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Thorn FM Stereo mod kit SD70 - any actually supplied?  

 
EmleyMoor
(@emleymoor)
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Some years ago now I bought a radiogram - an Ultra, model 6338. Among the many things I did with it were replacing the turntable (old one had a tricky speed control and a lot of vibration) and adding a power outlet for a tape deck.

It was in original condition, with two October 1972 dates stamped in the cabinet, and provision for an "FM Stereo" indicator light, but this required a mod kit, type SD70.

Thorn told me at the time that no-one had actually had this fitted to this or any similar model. I did briefly consider adding a Maplin kit to convert the set to stereo, but the problem became moot due to transistor failures before I got round to it. Was the mod kit ever actually supplied?

A few years earlier I had acquired a Ferguson Studio 6 music centre, model 34634 - unfortunately it needed expensive cassette deck repair and scarcely lasted a year before the problem recurred. I seem to recall that when my father and I stripped it down to move its turntable into an Amstrad TS35*, the radio/amp assembly was quite similar to that of the Ultra 6338, although with a somewhat different tuning scale arrangement and lamp positioning. This had FM stereo from new. Were the similarities in fact more than just "passing"? I often wondered if the Ferguson's parts would have provided spares for the Ultra.

*(In case you're wondering why we did that, the BSR P267 supplied with the Amstrad had proven, for us at least, pretty hopeless - actual speed was somewhat random - whereas the Ferguson had a changer that had always run at a good speed - it did mean the lid of the Amstrad could only, afterwards, be closed if the stub spindle was fitted and the overarm down, but proved to be a worthwhile project. The only slight puzzle was finding a mains feed inside the Amstrad to run it, but there was a connector, not connected anywhere, with mains present when it was on, so we used the wires going to that.)

"Yes, a bit of wet string may get you a good TV signal here on four channels, but you'll have to dry it out to get Channel 5!"

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Posted : 25/12/2019 12:26 am
Cathovisor
(@cathovisor)
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From my experience of dismantling radiograms and stereograms as a teenager (late 70s/ early 80s) I never saw any retro-fitted decoders in them; but given that stereo radio didn't come our way until 1980 that may not be a surprise. The spread of VHF stereo seemed very slow across the UK and apparently limited to a few major transmitters at the start - a six-element aerial pointed at Belmont around here wasn't uncommon for stereo radio aficionados until Peterborough went stereo in 1980.

I'd venture to suggest that many a stereogram was equipped for an add-on decoder but never actually lasted long enough in service to gain one.

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Posted : 25/12/2019 11:22 am
Jayceebee
(@jayceebee)
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I fitted the optional add on decoder to our HMV 2342, this was obtained from the Thorn Glasgow service department C.O.D. I don't remember how I became aware of it's existence, whether it was mentioned in the instruction book or from the red RTVS books. It performed reasonably well with just just the trailing wire for an aerial but the gram wasn't well placed in the room for best effect.

My mother hated the cabinet design, it reminded her of a coffin but she always said it had a "nice tone" ?. Surprisingly there are a couple on Ebay at the moment.

John.

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Posted : 25/12/2019 12:31 pm
Nuvistor
(@nuvistor)
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There were few radiograms fitted with stereo decoders in the 1960’s, Wrotham transmitter was first with stereo around 1960 from what I can find with Sutton Coldfield and Holme Moss later in the 60’s. This was only the Third Programme, which became Radio 3, not the most popular of stations and as such if a decoder and stereo were  available buyers in general were not interested. Stereo transmissions were only a few hours a week.

With the digital transmission of the link for VHF FM to the more remote transmitters and Radio 2,4 including stereo in around 1972-3, makers started to include decoders as standard especially in the “audio unit” type receivers that were popular, radiograms going out of fashion.

The IC type decoders available in the early 70’s made them easier to make and as such more affordable to include as standard.

 

Frank

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Posted : 25/12/2019 7:30 pm
Red_to_Black
(@red_to_black)
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@emleymoor

My late father had the Ferguson Studio 7, it was the current model when he bought it.

I think my Mother still has this in the loft somewhere ? , it too suffered from cassette player problems after a few years, I did manage to fix (bodge???) it in a fashion, one of the belts had become slack, I fitted one out of my Meccano set, it sort of worked but not correctly (of course) I would have only been about aged 9 or 10 at the time, amazing what my parents let me play with ? 

"This is my multimeter. There are many others like it, but this one is mine. My multimeter is my best friend. It is my life. I must master it as I must master my life. Without me, my multimeter is useless. Without my multimeter, I am useless."

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Posted : 25/12/2019 9:02 pm
EmleyMoor
(@emleymoor)
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@red_to_black

The issue on the Studio 6 was something to do with the mechanical latching of the keys... if "PLAY" fully engaged, it was always too fast by far, unless recording when it was too slow by far (recordings made on it played "too fast, but slower" on other machines). However, if "PLAY" would not actually latch, it ran at normal speed if you held the key down.

Unfortunately my dad's first attempt at fixing it, in 1982, had somehow broken the recording circuit, increasing the eventual repair cost. Understandably I was really annoyed when it went wrong again before the end of 1983.

As for the Ultra, it might have been sensible to add FM stereo to it if, by the time I got round to it, it hadn't already been 1990.

"Yes, a bit of wet string may get you a good TV signal here on four channels, but you'll have to dry it out to get Channel 5!"

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Posted : 26/12/2019 12:07 am
EmleyMoor
(@emleymoor)
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@jayceebee

Hmmm... the 2342 has the "lower half" speakers and no tape input (unless it's the type that piggybacks on "GRAM") - rather like the Marconiphone that my neighbour had. I did prefer the Ultra's "end box" speakers on the whole.

Still trying to remember what the layout of the one we had in the 1970s was, in terms of the speaker position - though it was a 1960s model as it had a BSR UA series turntable in it. I am certain it was a Ferguson, at least.

"Yes, a bit of wet string may get you a good TV signal here on four channels, but you'll have to dry it out to get Channel 5!"

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Posted : 26/12/2019 12:21 am
Cathovisor
(@cathovisor)
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Posted by: @jayceebee

I fitted the optional add on decoder to our HMV 2342, this was obtained from the Thorn Glasgow service department C.O.D. I don't remember how I became aware of it's existence, whether it was mentioned in the instruction book or from the red RTVS books. It performed reasonably well with just just the trailing wire for an aerial but the gram wasn't well placed in the room for best effect.

My mother hated the cabinet design, it reminded her of a coffin but she always said it had a "nice tone" ?. Surprisingly there are a couple on Ebay at the moment.

Unless it's the same ones "doing the rounds", they are surprisingly common on the old 'Bay. There were some very stylish stereograms in that period, one of my favourites being the Bush SRG143 which by comparison is in the "hen's teeth" league.

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Posted : 26/12/2019 1:02 am
Nuvistor
(@nuvistor)
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More detailed information on the roll out of stereo on VHF FM, from the ground breaking PCM system to NICAM that was also used for TV sound.

http://www.audiomisc.co.uk/BBC/PCMandNICAM/History.html

The BBC R&D dept had a outstanding record of designing and building transmission systems.

 

 

Frank

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Posted : 26/12/2019 11:02 am
Cathovisor
(@cathovisor)
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That's a very informative link Frank - thanks for posting it. 

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Posted : 26/12/2019 12:10 pm