sredmyer

Ah there is the difference I am using a frequency of 1hz you are using 10 So I guess we are both correct Is there anything wrong with using 1hz. I did it this way because the amps specs say that it's bandwidth goes down to 1.75hz

Oops that 15.9 uF was a typo. However my calculation does yeild 1.5915494309189533576888376337251e-6 which, as you point out is not 15.9 uF. But doesn't uF stand for micro farad and micro is 10^-6 therefore the number above is 1.59 uF not .159 uF...Am I wrong?

I get the same pop. Well I tried what was suggested by the HK service tech, inserted a 50kohm 10 turn pot in the hot lead of the interconnect between the preamp and the amp. And yep sure enough if I apply enough resistance the pop goes away. Of course so does 50% of the volume so this is a no go fix. While I had it all pulled out and an interconnect butchered up I decided to go ahead and try the capacitor idea. I just happen to have a couple of .1uf Polyester film caps so I used them...Gues what NO POP!!! that fixed it. I did not play it long or loud just wanted to see what happened before I spent the money for some good audio quality caps like the ones DrWho suggested. BTW if DrWho is monitoring this post, I discovered that the imput impeadance of my Adcoms is 100k and the specs rate them down to 1.75hz so I redid the calculation (using 100k and 1hz) and came up with a capacitance of 15.9uf. Can you verify that value. Thanks again for all the help

I do not know of any HK forum (of course that does not mean that one does not exist) As for the "somethings gotta go" thing that is just not an option at this moment...wifey is thinking I have spent too much money on this hobby this year already...cousre she did by me a SMS-1 for Xmas so maybe there is hope. As for what plays nice with the HK I gather, from a guy on another forum, that the Sunfire TGA-7400 amp plays very nice indeed with the HK. As a bonus this amp is a full seven channels so I would not have the timbre issue I currently have between my mains and center channel. Alas I probably not be able to get one for a while though as they cost around 4 grand I think. Thanks all for the help

One more thing...since this "fix" will not eliminate the problem but simply lessen it to an acceptable level is one of the devices a poor design? Should I still consider the capacitor coupling fix?

Is this type of mis-match something that the specs of either the HK and the Adcoms should have made obvious to me. In otherwords how would I know when considering an amp or preamp about this level matching. How do I know what is expected by the Adcom and what is output by the HK...what is this spec called. Is this something that one normally would look at when purchasing an amp and/or preamp?

Ok, so here is the diagnosis from the HK warranty service tech. The output level of the HK does not match well with the Adcoms. The suggested fix is to put a resistor in series with the pin lead of the RCA connector. To find the appropriate resistor size they suggested using a 100k multiturn pot and just dial it in till the pop is unnoticable. The tech support people at HK had actually suggested this early on but either I misunderstood or they told me incorrectly how to implement this. What I had done earlier was to add a 10k ohm resistor in parallel with the RCA. IOW I connected one side of the resistor to the pin lead and the other to the ground lead. As described in the original post this resulted in a really nasty hum/buzz. As I understand it, adding this resistor will lower the signal level from the preamp to the amp. The result of this will be that the volume control on the HK AVR will need to be higher to achieve the same SPL. I have not yet tried this (I will this evening when I get home). So what do you guys think...will this work...is this a good solution?

Seems the Film/Foil is the way to go, which should put you right around $25 for the mod (yikes). I don't even know if it'll guarantee a solution either. I wish I could tell you better - maybe someone else will chime in. What about ceramic disc type capacitors? Which of the three types listed above are they? I only ask because these are easily aquired from RS. Also would the required capacitor need to be polarized?

No I don't. Can you give me some more info on installing the capcitors between the HK and the Adcoms like the HK techs suggested. How should they be installed? How does one calculate the correct size and type of capacitor?

Ok now I am completely lost. I bit the bullet today and made the drive to the warranty center it turned out to be in Greenville, OH not Cincy which ment it was a 3 hour one way trip not 1.5. I left my 7300 and they sent me home with a 635 as a loaner. Guess what...THIS DAMN THING POPS TOO!!!! So as i say I am completely confused.

