Bryston question

Discussion in 'Archived Threads 2001-2004' started by RobertHO, Mar 15, 2003.

  1. RobertHO

    RobertHO Extra

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    Hi all,

    Well, I just hooked up my Bryston 3b st to my paradigm studio 40's using a sony da4es as a preamp. I must say the combo sound awesome! Extremely smooth and detailed, much smoother and less harsh than with my onkyo 595 amps.

    Anyway I love the sound, but the clipping indicator lights on the bryston flash red occasionally when listening to loud music (classical). Although this only happens at very loud points in the track.

    Question:

    In the 3B ST manual it states that when the clipping indicator lights are on for more than a "moment or two" it could damage the speaker. Can somebody define "a moment or two" more precisely? Am I in danger of damaging my speakers if the lights occasionally flash red, say a second or two?

    Also, does anybody else have this combo and what is your experience?
     
  2. James Hibbert

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    I was driving my Paradigm 100s with a 3b sst for awhile without any problems. Your best bet is to contact Bryston tomorrow via phone or email, they're very prompt.
     
  3. wayne p

    wayne p Stunt Coordinator

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    How loud are you listening and how big is your room? Barring a problem with the amp or a very large room you could be doing damage to your hearing. The 3b is a very capable amp indeed.

    Wayne
     
  4. MikeTz

    MikeTz Stunt Coordinator

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    I have a Bryston 3B in a 20x20 foot room and even loud classical music fails to drive the amp into clipping. The Bryston amps are known for handling difficult speaker loads below 4 ohms, so unless your speakers are large and inefficient (many are) AND your room is very large, the Bryston should make your ears bleed before clipping. Also, when listening to loud music in a modest size room the average power delivered by the amp is a fraction of its total output power (30 watts average is loud) but on transients that contain lower bass information the 3B may hit its limit. When this happens it is usually for a very short amount of time (a second or less).

    What kind of speakers do you have? How is the output of the 3B connected to your speakers (speaker wire, bananas, spades, etc)? Can you detect any sonic issue with the 3B? How big is your room? How do you connect the 3B to AC power (through a conditioner, surge suppressor, etc.)?

    The answers to these questions might help us give you more informed advice. I have seen people blow speakers because of amplifier clipping.

    MT
     
  5. Jacinto

    Jacinto Second Unit

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    I agree with James - contact Bryston. I've had my 3B ST for four and a half years, and I've never once seen that light come on. And yes, I really crank it up once in a while.
     
  6. RobertHO

    RobertHO Extra

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    Thanks for the replys guys!

    Okay I hooked the Bryston up to my Paradigm Studio 40's using bare wire ends. (10 gauge monster speaker wire) My room is about 2500 cubic feet but it has 10x10 foot openings to the kitchen and the foyer. The kitchen and the foyer add another 2500 cubic feet for sure. Plus a 8x4 foot opening to a hallway leading to the bedooms.


    I cannot detect any sonic issues even at the extremely loud levels I listen to sometimes. Yet the lights on the bryston do flash red on especially high points in the music. BTW I hook up to AC directly into the wall outlet.

    I don't think there is anything wrong with my amp. I do want to know how far I can push it without damaging anything. Also what are other owner's experiences concerning when the 3B will clip.

    BTW does anybody know how to determine the manufactured date of the Bryston.

    Thanks for the help.
     
  7. Yogi

    Yogi Screenwriter

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    Its not hard to clip an amp. DD mandates a 20db headroom for movie soundtracks which means transients could demand 100 times more power compared to the softest passages. You typically listen to a few watts (2-3) at normal dialogue level with say a 90 db efficient speaker. If you have inefficient electrostats at say 86db then you probably would be listening to 7-8W at normal listening levels. On transients the power request could go up to 700W for a fraction of a second and could cause an amp to clip. So if you have a large room with lots of open hallways etc and inefficient speakers then it wouldn't be surprising to clip a 150W amp on occasion. As long as its only for a fraction of a second the speakers should be able to handle it without any problems. Bryston is right that if you are having this for any extended amount of time of say over 2-3 seconds then you will most definetly damage the speakers drivers.
     
  8. RobertHO

    RobertHO Extra

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    I really appreciate all the input.

    I measured the spl with a radio shack meter and the peaks in the music when the amp starts to clip are at 100-103 db.

    So I can't even reach reference levels without clipping the Bryston. I just thought I would have a little more headroom than that. I guess my large room with it's large openings to basically every other room in my house has something to do with it?
     
  9. Martin Rendall

    Martin Rendall Screenwriter

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    If you want to make sure you are legitimately clipping the amp (as opposed to some sort of fault), try plugging your stats into this web site:

    http://www.myhometheater.homestead.c...alculator.html

    I did a quick approximation, and it certainly does seem possible that you are driving the amp to clipping.

