Denon AVC-x6800 pre-amp problems, any suggestions?

[Brambo67]

Hi all, recently my, less than one-year-old, Denon 6800 is giving me problems. I’ve written a bit about my setup and it is in my avatar. I use it in a hybrid mode; 4 Atmos speakers I drive through the 6800’s internal amps and the rest is driven by the Marantz MM7025 and 7055. I use oké-ish cables and have set it up both with Audyssey as well as Dirac.

The problem I experience is the front right channel drops in output to almost ‘whisper’-level. Of course this is very noticeable while listening in stereo mode however also in surround mode. When it happened a few times, it always is solved by switching off and on the system again, I decided to take the MM 7025 out my cabinet and switch the RCA-inputs (L->R and the other way around) I did it ‘live’ and immediately the front right speaker picked up the level and the left dropped. So my conclusion; no MM 7025 issue and no speaker issue. Leaving the 6800 and the RCA, the last seaming not likely to be the culprit.

What I did then is doing stereo without Dirac and the same occurred. It is NOT completely switching off the channel but very much lowering the sound level. Again; switching off and on again solved the issue for a while.

If I remember correctly it all started after my most recent Dirac calibration after I installed the second sub. Hence the idea Dirac could be causing it but alas, not the solution. So before I put in its cardboard box again and take it a few hundred km’s to the shop I sourced it, and having to wait for it being reproduced and hopefully repaired, what suggestions do you have? Right now it’s of the power. I could probably factory reset is or is it likely to be ‘hardware-driven’? I already changed the way I drive the front channels from ‘pre-amp only’ to ‘pre-amp and speaker’. This didn’t solve it either. Oké, open to suggestions…

Edit: did start it up again. In stereo the right channel is going down and up again from itself. No stable sound level anymore.

 

[nerdstrike]

Maybe look for a L/R pan setting going rogue? Or even a knob if such a thing exists on these modern AVRs. That's the simplest way I can think of to produce the effect if I wanted it.

 

[Devnull]

If it's less than a year old then put in a warranty claim

 

[amadeogt]

My Marantz SR5005 developed a similar channel imbalance "syndrome", with a difference: it only affected the headphone output. I tried different cables and headphones, of course.

It would get worse and worse (the imbalance would increase over a period of weeks), then a factory reset would fix it. Only for the problem to start again a few weeks later. It drove me mad, and the receiver was out of warranty.

After some time, and a few resets, the problem went away and never came back (fingers crossed). My guess is it had something to do with buggy Marantz/Denon firmware.

 

[Laika2]

Back up to usb, factory reset, restore backup, this always fixes issues so far, these things are half computer and seem to screw now and then. Consider this a factory reboot. If it does not work then it's something bigger than scrambled chip. I say this because it appeared after a Dirac calibration and worked fine before. (I have the 6800 in pre amp running endless monoblocks. I am not saying dirac did it, I'm saying I think something glitches on the memory chip in the process.

After done I would not run the dirac configuration that may have triggered the issue but delete it and run a new one. Good luck

 

[Brambo67]

Thanks for the feedback so far. Last few days I had other priorities but the issue kept occurring sometimes immediately, sometimes after a few hours. It still never fully shuts down the channel but indeed lowers output. By increasing the channel output by 12 dB in the app the balance seems to be restored. Of course this is not a workable solution!

I consider disconnecting the RCA cable and measure the output on the cable if possible (multi meter?) Just to see what happens. The box is warranted for 2 years and the 1st hasn't even passed (until November). Since I'm considering changing the lay out of my speakers and subs and applying some room correction material, I may wait for that and do a factory reset before setting it up again and calibrate from scratch with both Dirac as well as Audyssey. Of course I will store everything on USB.

I'll make sure to have enough time to run and test it for quite a while before the 1st year of warranty ends. The outlook of having to go through all the calibrating doesn't make me happy as the last time it took a few hours to do Dirac alone, however; no pain no gain ;-) I'll update this thread after each step I take.

 

[peng]

Thanks for the feedback so far. Last few days I had other priorities but the issue kept occurring sometimes immediately, sometimes after a few hours. It still never fully shuts down the channel but indeed lowers output. By increasing the channel output by 12 dB in the app the balance seems to be restored. Of course this is not a workable solution!

I consider disconnecting the RCA cable and measure the output on the cable if possible (multi meter?) Just to see what happens. The box is warranted for 2 years and the 1st hasn't even passed (until November). Since I'm considering changing the lay out of my speakers and subs and applying some room correction material, I may wait for that and do a factory reset before setting it up again and calibrate from scratch with both Dirac as well as Audyssey. Of course I will store everything on USB.

