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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

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Old 19th Mar 2012, 10:24 pm   #1
BBRQ229
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Default L Ormond Sparkes - kits/cicuits (circuits) - 1950s

Following an earlier query of mine and two interesting/helpful responses, does anyone know where I might get hold of copies of the circuits marketed by Mr Sparkes in the early to mid 1950s.

A long shot, I know......
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Old 20th Mar 2012, 12:00 pm   #2
lesmw0sec
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Default Re: L Ormond Sparkes - kits/cicuits - 1950s

Tony,
Although I have already mentioned that I do not have any copies of the data sheets, the following memories might be of help:

I recall two units in particular. One (mains, live chassis) used the U series of valves (series heaters). The first stage was a pentode in a regenerative circuit with leaky-grid detection. The feedback for regeneration was from the cathode to a tap on the tuning coil. The amount of reaction/volume was controlled by varying the screen grid voltage via a 100K pot. The anode circuit contained an HF choke to remove RF and the audio was coupled to a UL84 output pentode. The gain was quite sufficient to drive a loudspeaker. There was a similar battery version using the DL series of B7G valves.
There was also a non-lethal mains kit which used the same detector/output arrangement but also had an EF80 RF stage. That set although just a TRF, gave very good selectivity and gain.
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Old 20th Mar 2012, 9:04 pm   #3
BBRQ229
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Default Re: L Ormond Sparkes - kits/cicuits (circuits) - 1950s

Hi Les2 - i thought that was a great story - L1 and L2. Loved it. Thanks for the additional information - very interesting. I had hoped to indulge in some nostalgia by building the same set that I did all those years ago - I have the coil! (I cant recollect what it was called though....); so hoped to find the data sheet/circuit. Must be in some archive somewhere.
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Old 11th Feb 2015, 11:38 pm   #4
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Default Re: L Ormond Sparkes - kits/cicuits (circuits) - 1950s

In approximately 1957/58 I built the "Sparkes Seafarer" from a kit. The "Sparkes Seafarer" was a T.R.F receiver which had a frequency range which included the 160 and 80 metre amatuer bands. It had two valves a D.F 96 and a DL 96 and "denco" coils. Unfortunately I no longer have the circuit diagram.
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