    As for the clipping duration, I would personally avoid it entirely. At most, I would allow the red light to be on only a few times a minute for less than a second each time.

    Sounds like an upgrade to a 4BST may be in order for you.

    Martin.
     
  10. Yogi

    Yogi Screenwriter

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  11. Joe Casey

    Joe Casey Stunt Coordinator

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    Based on what you're describing, I don't think there's anything wrong with the amp. I've clipped Bryston 7B-ST's on occasion when driving somewhat inefficeint speakers (84 db). Just watch you don't let them stay in that state for more than a second or so, or you may fry a tweeter.
     
  12. MikeTz

    MikeTz Stunt Coordinator

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    Robert:

    Your Paradigm Studio 40s are efficient speakers. They produce 91dB SPL at one meter with one watt of input. At 10 watts of input the SPL at one meter will be about the level you said you experienced clipping. This should not be occurring on an amp the produces more than 100 watts continuous into an 8 ohm load.

    Since you do not appear to be choking the Bryston amp for current, have verified that all connections are tight, and can hear no sonic degradation, I would send Bryston an e-mail describing the situation. Their customer service is quick and comprehensive. Give it a try for peace of mind.

    Good luck

    MT
     
  13. RobertHO

    RobertHO Extra

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    Okay,

    Due it the differing opinions I have copied and emailed this thread to Bryston. Let's see what they say.
     
  14. Yogi

    Yogi Screenwriter

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  15. Martin Rendall

    Martin Rendall Screenwriter

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    MikeTz,

    As Yogi said, you forgot to factor in the listener's distance from the speakers.

    Yogi,

    I think it's 6dB per doubling of distance.

    Martin.
     
  16. Yogi

    Yogi Screenwriter

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  17. MikeTz

    MikeTz Stunt Coordinator

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    Martin and Yogi are both correct about distance from the speaker versus SPL loss. Since I didn't know where Robert measured the SPL, I used the common 1 meter measurement point.

    Now I remember when I lived in a college dorm many years ago I might have actually listened to music 1 meter from the speakers. However most humans that don't live in a shoe box probably listen 2-4 meters from the speakers. With the Paradigm 40s you could get 101dB at one meter with 10 watts, and with 6dB loss for every doubling of distance, at 4 meters you would need 12dB more power (more than 10 times 10 watts) to get the same SPL. As Yogi pointed out, you may be getting close to clipping at that point.

    This assumes your speaker impedance is 8 ohms. If you speakers operate at an average of 5 or 6 ohms the Bryston will be capable of more power than it provides at 8 ohms. Bryston amps usually have a fair amount of headroom also.

    Another issue to consider is the Paradigm speaker rolls off at around 35Hz. Right now the Bryston is puffing to get high SPL at the lowest audio octave and the speaker can't reproduce it well. So Robert could use a powered sub crossed over around 80Hz, and the Bryston power could be applied to music above 80Hz, which takes less muscle to reproduce. I don't know if this is possible for you Robert but it might be worth considering since you can get a good sub for less than the cost of a new 4B SST.



    MT
     
  18. RobertHO

    RobertHO Extra

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    Mike,

    I do have a HSU VTF-2 subwoofer in my system. I have tryed crossing it over as high as 120 Hz using the sony da4es's very flexible bass management. Surprisingly or not the clipping indicator lights on the Bryston still flashed red at exactly the same points in the music at the same SPL.

    Question:

    Can an AC outlet's condition (like breaker amperage and other devices on the same circuit) affect the watts that an amplifier will produce?

    Thanks to everybody for your input.
     
  19. Martin Rendall

    Martin Rendall Screenwriter

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    Question answer: no. The amp will draw whatever it needs... until the breaker goes.

    Martin.
     
  20. Mike OConnell

    Mike OConnell Second Unit

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    Robert:

    The 3BST should not be clipping with the Paradigm's unless you are driving those speakers to a ridiculously loud volume. I am using a 3BST to driver Dynaudio 1.3SE's, which are not known as terribly efficient speakers: Sensitivity (2.83 V/1 m): 86 dB. The room is rather large about 20 x 30 x 9.5.

    I purchased a 3BST off of eBay and at first it indicated clipping like you describe all the time, even at relatively low volumes. I then contacted Bryston, and for the cost of a box (they REQUIRE you to use the original style box if you don't have one) and shipping to their repair center they checked out the unit and the clipping indicators were bad. They fixed them, bench checked the unit and it was back to me in less than a week.

    I have not had a clipping indication since.

    Gotta love that 20-yr transferable warranty.

    Good chance you are experiencing the same problem.

    Mike
     

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