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ARCHIVED FORUM -- April 2007 to March 2012
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This is the first Archived Forum which was active between 17th April 2007 and 1st March February 2012

 

Latest post 05-04-2009 3:11 PM by henrykin. 61 replies.
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  • 04-29-2009 12:51 PM In reply to

    Re: Beo Master 7000

    henrykin:

    Sorry if I appeared rude.

    Don't worry about it,  we all want the same - that you enjoy and get the best from your B&O Yes -  thumbs up

    Ray

    Я люблю Банг и Oлуфсен

  • 04-29-2009 1:47 PM In reply to

    Re: Beo Master 7000

    I'm trying things out of curiosty. The mod seems to have worked for the

    quality of sound now I'm trying to improve on the volume at low end.

    It's now become an addiction.

    I'll probabley be dead and buried by the time this is sorted. LOL

    What else I find crazy it comes with a connection for a graphic equlizer

    and B & O don't do one.

    If anyone has any info on upgrading the preamp thats in it I'd be grateful

  • 04-29-2009 2:19 PM In reply to

    Re: Beo Master 7000

    Sorry everyone I got this mod from beo central not the workbench

    sorry everyone for misleading info.

    http://notebook.beocentral.com/beomaster-5500-6500-and-7000/

    Beomaster 5500, 6500 and 7000

    6th January 2009

    If you have owned a lot of B&O equipment then you will have probably noticed that thesse models give a slightly disappointing sound when used with passive loudspeakers when compared to some of the earlier designs. This is surprising as the power amplifier circuit is very similar to that of the Beomaster 2200, Beomaster 5000 and the Beocenter 7700 (amongst many others), all of which give very satisfactory performance.

    The Beomaster 5500, 6500 and 7000 have a rather basic pre-amplifier circuit compared to that used in the original 5000 model but this is not the cause of the problems, the same arrangement is used in the Beocenter 9000 where it seems to work reasonably well. Therefore the power amplifier circuit was investigated to see what could be causing the trouble.

    The only substantial difference between the Beomaster 5000 circuit and that used in the later models is the addition of four 220nF capacitors C215, C216, C415 and C416. They are not shown on all the Beomaster 5500 circuit diagrams but many sets have them. As these do not appear in any other versions of the circuit it seemed safe to remove them and see if the performance improved. With the capacitors in circuit the sound from one Beomaster 5500 was lifeless, bland and uninteresting, without them it was more similar to a 5000, engaging and lively with a full, rich tone.

    It is not clear what the purpose of these capacitors is but performance definitely improves if they are disconnected. Before doing this make sure that the muting relay 3RL1 is in good condition (contact resistance less than 0.5R at rest) and that the output bias current for each channel is correctly set. [Beomaster 5500Beomaster 6500Beomaster 7000]

  • 05-01-2009 9:49 AM In reply to

    Re: Beo Master 7000

    Just to keep you all informed my amp is still working

    with no problems. From last friday

  • 05-01-2009 1:42 PM In reply to

    • Dillen
    • Top 10 Contributor
    • Joined on 02-14-2007
    • Copenhagen / Denmark
    • Posts 5,008
    • Founder

    Re: Beo Master 7000

    Good !
    Perfectly safe to remove those caps then. Sorry that I raised doubt.
    Stupid guys to add them in the first place, what were they thinking ?  Laughing

    Martin

  • 05-01-2009 3:01 PM In reply to

    Re: Beo Master 7000

    Thankyou.

  • 05-02-2009 7:28 PM In reply to

    Re: Beo Master 7000

    Die_Bogener

    wrote 

    BM5500 and BM6500/7000 have different software levels.

    A BM5500 has up to 60 volume steps, but the BM7000 has 78.

    60=78, it's just a software question... the real hardware chip for volume is identical and has 255 steps. 

    ----------------------------------------------------------------------------------------------------------------------------------------

    Both my 5500 and 7000 vol go from

    00-78.  If you could tell me what chip it is

    would it be possible to copy the software from my 5500

    on to a blank chip to replace in my 7000 as I have the programmers to reprogram chips.

