iMac (mini misplayport) to Pioneer KRP (HDMI)


Prominent Member
What is the best way to connect my iMac (in my office) to my Pioneer KRP which is in my music / cinema room, about 8-10m away through a wall?

I would have gone the apple TV route, but my iMac isn't new enough to do the video mirroring when OSX Mountain Lion comes out.

I have bought the Moshi MDP-HDMI adaptor, but am having trouble with HDMI cables.

I have tried several 10m HDMI cables without success. I know that the adaptor works because I have successfully tested it with a 5M HDMI cable. My iMac is a late 2009 27" model which has the mini display port activated for this very purpose.

The 10M HDMI cables are of good quality, are labelled "24AWG HDMI STANDARD with ETHERNET" and claim "These cables will handle 1080p full HD at distances of 25m without requiring boosters or amplifiers", but don't seem to work when used in combination with a mini display port adaptor.

Will using a 2-3M Mini Display Port cable, then the adaptor, then a 5-7M HDMI cable be a better bet than using just the adaptor and a 10M HDMI cable ?

Should I try another brand of mdp-hdmi adaptor ?

Should I be using an HDMI cable that is labelled "HIGH SPEED" rather than "STANDARD" ?

I already have a 10m optical cable connecting the iMac to my home cinema amplifiers, so sound is sorted - it is just the vision that needs to be sorted.

Does anyone have any first hand experience of solving this problem ?

I have posted a similar question in the HDMI cable forum, but didn't get an answer with a proven solution.

Thanks in advance.
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Distinguished Member
Passive displayport to HDMI adaptors like the Moshi dont work too well if your going over 3-4 meters.

Displayport can connect to HDMI but the distance limitation is severe indeed.

HDMI itself has trouble in general with connections over 8 -10 meters , that in conjunction with the much tighter limitations on passive displayport to HDMI adaptors and your solution is highly unlikely to work , as you have found out.

What you need is an active displayport to HDMI adaptor , see the article here , the active models either have their own power supply or take the extra power needed from a USB connection.

An active adaptor along with the cable should work.


Prominent Member
Thanks Andy,

I can't see an active link in your reply - if there is supposed to be one please can you check that it is there.

I tried (by moving my iMac into the same room as the plasma) a 5m HDMI cable with the Moshi mdp-hdmi adaptor and it worked. But this is not a permanent solution. I just need to find a solution that works for the extra 3 or 4 metres, without breaking the bank.

To my way of thinking there are 3 elements in this equation, plus the complicating factor of how the three elements get on with each other:

1. Mini Displayport cable
2. MDP-HDMI adaptor
3. HDMI cable

Would having a longer MDP cable be a good idea? (so that the HDMI cable is limited to 5M).


Would an active HDMI cable do the job (presumably drawing power from the Plasma end of the chain) ?

I await with interest your link to active mdp-hdmi adaptors.

I can't believe that I am the only person on here that is trying to do the same thing - surely someone has done this before and succeeded?
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