CAC-1087 – performs worse than a $15 adapter?

2 on 03-12-2022

my setup – 

rtx 4090



Sony STR-DN1070 receiver

4090 to the CX via the 1087 works fine-ish, minus the Gsync support (the gpu says gsync is still supported and i can turn it on, but the screen flashes) i knew this going in and didnt intend to use it on my main display anyways.  it did take a lot of screwing around to get it to work correctly though. (kept over stretching the display and making things blurry)

the real problem though, and why i bought it –

i send hdmi 2.1 to my tvs hdmi 2.1

i send hdmi off my gt1030 to my receiver for audio. everything works perfect and as intended this way. except i cant enable Rebar or dlss3 (3dmark test is telling me i cant, but thats the only thing i have to test with right now)

now i wanted to go hdmi to tv   and DP/HDMI to receiver and be able to eliminate the 1030.

this 1087 has displayed multiple issues with this already.

1. when i first plugged it in and set it up, my receiver detected a 5.1 signal and 48khz audio, but the audio played for 3 seconds, turned off for 3 seconds, played for 3 seconds, repeat on and on.

2. i tried a different DP port – audio cut out in a different pattern, played for like .25 seconds, cut out for .25 S, and that just continued till i pulled the plug.

3.  after playing around with things more, i went back and tried the original setup one last time.  DP/Hdmi to the receiver, original hdmi 2.1 cable from the 4090 to the tv.   the 1087 will no longer pass any audio above 2.0 stereo.  windows will see 5.1, but my receiver says its only receiving 2.0.

4. this has happened with every cable and adapter ive tried, and this one is no different.  with the DP plugged into the receiver, my system will not boot. the tv just displays no signal and my keyboard lights wont come on which tells me its not making it past post.  as soon as i unplug the dp cable and reboot, everythings good.

with all that said, a damn $15 passive adapter will pass the full audio signal to my receiver in 5.1, but likes to drop the audio if the cables at the wrong angle.  an active adapter doesnt drop the sound, but causes my speakers to have a faint but audible pop every couple of seconds.  can only be heard when the systems muted or audios not playing.

so, thoughts or suggestions?  onboard hdmi isnt an option either.  my cpu doesnt have an igp.

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1 on 03-12-2022


i spent more time playing around with this again, and im 95% satisfied now.

audio is working via DP/HDMI to my receiver, and the receiver is seeing 5.1 48khz.  i never had bothered to install the hdmi audio drivers from nvidia because…. well, it was never needed.  it just sent the signal to the receiver and the receiver did its thing.  now with the drivers installed the correct signal is being sent.


there is a minor issue with the audio though, and i think it has to do with the physical connection.  if the cables not 110% seated on the DP side, the audio stream will have little micro drops in it.  just enough to be really annoying.  but i found if unplug it and reinsert it into a different port, it seems to be fine.  ill need to keep an eye on this, im not sure if its happening after every wake, or it just happened because i came back from a full reboot, and then started testing sleep/wake.


sleep/wake works fine.  and this was a full, real cycle.  pc went to sleep, monitor and receiver turned off and powered down.  monitor and avr powered back on first like i always do, and then the pc woke up.


full reboot is still a no go with the dp cable plugged in.  i need to have the dp cable removed when i restart the system or its not booting. 


and the gt1030 is now out of the system and dlss3 can be enabled.


club3d – if you guys have any more thoughts or suggestions on getting the system to be able to reboot, or permanently clearing up those micro drops on the audio stream, id like to hear it. 

on 05-12-2022

Try and mail [email protected] for a possible firmware update on the CAC-1087.

Good that you solved 95% of the issue, hope support maybe able to help you with the sound issue.

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