Problem wth HDMI to DVI cables

SillySausage

Active Member
Good evening all.

I have been using a 1mtr HDMI (From Onkyo 876) to DVI into a HD Fury then out to Panasonic series 6 HD plasma.

This works well and allows me to watch 1080p films and 1080p through the PS3.

The screen is only 720p, but I also have a 1080p PJ so want things all set to the highest resolution to avoid messing with settings every time I change displays.

However after changing the room around I needed a 7.5 mtr cable and duly bought a relatively inexpensive thing from fleabay (thinking digital was digital so no need for a pricey cable)

Now when in 1080p from the PS3 the picture is all fuzzy and missing detail. It is a uniform error though, which makes me think it isn't just a faulty cable.

In 1080i down it is fine.

Have tried 2 cables from the same supplier - both have same fault.

Is it possible that the cable doesn't 'support' 1080p or is it likely to be a cable length issue?
 

Joe Fernand

Distinguished Member
AVForums Sponsor
A heavier gauge cable is likely to solve the problem - look at Bettercables, you may want to go with an 8m High Speed HDMI cable plus a short HDMI to DVI adapter.

Are you using a PSU with the Fury?

Joe
 

SillySausage

Active Member
Hi Joe,

Thanks for the answer.

Yes I am using a PSU to the Fury.

I forgot to mention in the original post that I also have to use a HDMI powered switcher box on both the PJ through a 7.5m lead and also the TV through any length cable.

The box used to be there just to switch HDMI sources before the Onkyo amp, but not it is used solely as it must boost the signal.

Ideally I'd like to utilise the twin HDMI out on the 876 and drop the switch box, but am unsure about buying more expensive HDMI cables if it won't help.

Tis all slightly confusing as I constantly read posts about people ranting that HDMI cables make no difference whatsoever, and then I and others seem to have issues with some.
 

Trollslayer

Distinguished Member
Hang on - is it PS3 -> HMDI splitter -> both TV and projector?
If so the PS3 may be falling backto 720p as this is the highest resolution supported by both devices.
Can you clarify the arrangement?

Also on HDMI cables - for performace there are specific terms that mean something:
Up to HDMI 1.3 there is Category 1 and Category 2 - Category 2 is the higher speed rating.
For HDMI 1.4 there is Standard Speed and High Speed, this is the same as Category 1 and Category 2, a more consumer friendly way of describing the same thing.
 
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SillySausage

Active Member
The hdmi box is a source selector not a splitter.

At the moment I connect either pj or tv to the out and just have the one in from the amp. Thus simply using it as a signal amplifier I presume.

The ps3 auto detects 1080p so the input to the fury seems to be working just not displaying properly.

With regards to cable, if I just go for hdmi 1.4 Cat 2 will this potentially be the best solution.
 
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Trollslayer

Distinguished Member
HDMI 1.4 High Speed you mean.
I got some from tvcables.co.uk for an installation and they work well at a good price - HDMI 1.4 Cables - TV Cables
I have a 5 metre cable in the wall with 1 metre at each end and 1080p is steady (plus future proofed).
 

Joe Fernand

Distinguished Member
AVForums Sponsor
HDMI hardware spec rev numbers should not be used in the marketing or marking of HDMI cables.

Cables are either High Speed or Standard Speed and I'm not aware of anyone with a High Speed certified non amplified cable longer than 8m.

If your having to rely on the EQ in the switch to drive the system there is a problem somewhere in the signal chain.

Are both outputs of the Amp having to rely on the Switch EQ?

A decent High Speed cable on sale or return would be a good starting point.

Joe
 
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Trollslayer

Distinguished Member
Joe, the ones I linked to are Hgih Speed up to 10 metres.
You raise a good point about the switch - SS, what make is the switch?
 

Joe Fernand

Distinguished Member
AVForums Sponsor
I wonder how they have managed 10m when the rest of the world is stuck at 8m?

Joe
 

SillySausage

Active Member
Thanks for your time guys - tis most appreciated :)

The switch is a different brand, but the same as the one below.

https://www.btowstore.com/epages/BT3449.sf/?ObjectPath=/Shops/BT3449/Products/111111

You have got me thinking about other possible problems, so will try disconnect a source from the amp and run the long HDMI cables direct from source.

Both outputs on the amp are the same and if I remember correctly when I had a 10m HDMI connected to output B as a test for the PJ initially (which didn't work without said switch box), the main output dropped out occasionally.

The amp can drive one or the other outputs, which is all I want, but maybe it needs a firmware update or similar.

Will go and test things directly this afternoon and see what conclusions I can draw.
 

SillySausage

Active Member
Well, have had a bit of a play this afternoon, and I think there are two problems compounding one another.

