Few problems with a NAD T775HD receiver, pick one and provide your thoughts please :) (1 Viewer)

[rick3r]

Hello community,

I just have received a receiver that I bought. Model is NAD T775HD, which had upgraded its audio board by a AM230 Digital Audio Board, and its video board by a VM300 Digital Video board. I have few problems, so if you can help with one of those, many thanks and kudos !

Most of my tests were run with a nVidia Shield Pro, hooked on AVR with a HDMI 2.1 cable, and all those issues weren't present before, with a Marantz receiver.

Problem #1 : AC3 (Dolby Digital) playback not working WHEN PRECEDED BY A DTS PLAYBACK (yeah, that's right!)

• All these tests are from Plex, an App inside the Shield Pro
• Tested both with and without HDMI passthrough (without, I only get dull PCM Surround)
• AC3 movie (MKV) playback is fine, logo DD light on the AVR
• DTS movie (MKV) playback is fine, logo DTS light on the AVR
• AC3 movie playback, followed by DTS movie playback is fine, DD logo is on, then goes off and DTS logo goes on
• DTS movie playback, followed by AC3 movie playback NOT WORKING
  • DTS logo remains on
  • DD logo lights on the AVR
  • No sound at all
  • AVR remains stuck in this state
  • The only way I found is to play per se a Youtube video, which switches the AVR to PCM Stereo

Problem #2 : Dirac Live calibration impossible to get done

• I always get the error "Low signal-to-noise ratio"
• Followed instructions here : https://live.dirac.com/content/uploads/2019/05/dirac-live-quick-start-print-version.pdf
  
• Using the original mic, with the USB adapter and the stereo-to-mono adapter
• Tried with different MIC gains, from the bottom, to the max of the safe zone, to the max of the red zone
• Adjusted the individual speaker gains to make them just in the beggining of the green zone
• Have only activated the correct amount of speakers
• Have tested many Master output levels, including a very loud test
• Have tested the Mic in the NAD's USb port, the NAD's front Mic port (was not working at all), and in my laptop's USB port
• The only time where I got a result is when I used only my laptop Mic, but the results were pretty bad

Problem #3 : Cannot read FLAC files at all

• Playback is from Plex App, within nVidia Shield Pro
• Playback was working fine with my previous Marantz AVR
• On screen, playback starts, but no sound at all
• NAD does not change sound mode at all, as if nothing was detected

Problem #4 : Firmware update check get stuck

• When trying to look for firmware updates, it gets stuck in "Please wait" message, forever
• Network connection is okay because I can connect with the NAD using Dirac Live Windows App
• I can see the NAD's IP address

Problem #5 : Playback from Windows 10 always PCM Surround

• NAD does not change its sound mode, always PCM Surround
• Tests were done in Plex App, not within browser, since browsers doesn't handle 5.1
• Windows sound is configured in 5.1
• Windows detects my sound device as a NAD T775HD
• Hooked in HDMI, with a HDMI 2.1 cable

So... if you all read this so far, first of all thank you for your time. Now, you may understand that my user experience is not, my I say, pure pleasure.

Please feel free to refer to any of these problems and give your (positive, please) input !

Thank you,
Eric

 

[Dave Upton]

Hello community,

I just have received a receiver that I bought. Model is NAD T775HD, which had upgraded its audio board by a AM230 Digital Audio Board, and its video board by a VM300 Digital Video board. I have few problems, so if you can help with one of those, many thanks and kudos !

Most of my tests were run with a nVidia Shield Pro, hooked on AVR with a HDMI 2.1 cable, and all those issues weren't present before, with a Marantz receiver.

...

Welcome to the forum Eric. You've got a whole mess of problems below, so I'll answer them individually. I'd start with a factory reset on your AVR, and then manually upgrade the firmware using a USB to RS232 adapter. That should get you in better shape to resolve the rest of these issues.