    It's just a thought! because this vol issue is driving me mad. The sound is audiable but it is

    really low until it gets to 18

    Thankyou Henry

  • 05-02-2009 8:37 PM In reply to

    • ducha
    • Not Ranked
      Male
    • Joined on 01-04-2008
    • Wisconsin, US
    • Posts 77
    • Bronze Member

    Re: Beo Master 7000

    Can someone please post a link to Die_Bogener's write-up on upgrading the BM5500, 6500, and 7000 preamp?

    Thanks much,

    Aaron

  • 05-03-2009 5:14 AM In reply to

    Re: Beo Master 7000

  • 05-04-2009 10:28 AM In reply to

    Re: Beo Master 7000

    Hi Aron

    If you try Die-Bogener's mod

    could you let me know how it goes.

    Thankyou Henry

  • 05-04-2009 11:07 AM In reply to

    • Dillen
    • Top 10 Contributor
    • Joined on 02-14-2007
    • Copenhagen / Denmark
    • Posts 5,008
    • Founder

    Re: Beo Master 7000

    I asked the tech guys at B&O, this is their response:

    "En af vore teknikere, har nu set på din e-mail.

    Vi kan sige, at de nævnte kondensatorer ikke har nogen indflydelse
    på lydkvaliteten. De er indført som en slags sikkerhed, hvis volumen bliver
    så højt at lyden "klipper", dvs. når der sker en forvrængning. Men de har
    ingen indflydelse på lydkvaliteten ved almindelig afspilning.

    Med venlig hilsen
    Bang & Olufsen a/s

    Helle Pramanik
    BeoCare"

    - which translates into this in english:

    - "One from our technical staff has seen your mail.
    We can say, that the capacitors in question have no influence on sound quality.
    They have been introduced as a safety precaution if the volume gets turned up
    enough to cause clipping, in other words when it starts to distort. But they
    have no influence on sound quality under normal playback circumstances."


    So my guess at soft-clipping was not too far out and I can see from the schematics that
    the anti- self-oscillation functionality lies in there as well.

    I've seen a case where mains fuses were bypassed to "minimize
    mains resistance" which should also improve performance - 'nuff said.
    I've stated my opinion and advice regarding these caps (which also goes
    for any other safety precaution introduced, especially during production) in this
    thread already.

    Which advice owners choose to follow and which modifications to introduce in their own machines is up to them.
    Eventual consequences likewise.
    I will not comment further on this matter other than ask people to inform future owners of any
    safety mods made in an eventual selling of the item.

    Martin

  • 05-04-2009 3:11 PM In reply to

    Re: Beo Master 7000

    Well I done it and it the improvement of sound is without

    a shadow of a doubt better.

    My amp is still playing and there is no distortion what so ever.

    Like I said before I haven't ask anyone to do it.

    I only put this post up to say thankyou

    not for any other reason.

    Certainly not to get into a dispute about it.

    I looked at Die-Bogener post that you directed me to

    and it seems to me more risky what he's done he ripped

    half the pre amp to shreads.

    It's seems like you have developed a grudge . I spoke with a B&O engineer 30yrs of experiance

    and he told me it was ok to do.

     

    6th January 2009

    If you have owned a lot of B&O equipment then you will have probably noticed that thesse models give a slightly disappointing sound when used with passive loudspeakers when compared to some of the earlier designs. This is surprising as the power amplifier circuit is very similar to that of the Beomaster 2200, Beomaster 5000 and the Beocenter 7700 (amongst many others), all of which give very satisfactory performance.

    The Beomaster 5500, 6500 and 7000 have a rather basic pre-amplifier circuit compared to that used in the original 5000 model but this is not the cause of the problems, the same arrangement is used in the Beocenter 9000 where it seems to work reasonably well. Therefore the power amplifier circuit was investigated to see what could be causing the trouble.

    The only substantial difference between the Beomaster 5000 circuit and that used in the later models is the addition of four 220nF capacitors C215, C216, C415 and C416. They are not shown on all the Beomaster 5500 circuit diagrams but many sets have them. As these do not appear in any other versions of the circuit it seemed safe to remove them and see if the performance improved. With the capacitors in circuit the sound from one Beomaster 5500 was lifeless, bland and uninteresting, without them it was more similar to a 5000, engaging and lively with a full, rich tone.

