Ruined Radio - The Eddystone 940

As a new recruit to the Eddystone User Group recoiling from Bill Lowe's comments, my learned Chairman who went on the record saying;

Some receivers are like chocolate eclairs, delicious to look at but when you bite into them, there is little of substance

His remark was probably based on the little EC10, a radio I had a deal of fun with.

But the big Eddystone was a 940 all right but when you picked it up, it didn't seem to have the rib-snapping weight I expected and a Plessey plug where we hoped to find a power lead. It had no power supply.

We lovingly made up a PSU with a transformer from a Vortexion WVB tape machine, decoupled up to the eye-balls against mains and modulation hum. I remembered Eddystones are noted for their audio so lets make the most of it.

When we plugged in, nothing happened. Everything lit up but that was it. Bags of HT, a reassuring blue glow from the stabiliser valve - but silence.

It was nice to see that after all this time, not even the S Meter zero needed adjustment but it was still very quiet.

A good antenna had the meter dancing about but an end-stopping signal only gave the quietest and most distorted signal known to man.

My chocolate eclair Chairman remarked I was wasting my time as every resistor will have gone high and every condenser will have gone low. Not so.

Abandoning the Company's electronic fault analysis systems for my AVO 8, I started prodding. Everything was as close to the book as parallax error would allow - except for one.

Not a volt to be had on the audio stage anode. And, Mr. Chairman, the anode load resistor was fine.

In this special release, the HT input was split. A main supply to all stages and a decoupled supply just for the audio amplifier. All I had to do was fit a series 10k and a 32uF stage decoupler to turn this into one of the most driveable radios I've ever had.

All I did to it in four years was rub a little WD40 into the cursor support bar as the pointer carrier would squeak when you spun the tuning from one end of the scale to the other.

Then it happened. Very slowly, one by one, each BBC station became slightly distorted. A curious sort of distortion, some parts of the audio spectrum sounding more distorted than the rest.

The Chairman's Rising Resistor problem? No - some stations sounded odd, others did not. Bite the bullet. Write to the BBC.

Why were the Domestic Services now so tiring to listen too?

As something of a writer on radio issues, I had heard that audio processing was becoming big business in the States. I learned that all AM broadcasters are now using some form of audio processing to improve the signal-to-noise ratio.

There was a time when the quality of the sound from your radio was determined by how much you were prepared to pay for it. And that Eddystone had it - the unprocessed sound of Radio 1 back in the Seventies was magic on the 940.

But not any more. The 940 was good enough to spot the start of the use of OPTIMOD on the 14th September, 1980.