The Brush Crystal Company of Shore Road, Hythe, Southampton, manufactured early transistors and diodes, germanium and silicon. In 1964 they were bought by Clevite Transistor Products, an American company that specialised in power transistors, and renamed Brush Clevite Company. Their entry in Graces Guide tells no more than this (less, in fact), and I have found no more company history on the Web. However, other traces remain: an advertisement in 'Wireless World' February 1944 for 'hand crystal microphones' made by Brush, a Brush advertisement in 'Aeroplane' September 13th 1957 for quartz crystal units, and an article in 'Service Engineer' November 1961 about a 'new device designed to take the place of conventional trimmers and even gang capacitors' that was in fact a silicon varicap diode. The same article mentions five transistors in the OC700 series, and a 'new range of zener diodes'.

However, I know that most of the transistors and diodes branded Brush were also sold by the German firm Intermetall, which was also owned by Clevite. How this dual branding/manufacture worked is unclear.


On small devices, Brush usually used a small logo of a capital B in a diamond, often indistinctly printed. On larger ones, and some smaller ones, they just used the word BRUSH in capitals.

I have two editions of the Brush "semiconductors short form catalogue", dated May 1963 and May 1964. These contain germanium and silicon transistors in the OC series (with Intermetall-style 3-digit numbers), a small number of ASY types, and several series of Zener diodes. If you have earlier editions, please

Brush OC700A

It seems that the OC700 series may be Brush Crystal's first series of transistors. They are silicon PNP types. The range includes several applications:

My image shows OC700A and OC702. I am seeking most of the others. If you have have some for sale or trade, please

Brush OC701

I do have one oddity which is this OC701. It is not in the small TO-1A can, instead it uses the larger SO-2 metal. Furthermore it has a K printed low down on it. Some Intermetall transistors use this outline; they have a K suffix that stands for 'Kühlkörper' which means 'heatsink'. The Brush Crystal Semiconductors catalogue from 1963 does not explicitly list K versions of the OC700 series, but the diagram of the encapsulation shows the two shapes, implying that the entire range may have come in two versions.

If you can explain this, please

Brush OC706

This OC706 is a puzzle. It is not in my Brush data books, or on radiomuseum. The supplier said it was used in Burns guitar amplifiers. The OC700 series does not seem to be shared with Intermetall, and is mentioned in the article in 'Service Engineer' that pre-dates the takeover by Clevite. Puzzlingly, the OC706 uses the same style of TO-1A outline as Intermetall's transistors, whereas other OC700 series types that I possess are slightly different.

If you have data for this type, please

The 1963 semiconductors short form catalogue also lists the following devices, all made by Intermetall as well as Brush:

The 1964 semiconductors short form catalogue adds:

2N2063 transistor

Here is a Brush transistor that I believe is not connected with Intermetall, although radiomuseum claims it is: a 2N2063 germanium PNP alloy-junction high-power AF amplifier/switch. This is not listed in my Brush or Intermetall data books, and in fact the only good contemporary reference that I have found is the Motorola Semiconductor Handbook for 1966. Intermetall did not make power transistors, although they resold some Clevite types. It's very likely that this 2N2063 is a re-branded Clevite device, as the raised areas around the fixing holes are virtually unique to Clevite.

As with most manufacturers, I have several Brush devices that don't appear in my data books or on the Web. These are:

If you have data for any of these, please