    It is not clear what the purpose of these capacitors is but performance definitely improves if they are disconnected. Before doing this make sure that the muting relay 3RL1 is in good condition (contact resistance less than 0.5R at rest) and that the output bias current for each channel is correctly set. [Beomaster 5500Beomaster 6500Beomaster 7000]

     

    THROW ME OFF THIS FORUM AS I PERSONALLY THINK YOUR A .

  • 05-04-2009 4:00 PM In reply to

    Re: Beo Master 7000

    I am happy with what I done

    the sound has improved ten fold.

    I spoke with a B&O engineer of 30yrs experience and showed

    him the mod I found on beo centrle and he said go for it and I did.

    First you tell me it'll go up in smoke then you say it'll distort the sound

    It hasn't done either.

  • 05-04-2009 4:24 PM In reply to

    • Dillen
    • Top 10 Contributor
    • Joined on 02-14-2007
    • Copenhagen / Denmark
    • Posts 5,008
    • Founder

    Re: Beo Master 7000

    "First you tell me it'll go up in smoke then you say it'll distort the sound"...

    I did neither.  No - thumbs down

    Martin

  • 05-04-2009 4:48 PM In reply to

    Re: Beo Master 7000

     Martin

    you wrote

    Won't you face a serious risk of self-oscillation in the amplifier if you remove the feedback caps ?
    It's quite common to see unstable DC-coupled amplifiers like this one go into self-oscillation at
    full power, typically at a high (inaudible) frequency, 100KHz or so, overrunning the amplifier without
    anyone knowing about it until it dies in smoke and flames.

    and also this

    They have been introduced as a safety precaution if the volume gets turned up
    enough to cause clipping, in other words when it starts to distort.

    you should remember what you write in previous posts.

    Henry

  • 05-04-2009 5:02 PM In reply to

    • Dillen
    • Top 10 Contributor
    • Joined on 02-14-2007
    • Copenhagen / Denmark
    • Posts 5,008
    • Founder

    Re: Beo Master 7000

    Peace my friend, we only have this one planet.
    I merely recommended a different mod and told you what B&O's answer was.
    Neither of us told you it would distort and I don't say it WILL go up in smoke.
    Please understand this.

    "They have been introduced as a safety precaution if the volume gets turned up
    enough to cause clipping, in other words when it starts to distort."

    - Was said by B&O. Not me !
    But it partly confirmed my guess at the caps function.
    Apart from that, the amplifier WILL distort if cranked up too high.
    Any well-proportioned amp will.
    The difference being the way it distorts. This way is called soft-clipping and is
    here to protect your tweeters rather than the amplifier since clipping causes a high
    amount of harmonics (edgy and sharp curveforms with huge amounts of energy).

    "Won't you face a serious risk of self-oscillation in the amplifier if you remove the feedback caps ?
    It's quite common to see unstable DC-coupled amplifiers like this one go into self-oscillation at
    full power, typically at a high (inaudible) frequency, 100KHz or so, overrunning the amplifier without
    anyone knowing about it until it dies in smoke and flames."

    - Was a question based on (more than 30 years of) experience with (not just) B&O and
    based on the fact that I sat down with the schematics and tech info sheets and asked myself why those
    caps were introduced in the first place.

    There's no way I can tell you it WILL go wrong. Clearly, lots of owners would
    have had this problem if that was the case.

    Clearly neither you, nor the experienced B&O tech guy you spoke to, have had
    enough Beomasters of this type on the bench to know when an amplifier has burned
    for "no apparent reason".
    I have only limited experience with this "somewhat new" B&O thing the Beomaster 5500 is
    but out of the maybe 70 or 80 Beomaster 5500 units I've seen, I think, 4 or
    5 cases of "mystic blows" of which at least 2 or 3 was beyond economic repairs.
    Neither of these had the caps mounted.
    I never saw a "mystic blow" in a Beomaster 5500 that had the caps, all faults
    in these could be explained otherwise. (Mainly cracked solders, idle current
    runaways, driver or speaker shorts, electrolytic leaks etc.).
    Yours may work fine for years.

