HK AVR 7300 thumps on source switch

My HK AVR 7300 has a very noticable and annoying thump when ever the audio source is switched or when ever the audio surround mode changes. The latter is the most annoying as this (the surround mode changes) happens randomly while watching OTA HD broadcasts of non HD content. I think the surround mode switching is the fault of the local TV stations feed and there is nothing I can do about it since the AVR will automatically go into Dolby Digital whenever it is available and the drop back to PLII when the digital signal is lost. I do not know why the local bradcasts have this problem but they do.

Anyway I was just wondering is this thumping normal? Is there something I can do to stop it?

Thanks
Steve

Bump

Has nobdoy else experienced this behaviour with this AVR. I know this is (or was anyway) a fairly popular AVR surely someone has some thoughts on this

Thanks
Steve

I am not using the internal amps except for the center and surround channels. The front mains are powered by 2 Adcom GFA-555s running bridged.

So can I assume (since you went back to internals) that although HK identified the problem they did not offer a solution?

Ok I know this is probably a really stupid response because I do not know much about elect. but... since both the Adcoms are plugged into the switched outlet of the HK (through a transitorized thingy made for me by a freind) shouldn't every thing have the same ground?

FirebirdTN,

I can not speak for your issue (though it does sound very similar) I am absolutely sure mine is coming from the AVR. In addition to gettting the pops when the dolby mode changes, I get this same popping when playing mp3s from my HTPC and the player switches from one song to another. This makes what one previous poster said about the muting "feature" sound like the culprit. Since I believe this "feature" is supposed to activate whenever there is a break in the audio signal.

I do not get the popping when changing from track to track on a CD though...but this also make sense...since the audio signal is not broken going from one track to another on a cd there is just silence on the signal between tracks.

Ok I just got off the phone with HK support and have a little better understanding of this issue. The problem is not the muting feature, infact this muting feature is designed to eliminate the popping we are experiencing. The problem stems from the locking and unlocking of the digital stream. The reason we experience the problem on external amps (and not when using the internal ones) is that the muting feature is not applied to the preamp section but only to the amp output stage. I think that part makes perfect sense. Another obvious reason some may experience this issue while others do not is the type of connection used between the source (DTV, HTPC, DVD, etc.). In order to have the issue the connection must be digital as there is no locking on analog signals. This explains why I do experience the problem when switching mp3 tracks on the HTPC (digitally connected) but not when switching tracks on a CD (analog connection). This definition of the problem also explains the popping experienced when viewing/listening to OTA HD broadcast of non-HD content. What happens here is that the local station has a DD encoder which is supposed to switch off and just pass the network feed of DD when the network feed is DD and switch on to provide DD encoding when either the network feed is not DD or the local station is not using network feed (ie. local comercials). This switching on/off of the DD encoding causes the reciever to lose and regain a lock on a digital stream thus causing the popping.

So given that as an explanation can anybody help with a solution? HK has said that there is no way to resolve this in the reciever. I guess that means that it can not be done with a software upgrade.

BTW the problem is more than just annoying, In my case I believe it is responsible for blowing the amp in my sub (twice).

Yes I understand this now. I brought this up to HK support when talking to them about the issue and they said although a good idea in general they doubted that it would have any impact on this particular problem. I plan to try it when I get home this evening though just the same. I understood most of what they were telling me but I am still a bit fuzzy on one thing. What exactly is being sent out the preamp outputs that is causing the external amps to thump? It seems to me that the external amps must be shotting a split second straight DC voltage to the speakers to cause such a thump. Is this true? If this is infact the case what must be being sent from the AVR's preamp outputs to cause the external amps to output a straight DC signal? Also shouldn't there be some type of device I can put in the preamp output connection that would filter it out before it gets to the amps?

Spydah,
I am not so sure this is as much an answer as it is a non-answer since they (HK) said there was no way to disable the feature and even if there were that would not fix the problem. Thus no solution...no answer.


