HELP! I think my receiever (SONY STR-DE725) killed 3 of my

Discussion in 'Archived Threads 2001-2004' started by james e m, Feb 23, 2002.

  1. james e m

    james e m Second Unit

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    I just got a whole complete Paradigm speaker set up and about a month later my

    center channel started to break up with dialogue. I took it back to the dealer and we

    tested it and sure enough it started crackling when we played the midrange

    frequencies from a test cd. He exchanged the speaker and I thought the problem was

    solved. But I went to calibrate my speaker with Avia with an SPL meter and I noticed

    the same crackling with my Mini Monitors that I use for surround!!!! Does anybody

    know why this is happening? My only theory is that my cheap receiver isn't powerful

    enough and it's doing the damage.

    Here are the specs for my receiver:

    SONY RECEIVER STR-DE725

    Built-in Dolby (AC3) Digital Decoder

    Digital Cinema Sound Virtual 3D Modes

    Stereo Mode: 100 watts per channel x2, 8 ohms

    or 4 ohms, 20 - 20,000 Hz, 0.09% THD

    Digital Cinema Sound with 3 Cinema Studio

    Modes

    Surround Mode: 100 watts per channel x5, 8

    ohms, 1,000 Hz, 0.8% THD

    S-Link Control Bus for A/V System Convenience

    4 Audio Inputs/1 Audio Out

    4 Video Inputs/3 Video Out

    1 Optical Input/Output

    Two Subwoofer Outputs

    Does anybody know what is ruining my speakers? I have 2 surge protectors so I don't

    think it's that. ANY ADVICE WOULD BE GREATLY APPRECIATED!!!!

    james

    ps I have run some tests and I know for sure that there is now something wrong with

    the speakers, I just don't know what caused it.
     
  2. John Garcia

    John Garcia Executive Producer

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    I would definitely say it is the amp. That amp will not deliver a true, clean 100Wpc at elevated listening levels, especially since you are running large mains. Honestly, I would recommend a new receiver, as the DE line does not deliver much in the way of amplification.

    Dump the CVs and put the minis up front, set them to small, get a CC370 (CC170 at the very least) and things should improve.
     
  3. Thomas_Berg

    Thomas_Berg Screenwriter

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    the receiver is definately the problem. make sure you stay away from all Sony DE model receivers in the future...they are crap IMO. [​IMG]
    look at Onkyo, Yamaha, Denon, H/K, and the like. you'll really notice an improvement!
     
  4. james e m

    james e m Second Unit

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    I realize it's not the best receiver, but it's that bad that it physically ruined my brand new Paradigm speakers?!? [​IMG]
    It kind of annoys me that the Paradigm speakers are that delicate!
    james
     
  5. Richard Harvey

    Richard Harvey Stunt Coordinator

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    James,

    For what it's worth, I had been running a STR-DE915 (5x100) up until yesterday for the past three years. I'm running Infinity RS-5 mains, Boston VR-910 center, Infinity sub, Infinity Minuette rears. I had originally been running Minuettes all around when I first got the system and as another poster here suggested, running a smaller speaker through the 915 worked pretty well (I think the Minuettes have a 15-80W range). Once I got the larger mains & center, I was less than impressed -- my sound quality really didn't improve much, and turning things up louder simply distorted sound (which I knew could do some serious damage to the speakers).

    Yesterday I upgraded to the Denon AVR-2802, and now I finally understand what people mean by "clean" power. I'm absolutely astounded. It's sounds like I didn't just buy a new receiver, but new speakers as well as they have come to life and sound absolutely incredible. No hiss, no distortion, absolute clean highs and lows throughout the dynamic range. My sub even has much cleaner "kick" in it.

    For myself, it took 3 years to be able to afford getting a new receiver so I know not everyone can simply decide to do this at the drop of a hat. However, if you can't do this in the short term I would take the other recommendations here and temporarily take your quality speakers offline and put smaller ones in place to prevent (or minimize) any damage.

    Rich
     
  6. Michael R Price

    Michael R Price Screenwriter

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    Were all your speakers set to 'small'? If you tried setting those speakers to large, especially with a less capable amplifier like the Sony, especially if you turned the bass up, you'd have a recipe for disaster. I'd bet neither your receiver nor your speakers could stand such a situation.

