Darbee Darblet causing HDMI instability - could it be faulty?

Discussion in 'Projectors, Screens & Video Processors' started by Bert Coules, Aug 2, 2018.

  1. Bert Coules

    Bert Coules
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    My basic setup is this:

    Sources -> Marantz amp -> Darbee Darblet -> JVC projector

    For a long time this arrangement had given HDMI problems, but from only one source: a Panasonic Freesat receiver/HDD/Blu-Ray recorder. And curiously the instability (white flashes, occasional complete loss of picture and/or sound) only occurred when playing discs or accessing the Blu-Ray/DVD menus: it never happened when watching Freesat channels or material recorded off air.

    I've experimented with different cables, using different output sockets on the amp (and input sockets on the projector) but to no avail. I bought an extremely budget Blu-Ray player and used that instead of the Panasonic.

    Today, it dawned on me to try removing the Darbee from the system and testing a DVD and a Blu-Ray disc on the Panasonic again - and the result was complete stability. I put the Darbee back and the problems immediately returned.

    Given that the Darbee doesn't appear to affect the signal from any other source, it seems unlikely that it's faulty, but I suppose it is a possibility. Or could there simply be some sort of incompatibility with the Panasonic?

    I did have the Panasonic checked by a local service agent and they found nothing wrong either in general or with the HDMI circuitry.

    I should be sorry to lose the Darbee since I'm used to its effect and like it, but it's good to have the Panasonic for discs. I'd be grateful for any thoughts; many thanks.
    .
     
    Last edited: Aug 2, 2018
  2. screenertime

    screenertime
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    Hi try replacing Darbee power supply to 5V 2000 mA . ( I have this on my Darbee DVP5000s)

    I have noticed my friends older Darbee power supply is 5V 1500 mA.
     
  3. Bert Coules

    Bert Coules
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    Thanks for the thought. I just checked the power supply: unfortunately, it's already 5V 2000mA.
     
  4. andy1249

    andy1249
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    What length are the cables to the projector?
    Are they rated high speed and do any exceed 8 meters.

    Darbee does its thing in part by increasing HDMI bandwidth throughput.
    White flashes and sound dropouts are typical symptoms of cable bandwidth problems.
     
  5. jfinnie

    jfinnie
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    In what way? I thought it was just applying a contrast enhancement / sharpness type algorithm implemented in FPGA.
    I have Darbee functionality in my Lumagen - the output format remains at whatever you choose, it is just the pixel content changes.
    Or do the Darblet boxes force a change to 4:4:4 or similar regardless of input?
     
  6. sim12

    sim12
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    I had very similar thing with mine, picture was dropping out and doing all types of unwanted things, cat6 HDMI extenders fixed the issue, i was using a 10 metre hdmi cable, some over this length are better than others, but I really be bothered with trying cable after cable. Cost me roughly £40.
     
  7. Bert Coules

    Bert Coules
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    Andy1249, thanks for that. I can check the exact cable details later, but from memory the one between the Panasonic and the amp is around seven metres, from the amp to the Darbee is half a metre, and from the Darbee to the projector, five metres.

    With the Darbee out of the circuit, the amp is directly connected to the projector by the five metre cable.

    If it is a cable problem, it seems surprising that it's only the DVD/Blu-Ray side of the Panasonic which is affected. The FreeSat output is rock solid.

    Sim12 did you insert the cat6 cable and extenders between the amp and the projector/TV or between a particular source and the amp?
    .
     
  8. sim12

    sim12
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    amp,darbee, lumagen,splitter,projector.

    Cat6 HDMI has always been at the splitter one signal to tv the other to pj(cat6 hdmi) last in the chain.
     
  9. andy1249

    andy1249
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    Enables deep color 30 bit 4.4.4.
    DVP Comparison

    This is part of the difficulty in Darbee producing a 4K model, as various UHD features use that bandwidth.

    Its Enough of a bandwidth increase to push a long HDMI cable over its limit.
    Usually , with a projector , the HDMI cable is long.
    Thats the troubleshooting angle I,m coming from.
     
  10. oakwood49

    oakwood49
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    had a similar issue with mine, works fine on everything i've ever tried with except one android box, picture drops out whenever i've tried it, take the darbee out, perfect, darbee in drop outs, tried different resolutions output from the box etc
    ditched the android box
    android box > av receiver > darbee > projector
     
  11. Bert Coules

    Bert Coules
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    Thanks for that. It sounds as though your issue wasn't so much similar as identical, or as near as dammit. If I want to keep the Darbee perhaps losing the Panasonic is the only answer. Annoying.
    .
     
    Last edited: Aug 2, 2018
  12. Quaddy

    Quaddy
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    try a longer cable from amp to darbee, 6ft or longer instead of the .5m hdmi one as some hdmi chips in some equipment apply too much of a gain/boost for such a short cable.