I'll make sure to have enough time to run and test it for quite a while before the 1st year of warranty ends. The outlook of having to go through all the calibrating doesn't make me happy as the last time it took a few hours to do Dirac alone, however; no pain no gain ;-) I'll update this thread after each step I take.

I would think for such a real flagship class AVR, it is better to deal with it now than later, especially in the event you have to send it to Denon for a proper diagnostic and repair. It sounds like nothing serious but something went wrong with the DSP and as long as Denon can make it happen quickly in their shops, it would likely be an easy fix.

As as the RC set up, you should be able to save the settings in both cases. For Audyssey, you can just use the App to save the settings/target curve, and for DL, you should be able to save the project easy enough, such that you don't have to do a re-run after a factory reset, that should be the first step, after that, it should be in Denon's hand.

 

[Brambo67]

I would think for such a real flagship class AVR, it is better to deal with it now than later, especially in the event you have to send it to Denon for a proper diagnostic and repair. It sounds like nothing serious but something went wrong with the DSP and as long as Denon can make it happen quickly in their shops, it would likely be an easy fix.

As as the RC set up, you should be able to save the settings in both cases. For Audyssey, you can just use the App to save the settings/target curve, and for DL, you should be able to save the project easy enough, such that you don't have to do a re-run after a factory reset, that should be the first step, after that, it should be in Denon's hand.

Thanks for you reply as well. In the case I will send the box to 'Denon' it will be send to a local (as in 'somewhere in the Netherlands') repair shop where they earlier also took care of my Marantz MM7025. Also my initial AVC-X3700h went there when it started to go into 'limp-mode'. I decided to buy the 4700 which recently was replaced by the 6800.

So over here it's not really Denon doing the work and since the Netherlands are a tiny country, I could even take it myself. The European warranty is 2 years so I should be safe. In any case I think I will find out soon enough (before November even).

Back then I decided not to wait for the 3700 to be fixed as they took ages to do so. A lot of testing, simulating etc. and, according to them, waiting for the right 'chips'. That should be better by now but it doesn't hurt to go through factory reset and try for a few weeks.

I'm not sure if I will use the old Dirac and Audyssey calibration settings. I think something went wrong after I added the 2nd sub and had to re-calibrate. If it turns out to be a hardware related problem, I'll find out soon enough. Starting fresh most definitely means I will rule out every 'old' setting to be the cause. So yes, it will cost me a Sunday and the family will not like it as they need to find something to do that day (including the dog ) If I face the issue again after all those steps it will mean taking it to the repair shop and sit out the long wait. For certain it will at least be 5-6 weeks.

 

[Brambo67]

My Dirac measurements from front right and left don't differ too much, I doubt it is Dirac...

 

[Brambo67]

So, just reset the box and installed the original configuration I made a back up of. Apparently Dirac also is part of the backed up config because I found it later on in my Preset 1. Audyssey I uploaded again on Preset 2. So, started in stereo and within 5 minutes the issue happened again. Restarting the box again, it went well for a few minutes and presto; similar issue as before. Probably I will turn around the RCA cable to check what happens. Perhaps tomorrow a new reset and do a manual setup just to check left and right. I find it very strange the output on the FR channel drops by a few dB but doesn’t shut down completely.

 

[Laika2]

So, just reset the box and installed the original configuration I made a back up of. Apparently Dirac also is part of the backed up config because I found it later on in my Preset 1. Audyssey I uploaded again on Preset 2. So, started in stereo and within 5 minutes the issue happened again. Restarting the box again, it went well for a few minutes and presto; similar issue as before. Probably I will turn around the RCA cable to check what happens. Perhaps tomorrow a new reset and do a manual setup just to check left and right. I find it very strange the output on the FR channel drops by a few dB but doesn’t shut down completely.

Starting to sound like a cable or one of the two related ports. The last chance is to see if it's processing. Factory reset, play unit with issues, are the dropouts still there, reinstall the backup.

Odd, if there are rca connections you are using do you push and twist them on, that often breaks or creates a short in a wire in a device. Fine first, warms up shorts of arcs can still often send a low level signal.

I learned the hard way that you only push rcas in, no twisting. Even if it takes nore force in the push.

Hope you get it working, good luck.

 

[Brambo67]

Starting to sound like a cable or one of the two related ports. The last chance is to see if it's processing. Factory reset, play unit with issues, are the dropouts still there, reinstall the backup.

Odd, if there are rca connections you are using do you push and twist them on, that often breaks or creates a short in a wire in a device. Fine first, warms up shorts of arcs can still often send a low level signal.

