Clarke & Smith 747 schools receiver/amplifier

[ppppenguin]

I have put a schematic for this set in the archive. It has been discussed recently in another forum. At the time of writing I believe this is the only published copy of the schematic. I also have a large dyeline print (between A1 and A2 size) but everything seems legible on the A3 copy that I scanned.

This compact set was used in schools. We had one for the hall's PA when I was at William Ellis School, Highgate, from 1967 to 1974.

It's mentioned with a photo on page 16 of this article, which is taken from the BVWS Bulletin: http://www.ferrographworld.com/pdf/A%20h...lletin.pdf

The compact all transistor 747 receiver amplifier from the mid 1960s was probably the last to be housed in the stout oak cabinet that became the trade mark of the earlier Clarke and Smith products. Many of these saw use in ILEA controlled schools and colleges throughout the London area. The unit is a fraction of the size of the earlier equipment and packs quite a punch in terms of facilities. The output is rated at 10 Watts, with provision for microphone, gram tape etc taken to P.O type sockets housed on the right of the unit. The VHF tuner is switch tuned for the reception of Light, Home and Third with user adjustment behind a concealed flap on the main control panel. The receiver actually has a conventional tuner covering 88-108 MHz which is only accessible when the receiver is completely removed from the cabinet, with a narrow band of VHF frequencies being adjustable in conjunction with the switch tuning. The loudspeaker output is on 100V line only with no provision for driving low impedance only speakers

[Mark Hennessy]

Very interesting - thank you

[ppppenguin]

It's nice to contribute something that's genuinely new to the 'net. It's a tiny thing when you look at the fabulous World Radio History site: https://worldradiohistory.com/index.htm

When I'm at Paul Marshall's house I look at the dozens of feet of shelving full of manuals etc, mainly for TV broadcast kit, and wonder how many of them are unique. And how little of that information is available online. The BECG www.becg.tv trustees, which includes me, have thought about our aims. Apart from preserving equipment, the documentation is just as valuable. To say nothing of tacit knowledge, the stuff that isn't even written down. In an ideal world we would be scanning and OCRing all of this stuff but we simply don't have the huge number of man-hours to do it. A lot of the manuals are on large sheets, some even bigger than A1. Other stuff is in tightly bound books. Without specialist scanners and software it's all even harder. See how WRH does it here: https://worldradiohistory.com/Scanning-f...istory.htm David Gleason, the WRH man, deserves the engineering history equivalent of a Nobel Prize.

I look at the relatively small amount of stuff on my own shelves. For example I have complete paper (photo)copies of the manuals of the BBC 625 to 405 standards converters. Some of it is here: http://www.bbceng.info/ti/aco-post-1960.htm but precious little. Will I ever get round to scanning them? I very much doubt it.

The BBC has done great service by putting all its archive of Engineering Research Reports etc online: https://www.bbc.co.uk/rd/search?Type=Publications

[BusyBee]

It's useful to have access to this information. There are many good places on the net. There are some interesting BBC papers there, and no-one could fault 'World Radio History'. I remember once reporting an issue and got rapid resopse via email. Smaller archives, like here, are very useful resources too. A good service.

Tracy

[Mark Hennessy]

I look at the relatively small amount of stuff on my own shelves. For example I have complete paper (photo)copies of the manuals of the BBC 625 to 405 standards converters. Some of it is here: http://www.bbceng.info/ti/aco-post-1960.htm but precious little. Will I ever get round to scanning them? I very much doubt it.

Talk to Jayger121 - he's not been on here for a while, but you should be able to send him an email. If you get no joy, I'll contact him directly. I can't recall the full details at the moment, but I know he's been involved with scanning BBC material (and is in touch with others also doing the same).