     
  13. Bert Coules

    Bert Coules
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    Quaddy, that's an interesting idea, though I'm still a little hazy as to why only one source is being affected: would a cable change make a difference to that? But I'll try it, thanks.
     
  14. andy1249

    andy1249
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    in the DVP comparison table I linked too above, they list minimum and maximum cable lengths.
    Thats a highly unusual thing for any manufacturer to do without a good reason.
     
  15. Bert Coules

    Bert Coules
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    A very good point. I'll see if I have a six foot (or thereabouts) cable to try.

    LATER:

    Right, I've now connected the amp to the Darbee with a 2 metre cable, that being the closest I have to the recommended six feet. I'll report back.
    .
     
    Last edited: Aug 2, 2018
  16. Quaddy

    Quaddy
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    yeah usually 6 foot or over is recommended for intermediary hdmi devices on forums/troubleshooting threads, had an issue with an old lumagen(was using a .5m chord cable) i used to have until their engineer suggested using longer cable(i'd never heard of it) - suffice to say it cured the handshaking issues for me, something to do with equalization or something, forgotten the exact lingo now. - obviously it may not be your issue, but when i saw you were using .5m i immediately remembered my situation - good luck! :smashin:
     
  17. Bert Coules

    Bert Coules
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    Well, that was... interesting. With the amp feeding the Darbee through a just-over-six foot cable, this was the result:

    With everything powered up and the amp input set to Sky (my Sky + HD box) everything was fine, as usual.

    Switching the amp to Blu-Ray and with the Panasonic set to FreeSat I got perfect sound but no picture. This is a step down from the previous situation, when the Darbee was in circuit with a different cable.

    After maybe a minute I saw a brief flash of picture. Though I couldn't say exactly what was wrong, the colours were out: the image was washy and had no depth.

    I tried changing the source selection on the amp. Perfect results from Sky (again) and my media player. Going back to Blu-Ray and nothing had changed: sound but no picture.

    I tried powering down the Panasonic and switching it on again. No difference.

    I tried loading a DVD. The FreeSat sound cut as the Panasonic switched to disc mode. I got a brief flash of the "disc loading" page but then a blank screen as before. When the disc started automatically to play, the soundtrack was audible but still no picture.

    And that's where things stand now.
    .
     
  18. andy1249

    andy1249
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    Check if the Panasonic player has deep color settings.
    If it does, turn them off.

    If that doesnt work , try dropping down the output resloution, this would be to check if its a bandwidth issue.
     
  19. Bert Coules

    Bert Coules
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    Andy1249, the Panasonic has no deep colour settings that I can discover, so I turned to your other suggestion. The relevant menu would seem to be "HDMI connection". These are the items, with the selected options in bold (as far as I know they've been set this way for several years):

    Video mode: On
    Video format: 576/480p, 720p, 1081i, 1081p, Automatic
    B-D video 24p output: Off
    HDMI audio output: On
    HDCP on HDMI output: On
    VIERA link: On

    I tried all the available video format settings in turn. Only on 576/480p could I get any sort of stable picture from the disc side of the Panasonic, and even then it wasn't all that stable: the screen blanked out several times while I was copying down that menu, for example.

    Oh, and at one stage I flicked the amp back to Sky to check something and discovered that I had a picture but no sound. Going to a different source and back again cured that, but it was a tad disconcerting while it lasted.
    .
     
    Last edited: Aug 2, 2018
  20. andy1249

    andy1249
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    What is the model number of the panasonic?

    BD 24p output should be “on” by the way.
    Blu ray content is mostly 24p , leaving that to “off” makes all blu ray content output at 60p , a significant increase in bandwidth.
    I dont think thats going to fix this issue, but it should be “on” regardless.

    I was kind of hoping you had a deep color option and it was on.
    If that had been the case then it could easily have been the cause of your issue.
     
    Last edited: Aug 2, 2018
  21. Bert Coules

    Bert Coules
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    It's a Panasonic DMR-BS705. For this evening I removed both it and the Darbee from the system and I've been enjoying a trouble-free couple of hours of viewing. Incidentally, my ultra-budget Tesco BluRay player does have a deep colour option and it's set to "off".

    As a last experiment for tonight I'll reconnect the Darbee and the Panasonic and try switching the latter's BD 24p output to "on" to see if it does make any difference.

    Thanks again for your advice.
    .
     
  22. jfinnie

    jfinnie
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    Fair enough.

    From that table I couldn't see if they were saying that they enable those features at the output, regardless of input format; or whether they were listing it as the maximum supported input (and the output matches the input). Would be nice to look at one of these with an analyzer and see what it is doing.

