MikeGinIllinois Posted December 8, 2012 Share Posted December 8, 2012 Hi, everyone. I haven't been out here in a long time. I have a Harman Kardon AVR-7300 which I got from Harman Kardon headquaters a few years back. They had repaired it and originally it worked just great. I run outputs to a Sony amp and a Yamaha amp. The Sony amp feeds a pair of Klipsch Synergy bookshelf speakers and the Yamaha feeds a pair of Radio Shack speakers. I input a DVD player and a Roku to the amp. My speaker wires to the Cornwalls are thick Monster cables. My problem is that my Cornwalls give a "bzzzzzz" when I turn on the AVR-7300. It's intermittent. I just turned the AVR-7300 and no bzzzzz. Then, after 5 seconds a soft bzzzz started. It will usually grow in intensity until it's annoying. The bzzzzz doesn't come out of my Synergy's or the Radio Shackers (supported by two other amps). How do I troubleshoot this setup? Take it all apart and start putting components back in? Can input devices cause the problem? Is it possible that the AVR-7300 is generating the bzzzzzzz? I appreciate any comments and tips. Thank you! Mike Gallery Quote Link to comment Share on other sites More sharing options...
Moderators dtel Posted December 8, 2012 Moderators Share Posted December 8, 2012 Maby try switching a speaker would be the easiest first, then switch an amp, if that don't work maby it's the HK outputs. Maby just switch the outputs on the HK if it's easier. It's going to be trial and error, being intermittent make it tougher. Good luck, you will find it. Quote Link to comment Share on other sites More sharing options...
MikeGinIllinois Posted December 8, 2012 Author Share Posted December 8, 2012 Can I switch the HK outputs? I haven't been behind the unit in a while. I don't have multiple choices for speaker outputs, do I? Thanks a bunch for your help. <-: Mike Gallery Quote Link to comment Share on other sites More sharing options...
WMcD Posted December 8, 2012 Share Posted December 8, 2012 Welcome back. I do think it is not something wrong with the CW, so don't start taking it apart.. There is nothing in there which would create a buzz. Of course if you drive a speaker real hard and something loose, there can be any number of artifacts, but that is not what you're describing. Also, sometimes strong radio freqs or magnetic fields get picked up by the speaker, maybe the autotransformer, -- leading the surprizing result that the speaker makes noise when no feed wire is connected to it at all. Now, you have to think that maybe the amp is putting out some strong magnetic field, but I tend to doubt something like that is being picked up by the CW if they are five or six feet away. From what you say, the CWs are the only units hooked up to the speaker output of the HK. Therefore I think it is the power amp section of the HK. To troubleshoot, you should connect your other speakers to the outputs to which the CWs are connected. You may well find the same but at a lower level given the great sensitivity of the CWs. If the amp has a headphone out and you have headphones, you can use those. to listen. BTW, when did this start? Did you have this set-up with the CWs and HK for any time in the past, and not have the problem? It is not clear. ' It is just a typical point of troubleshooting to discuss when the problem started, and what, if anything, changed before the problem started. Let us all know. WMcD Quote Link to comment Share on other sites More sharing options...
MikeGinIllinois Posted March 5, 2013 Author Share Posted March 5, 2013 Thank you for these helpful suggestions. It's been three months since my post. I'll summarize. I still have the HK AV7300. The buzzing problem I describe in this thread was still there. I decided to dig in. I disconnected one of my Cornwalls from my HK and powered it off of my Sony. No problem. Then I turned on my HK. As the unit warmed up I could definitely hear a strong static output. It sounded like the fan in the HK was generating RF like crazy and feeding it right into the Cornwall it was sitting on. The more the unit warmed up the louder the static. I moved the HK amp about five feet away from the Cornwall and that problem is now solved. However, I have a second less bothersome problem. When I first turn on the HK 7300 I have zero static or bzzzz in my Cornwalls. None. After about 10 to 15 minutes I get a minor bzzzzzz or hmmmmmmm in the Cornwalls. It's minor but sometimes gets a bit loud. I hooked up one of my Synergies to the same output as I have the Cornwalls on and both the Cornwall and the Synergy had the same hmmmmmm. If I turn off the amp, wait 10 seconds, and turn it back on, I have zero static but after 10 to 15 minutes the hmmmmmm comes back. Are you thinking this a power amp problem? I was given the name of Electronic Express in West Chicago, IL, by Harman Kardon today. A nice gal named Stacy had a long talk with me. I was thinking of taking the unit there after another discussion with her. Has anyone had any experience with Electronic Express? Is there someone else you know of who really knows these HK's? Thank you! Mike Gallery Crystal Lake, IL Quote Link to comment Share on other sites More sharing options...