    "you should remember what you write in previous posts."

    - ...
    I'm lost for words so I'll just shut up. I know nothing about electronics and if you need advice or help
    I suggest you ask an experienced guy (=someone else). 

    Martin

  • 05-04-2009 5:08 PM In reply to

    Re: Beo Master 7000

    OK peace we will agree to disagree.

    End of

    Regards Henry

  • 05-04-2009 5:21 PM In reply to

    Re: Beo Master 7000

    Martin

    I'm lost for words so I'll just shut up. I know nothing about electronics and if you need advice or help
    I suggest you ask an experienced guy (=someone else). 

    Not once did I imply that you know nothing

    Your knowledge and imput is as valuable as anyone elses and I wouldn't hesitate to ask

    you for help and I also would like to think you would tell me I was saying something wrong

    Just because I didn't agree doesn't mean I don't listen.

    Sorry if it got a bit over heated

    Henry

  • 05-04-2009 5:52 PM In reply to

    Re: Beo Master 7000

    Martin is one of the most knowledgeable people about B&O that I know. His opinion is highly respected throughout the B&O world. His collection has also been one of the largest. He is a top contributor both here and on Beocentral where he has donated many superb pictures from his own collection. The modification to the 5500 was indeed made because of instabilities, particularly in multi-room set ups. I have two 5500s - my main one has the capacitors in place - the other one has had them removed. I actually detect little difference with CX speakers - more with RLs. I will not be changing my 7000 though or indeed the other 5500. If Martin says they are there for a reason, that is good enough for me. I am sure that removing them will have an effect - but it would appear that the effect is both good and bad. I think therefore that it should be the decision of the owner whether to take the risk.

  • 05-04-2009 6:17 PM In reply to

    Re: Beo Master 7000

    Peter

    I totally agree with you Martin has vast knowledge

    and it is up to the owner what they do.

    It was a clash of ideas thats all nothing more nothing less.

    Henry

  • 05-04-2009 7:57 PM In reply to

    Re: Beo Master 7000

    I'll be deleting my acount tomorrow. martin So your littie click can stick together.

  • 05-05-2009 4:35 AM In reply to

    • 9 LEE
    • Top 10 Contributor
    • Joined on 02-14-2007
    • Moderator - UK
    • Posts 5,223
    • Founder

    Re: Beo Master 7000

    Eh?  Where did that come from? Unsure

    I've just read this thread, twice - and i thought it was informative, fair and balanced. If we all agreed about everything, the forum would be dull - but when it comes to 'black and white' tech specs i assume it's less of a grey area than a simple opinion, surely?

    Anyway - i don't see any 'clicks' here - only people trying to help and offer their advice/knowledge...  Sorry you feel that way.

    Lee

    BeoWorld - Everything Bang & Olufsen

  • 05-05-2009 8:04 AM In reply to

    Re: Beo Master 7000

    I took your advice I have just come back from an electronics shop I took the mod that you recommended  and asked what he thought and his opinion was it's beyond the extreme. I would not attempt it.  The man has been in the shop from school and his father before him.

  • 05-05-2009 10:00 AM In reply to

    • Medogsfat
    • Top 10 Contributor
      Male
    • Joined on 02-21-2007
    • *Moderator* Leeds, Yorkshire
    • Posts 4,045
    • Founder

    Re: Beo Master 7000

    henrykin:

    I took your advice I have just come back from an electronics shop I took the mod that you recommended  and asked what he thought and his opinion was it's beyond the extreme. I would not attempt it.  The man has been in the shop from school and his father before him.

    Are you referring to member Die Bogener's (also called Martin) modification here?

    If so, it isn't THAT complicated and I certainly wouldn't rate it as being "beyond the extreme"Confused

    Chris.

     

    The use of metaphors should be avoided like the plague. They're like a red rag to a bull to me.

  • 05-05-2009 10:16 AM In reply to

    Re: Beo Master 7000

    I am but I was not slating it. I looked at the mod at the suggetion of

    Dillen  and took his advice to ask elsewhere. Thats all

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