Problem with Burmester 911 in dual mono

[JaapV8]

Hi, I'm new to this forum so I will introduce myself before going into the subject.
I'm Jaap, 48 years and working in the entertainment industry as a stagehand/stagebuilder. I'm also a part time photographer (who isn't these days ;-)

Although music is my life (and my job), and I have always had a decent installation in both my car and at home, I only recently got into the 'high end' audio.
In fact it started at a photography job I got at a MBL demo in a high end audio store in Belgium. They had multiple setups , up to the giant reference set (with the ugly black/gold components, matter of taste I presume) and the huge omnidirectional speakertowers. While doing my job as a photographer, I also joined the lsitening session and was impressed. I never heard music like this , apart maybe from live accoustic sessions, So I decided to get my own high end set.

I already owned a pair of B&W 802N's, driven by two Vincent 331's in bi-amp mode. According to some reviews, the Vincents should sound as well as amps way above their price level but when I started my search for better amps, I found out that this claim was exaggerated, and not even mildly.

I listened to many systems; Krell (KAS 2), Pass Labs 250.5, temporarely owned a pair of Mark Levinson's 20.6 monoblocks (with which I had a hard time finding the right preamp for them), I found many differnces in sound signature, and price levels of course and wasn't able to find a set I both loved and could afford. Until one day I was visiting a friend who had the same B&W speakers and had borrowed a set from a friend to put up for sale. This set was a Burmester 061, 035 and a 911MK3. I was immediately sold. This was definitely the soud I was lookig for and although the price was still above my budget (or rather what I wanted to spend), the price was a bargain compared to the new price (10.000 euro for the whole set ,which was 6 years old). So I didn't hesitate and bought it.

While very happy with the sound, after a while I wanted more (of course). So I upgraded my speakers to a pair of 800D's, this definitely improved the bass and depth of the sound. Then after reading many fora and reviews I learned that an extra 911 would be the way to go next. So I did.
I found a pre owned 911 at a Burmester dealer and bought it together with two mono adapters (original Burmester silver) to bridge my stereo configured 911's.

That is when the problems started. Yes, I got more power, bigger soundstage, even more bass and depth but somehow the balance in the sound seemed off. Also the dynamics seemed to suffer. Where before I turned the volume to listening level and never felt the need to adjust it (unless I changed the CD of course). Now suddenly the louder parts in a song made me run for the remote to turn it down. Mainly because some oversteering seemed to happen in the high frequency range. I also noticed that some hiss/noise (no hum) was coming from the tweeters when no music was playing. Before there was also a slight hiss, but only audible when you put your ear right next to the tweeter.

After discussing the problem with the Burmester dealer (he even visited me), he concluded that my preamp was causing the problem. And while I was selling off my surround gear anyway bc it didn't add much to the great sound I got from my stereosystem, he made me a great deal, all my surround stuff + my 035 and 061 (and some extra cash) for a brand new Burmester 111!

When I got it and installed it (together with the dealer), the problem remained. The dealer could hear it too, but the only solution he could think of was a problem with the power distribution so he gave me furutech power distributor in exchange for a pair of (now obsolete) Burmester silver interlinks. Again, a good eal but it didn't solve the problem.

Because the dealer couldn't provide an explanation for the problem , I tried to do some research myself. Problem is, although I work with professional audio, I have no technical education or background so most terms and specs have little or no meaning to me. What I did notice however when I compared the spec sheets of the various Burmester preamps is that while the 088 and 077 which are often used in combination with 2 911's in the reviews have an output voltage of 24 volts, the 035 and 111 provide only 12 volts of output (even though the 111 has an 077 built in). I wonder if this might be tthe cause of the problem. I mailed Burmester about this but they claim it shouldn't be a problem at all and that they use this setup regularly in demo's.

Does anyone here know what might be the problem with my system and/or is my theory about the voltage output right?
My setup is as follows; Burmester 111 connected to 2 911's mono bridged by Burmester silver mono adapters with a Burmester silver XLR extension interlink to the Burmester 111.

BTW , I also tried bi-amping with regular XLR splitters, which reduced the problem but at the cost of the power, definition and other benefits I had with the dual mono. The only real solution so far is connecting the 111 to one 911. Which gives me back the sound I loved with my initial configuration, the balance and dynamics are back and more defintion (I think) probably bc of the superiour preamp/dac of the 111 compared to the 061 + 035. But hardly justifies my expensive upgrade path.

 

[Legolas]

Sounds like you have a phase problem to me. Nice room by the way.

I would get another tech round to your house. Have you tried ringing Burmester factory?

 

[JaapV8]

Thanks for the compliment astrostar, it's all self styled/made.

I did email the Burmester company, the spokesperson said he consulted their techs and they were of opinion that the setup should work fine.
Both the mono adapters and extension links are Burmester originals (although the adapters are of the older generation BM silver, while the extension interlinks are of the newer version) so I guess there can't be a phaseproblem there. (odd thing happened yesterday though, I tried regular XLR interlinks as extensions on the mono adapters, the result; no sound at all! Which is strange bc they work just fine when connected straight from the preamp to the 911 without the mono adapters)The powercords are also Burmester original which I phased the right way. Maybe I could try to reverse them.
Or what do you exactly mean by a 'phaseproblem'

 

[RogerD]

I think you have a adapter connector issue. The higher level of hiss at the tweeter suggests to me the a very minor connection issue effecting the internal ground scheme between components chassis.
I personally have reduced problems like this by attaching a jumper wire between the preamp and amplifiers chassis.
In my experience adaptors can be problematic when used connecting between the preamp and amps. FWIW Good Luck

P.s I read through part of the excellent 911 thread elsewhere on WBF. If your dealer confirmed what you think is a problem, have him get another pair of adapters. I don’t know what else it could be. Make sure you connections are clean. From what I read the 911 dual mono configuration is fantastic.

