AFAIK.
I intended to post a picture of my favourite piece of plastic but haven't quite worked out how. Patience...
In the meantime, after struggling for years to understand the whole recorded music thing, I've reached the 80s and decided to investigate digital audio, in the form of an early CD player.
Not a classic by the standards of others I know but I love it and hope to make it better. It is a Trio, made by Kenwood, with a beautiful plastic Toshiba mech, chunky plastic loader, and early Sony CX20152 DAC, complete with associated circuit from the Sony datasheet, that I'll post when I work out how.
I notice that this DAC has been condemned more than once over the years by audio-stage minimalists who have tried attaching a simple buffer stage directly to the DAC output, like they might with a TDA1541, but with rather less success. Not surprising because its current output is PWM.
Once I've armed myself with a few photos of the chip and following two stages in operation I'll introduce the issue appropriately.
The reason I landed here in particular is I noticed there's a forum for class D, and it struck me that there may be some better way of dealing with the output from this DAC that Sony didn't have access to at the time.
More generally, I've been making valve amps for years, so I may be able to contribute in that area. A valve output for this DAC might be a bit interesting.
OTOH, it could soon turn out that the device fundamentally and irretrievably lacks precision. But I won't know until I've sorted out better ways of measuring distortion than the tools that were good enough in the 1950s. This is where I hope for most help, probably.
I intended to post a picture of my favourite piece of plastic but haven't quite worked out how. Patience...
In the meantime, after struggling for years to understand the whole recorded music thing, I've reached the 80s and decided to investigate digital audio, in the form of an early CD player.
Not a classic by the standards of others I know but I love it and hope to make it better. It is a Trio, made by Kenwood, with a beautiful plastic Toshiba mech, chunky plastic loader, and early Sony CX20152 DAC, complete with associated circuit from the Sony datasheet, that I'll post when I work out how.
I notice that this DAC has been condemned more than once over the years by audio-stage minimalists who have tried attaching a simple buffer stage directly to the DAC output, like they might with a TDA1541, but with rather less success. Not surprising because its current output is PWM.
Once I've armed myself with a few photos of the chip and following two stages in operation I'll introduce the issue appropriately.
The reason I landed here in particular is I noticed there's a forum for class D, and it struck me that there may be some better way of dealing with the output from this DAC that Sony didn't have access to at the time.
More generally, I've been making valve amps for years, so I may be able to contribute in that area. A valve output for this DAC might be a bit interesting.
OTOH, it could soon turn out that the device fundamentally and irretrievably lacks precision. But I won't know until I've sorted out better ways of measuring distortion than the tools that were good enough in the 1950s. This is where I hope for most help, probably.
Hi PlasticIsGood - and Welcome to diyAudio!!!
To post photo's click on the "Go Advance" button just below the text box and scroll down a bit until you see the "Manage Attachments" button. If you click on that it will allow you to upload a photo (within size limits listed) or link to a URL. JPEG or GIF photo's seem to work best.
Again - welcome aboard!!!
To post photo's click on the "Go Advance" button just below the text box and scroll down a bit until you see the "Manage Attachments" button. If you click on that it will allow you to upload a photo (within size limits listed) or link to a URL. JPEG or GIF photo's seem to work best.
Again - welcome aboard!!!
Thanks
Thanks for the welcome!
Just experimenting with links and pictures.
Should be pic of Trio DP770, DAC and audio section laid out like datasheet for that Sony DAC:
CX20152 datasheet pdf datenblatt - Sony Corporation - Dual 16 Bit, 88kHz, Multiplexed D/A . ::: ALLDATASHEET :::
and a pic of the output from the integrator at full scale, 1kHz, jiggling because 44.1 isn't an integer, drat.
and an avatar, being my Plastic of the Month.
Thanks for the welcome!
Just experimenting with links and pictures.
Should be pic of Trio DP770, DAC and audio section laid out like datasheet for that Sony DAC:
CX20152 datasheet pdf datenblatt - Sony Corporation - Dual 16 Bit, 88kHz, Multiplexed D/A . ::: ALLDATASHEET :::
and a pic of the output from the integrator at full scale, 1kHz, jiggling because 44.1 isn't an integer, drat.
and an avatar, being my Plastic of the Month.
Attachments
Nice polistyrene caps ! Also the hybrid flat thing in the middle of the pic .
can't say much else except from , try to replace the electrolytic caps on the output ( coupling ) with film ones ,not necessarily the same value ( maybe put higher resistors to maintain the same constant ) .
It reminds me of the first cdp I bought in the late 80's , it was a Sony and had the oversample feature ( 4 X)
can't say much else
except from , try to replace the electrolytic caps on the output ( coupling ) with film ones ,not necessarily the same value ( maybe put higher resistors to maintain the same constant ) .It reminds me of the first cdp I bought in the late 80's , it was a Sony and had the oversample feature ( 4 X)
I'll be going to the digital sources forum to discuss the DAC and circuit. Caps are all Elna, as are the boards that have no ground plane. Polystyrene caps are specified in the Sony datasheet, as are the flat things...Murata filters...and that DIP16 after the quad opamp, which is part of why all those HF caps are needed. It's a box of "audio switches" used for sample and hold. That's the part I hope to improve on. That and the apparent absence of a crystal...
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