H/K 325 Crossover Issue

Discussion in 'AV Receivers' started by Mike Stoll, Feb 13, 2004.

  1. Mike Stoll

    Mike Stoll Auditioning

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    I posted the text below in the Ascend forum and would also like to get some feedback from users on this forum. It describes an issue I noticed with my AVR 325 when the crossover is active.

    _____________________________

    I came across a problem within the last two days and thought I would share my findings since a number of people have H/K receivers paired with their Ascends.
    Quick background of my setup: CBm-170's L+R, 340 Center, HTM-200's rear and Adire Audio Rava sub. H/K AVR 325 receiver, Denon 1600 DVD, Old Sony ES series CD player with optical and coaxial digital outs. Using sound king 12 gauge speaker wire. Have Dayton audio (parts express) optical and coaxial dig cables and RCA patch cables. Normally have speakers set to small with 80Hz crossover for all speakers. I made the jump to a home theater system in Nov. of 2002 from my 2 ch system after buying my Ascends.


    Problem: Noticed this when listening to the new Norah Jones CD. I thought I heard a speaker problem that sounded like a blown tweater with a few passages in the left speaker only. The odd thing about the problem is that it does not happen as often as would be expected if it was indeed a problem with the speaker reproducing certain frequencies. I isolated a passage on song # 10 aobut 2:05 into the song where a guitar solo begins and used this as a test passage. I brought the left speaker and disc up to my bedroom system (2 ch Sony ES series integrated amp 105W/ch-weighs more than my H/K with 5 amps!, Denon DVD-1815 changer connected through analog RCA patch cables and a pair of Paradigm mini monitors). The problem was not present with the second system regardless of the speaker choice. So that indicated it was not the disc or the left CBM-170. I thought maybe it was the digital cable(s). I next tried the analog outs from both my CD player and the DVD player fed into the 6 ch preamp inputs of the H/K. This is the only way to amplify an analog signal in this receiver without converting to digital. The problem was gone with both players. I next connected the RCA analog outputs from both players to the RCA CD inputs on the HK. I learned a while back that these inputs will convert the analog input signal to digital in order to perform bass management. The problem was back again.


    OK so at this point it is apparent that the problem originates in the receiver. I assumed that it was the DAC inside the receiver. It seems kind of odd because I have never heard it before and it seems to only occur on the left channel. Then I tried one more test. I set the speakers to large and selected no sub to eliminate an active crossover within the receiver. I used the CD player connected with the coaxial cable and the problem was gone (this also eliminates the cable as the problem). So after all my testing it seems as though the digital bass management is distorting the signal being sent to the left speaker. It did not matter what the crossover freq was set to.


    Has anyone else noticed a similar problem with their H/K receivers? I am wondering if this is something H/K will look at and fix.


    I should mention that I have no idea why I only notice the problem on this particular disc. May have to start listening to more of my collection to see if I can replicate the problem. I checked a few discs quickly and nothing jumped out.

    Take care

    ______________________________

    I called HK today and they have never heard of the issue. I live in NM and there is no service center in the state so my only option is to send it to a HK service center in California. One of the additional downfalls of this finding is that I had intended to use the 325 as a pre/pro as I move to a power amp and possibly to full separates. I guess it will suffice for HT use but I may have to think of another solution for 2 ch use with my sub.

    Mike
     
  2. Geoff L

    Geoff L Screenwriter

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    Hi Mike

    You certainly appear to have done everything and definitely isolated the problem down to your H/K.

    I do not own the 325, but like you, my use for it (if purchased) was going to be as a Pre. The more I investigate/read about the 25's and specifically the 325, the more I have doubts as to picking one up.

    First it was the problems reported on breaking 25 series units, spotty and seemingly not a spicific problem when they do break. More amp probems than any other thing I've read about so far.

    Then the supposed double BM crossover problem when selecting different ones 60-80-100Hz etc, for different reaching Hz speaks when doing HT use.. Not exactly clear as to if this is a real problem, or a user set up thing.
    Only an issue as I understand, when selecting & using multi cossovers points and not a single 60, 80, etc, for all speaks.

    Now your interesting find with your unit and this CD, finding distorted music in the left channel using the BM crossover and receivers DACs.
    This might be just your unit, tho others may just not have their 325 set up in a simalar fashion and litening for it.

    Sorry that I can be of no help.. [​IMG]

    Your post is just another possible thing that concerns me about the H/K. It has what I want/need, is priced right now "when they seem to work", BUT I seem to continue to have very cold feet..
    I'm not bashing on H/K, just the posted diddys I'll call them, along with the break rate I see posted often, like (my H/K died today type thing), really has me leary of chancing on one...

    Hope someone may have some real helpfull information for you, be that what it may..:b, or at least can vouch as to finding the same issue with their unit.

    If you do send it off to H/K-Calif repair, that the problem can actual be fixed....

    Regards
    Geoff
     
  3. Mike Stoll

    Mike Stoll Auditioning

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    Geoff,

    I understand your apprehension with the 325 and HK. I should point out that I have been completely happy with the unit before I noticed this problem. The other thing I should mention is that I still have not been able to isolate the issue on another disc. I watched the Allman Brothers new concert DVD last night and everything sounded great. As you mentioned this problem may be specific to my set-up and this disc.

    I originally purchased a 320 receiver for about $380 as my first unit. I learned over in AVS forum that on some of those units the Back surround amps were faulty. After confirming that my unit had this issue I phoned HK and they replaced the unit with the 325, which had just come out. So I got the 325 for about $420 (had to pay shipping charge for 320 bck to HK). I guess I should not complain that much.

    I am not familiar with the double BM crossover issue. Maybe this is not an issue for me since all my speakers are currently crossed at 80Hz. However, I am likely to upgrade my front L+R to Ascend 340's. I will probably cross these over at 60 Hz and the remainder at 80. Could you describe the double crossover issue in more detail?

    Mike
     
  4. AndrewErickson

    AndrewErickson Stunt Coordinator

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    First off, it's Triple Crossover Bass Management. I've never had any problems with mine.

    When you have the problem, are you using DPLII, NEO6 or Logic 7 processing? If you set the receiver to stereo, the fronts to large and the sub off, you bypass any digital processing done by the receiver. If the problem goes away then the cause is the DSP board, which they can replace.

    Keep in mind that modern solid-state electronics are modular by design. They can replace every board in the receiver.
     
  5. Mike Stoll

    Mike Stoll Auditioning

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    No, I am not using any DSP modes when the problem occurs (Neo 6, Logic 7, etc.)

    As I mentioned in my original post, and as you suggested, the problem is gone when the speakers are set to large and the sub is off. When using an analog signal from the CD player the only way to keep the analog signal after it enters the receiver is to use the 6/8 channel inputs. Using the regular CD RCA inputs on the receiver converts the analog signal to digital, which can't be deactivated. In that case one may as well use a straight digital connection from the source to the receiver to avoid another AD conversion.

    In any event, I have listened to a number of CD's over the last couple of days and have not experienced the problem. It may be that this particular disc coupled with the chip that performs the bass management inside the receiver manifests the problem. Over at audioasylum.com in the digital forum someone has mentioned that they have had problems with this disc on certain players. They believe it may be due to copy protection. I am not sure copy protection is the problem since I have made a copy of the disc for use in my car where I find my discs can get scratched badly over time. I may pick up the SACD when it comes out to see if the problem still exists.

    Thanks for the suggestions.
     

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