OO1 Posted March 5, 2013 Share Posted March 5, 2013 I dont know much about your HK amplifier - it looks like it is a very well built on the inside - but if the amp is bad , it may damage your speakers , from what you are indicating - this hum is like very high feedback going straight into the woofer -midrange and tweeter magnets and rezonating as a hum - 1) -check your wiring as a first step - from the amplifier to the speakers , are you properly connected in the positive and negative terminals -go through the basics of the hookup to make sure that you are wired correctly - I would also check for grounds - if ok go to step no 2- -2) check your crossovers in the Cornwall - any loose or unsoldered wires -this a long shot as crossovers rarely can create such an issue -but check them anyway - if ok then - the amp is next - -3)the amplifier looks too high tech to be the issue - but unless a technician gets a look at it - you will not know - do a google search for similar problems - 4) I would call HK ASAP and ask if they have heard of similar problems - they usually log into their databases - lookup the different issues - so they definitely can be of help here - by the way -that amp looks like a gem on the inside - what a beauty - take care - -by putting the amp away - the feedback is reduced - that is normal - similar to some turntables being close to amps or speakers - I would avoid using the amplifier before getting it checked if the wiring and hookup is ok - blown diaphragms can be your next problems - so be careful- - Quote Link to comment Share on other sites More sharing options...
MikeGinIllinois Posted March 15, 2013 Author Share Posted March 15, 2013 After troubleshooting my home speaker wiring and finding no problems I sent my Harman Kardon AVR-7300 to a repair shop in West Chicago. ElectronExpressInc.com advised me that I have a few bad capacitors on the audio board. They're going to replace them and test the unit for a week to see if anything else is bad. Total cost so far - $183.25. I did incur a $50.00 shipping charge to messenger the unit down there. Thanks! Mike Gallery Quote Link to comment Share on other sites More sharing options...
Schu Posted March 15, 2013 Share Posted March 15, 2013 isn't this a ground loop issue that may be manifesting itself as a buzz as opposed to a hum? Quote Link to comment Share on other sites More sharing options...
MikeGinIllinois Posted March 15, 2013 Author Share Posted March 15, 2013 I don't think it's a ground loop problem. I hooked up a different amp to my speakers and had zero problem. I was able to increase and decrease the volume of the bzzzz by adjusting the volume on my Harman Kardon. I'm feeling pretty sure that this is an amp problem. Quote Link to comment Share on other sites More sharing options...
beeker Posted March 17, 2013 Share Posted March 17, 2013 Hi, everyone. I haven't been out here in a long time. I have a Harman Kardon AVR-7300 which I got from Harman Kardon headquaters a few years back. They had repaired it and originally it worked just great. I run outputs to a Sony amp and a Yamaha amp. The Sony amp feeds a pair of Klipsch Synergy bookshelf speakers and the Yamaha feeds a pair of Radio Shack speakers. I input a DVD player and a Roku to the amp. My speaker wires to the Cornwalls are thick Monster cables. My problem is that my Cornwalls give a "bzzzzzz" when I turn on the AVR-7300. It's intermittent. I just turned the AVR-7300 and no bzzzzz. Then, after 5 seconds a soft bzzzz started. It will usually grow in intensity until it's annoying. The bzzzzz doesn't come out of my Synergy's or the Radio Shackers (supported by two other amps). How do I troubleshoot this setup? Take it all apart and start putting components back in? Can input devices cause the problem? Is it possible that the AVR-7300 is generating the bzzzzzzz? I appreciate any comments and tips. Thank you! Mike Gallery If your using rca to 1/4" cables(avr to amp)be sure your 1/4" as well as rcas are attached securely. I had an $80 pair of dual rca to dual1/4" cables that would not let the 1/4" end seat in the amp input without some compression ...the 1/4" cable(was running mono)would litterally fall out. I simply switched it with a cheap livewire rca to 1/4" and the hum was gone. I also see rcas that do not seat firmly and with a high performance network such as in the cw even a simple rca not seating firmly would create wire feedback. I have 100's of cheap radio shack and even nice braided rcas that need attention as well as $130 rcas cables that need attention time to time. Also the soldier inside the rcas can get jinxy which can be checked by(sometimes unscrewing)then/pulling the metal sheath back and you will see the soldiers. The best rcas around can fail and have us chasing our tails unfortunately. Supply and demand can weigh down on quality at times and the great hand made cables fail. I Like to build or rebuild my own when i have time. Normally when i see one has failed. This is also sometimes due to pulling cables hard or very tight. Quote Link to comment Share on other sites More sharing options...
OO1 Posted March 17, 2013 Share Posted March 17, 2013 Hy Mike - since you have 3 amplifiers - 1) I would suggest that you try hooking the kLIPSCH CORNWALLS to the 2 other amplifiers - and test to see if the BUZZ is still there - the Cornwalls dont need a lot of power - 2) swap the speakers wiring as well in order to check the Cornwall's with regular speaker wire and the Huge monster cables you have feeding in the AVR - Klipsch ran regular speaker wire for years in the Heritage series with no issues at all - so any speaker wire will do for the testing - 3) do not over test with the BUZZZZZ to avoid possible damage to the Cornwall speakers - 4) if you can listen carefully - try to determine from where the BUZZZZZ is coming from - WOOFER -MID -OR TWEETER - regards - Quote Link to comment Share on other sites More sharing options...
MikeGinIllinois Posted March 19, 2013 Author Share Posted March 19, 2013 Hi, RandyH. I did test for the existence of the problem with my 2nd amp. In fact, the second amp is hooked up now while my HK is in the shop. NO problems at all with it. <-: I've already swapped speaker cable and did that when the HK was hooked up.That didn't make any difference. The HK is at the shop.They tell me the capacitors on the audio board need replacement. I'm hoping this fixes it! It sure sounds like it was the amp. Thanks for your suggestions.[] Mike Gallery Quote Link to comment Share on other sites More sharing options...
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