Firstly.
When connected direct to the TV, both Sky HD and the PS3 work fine without the powered switch box - but PS3 does not work at all on 1080p

When connected to the PJ directly without powered switch box, everything works at full resolution.

When connected through the amp, nothing works without powered switch box in line on either main or sub HDMI output.

So, I half conclude that the cable to the TV (HDMI to DVI) is no good for 1080p.

But more importantly, my amp doesn't like HDMI out.

It isn't possible to move amp closer to the screen and try a shorter lead, but as I had the same issue (needing box, not the PS3 issue) with the shorter leads connected without the switch box before I don't think lead length is a issue there.

The amp is set to through for all the HDMI ins and outs so in theory shouldn't be doing anything with the signal.

So maybe I have a duff amp :(

Will look further into amp and maybe post a similar thread in the relevant section, unless of course you two guys are willing to assist in here.

Cheers.
SS
 
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Trollslayer

Distinguished Member
I wonder how they have managed 10m when the rest of the world is stuck at 8m?

Joe
Physical construction makes a difference - I've had a few cables and the way this one is put together is far superior. Keeping the spacing of the twisted pairs consistent, good dieletric material etc. make a difference.
 

Trollslayer

Distinguished Member
Well, have had a bit of a play this afternoon, and I think there are two problems compounding one another.
When connected through the amp, nothing works without powered switch box in line on either main or sub HDMI output.
SS
So maybe I have a duff amp :(
SS
Afraid that looks likely. :(
 

Joe Fernand

Distinguished Member
AVForums Sponsor
Hello all

Trollslayer - we use 24AWG gauge, silver plated, gas injected dielectric, triple shielded cable stock on cables from 1m through 15m. The non amplified cable assemblies are High Speed up to 8m - with the Amplified cable assemblies High Speed at 8m, 10m and 12m and Standard Speed at 15m.

I'm not aware of anyone getting High Speed at 10m for a passive cable assembly!!!

SillySausage - keep in mind with the AV Amp in pass-thru mode you need to combine the lengths of the Input + Output cables to see the total run length your Source is having to drive.

You do have a fair few potential problem points in your system - a decent gauge 8m High Speed cable ought to do the trick between the AV Amp and the Projector and once working the same cable assembly ought to be fine with the run via the HDMI to YUV converter to the Display.

Joe
 

SillySausage

Active Member
Cheers Joe.

Now that everything is in the final resting place, I'll measure up and get a decent spec cable of the shortest run I can find.

Will start with the PJ as it is a simple 1080p out and in hopefully, and then move onto the TV.

Point taken about the 'through' thoughts with regards to cables, but even with 2 mtrs only of cable between source, amp and screen I got the same 'no picture without selector box' scenario.

Maybe all the cables I have are pants, but surely one of the 10 or so 1mtr lengths would have worked.
 

Trollslayer

Distinguished Member
Hello all
I'm not aware of anyone getting High Speed at 10m for a passive cable assembly!!!
Joe
Joe, this is the one i am referring to: 10m HDMI 1.4 Cable High Speed v1.4 with Ethernet Channel Audio Return HEAC Only £20.42 at TVCables
I have used their 5 metre cable happily and it has the speed category marked on it.
A couple of technical points though:
1. I have worked on RF measurement of 3G systems and for high performance cable we use solid dieletric cables - either PTFE or Gortex (a variation of the material used for weather resistant clothes). Gas injected materials are not quite as stable but are easier to handle. On the oter hand PTFE/Gortex dielectric cables are no good for putting in walls because they kink. The other factor is dimensional stability, I tried two different HDMI 1.4 cables and the one I settled on has a much more stable construction.
2. Pass-through mode means that there is no scaling, there is still a HDMI receiver, buffer and transmitter. If you check the EDID information (this can be done plugging in the graphics output of a PC and checking the display information in the device manager) then you will see the AV receiver ID information rather than the TV ID.
 

Joe Fernand

Distinguished Member
AVForums Sponsor
Hello all

Trollslayer - lots of AV Amps have very poor HDMI handling both in terms of HDCP and EDID (in a complex system) and signal integrity, many simply wont drive long cables.

A big problem in the cable game is folk marking every cable assembly formed from the same cable stock as 'High Speed' when in fact the cable stock is only rated as High Speed up to a certain length and I've yet to see HDMI.org grant a High Speed Cert for a 10m non active cable assembly!!!

SillySausage - lots of cables will be fine in a system at 1080i but fail at 1080p if the Sync device cant cope with much (if any) of a voltage drop.

Hopefully you get the PJ going at 1080p and then move over to the more complex 'to Component' run.

Joe
 

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