Connect with us

Optical to Analog Conversion

Discussion in 'Electronic Design' started by Jim Thompson, May 1, 2005.

Scroll to continue with content
  1. Jim Thompson

    Jim Thompson Guest

    My oldest son has a Sony STR-DE995 audi/video system with multiple
    audio-source inputs, optical and analog (RCA).

    Problem: There is NOT a common line-out...

    Any optical input "lines-out" only optical

    Any analog input "lines-out" only analog

    The son would like an analog signal (stereo) suitable for passing to
    monitors in other rooms, but these other monitors only have RCA inputs
    for audio.

    Is there an off-the-shelf optical-to-analog converter available?

    Or schematics for build-your-own?


    ...Jim Thompson
  2. I read in alt.binaries.schematics.electronic that Jim Thompson
    Some sort of anti-copying measure? If you can get a schematic from a
    consumer product manual supplier, you might be able to make a bridge
    between the channels.
    Maybe you can get a hi-fi preamp with optical inputs and analogue
    It's not a trivial task at all; not that I'm saying you couldn't do it,
    but it's a lot of work.
  3. jim dorey

    jim dorey Guest
    i was working on this a while back, it's for converting ethernet to
    optical. it needs a lot of work, but it's a start, one that uses a prism,
    the other uses separate optical parts. you definitely wouldn't need the
    inverter. the connector that's on the optical out can probably have some
    fibre driven into it, you run the fibre to the room you want it to supply,
    then you add a storebought ir transistor with integral holder, some power,
    and an rca plug. the ends of the fibre needs to be near perfect flat, you
    can use a hot razor blade to do that. but don't mind me, i have no idea
    what i'm blathering on about.
  4. Boris Mohar

    Boris Mohar Guest

    Have look at
    DA96: 4 channel, 24 bit, 96 kHz ADAT optical to analog converter - 1/2 rack

    I have no experience with it but might in the future. My daughter has
    embarked on a musical carrier and since dad is "into electronics" all of the
    tech support should be easily accessible. Looks like I have to embark on
    crash audio course..
  5. I read in alt.binaries.schematics.electronic that Boris Mohar
    Not the Brian Ferry? (;-)
  6. John Larkin

    John Larkin Guest

    I guess since Sony owns so much program material, they want to keep it

    Why not just tap the speaker drive, voltage divider and transformer
    maybe? Even that will get interesting as more stuff goes class-D.

  7. Jim Thompson

    Jim Thompson Guest

    Yep. That's what I'm getting here too... dad is "into electronics".

    But it's to my advantage... oldest son is a _very_good_ programmer, so
    I'll meet his electronics needs... in exchange for him writing me some
    more PSpice utilities... maybe a netlist comparator ;-)

    ...Jim Thompson
  8. Jim Thompson

    Jim Thompson Guest

    That was the first thought. Have any keen ideas on leveling it?
    Otherwise somewhat of a nightmare to keep proper levels at remotes.

    ...Jim Thompson
  9. I read in that Jim Thompson
    Not only at remotes, in UK. TV audio levels vary over almost a 20 dB
    range (same channel, more that 10 dB within the same programme) since
    no-one is apparently now employed to watch the level meters.

    That Corp. THAT4301 can apparently be used as an AGC (not compression)
    device that gives an approximation to 'constant loudness' audio output,
    although the makers don't say so, AFAIK. I'm working on the design now
    (between commuting round the world on standards business).
  10. Radio Shack sells an inexpensive ($15) analog to SPDIF/
    TOSlink converter (15-1242) Alas, seems like the wrong
    direction. (Unless he uses it on one of the inputs.)
  11. Ian

    Ian Guest


    Is the optical output 44.1KHz S/PDIF (TOSLINK)? If it is, I've just
    designed a board that converts just that into stereo line-level
    audio. It isn't trivial (and my design certainly isn't audiophile
    quality - only 12-bits for a start). It was done mostly as a learning

    If it's DTS 5.1 surround (or anything other than plain stereo) then
    your cheapest option is probably a PC with a soundcard that has an
    optical input - amps with optical in look expensive.

    Let me know if you're interested in my decoder design - here's a
    snap of it (only just today commissioned the PCB!):

    I intend to put it on the web eventually anyway, just a matter
    finding the time!

  12. Joerg

    Joerg Guest

    Hello Jim,

    If this is a Toslink output you might want to search Google for "Toslink
    adapters". I have seen them in a large store, but cannot remember where
    because I didn't need one. We lucked out since our mini-disk unit had
    both fiber and regular line outputs so I didn't buy the converter.

    Regards, Joerg
  13. Fred Bartoli

    Fred Bartoli Guest

    Ha ha ha... excellent John.

    Isn't the Brian Ferry a kind of "boite à musique" ?
  14. Fred Bartoli

    Fred Bartoli Guest

    How much jitter will you get into the output?
  15. Jim Thompson

    Jim Thompson Guest

    I looked-up that part. Seems promising. What sort of application are
    you working... your audio loop?

    I downloaded the data sheet and all the apnotes.

    Since the speakers are likely bridge driven, do you have
    recommendations as to how to take off the signal? Transformer?
    Ground loop issues?

    ...Jim Thompson
  16. Robert

    Robert Guest

  17. Joerg

    Joerg Guest

    Hello Jim,
    Just a thought: If this is a Toslink output (should say in the manual)
    then you might be able to buy a converter. I have seen these a long time
    ago in a big box electronics store but forgot which one. It wasn't very

    If you have to impress your son you could still provide your own
    enclosure, or pretend it had to be flown in from Japan ;-)

    Regards, Joerg
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day