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Thread: Burmester 911 mk3

  1. #1051
    VIP/Donor [VIP/Donor] microstrip's Avatar
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    Mechanical hum of transformers happens more frequently than should and, independently of the reason, is a design/manufacture fault/problem. It affects even some very high performance well known brands.

    It results from mechanical noise due to vibration of transformers and can be really a nuisance. Although it is not the case (Burmester is made in Germany), sometimes electronics coming from the US that are tested locally only at 60 Hz, become noisy when operated at 50 Hz, as flux is higher and harmonics have different frequencies, exciting resonances that did not exist at 60 Hz.

    In some cases mounting the transformer on silent blocks reduces the perceptible noise to inaudible.

    DC blockers increase significantly the mains impedance and IMHO are a last resource. Burmester has power conditioning that eliminates DC from mains without inserting elements in series, but is very expensive.
    At last settled around the DCS Vivaldi 2.0 stack and a pair of Wilson XLF's : Forsell Air Force One, ARC Phono 2SE, cj GAT 2, cj ART monoblocks , TA OPUS MM2 IC's and sp, TA XL digital, TA XL gen V power cables, CenterStage footers and Nordost Qkore8's!

  2. #1052
    Hi Microstrip, thank you for answer. So, what I should do ? Is it any way to test if DC component is present in the mains? Is it possible that amp is noisy due to age ?

  3. #1053
    VIP/Donor [VIP/Donor] microstrip's Avatar
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    Quote Originally Posted by cypher View Post
    Hi Microstrip, thank you for answer. So, what I should do ? Is it any way to test if DC component is present in the mains? Is it possible that amp is noisy due to age ?
    If you have easy access to a power regenerator, such as the PS Audio P10 or P5, I would try connecting it through them. I can not see how age can affect a power transformer.

    You can also try it in another place, that is not served by the same power line.
    At last settled around the DCS Vivaldi 2.0 stack and a pair of Wilson XLF's : Forsell Air Force One, ARC Phono 2SE, cj GAT 2, cj ART monoblocks , TA OPUS MM2 IC's and sp, TA XL digital, TA XL gen V power cables, CenterStage footers and Nordost Qkore8's!

  4. #1054
    Member Sponsor Addicted to Best! sujay's Avatar
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    I agree with microstrip. Age probably has nothing to do with that. My older 911mk3 is now 9 years old. The burms are amongst the quietest electronics but I think they are susceptible to interference from other equipment around them, especially TVs. My amps hum only when the TV is on. It is almost negligible now after I installed a Bryston BIT 16 power conditioner. So, microstrip's suggestion of a power regenerator is probably the right way to go. You could also install an isolation transformer like the Torus or the Bryston, which I have and successfully reduced the hum. To reiterate, though, it only hums a little now when the TV is on but I don't usually have the TV on when I am listening to music. So essentially they are dead quiet. You might want to first check if you have noisy equipment around and then turn them off and see if the hum persists. In any case, installing a regen or a trans should help immensely.

    Cheers

  5. #1055
    Quote Originally Posted by sujay View Post
    I agree with microstrip. Age probably has nothing to do with that. My older 911mk3 is now 9 years old. The burms are amongst the quietest electronics but I think they are susceptible to interference from other equipment around them, especially TVs. My amps hum only when the TV is on. It is almost negligible now after I installed a Bryston BIT 16 power conditioner. So, microstrip's suggestion of a power regenerator is probably the right way to go. You could also install an isolation transformer like the Torus or the Bryston, which I have and successfully reduced the hum. To reiterate, though, it only hums a little now when the TV is on but I don't usually have the TV on when I am listening to music. So essentially they are dead quiet. You might want to first check if you have noisy equipment around and then turn them off and see if the hum persists. In any case, installing a regen or a trans should help immensely.

    Cheers
    Thank you, I will try to investigate source of interferences. Friend of main has large isolation transformer I will borrow it for test..

    In the meantime, I have another question how hot 911mk1 should run after few hours of listening to music? My has only 28 Celsius on the left radiator and 30 Celsius on the right. Seems lite bit low. Perhaps the bias is set to low? I wonder if some one could share with me bias setting procedure ? (I'm relatively experiences in DIY and I have all gear from signal generator to oscilloscope)..
    Regards

  6. #1056
    Member Sponsor Addicted to Best! sujay's Avatar
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    Quote Originally Posted by cypher View Post
    Thank you, I will try to investigate source of interferences. Friend of main has large isolation transformer I will borrow it for test..

    In the meantime, I have another question how hot 911mk1 should run after few hours of listening to music? My has only 28 Celsius on the left radiator and 30 Celsius on the right. Seems lite bit low. Perhaps the bias is set to low? I wonder if some one could share with me bias setting procedure ? (I'm relatively experiences in DIY and I have all gear from signal generator to oscilloscope)..
    Regards
    I may not have the answer to the specific question as to the exact temp range but it really would depend upon and vary with the load and the SPL I would guess. My 911 monos run quite cool even when I run them hard and despite my speakers being a difficult load. But it's quite peculiar that one of the amps usually runs cooler than the other. I checked with Burmester and they say it's normal for that to happen. You will need to get the bias specs from Burmester. They will mail it to you. The bias pot is highly sensitive ime. I had taken the help of a techie who took almost 30 min to reset the bias on both amps back to spec. They do tend to go off a little bit with time.

    Hope that helps

    Cheers

  7. #1057
    Member Sponsor Addicted to Best! Elberoth's Avatar
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    I have no experience with mk 1, but my 911 mk3 did not run hot at all - it was barely warm to the touch.
    Adam

    Speakers: Magico M3
    Amp: MSB M202 / D'Agostino Momentum Stereo
    Digital: Lampi Golden Gate DSD only + Lampi DSD Komputer server
    Cables: AudioQuest WEL Signature IC / Shunyata Anaconda Z-Tron SC

  8. #1058
    Thank you ;-)

  9. #1059
    Hi Guys,
    Using what amp input (XLR/RCA) you got a better sound, I'm planing to play around with preamps and I wonder if it's worth to look something with RCA connection ..

    Regards,
    Artur

  10. #1060
    How do you know when the biase needs adjustment? by the temperature? When I got mine from a dealer, second hand, it was sent for servicing first to check for any problems before purchase and they adjusted the biase. That was three years ago.

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