No...the subwoofer channel should have been playing...As I say I believe (now) that there is definitly a problem with the subwoofer preout. This subwoofer preout problem is likely the cause of all the problems with the RSW-12 I have been having. And although this subwoofer preout does point to a definite problem with the HK I am not sure that it is in anyway associated with the popping problem. I still need to try connecting Adcoms to other channels (other than mains and subwoofer). This is a bit more difficult (due to it requiring moving of quite a bit of heavy equipment) and therefore I have not yet tried it. I have a friend who is bringing by a couple of Carver cubes (M400a) amps to test with but I do not know if those amps are direct coupled or not. If they are not they will not likely exhibit the popping but that will not mean that the HK is ok. The HK is still under warranty (they have a 2 year warranty). Would this circuit eliminate the thump I get on power up? I think this thump (different than the popping we are discussing) at power up is due largely to the fact that all devices (HK and both Adcoms) are being powered up simultaneously. The in-rush current draw of all the caps in these amp charging and all of the massive transfomers stabilizing is quite significant. I get a mini brown-out when I power this system up. Well I appreciate all of the help here but now with this certain problem (no output on subwoofer channel) I will be taking the HK to the warranty service center. I would have done this earlier but the HK techs were working hard to convince me there was no problem with the HK. I still worry that, while they will surely fix the subwoofer channel, they may not do anything about the popping issue (claiming that it is not a problem with the HK). Of course the other issue with taking the HK in for repairs is that the closest service center is in Cincinatti (bout 1.5 hours away) and I am sure I will have to leave the unit. The latter would be the most inconvenient since I use the HK for audio as well as video switching...without some serious re-wiring I will have no audio or video while it is gone.

Tried that (see the original post)...No pop when speakers connected directly to HK's internal amplifiers regardless of source or mode switching or muting. I think the issue here is that the HK uses some form of capacitance coupling internaly between it's preamp and its own internal amps. However I think this is not done on the preamp output circuit therefore when the mute is engaged a DC shift or transient or whatever is created on the outputs. Since there are no filtering caps in the HK and the Adcoms are direct coupled (again no filtering caps) this DC spike is simply amplified on out to the speakers. This problem is exacerbated by the fact that in the current configuration I have 600 watts available to each of the RF7s. That high power when coupled with the RF-7s high efficency makes what might otherwise be a slight pop a much louder and annoying (possibly damaging) one. This jives with what the HK tech told me...but it just seems backward to me. It seems to me that the spike (if in fact created by the muting) should occur when the mute is disengaged not the other way round.

Will try it and let you know Cant tell can not get any output from subwoofer out??? very curious this is likely the part of the sub issue but I do not think this has anything to do with the popping??? Does it? Will try it and let you know Nope still pops

yes Will try it and let you know I think it is fairly loud and system volume has no impact on how loud the pop is Will try it and let you know About 1/2 I agree, the guys at Klipsch (Steve Phillips) have convinced me that the pops were not the cause of the subwoofer problem. I also agree that the HK is the likely culprit but when I talk to the tech support there they say it is the either a ground issue (which prior to the helpful insight I've gained here I did not understand) or it is a problem with the Adcoms. I do not understand that one either as they are just amps...they do not create anything...just amplify what they are given (including DC spikes)

Ok all devices are plugged in using only 2 prongs (cheater applied where needed)...still get the pop Disconnected all signal conections (other than optical) except those for the preamp outputs to the Adcom...still get the pop So does this mean it is not the ground thing?

Ok I understand...I will do what you suggest (using the cheater plugs where needed). If this works you will be the bomb...such a simple solution to a problem which I have been fighting for a few months now.

Yes the TV and the DirecTV receiver are connected to the AVR via RCA component video cables. I do see what you mean about the possible grounding issue (I do not fully understand it though). I am not sure about the plugs on these devices (weather they are 2 prong or 3) but they are plugged into the same power strip as the AVR. Wouldn't that mean that their ground is the same as that of the AVR? Regardless I will try disconnecting devices this evening when I get home to see if that helps.