    Your speakers may be damaged but not destroyed. I'm sure you could replace the problem driver/crossover if needed, for a much lower cost than replacing the speaker.

    The Paradigms are not 'delicate'. However, no speaker of that size could withstand either heavy bass input, or significant amplifier distortion. I don't think it'll cost too much to fix your problem, though. Check the receiver settings (especially small/large and the bass level). And contact your dealer to see about the minimonitor parts.
     
  7. John Garcia

    John Garcia Executive Producer

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    I wouldn't say Paradigms are delicate, I've gone through (sold, upgraded, etc...) 8 pairs in the last 2 years, Atoms, Titans, and Mini Monitors and have yet to experience a problem with any of them.

    A weak amp will kill a speaker much more quickly than a powerful one, as it is distortion that kills more often than overdriving.
     
  8. james e m

    james e m Second Unit

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    Thanks for the advice guys! Yes my speakers, except the Monitor 11's were all set to small and I havn't played anything too full of bass. The problem sounds to be coming from the tweeter. I just wish I knew what was causing this?!
     
  9. Selden Ball

    Selden Ball Second Unit

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    James,

    Your receiver's weak amplifier section is damaging your speakers. It's caused by "clipping".

    When you try to get a very loud sound level out of a low power amp, it "clips". Insteaed of generating smooth sine waves, the tops of the waveforms are chopped flat when the receiver tries to produce an output voltage greater than is available from its power supply. This abrupt change in the signal puts lots of energy into high frequency noise, most of which is such high frequencies that you can't hear them. No tweeters are designed to handle this well. They eventually overheat and burn out.

    Your Monitor 11s are quite efficient, so my guess is that you have a rather large room with plush, sound-absorbant furnishings, so the individual channels had to be turned up significantly in order to get to reference sound levels.

    When you go looking for a replacement receiver, you need one that's rated at better than 150Watts per channel, all channels driven, 20-20KHz, into an 8 Ohm load. The phrase "all channels driven" is important. Your current Sony is not rated that way. In order to be able to say it puts out 100 Watts per channel, they limit the output to 1 channel driven at a time. If it were rated the other way, it'd probably be only 20 or 30 Watts.

    A higher rated receiver is going to cost a lot more, I'm sorry to say. If you like Sony, and a lot of people do, you might consider getting an -ES receiver. Prices on the used market are often reasonable. Sony's -ES series is much more conservatively designed than their lower cost models.

    You have my sympathy.
     
  10. Richard Harvey

    Richard Harvey Stunt Coordinator

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    Selden,

    Exactly which ES series could even do this? There are many quality $4000 receivers that can't pump 6 channels of 150W per channel 20-20kHz @ 8 ohms, but I'm certain most if not all of them could drive these speakers quite well.

    Rich
     
  11. Mike Brantley

    Mike Brantley Stunt Coordinator

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    I have a Sony STR-DE945 receiver with similar power ratings, and I also recently have heard clipping in my rear speakers when playing some DVD demo/test material at a high volume. This has strengthened my resolve to move up the food chain and get a better receiver. I sure hope I didn't damage my speakers.
    A higher-end Yamaha is on order. [​IMG] It's only rated at 100 watts, but I believe it's 100 per channel simultaneously, unlike the Sony "trickery" with how it rates its low-end and middle-end receivers receivers. (I'm sure the Sony ES stuff is nice.)
     
  12. Selden Ball

    Selden Ball Second Unit

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    Rich,

    I picked 150 Watts to make sure that the necessary headroom would be available, not thinking of specific Sony models.

    You're right, of course: their current top-of-the-line ES receivers, the STR-V555ES and the 444, are both rated at 120 Watts/channel. Bear in mind, however, that a 30 Watt difference at that level is almost inaudible. Even a unit rated at 100W/ch should be adequate if that much is actually available when all channels are driven at the same volume.

    A quick way to check this is to look at the back panel. It'll have the maximum total power consumption either in watts or amps. The maximum power the unit is rated to draw at 120Volts AC should not be less than about 600 Watts or about 5 Amps. "High Current" designs can be as much as two or three times that, and cost a *lot* more.

    I hope this helps a little.
     
  13. John Garcia

    John Garcia Executive Producer

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    Current? The 333, 444, 555 and 777 were all discontinued last year. The current models are the DA3ES and DA5ES, not sure if they will have a 4 or 7.
     

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