|NOTES||Another piece of top quality kit from Marconi. It is however
very difficult to determine it's release date as all Marconi equipment used
very similar styling throughout the 50's and 60's. An identical looking
instrument to this one - the TF1102 - is featured in a 1956 advertisment
so one would logically assume this instrument is earlier. However, some
of the electrolytics, which look like they are the original ones, are dated
July 1965 by which you would have thought some blasted tr*ns*st*rs would
have sneaked their way in.
Cheaper audio frequency generators tend to utilise variable resistors to alter the frequency of oscillation. This allows comparatively large fixed capacitors and lower impeadance resistances to be used. However this kit uses a variable capactor ; such capacitors are seldom available in much more than 500pF capacity so large value resistors are necessary (~15MOhm for 20Hz). The advantage is far superior temperature stability and repeatability, but the flip side is the circuitry is very sensitive to stray capacitances and coupling to other circuitry. For this reason the tuning components are held in a screened box.
|CURRENT STATE||Immaculate inside and out.|
|WHERE FOUND||A Donation from Dave.|
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THE SIG GEN GALLERY
17th January 2004