I learned the hard way that you only push rcas in, no twisting. Even if it takes nore force in the push.

Hope you get it working, good luck.

I've swapped L and R, so pre-amp out Front Right to power amp in RCA left to check what happens. If the same happens but now on the front left channel it is either in the pre-amp section of the box or in the RCA cable. I have an alternative cable lying around I can use, may change that tonight and see. However, I belief it is in the pre-amp section

 

[Laika2]

I've swapped L and R, so pre-amp out Front Right to power amp in RCA left to check what happens. If the same happens but now on the front left channel it is either in the pre-amp section of the box or in the RCA cable. I have an alternative cable lying around I can use, may change that tonight and see. However, I belief it is in the pre-amp section

Sounds like a plan, it looks like you are down to 3, the cable, or the hookup connections on either end. Crossing my fingers you are wrong and it's the cable (though no reason to believe that yet, it's just the simplest cheapest fix, the other two not so much)
Good Luck

 

[Brambo67]

Did a factory reset again, changed the RCA for a new one and yesterday evening no issues. Again, not holding my breath here as I assume at some point it may happen again. The RCA I took out is a very sturdy (and expensive) AudioQuest and there simply isn't any movement that could have caused the cable to wear. Anyhow tonight I will test again in stereo and surround. I have ample time to take it to the repair shop later.

 

[KenMasters]

Did a factory reset again, changed the RCA for a new one and yesterday evening no issues. Again, not holding my breath here as I assume at some point it may happen again. The RCA I took out is a very sturdy (and expensive) AudioQuest and there simply isn't any movement that could have caused the cable to wear. Anyhow tonight I will test again in stereo and surround. I have ample time to take it to the repair shop later.

The problem you're describing sounds like it could be an issue with the microprocessor.

I had an issue where an auto firmware update was performed midway through a manual calibration of Audyssey. This resulted in random audio dropouts and incorrect assignment of channels post calibration.

A Factory Reset can't solve issues of this nature, for that you need to do a full Factory Restore:

Factory Restore AVC-X6800H

manuals.denon.com

 

[Brambo67]

The problem you're describing sounds like it could be an issue with the microprocessor.

I had an issue where an auto firmware update was performed midway through a manual calibration of Audyssey. This resulted in random audio dropouts and incorrect assignment of channels post calibration.

A Factory Reset can't solve issues of this nature, for that you need to do a full Factory Restore:

Factory Restore AVC-X6800H

manuals.denon.com

Thanks for the response. I'll leave it as it is right now as it yesterday performed well. If it occurs again I'll do the factory restore.

 

[peng]

The problem you're describing sounds like it could be an issue with the microprocessor.

I had an issue where an auto firmware update was performed midway through a manual calibration of Audyssey. This resulted in random audio dropouts and incorrect assignment of channels post calibration.

A Factory Reset can't solve issues of this nature, for that you need to do a full Factory Restore:

Factory Restore AVC-X6800H

manuals.denon.com

Excellent point, I though he did do a restore, if not then he should do it if the trouble comes back. There’s a reasonable chance a full restore may fix it as it would need to reinstall the latest fw.

 

[Brambo67]

So far so good. Yesterday watched a few movies both in Dolby Surround, Atmos and Stereo. Also listened to some music. The problem didn't occur again. Somehow I start to belief it's working again now.

 

[peng]

So far so good. Yesterday watched a few movies both in Dolby Surround, Atmos and Stereo. Also listened to some music. The problem didn't occur again. Somehow I start to belief it's working again now.

Let's recap, so you did a reset once, the problem did return after, then you did another reset, and so far so good?

If so, then it means those so called factory reset may have to be done more than once (as reported on forums by users), before it fixed certain weird issues.

Or, did you actually do the "Factory Restore"? In that case, it should either have fixed the issues after one such restore, or it won't fix the issue and the unit would need to be sent to a Denon authorized repair shop.

 

[Brambo67]

Let's recap, so you did a reset once, the problem did return after, then you did another reset, and so far so good?

If so, then it means those so called factory reset may have to be done more than once (as reported on forums by users), before it fixed certain weird issues.

Or, did you actually do the "Factory Restore"? In that case, it should either have fixed the issues after one such restore, or it won't fix the issue and the unit would need to be sent to a Denon authorized repair shop.

I had to reset it twice. Also I changed the RCA cable but I guess that's not the reason why it's doing what it's supposed to do. Played music in stereo and fed it all kind of content from Blu-Ray (Atmos) as well as Netflix streaming etc.