    From a darbee FAQ re an update:
    So it does seem that Darbee boxes (at least with certain FW/FPGA versions) don't upconvert the output to 4:4:4 (though they do process in 4:4:4 internally)

    It doesn't help the OP, but on the Lumagen box the Darbee algo is enabled regardless of chosen output format - it works "perfectly well" with 4:2:2 output. (not clear if you get less darbee effect than at 4:4:4)

    Re: cable length - I guess they're differentiating between the features they added on the CI version where they've added some kind of cable EQ chips at the input / output it seems.
     
  23. Bert Coules

    Bert Coules
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    One final set of observations for tonight.

    I reconnected the Panasonic and the Darbee and powered everything back up, and while the Panasonic was in FreeSat mode switched the BD 24p output to on. Then I tried playing a disc: once again, sound but no video.

    I don't think I've mentioned before that I have a small TV connected to the Marantz amp's second HDMI monitor output. I thought I'd see if the image was getting through to that, so I switched the TV on - and there was the picture. And suddenly, there it was too, on the projector's output. It wasn't completely stable but it was there.

    I turned off the TV and the projector's screen first went blank then showed a wildly unstable picture, the worst I've yet seen.

    Life was so much simpler when all I had was a single TV set. I miss those days.
    .
     
    Last edited: Aug 3, 2018
  24. andy1249

    andy1249
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    That is a key piece of information.
    If your amp is splitting a HDMI output then its modifying the output signal so that its compatible with both displays.
    The amp may be having trouble finding a common signal that works with both.

    Disconnect the second HDMI output completely and try it.
    Note: you must disconnect the second HDMI output completely as the HDMI 5v line powers a displays EDID circuitry even when switched off.
     
    Last edited: Aug 3, 2018
  25. Bert Coules

    Bert Coules
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    I'll try that today, thanks. The Marantz also has a zone 2 HDMI output, to which I have another TV connected. Is the circuitry for that likely to be completely separate? In any case, I'll try disconnecting that too.
    .
     
  26. andy1249

    andy1249
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    For troubleshooting purposes , only one display at a time should be connected.

    If that works , then you have to look at the capabilities of all the screens connected.
    With split HDMI and multiple screens , the output is forced to the lowest common signal.
     
  27. Bert Coules

    Bert Coules
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    Right, thanks. I'll report back...
     
  28. Bert Coules

    Bert Coules
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    Well. With the Marantz's other HDMI outputs disconnected and the Darbee in the circuit between the amp and the projector, I just tried everything again. Perfect AV output from the Sky box but playing a disc on the Panasonic gave me sound but initially no picture at all. Then after forty seconds of blank screen I got a single white flash. That was it.

    I've now powered everything down. I'm reluctant to do too many tests at close intervals because I imagine it's not exactly doing wonders for the projector's lamp life.

    OK, one more test for now: I'm going to try using the Marantz's second monitor output rather than the main one (which is labeled ARC where the second one isn't)...
    .
     
    Last edited: Aug 3, 2018
  29. Bert Coules

    Bert Coules
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    Well, that gave me a picture from a disc, but it was only precariously stable. I tried skipping forward a chapter and the screen immediately went blank. Waiting produced no result so I skipped forward again. This time, after some twenty seconds, the picture returned. Stopping the disc and returning to FreeSat, which had always been completely reliable before, blanked the screen again, then generated flashes of washed-out colour images which never stabilised.

    The whole situation is ridiculous. Unless anyone has any other suggestions for things to try, I think I'll have to revert to my budget BluRay player and hope that the Panasonic returns to being reliable when used solely as as a FreeSat PVR. Either that or lose the Darbee which I really don't want to do.

    Thanks to everyone for the help and advice.
    .
     
    Last edited: Aug 3, 2018
  30. Bert Coules

    Bert Coules
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    I'm sorry to keep replying to my own posts, but here's the latest situation. I put everything back the way it was when I started this thread: all my sources to the Marantz amp's HDMI inputs and the amp's outputs like this:

    Monitor 1 (ARC) -> Darbee -> projector
    Monitor 2 -> TV
    Zone 2 -> second TV

    The result was rock solid images from my Sky+ HD box and my AZ Box sat tuner; disappointing performance from my Tesco BluRay deck (occasional brief flashes where before there were no problems at all); and sound but no pictures from the Panasonic (in FreeSat mode). This is actually a major step backwards, since the FreeSat tuner used to give excellent results.

    About the only thing I can think of to try now is to strip down the entire system, sources as well as TVs and projector, and slowly connect everything up again one item at a time to see if any one unit causes a problem.

    Or, as I said before, to ditch the Darbee, since previous evidence suggested that without it everything was fine, the Panasonic included.

    More fun and games tomorrow, I guess. Goodnight until then.
    .
     
    Last edited: Aug 3, 2018

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