No Video Signal with Cable Matters HDMI 2.1 certified active cable

I bought this cable https://www.cablematters.com/pc-1337-139-certified-active-ultra-high-speed-hdmi-cable-fiber-active-optical-8k-hdmi-cable.aspx to use in the spectrum, and have successfully used it with the same GPU (with an EVGA 3090) on my 4k 120hz tv, which supports hdmi 2.1. But in the spectrum, I get no video output. I can use other shorter and non active hdmi 2.1 cables which work just fine, but these aren’t an option as I need a cable that can span over 50ft.

Is there a fix in mind? I know for a fact this active cable fully meets the specs due to a number of reviews and analyses, and Cable Matters has a long history and reputation for making quality cables.

I’ve tested the Cable Matters cable with other monitors with the same GPU, works just fine. I’ve tested other 2.1 cables with the Eve spectrum and same GPU, they work just fine. The spectrum clearly has a bug with this specific active cable.

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Hi @Andrew_Kennedy,

I know you’ve probably done this but can you please verify that you have the source end and display end connected the right way, with the source being plugged into your PC and display plugged into your monitor.

I have indeed done this, as the cables have the ends labeled clearly. I tried reversing it just in case the cable had a serious defect of reversed labels, but nope.

For additional clarification, the GPU is a 3090 FTW3 ULTRA by EVGA, and I’m running the latest nvidia drivers on windows 10, version 497.09

What I would try and maybe suggest to do is it’s not having enough power delivery, I would spilt the cable up 2x 25 ft maybe and add a hdmi 2.1 switch that supports power to it. Seems eve s needs a bit more power from the hdmi cable.

I’m not sure what you’re asking… Eve is not “powered” over hdmi, that’s not how hdmi works… Hdmi is 5V only and cannot possibly power a monitor.

@MarvyMarvz wanted to link you back in explaining that I’ve tried your suggestion.

Yes, but the longer the cable the decrees in voltage that’s goes along it. Hence why you would split the cable up in 2x25ft and add a switcher or splitter with power input that would ensure that the hdmi is still running 5v to display.

Hi @Andrew_Kennedy,

Apologies for the delay.

I’ve looked into the Active HDMI 2.1 Cable you’ve purchased but I believe it’s only designed for consoles (Xbox Series X Especially).

It’s an active caboose though, with circuitry to prevent this from happening. That’s the whole point of active cables.

Is there an officially recommended active 2.1 cable that can be used? One that’s longer than 10ft?

Hi @Andrew_Kennedy,

There’s not, unfortunately.

I’ve been looking around and the only active HDMI 2.1 cables that are somewhat trustworthy are these.

Where are you based, if I may ask?

I’m based in the US, in California. I know the active cable I bought has full certification for 2.1 and works great with other hdmi 2.1 sources and sinks so I’m just trying to figure out what I can do to make my monitor work a passive cable would be too short for what I need :sob:

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@MarvyMarvz I just wanted to follow up and the problem definitely seems to be with the Spectrum monitor. It does not work with any active cables I have tested, including https://www.amazon.com/Monoprice-Cabernet-Ultra-Active-Speed/dp/B015121JHY/ref=sr_1_3?keywords=active+hdmi&qid=1642157435&sr=8-3

I tested my existing cable matters cable and this monoprice one with my LG C9 TV and my PS5, and both work flawlessly. Am I able to return the eve as I absolutely must have support for long cables to make this monitor at all worth it.

Hey @Andrew_Kennedy I will ask the community team including @MarvyMarvz if we can recommend an active cable for you. I am personally not aware of any one reporting an active cable that works but that doesn’t mean the answer isn’t out there!

For returns you need to create a support ticket - the support team can help you with the return process.

edit: oops forgot the support link Support – Eve

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Hey @Taalyn! I’d also love to find out if this is fundamentally a hardware limitation or a firmware one, like, would it be possible that via a firmware update the Spectrum could support active cables in the future? I’m unsure what about the hdmi spec is missing with the use of active cables.

@Andrew_Kennedy I don’t want to keep advising you to spend more money to test the connection but I’m out of ideas to try with just what you have on hand. I assume with your testing you are connecting PS5 to LG C9 TV with the monoprice cable and it works. Swap the cable over to the Spectrum and no input. PC with the EVGA 3090 to the LG C9 with the cable - works. swap the cable to the Sepctrum and no signal …

Cable Matters (How do active HDMI cables work?) says:

Cable Matters offers a certified HDMI 2.1 cable with fiber optic technology, available in lengths up to 34.2 feet. This cable is also Designed for Xbox, meaning it is built and tested to meet the demands of 4K 120Hz gaming on the latest Xbox Series X game console.

which seems to indicate they offer an ultra high speed passive cable at 34.2 feet - but with that wording they also might be refering to a active cable at that length. However, by saying its built for demands of the PS5 also raises a concern. The cable that comes with the XBox (which I believe is a cable matters cable) is listed as a “High Speed HDMI cable” and “Supports HDMI 2.1” but there are questions about whether the Xbox supplied cable fully supports the data transfer of the 2.1 spec with the data throughput seemingly capped at 30-32 GB instead of the 40GB required in the HDMI 2.1 spec.

You could try a powered HDMI signal booster/repeater but virtually all of the ones I can find are limited to 1080p and 60Hz. Plus I don’t know if trying one will give us any answers towards the solution you want.

edit: clean up the formatting

Given that there’s chips at each end converting between an electrical signal and an optical signal, I’d say that it has to be an active cable.

The big unknown with these types of cables is how much they try and interpret the signal that’s being sent. At a minimum they need to know the frequency of the data being sent across the wire, so they can read individual bits at one end and reconstruct them at the other.

If a cable is trying to be extra clever in how it does things, the chips inside of it may expect only standard HDTV picture signals. That means standard resolutions, refresh rates and timings. Anything outside of these may cause the cable to barf with that signal.

I don’t know if the Spectrum is using custom timings for anything, but if it is, that could possibly explain why other HDMI 2.1 devices work with an active cable but the Spectrum doesn’t.

In theory, the firmware dev team could obtain an active cable and use that to track down the problem. If they can get one cable working, it’s quite likely that most other cables would also work.

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The cable I have is from Cable Matters and is confirmed by them to be active via fiber optics, just to clarify. I’ve confirmed via the LG TV debug menus and via some windows tools that my 3090 is sending full 40gbps HDMI 2.1 4K at 120fps with full hdr 4:4:4 color. The cable can definitely handle anything thrown at it via the PS5 or the 3090, so long as the output end is the LG C9 and not the Eve Spectrum. I wish the spectrum team could acquire some active fiber cables to get them working!

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Just so you know, we are actively trying to do that ourselves, @Taalyn has spoken to me about doing this, and I am looking around to find a couple also - I can’t test every one that is out there in the market, as that would just be a waste of money, but this exact Active copper2optic cable is on my list to test for sure.

Thankfully, I have an office that is across the halls from my bedroom, where my LG C1 is, so I can easily verify that the cable is working and if the Spectrum works with it or not. It’s just not going to be this week, probably next week at the earliest before I even have preliminary reports. But I am going to test this as much as I can.

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Hey @nkyadav! Any updates?