Thanks for the response. I know you are right about the local gurus...I have availed myself of some of the expertise here before regarding my subwoofer. These guys are very helpful. For me the problem happens on all sources. The only common point is that it happens when the audio signal is muted by the HK. It does not matter weather that muting is done manually (by pressing the mute button) or auto-magically by the HK due to a break in the audio stream resulting from source mode changes. As for grounding, I do not think that can be an issue. All of the components are plugged into the same powerstrip. The Adcoms have their original cords/plugs and are only two conductor. The Adcoms are connected to the switched outlet on the HK AVR thru a SSR. The power for the SSR is sourced via the same outlet strip as all other components. This outlet strip is then pluged into a non-dedicated (some misc. lighting is also on this circuit) 20 amp outlet. This arangement allows me to leave the power switches on the Adcoms in the on position and have them turned on and off whenever the HK is turned on/off

I hope some of the more technical here might be able to help with this. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> First let me explain my setup: I use the HK AVR 7300 in my home theater, which is a 5.1 setup. I also use the HK to drive a second zone. The second zone is only used occasionally and is a music (2 channel) setup only. The 5.1 system includes the HK AVR7300, 2 Adcom GFA-555s (running bridged as mono blocks), a DVD/CD player, an HTPC (used to serve mp3s only), a DirecTV receiver, and a 50" plasma display. All source devices are connected to HK 7300 via digital audio (either optical or coaxial) and component video (YPbPr). The HK 7300 is then connected to the display via component video (YPbPr). The HK 7300 is used to directly drive the center and surround channels. The front main L/R channels are driven by the Adcoms (1 Adcom for each channel), which are connected, to the pre-amp outputs of the HK 7300. A powered subwoofer is also connecter to the sub/LFE output of the HK 7300. The sub is a Klipsch RSW-12, which uses a 650watt rms BASH amp. Now the problems: Since initially connecting this system I have had a loud pop from my main speakers whenever the system switches audio sources (i.e. from CD to SAT. TV) or whenever the system switches audio modes (i.e. from Dolby Digital to Logic7). I had always just assumed this popping was a normal thing due to DC transients created by the switching and although I did not like it, it did not seem to be causing any real problems. This system has been in place and being used for about a year now. During this time I had a problem with my Klipsch subwoofer in which it (the sub) blew out its amplifier, which caused the driver to also get fried. The driver was replaced and the amp rebuilt. Then after a few weeks the sub's amp was blown again. It is this blowing of the sub's amp that has caused me to start wondering if the DC spikes causing the pop that I hear might actually be a problem. I began researching the issue and learned from other HK owners that the popping was not normal. Other users with a similar setup have told me they do not experience the popping. In an attempt to further understand (and find a solution for) the problem I contacted HK tech support and explained the problem to them. They informed me that the 7300 has an auto-muting feature, which mutes the audio (by dumping it to ground through a "muting transistor") whenever the audio stream is broken (such as when source or mode are changed). They further stated that since the signal was being "dumped" to ground through a transistor there might be some residual voltage remaining in the capacitors and this residual voltage would create a DC spike at the output as soon as the mute was disabled allowing signal to flow to the amp. Some tests I have done to identify the problem: 1) A simple test to verify what HK tech said about muting. I checked this by muting the system (using the mute button) then un-mute it. What I found was that the system pops going into mute but not when coming out of mute. This behavior is completely repeatable. Now given the explanation from HK this results confuses me, I would expect the exact opposite. 2) Tried to measure the DC spike voltage at the RCA connector using a VOM. I found no voltage spikes here. Note this is likely because the meter used (a digital one) was to slow to see the spike. 3) I have connected the speakers up directly to the HK (using its internal amps). In this configuration there are no pops. 4) I have tried using a different preamp (a Carver C1) this configuration did not exhibit the popping problem. Based on these tests I think I can just about definitely say the problem is with the HK. Some of the things I have tried to fix this are: 1) Per a suggestion from a tech at HK I installed a 10kohm resistor between the two conductors of the each of the RCA interconnects between the HK and the external amps. This just caused a loud scary buzz. 3) Tried grounding the chassis' of all the equipment (both Adcoms and the HK) with a simple ground wire connected to all of the cases. This produced a slight hum but did not fix the popping. Finally I called HK tech support again and explained all the above, their response was that it was a ground problem. More specifically there is a potential difference between the ground references of the Adcoms when compared to the HK. They said that there is really no fix for this. Although they did say that I might connect a .01uf or .001uf capacitor to the HK's output and this would likely stop the popping but it would also likely degrade the sound quality. So after all of this explanation I am hoping that some of the more technical folks here can chime in with opinions as to: 1) The cause of the popping 2) Possible solutions 3) If the capacitor is indeed a solution that will work with minimal impact on sound quality...how should the capacitor be installed? Thanks for your help.