The following was copied from the Anthem web site http://statement.anthemav.com/HTML/Products/D2/D2.html

Based on this statement it appears to me as this popping (or thumping) on source switch is not an HK issue. That being said though other preamp manufacturers have obviously figured out how to control it. While I realize the HK AVR7300 is not in the same class as the Antem D2 it is no slouch either. Furthermore many much less expensive receivers do not have this issue (or at least the issue is controlled to the point it is not noticed by the end user) so why can't HK engineer a solution that works? I think their solution to the problem (muting the output momentarily) is ingenious but unfortunately it is an incomplete solution (only protects when using internal amps). Please do not take this as a flame on HK aside from this issue I love this AVR. I have owned it for nearly a year now and have just put up with the popping cause otherwise this thing is great. I would still be just putting up with it except for the fact that this issue now seems to be the the cause of me blowing my $1k Klipsch RSW-12 sub's amp twice. Obviously with this problem this popping issue has become a deal breaker for me...if I can not find a solution soon I will be getting rid of it and getting something else ...maybe that Anthem D2 and a few more of the Adcoms

I do not think they were saying that it was a literal imposibility...just that there were no user settings, software configurations or firmware upgrades which would change this behaviour.

B&W700guy,
In Spydahs original post to this thread he stated that he had the HK 635.

I believe he contributed by simply stating that he was experiencing the same or similar problem as I am with my 7300. He further mused that since both these different recievers exhibited these similar behaviours it must be a fault common to HK.

With that said, I would like to take a moment to agree with your point on this reciever...I have had it for nearly a year now and (except for this issue) I love the thing. I really love all of its features and for surround I really enjoy its sound and power. However, I think that it is not a very accurate amp (note this is an opinion only). For music I prefer 2 channel stereo listening and I want my HFs to be as bright as they were intended to be. The HK (in my opinion) tends to soften the HFs a bit. It is for this reason (and to add some headroom for tighter bass control) that I use external amps for the front mains.

I have tried all of the various multi-channel modes offered by this reciever on music and I just dont find them very appealing. To me listening to music like this is like listening in a very bad room where reflections are muddying the intended sound. To be fair here though, I should mention that I have not had the opportunity to listen to any music that was mastered in multi-channel (SCAD, DVD-A). I have quite an extensive mp3 library (over 100gigabytes ripped at 256kbps from standard CDs), which is the source for the majority of my listening.

I have heard (read) that many like the multi-channel music formats. I do not really understand this, possibly because (as stated above) I have not heard any that was recorded that way. When I listen to music I want it to sound like it would if I were listening to it live at a concert or in a club. I have not been to a great many concerts (do not enjoy the crowds) but I have been to a few and I have been to many club performances. In all of these live performances the sound stage comes from the stage which is infront of me (no surround here). For me music, unlike movies, is not attempting to envelop me or make me feel like I am part of the scene. Music is a performance happening infront of me. Movies on the other hand should make efforts (through sound as well as visual cues) to make me feel that I am part of the unfolding action/drama. So for me surround sound is for movies and 2 channel is for music. I might enjoy the inclusion of a center channel for music listening to anchor the sound stage for "2 channel stereo" music, but none of the 3 channel modes of the HK give me a satisfing experience. This is in part due to the fact that although all of my speakers are timbre matched (Mains Klipsch RF-7s, Centet Klipsch RC-7, Surrounds Klipsch RS-7s) the mains are amped by (as mentioned above) external Adcom GFA-555 amps while the center is amped by the HK 7300. The difference in the HFs between the mains and the center in this configuration is quite noticable.

B&W700guy,

Now that I have completed that long winded rant I am very interested in your setup. Based on some of your previous post to this thread I gather that (at least in the fact that you are using the 7300 for a preamp for your mains) our setups are similar. I would like to know how our setups differ since you do not experience the issue. Maybe I simply have my system configured wrong. Lord knows that with all the features and settings in the 7300 I have no idea if mine are optimal (or even correct). This HT thing has been a real learning experience for me and there are certainly some settings (most having to do with the Foruga processing) that I simply have no idea what they are for or how they should be set.

I also did not think that particular apparent slam on HK was warrented. Their systems work exactly as designed and many have no problem with that design (loss of a few milliseconds of audio on source switching).

No I have not yet gotten to trying that. My system is not very friendly when it comes to changing wiring (requires alot of heavy lifting). I hope to tear in to it and try the ground thing this afternoon.

Again though, can we investigate the differences in our setups? Maybe that will lead to some resolution here.