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1970s Design Indulgence

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The EQ Kid

Joined: 11 Jan 2008
Location: South Yorkshire
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 02 Oct 2022 at 3:43pm

2001 a CES oddity

I was subby to Ferranti Zetek's CES exhibition contractor and I'm not sure now if it was 2001 or 2002. It was the introduction to the Zetek class-D amplifier chipset and magnetic filters. A Sheffield theatrical props firm was recruited to make a larger than life portable CD player and the CD drawer opened to display an AV presentation, with audio via the class-D amp.

It was all timed by a Basic program run on a PC, and output on RS232 which switched a gang of relays. My job was to design and make the digital interface, which I did using a Harris 40 pin chip micro and ancillary electronics, and that operated the relays.

I also had to design a hardware random subject selector to control a display of other Zetek products, if somebody hit a button. Actually it was pseudo-random, not that you could tell.

My third task was to figure out a power supply to power the class-D amp. The development board - the only one - the one for CES - had just been flown in from... China! The power supply information should have been included with the documentation, but somebody in China had omitted to pack any documentation! Nobody at Zetek (Ferranti) could answer my question, except for suggesting a voltage, and suggesting I "play about with it". I got that done, and the resulting linear power supply was several times the size of the development board, but that was to be hidden under the counter anyway.

On the final meeting at Ferranti Oldham, I had to tag along, and on route through the building there were windows looking into the chip labs, and sadly they were all mothballed. It had all moved to... China.

Guess which bit of my ingenuity impressed the Ferranti boffins most? The random selector. None were able to figure it out. They could not figure out the pseudo random pattern. It was only a few logic chips and an astable. I thought my RS232 relay interface was more impressive but it was never mentioned once.

A few weeks later it was all shipped to CES, and that was the last I knew anything about it, or Ferranti.
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Graham Slee View Drop Down
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The EQ Kid

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 03 Oct 2022 at 8:43am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote BackinBlack Quote  Post ReplyReply Direct Link To This Post Posted: 03 Oct 2022 at 10:27am
Love it, far more interesting than a lot of the drivel on TV today. LOL
Just listen, if it sounds good to you, enjoy it.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Fatmangolf Quote  Post ReplyReply Direct Link To This Post Posted: 03 Oct 2022 at 5:50pm
Nice.
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote TheScorpionsTale Quote  Post ReplyReply Direct Link To This Post Posted: 06 Oct 2022 at 11:39pm
Originally posted by BackinBlack BackinBlack wrote:

Love it, far more interesting than a lot of the drivel on TV today. LOL


It does me good to get away now and again to see some television - we haven't owned one for years. We've just returned home after a few days, and of course there was a television in the hotel room. Drivel? You're not kidding. How do they get away with it? I say it does me good, because it reminds me why we don't own one. Give me a pile of records any day. Big smile
Graham

SL1200 II with SME M2-9R and various carts / Revelation M with PSU-1 / Cyrus amp, CD and streamer / Kralk Audio BC30-3 Floorstanders
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 07 Oct 2022 at 10:45am
I am seriously convinced that those who master and re-master records for digital distribution suffer from high frequency hearing damage.

When they were younger (I'm only guessing here that they were younger on earlier albums?), and also when albums were on vinyl, very often you'd need a bit of treble boost, because old amplifiers were generally flat.

Then came hi-fi-fo-fum's 34 rpm pulley's, which sparkled up the highs by making all frequencies a tad higher than they are. And ultra-light turntables which took away the bass - or made it tighter which is the preferred way of lying in this industry. Did you ever hear the saying "he's so tight his shoes squeak"?

Tone controls became the tools of the devil according to the industry. By then hi-fi felt like one of those nightmare movies starring Christopher Lee.

Then relief came in the form of used Technics SL whatever's, which ran at the correct speed and had some weight to them.

But, digital remasters got brighter and brighter, and nobody complains but me? Perhaps as we got older we needed more and more treble boost?

Well, count me out on that! My cut-off is 13kHz these days, but below that my hearing's flat.

Watch football? Each player has a function - they don't all chase after the ball!

The bass player plays bass, but when digitally remastered, even the bass goes up in frequency to follow the frequencies into the stratosphere!

I have to conclude that those who remaster, and all those that mastered anything starting from the early 80's had gone deaf, and have no musical training.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Sylvain Quote  Post ReplyReply Direct Link To This Post Posted: 07 Oct 2022 at 5:42pm
Bad news for me nearing to 70....and I collected but the remasters of the 90's ..Steve Wonder Bob Marley never sound good on CD's perhaps their acoustic instruments and vocals did not conform to digital sampling  but as my LP's collection of the 70's were getting scratch thought the '' Remaster labels'' were a God send to revive poor recording of 16 Bit. But yes, perhaps as I believe Digital sampling '' dull '' the sound and Remaster try to inject a bit of body and dynamics assertion  higher frenquencies. i have registered the tone of cymbals and metal tube in triangles hit or scratch by a fork in some folk music and the ''Contre-Basse'' along the Tunnel Metro Platform of Paris network is well registered to my music area of my grey matter and use that imprinted memory to assit my hearing or perception with CD' distorting  
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