEI, itself a combination of British Electrical manufacturers. The plan was to pool its combined activities in Valves, CRTs and Semiconductors. Manufacturing was in Brimsdown (adjacent to Ponders End - the site of the Edison Swan Company).

EDISWAN transistors were also part of the group, and its transistors were manufactured in Ponders End.

The original Cosmos Lampworks factory built in Brimsdown was adjacent to the equivalent Edison Swan factory. Through acquisition and growth it seems the…

The First Flash Drive

In the photo is an M-Systems demonstration Disk-On-Chip from the 1990s, the forerunner of memory sticks and cards. The normally all black plastic package is top-filled with clear epoxy.
The company was founded by Dov Moran and was based in Israel.
The architecture remains the same for flash cards, SD etc. A high density standard memory chip and a separate controller chip (larger chip on the left above).
IBM were the first company in the US to market flash drives, buying M-Systems' products and re-branding them.
M-Systems were acquired by SanDisk.

Philips and Dolby HX-Pro

Inside the Philips FC920 cassette deck from 1993. Recent purchase for a very small amount of money, to explore analog cassette tapes with better sounding equipment.
This machine was equipped with Dolby HX-Pro which improved the overall sound of pre-recorded cassette tapes. It wasn't a noise reduction system like Dolby B or C, but was a dynamic signal bias system, implemented during the tape transfer process. Standard biasing mixed a high frequency fixed signal  to the source, to make the signal more linear (and better sounding).    HX-Pro (invented by Bang and Olufsen), made the bias dynamic, by reacting to the high frequency components of the music,  inside a feedback loop.
The NEC chip implemented the HX-Pro function in the cassette deck.
The cassette decks also had to be biased for different tape types, Ferric, Chrome or Metal, during production. You can see the adjustment components next to their text.

USSR Germanium Transistors

The image shows a 'Top Hat' germanium transistor from the early 1960s.
The Soviet semiconductor industry started in 1947 with point contact germanium diodes for detectors in radar systems. These were based on German devices. The USSR further developed its industry through a combination of internal innovation and development, and reverse engineering of Western products. The transistor, a P422 was part of a series of high frequency devices. The manufacturer is unknown. It is sitting on a photo of the internals of a SELGA 7 transistor radio which was made in the Riga Radio Rupnica Factory in Latvia in the early 1960s. A similar transistor can be seen with an orange mark to the left, (artistic blurring to the photo :-).

This works - germanium PNP, hfe (gain) = 51, Vf=298mV.

Fairchild Semiconductor's First Product

Double diffused base silicon mesa transistor 2N697, Fairchild's first product was launched commercially at the Wescon show in August 1958.

Fairchild's first product was a commercial success due to its benefits over other transistors on the market. IBM were Fairchild's first customer, using the 2N697 as a ferrite core memory driver on the XB-70 avionics contract. IBM paid $150 per transistor for the first order, 30 times the industry price. The Fairchild 2N697 was silicon, hence it had high temperature benefits over germanium and had lower power dissipation than other silicon equivalents, due to Fairchild's diffusion process.

Fairchild Semiconductor (in the late 50s and 60s) were one of the most innovative and influential companies in semiconductor history, developing the planar process and the first integrated circuits.

Former SGS-Fairchild Semiconductor Facility in Falkirk

I took this photo in 2012, and was driving past last year, and noticed the buildings had been levelled and the site cleared. When I saw it in 2012, the former Fairchild semiconductor manufacturing buildings had been incorporated into a local college.

SGS-Fairchild was a JV by SGS of Italy and Fairchild Semiconductor. They had three manufacturing sites in Europe for micrologic DTL circuits, in Catania, Rennes and Falkirk.

The Falkirk, Scotland facility was established in 1968 and closed in 1981, a major downturn year in semiconductor history. By then it was manufacturing CMOS circuits, but a little too late.

In 1967 Marconi-Elliott had their equivalent DTL diffusion plant in Glenrothes and were establishing a MOS research lab, also in Glenrothes. General Instrument had established their MOS plant also in Glenrothes around the same time, similar timing to Hughes Aircraft's MOS process development in Glenrothes. National Semiconductor were planning their bipolar wafer fab in Greenoc…

Philips CD-i 220 - Perhaps Also a High End CD Player ?

The Philips CD-i was the first CD based movie and game unit. Before PC CD-ROMs and the PlayStation. It was so ahead of the curve at the time. Philips was a major consumer electronics innovator.

The Crystal CS4328 was a well regarded Digital to Analog converter in the early 90s. A number of high end CD players used it, for example the Quad CD-67 from 1993. The CD-67 retailed at 795GBP. 1,539GBP in today's money ! And it used a Philips CD transport mechanism.

The CS4328 is a high performance 18 bit DAC and the AD7528s are dual 8 bit DACs. The K version of the CS4328 shown here is the -93dB typical (-90dB max) higher THD+N spec version. SNR is 120dB min. Power supply filtering is good on the device with tantalum and surface mount ceramic capacitors in parallel on the +/-5V analog supplies and +5V digital supply.

If you look at the service manual schematics there are different player options. One uses the Philips SAA7321 Bitstream DAC and the other uses the CS4328.

It looks like the …