Did SHARP ever make DACs in 80s? - diyAudio
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Old 16th June 2014, 03:12 PM   #1
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Default Did SHARP ever make DACs in 80s?

Other than Marantz, Sony Philips etc. did Sharp electronics make anything to contend/compete on the CDP / DAC market,

Anyone know?
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Old 16th June 2014, 07:48 PM   #2
Mooly is offline Mooly  United Kingdom
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Sharp made a few CD players in the very early days of CD and I remember working on them at the time but couldn't recall now what the DAC was.

DX50 ? 60 ? DX150
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Old 16th June 2014, 08:12 PM   #3
adason is offline adason  United States
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could this help?
CD-Player-DAC-Transport List
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Old 16th June 2014, 09:23 PM   #4
tvi is offline tvi  Australia
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The closest I have seen is the dx-sx1 but it an integrated amp really
Click the image to open in full size.

uses a sm5844 to a tda1307

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james
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Old 17th June 2014, 05:48 AM   #5
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Sharp was never big in making chips for audio, except voltage regs. I have definitely never seen a Sharp dac chip in 30+ years in audio biz.
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Old 17th June 2014, 12:37 PM   #6
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Interesting whats interesting on this one below is the music program indicator - very solid work from SHARP on a whole.
going to browse that list (thanks). I know where to go if I choose to mod something in future ... Classic retro looks
Click the image to open in full size.
vintage-audio-laser.com/Sharp-DX-3

I don't recognise any of the internal DAC chips on this one, any idea's what's used? Oversampling etc?
Click the image to open in full size.
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Old 17th June 2014, 02:41 PM   #7
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Managed to find out DAC used, "Sony CX-20012" apparently,

Broken link above in previous post, sorry Vintage Audio Laser and more here.

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Old 17th June 2014, 03:20 PM   #8
Mooly is offline Mooly  United Kingdom
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The picture shows a CX20017 DAC, same as the original CDP101. These were time shared between channels, in fact if you read the bit in this article called "Inside the Sony CDP101", you will see how I believe Sony made a token gesture at eliminating the audible effect of time sharing the DAC.

Adrian-Kingston.com - Sony CDP-101 CD Player

I say "I believe" because it was me that told this guy about this some years ago... and I see he's added the info to his site with no acknowledgement.
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Old 17th June 2014, 03:39 PM   #9
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Fascinating stuff, gonna read that.
Funny, when browsing the vintage audio laser website I came across an ancient technics player, the dac inside: PCM53JP-V.
I research the chip, apparently it's another original NOS implimentation.

So essentially these are the chips used before over/upsampling was introduced.
Correct me if i'm wrong but
As I recall the soul purpose of oversampling was to aid analog filtering after the reconstruction stage but why is filtering so important?
I'm sure most decently built equipment can handle beyond 20khz...
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Old 17th June 2014, 06:01 PM   #10
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Yes, oversampling allowed the use of much more "gentle" filters on the audio output. The CD standard ensures that there is no audio present beyond 44.1 /2 KHz (so 22.05kHz).

You need to read up on sampling theory and "aliasing" to understand the whys and wherefores of what happens if you try and record a frequency higher than one half the sample rate. But all that's on the recording side of things...



On playback, a non oversampled convertor produces a lot of hash that has to be removed. To remove it from a non oversampled convertor needs a filter with really steep roll off... and that can have a detrimental effect on the wanted audio. An oversampled player pushes that noise way up in frequency and so it can be removed much more easily without impinging on the audio band.

Have a search for "CD brickwall filters" and look at the images showing the response.

If the hash and noise were passed to an amplifier it could cause all sorts of distortions and problems (depending on the amp). Speakers may not appreciate a high hf content of noise too and it could cause audible problems as well.
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