Problem #1 : AC3 (Dolby Digital) playback not working WHEN PRECEDED BY A DTS PLAYBACK (yeah, that's right!)
This sounds like a handshake issue or an issue with the Shield. Does the same problem happen with other sources, or the shield only? I think your AVR firmware could probably use an update - see response to #4 below. That said, you should also try a factory reset using this method:

Problem #2 : Dirac Live calibration impossible to get done
This is a fairly common one, usually a result of noise power lines or just getting your setup slightly wrong. You should be using a USB microphone connected to your laptop, not to the NAD. It sounds like your mic isn't properly configured. You can purchase a UMIK-1 from MiniDSP that works properly with Dirac. That might be your best option. Here is a good series of videos for Dirac on NAD: and

Problem #3 : Cannot read FLAC files at all
Sounds like you are bitstreaming (passthrough) to your AVR and it can't decode it properly or again, a handshake issue. The Shield has a pretty long track record of issues with audio output. Have you seen if you have the same problem with local FLAC files or is it in Plex only?

Problem #4 : Firmware update check get stuck

You probably need to do it manually. Download the firmware from: https://nadelectronics.com/product/t-775-av-surround-sound-receiver/
and apply using a USB to RS232 adapter. You can pick one of those up anywhere and just need the COM port number to proceed. Here's a good example of one. This is an essential step after replacing parts using MDC.

Problem #5 : Playback from Windows 10 always PCM Surround
Again, focus on firmware updates first. Then try removing the device and reconnecting. You may need to update your graphics card driver to better support HDMI audio.

 

[rick3r]

@Dave Upton thank you for those sharp indications ! Here is a followup of my last actions.

Problem #1 (AC3/DTS) : After more tests, it appears that the problem comes from the nVidia Shield. Indeed, I found that when the receiver does not play sound anymore, a reboot of the Shield corrects temporarly the situation. This has been confirmed by on many on nVidia forums. Not a cool workaround, but a reboot and it's okay to play again AC3 content.

Problem #2 (cannot calibrate with Dirac) : I am on touch with Nad's support, and they confirmed that the white USB mic adapter was known to produce issues. Waiting to see if they are offering me to send a new one.

Problem #3 (FLAC) : The problem was occuring in Plex, as it was the only environment I tried. I did a hard reset of the receiver and Bam!, FLAC files are now playing right. In fact, much more than just right, this Nad surpasses my current DAC, surprinsingly !

Problem #4 (firmware) : Did not try it yet, as I'll have to get the RS232/USB adapter before.

Problem #5 (Windows) : Did not give it a try yet, I was too excited to explore the sound capabilities of the receiver from the Shield/Plex. I did take note of the steps though, and will do it soon to ensure that if I need to revert to my HTPC, it will be a viable solution.

Thank you !
Eric

 

[Dave Upton]

Glad to hear you're making progress! Did you have any luck updating the firmware over the weekend?

 

[rick3r]

Not at all. I am still stuck, waiting for Nad's support. But they're only open on weekdays, and on december 23rd, I suppose it will go in a couple of days. I'll keep you updated here for sure.

Thank you!

 

[rick3r]

@Dave Upton just FYI, I received from NAD a replacement USB Mic adapter and it works well. So, Dirac is quite easy to run after all, with great results, as long as you have the microphone working correctly !

So, to recap, problem #1 is identified and related to nVidia Shield, problem #2 was related to a faulty USB adapter, problem #3 is related to problem #1 (a reboot of the Shield and FLAC works very well).

Problem #4 is still pending, and problem #5 have not been investigated, since the video quality from an onboard video card (Intel 530) is below the video quality of the Shield.

All in all, I have better sound with this NAD than with a Marantz SR6007.

Conclusion : NAD is great !

 

[JohnRice]

For #5, PCM isn't actually a surround mode. It's a digital audio format, which is a slightly different thing. If your receiver is receiving PCM from the computer, then it means the computer has already decoded the original surround format (DD, DTS, etc.) and output it as an uncompressed digital stream.

You can leave it as it is, or set the computer to output bitstream instead of decoding the soundtrack. I have no idea how you do that in Windows.

 

[Dave Upton]

For #5, PCM isn't actually a surround mode. It's a digital audio format, which is a slightly different thing. If your receiver is receiving PCM from the computer, then it means the computer has already decoded the original surround format (DD, DTS, etc.) and output it as an uncompressed digital stream.

You can leave it as it is, or set the computer to output bitstream instead of decoding the soundtrack. I have no idea how you do that in Windows.

It depends on the software. Windows has a built in layer called WASAPI (Windows Audio Session API) that software can use to bitstream.

In @rick3r 's case he'll need to change the settings in Plex to get this working. If it still doesn't, he may need to update his chipset and video drivers:

https://forums.plex.tv/t/bitstreaming-audio/181336