A NIB pair of AW-650's on ebay http://cgi.ebay.com/KLIPSCH-AW-650-OUTDOOR-LOUDSPEAKERS-A-PAIR-SEALED-BOX_W0QQitemZ160067141902QQihZ006QQcategoryZ14995QQssPageNameZWDVWQQrdZ1QQcmdZViewItem and the matching sub woofer http://cgi.ebay.com/KLIPSCH-AW-800-SW-OUTDOOR-SUBWOOFER-LOUDSPEAKER-SEALED_W0QQitemZ160067664709QQihZ006QQcategoryZ14995QQssPageNameZWDVWQQrdZ1QQcmdZViewItem I am not affiliated with nor have I ever dealt with this seller so do your due diligence (check feedback, etc.)

Yeah these RB-75's seem to be fairly rare, I have been looking for a black set for quite some time now...seems they rarely come up on ebay and never when I actually have the money to spare[]. If anyone notices a pair on ebay or audigon I would appreciate a shout. Steve

LOL yeah she complains frequently about the amount of money I spend on this hobby but I know she also truely enjoys it. Plus she likes doing nice things for me. I love my wife...she da bomb-ba[]

Well I was correct the wifey did get this for me[]...but it has not come yet[]. She printed out the ebay listing and a picture (I assume she downloaded from the Velodyne web site) stapled them together then buried them in a big box stuffed with shedded paper and wrapped it up. BTW I was also correct in assuming that she has no idea what it is. She told me she just remembered me wishing I had an SMS-1 on several occaisions when we would be listening to our system. She did an ebay search for SMS-1 and found this one. She was more that just a little bit aprehensive since she did not know what it was. As fate would have it I have been having some issues with my sub (some of you may have seen my post in the Powered Subwoofer forum about my RSW-12 problems). Since the listing stated that this unit was a subwoofer controller she decided to go ahead and get it, figuring it was something I needed to fix or atleast help to resolve the issue with the sub. She told me that she would not have spent so much money on something (that would be difficult to return) unless she was certain I would like it. So I can thank all the problems with my sub for this gift...The lord does indeed work in mysterious ways. Now I hope my sub gets back from being repaired (it is in Hope AK) by time the SMS-1 get here. I hope you'all also had a very merry Xmas Steve

I just found out my wonderful wifey got me this for X-mas[] http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ih=008&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=180065892934&rd=1&rd=1 I had been telling her that I wanted one for awhile now...I don't even think she knows what it is[] Well I assume she got it for me, otherwise somebody else is using my ebay/paypal account. Hope you guys can help me set it up and tweak it in when it gets here. Merry X-mas all. Steve

Seadog you are indeed a lucky dog. I hope you will tell us know how these sound. I have been considering these for my sunroom (zone 2) to replace the Polks I currently use there. The Polks have a much sweeter sound. It is not that they sound bad it is just that I have become quite attached to the precision of the HF from my RF-7s in the main listening room. I will be very interested to hear your impressions of these speakers, specifically regarding their HF. IOW do they have that wonderful Klipsch sound? Anyway congrats on the new speakers and I look forward to hearing your impressions. Steve