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| April 15, 2010, 8:43 am |
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KDF-50WE655 HDMI input. Worse than analog??? |
andrew_debbie
Rank: Sony Buff
Joined: Dec 27, 2004
Posts: 11
From: Atlanta
 |  Posted: 2005-01-04 09:35
I've been looking at the schmatics for the HDMI input on the KDF-50WE655. 42WE655 is identical. I wouldn't be surprised if many other sets use the same circuit.
The HDMI input connects to a SiI 9993 HDMI reciever. http://www.siliconimage.com/docs/SiI-PB-9993.pdf So far no problem. The chip extracts the audio and sends the audio to a CS4335 audio DAC. Not audiophile but not bad either. Fine for driving the TV speakers.
Sony uses the component analog outputs from the 9993 and routes them to the same analog video switch as the component analog connectors on the back of the set. The SiI 9993 has a 10-bit Video DAC. A little later the analog component video is converted back to digital using a TLV 5734
http://focus.ti.com/docs/prod/folders/print/tlv5734.html
This is an 8-bit 30MHz ADC.
For the LCD sets I don't see any advantage using the HDMI input. Using the HDMI output from the DVP-NS975 might even give a WORSE picture. Save your money and get a NS775 and use the component outputs. I'm not sure with other devices like the Motorola DVR. Depends on the video dac used.
Does anyone have schematics for other HDMI sets?
[ This message was edited by: andrew_debbie on 2005-01-04 11:32 ]
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ptk
Rank: Sony Buff
Joined: Dec 27, 2004
Posts: 15
From:
| Posted: 2005-01-05 04:46
Hi Andrew,
Thanks for detailed analysis. Based on this HDMI is good to reduce noise in cables which connect TV and receiver only.
Still that should provide better quality.
Purvesh
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andrew_debbie
Rank: Sony Buff
Joined: Dec 27, 2004
Posts: 11
From: Atlanta
| Posted: 2005-01-05 10:15
>>Still that should provide better quality.
Are the improvments big enough to be visible?
In part this depends on the DAC in the external device vs. the DAC in the SiI 9993. It could also be that any small differences in quality are negated by the TLV 5734 or the LCD engine. 8-bit dynamic range is 48dB. Any small improvments in S/N aren't going to be visible.
I do have a lab grade digital luminance meter.
http://www.mx-electronic.com/english/marx-mx.pdf
The minimum sensitivty is .1 cd/m2. I don't know if this is sensitive enough. Maybe I should invest in a DVI-HDMI cable just to find out if I can measure a difference.
----------------------------------------------------------------
It looks like Sony just didn't have the time to redesign the digtal part of the set to work with HDMI. By converting back to analog, they can treat the HDMI source just like another analog input.
What about the KD-34XBR960 or one of the Plasma sets? With their better black levels I'd expect you could see the difference. Did Sony take the same short cut with the HDMI input? Does anyone have the schematics?
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jehill
Premium Member
Rank: Sony Senior Advisor
Joined: Mar 13, 2003
Posts: 11817
From: Sewell, NJ
 | Posted: 2005-01-05 20:01
The KD-xxXS955/KD-34XBR960 series all use the YCbCr output of a SiI 9993 HDMI receiver. I suspect that the same is true for all current models.
-----------------
-John
Sony A/V System: KDL-55XBR8, BDP-S550 and AVD-LA2500PKG consisting of AVD-C70ES Super Audio CD/DVD Receiver, 4 SS-LA500ED surround speakers, 1 SS-LAC505ED center channel speaker and 1 SA-WD200 Active Subwoofer
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ptk
Rank: Sony Buff
Joined: Dec 27, 2004
Posts: 15
From:
| Posted: 2005-01-06 03:28
Hi Andrew,
usually there is dissipation in the cables due to various factors and improvment is noticable in my case. Though of course I don't have component cables by S-Video which itself is inferior to component and hence cannot comment more.
I would appreaciate your experiment with HDMI cable - and maybe we can ask SONY for an explanation as to why this is being used as marketing mantra, if your measurements turn out to accentuate your analysis.
Thanks,
Purvesh
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