 

[JaapV8]

From what I read the 911 dual mono configuration is fantastic.

That was the reason I bought the 2nd 911.
About the adapters, When I bought my 2nd 911, the dealer used my 2 pairs of older BM silver interlinks to assemble them into mono adapters, when I mentioned the problem he ordered a factory assembled pair of adapters and exchanged them. Maybe the combination of the older BM silver with the newer verion (the extension) is a mismatch and the cause of the problem. in that case I should try to get a pair of older interlinks to use as extensions or a pair of new version adapters (if they are yet available, bc they weren't a few months ago)

But what about my output voltage theory? Does it make any sense? Because I seem to remember having read a thread about amp matching (also on this forum I think) that next to the most important thing which was IIRC output/input impedance , a too low output voltage could also cause problems, and the problems the writer described resemble mine; oversteering in the high frequencies, imbalanced sound etc.
And I still find it strange that although the 111 has a built in 077, the data on the spec sheets of the 111 and the (stand alone) 077 vary on several points, like the output voltage (12v vs 24v) and the seperate 077 has a better S/N ratio (<97 vs <107)

I personally have reduced problems like this by attaching a jumper wire between the preamp and amplifiers chassis.

How exactly can I do that?

ps, the louder hiss is not even my main concern, merely an extra indication that something is wrong. The main thing is the sound is just unpleasant overall with sharp/oversteering highs

 

[RogerD]

I think you have a adapter connector issue. The higher level of hiss at the tweeter suggests to me the a very minor connection issue effecting the internal ground scheme between components chassis.
I personally have reduced problems like this by attaching a jumper wire between the preamp and amplifiers chassis.
In my experience adaptors can be problematic when used connecting between the preamp and amps. FWIW Good Luck

That was the reason I bought the 2nd 911.
About the adapters, When I bought my 2nd 911, the dealer used my 2 pairs of older BM silver interlinks to assemble them into mono adapters, when I mentioned the problem he ordered a factory assembled pair of adapters and exchanged them. Maybe the combination of the older BM silver with the newer verion (the extension) is a mismatch and the cause of the problem. in that case I should try to get a pair of older interlinks to use as extensions or a pair of new version adapters (if they are yet available, bc they weren't a few months ago)

But what about my output voltage theory? Does it make any sense? Because I seem to remember having read a thread about amp matching (also on this forum I think) that next to the most important thing which was IIRC output/input impedance , a too low output voltage could also cause problems, and the problems the writer described resemble mine; oversteering in the high frequencies, imbalanced sound etc.
And I still find it strange that although the 111 has a built in 077, the data on the spec sheets of the 111 and the (stand alone) 077 vary on several points, like the output voltage (12v vs 24v) and the seperate 077 has a better S/N ratio (<97 vs <107)


How exactly can I do that?

ps, the louder hiss is not even my main concern, merely an extra indication that something is wrong. The main thing is the sound is just unpleasant overall with sharp/oversteering highs

Boy after reading about this amp, I have to think it’s the adapters.
You can take a length of of heavier stranded copper wire and make a 3 point jumper with connectors that can attach to a chassis screw on the preamp and each amplifier chassis. See if that lowers the the noise from the speaker and improves what you hear.
Before doing that clean those connections on the adaptors with a cotton swab and denatured alcohol or if you have some deoxit.
If the factory doubts the voltage theory, I would try and find new adapters.

 

[RogerD]

Thanks for the compliment astrostar, it's all self styled/made.

I did email the Burmester company, the spokesperson said he consulted their techs and they were of opinion that the setup should work fine.
Both the mono adapters and extension links are Burmester originals (although the adapters are of the older generation BM silver, while the extension interlinks are of the newer version) so I guess there can't be a Phase problem there. (odd thing happened yesterday though, I tried regular XLR interlinks as extensions on the mono adapters, the result; no sound at all! Which is strange bc they work just fine when connected straight from the preamp to the 911 without the mono adapters)The powercords are also Burmester original which I phased the right way. Maybe I could try to reverse them.
Or what do you exactly mean by a 'phaseproblem'

Also I read that Burmester uses a different pin hot configuration on their xlr connections....that’s probably why there was no sound.

No, there is no active circuitry involved. The input is a differential input.

The Burmester RCA to male XLR adapters short pin 2 to ground, and connects pin 3 to the "hot" pin of the RCA - because Burmester (like many European amps) take pin 3 +ve and pin 2 -ve.

If you use a Cardas adapter or any other US-made adapter, you will short pin 3 to ground and connect the hot pin of the RCA to pin 2 - resulting in an amp that inverts phase. Because the 911 is a differential amp, you can just reverse the speaker terminals, and it "should be OK". Some have claimed to hear the difference, others claim to hear no difference. I think that it boils down to the comparison of the sound of the Burmester RCA-XLR adapter vs the Cardas adapter. A properly balanced differential power amplifier should sound identical whether a signal is connected to pin 2 or pin 3.

 

[sujay]

Hi JaapV8,

While I am not an expert I think you have two options- send the amps to the dealer for opening up and checking. Or send the amps to Berlin ( preferred though arduous). It sounds to me like a gain issue but it’s an amateurish guess at best. If your preamp can adjust gain, would suggest going all the way down and checking.

I currently have a pair of 911 amps in mono with the 088. They work beautifully and I only have a very low, normal level hiss at the tweeters when I put my ears against them. I drive Rockport Aviors @ 89.5 db sensitivity which are very close to the B&W 800’s sensitivity in my view.

What puzzles me though is that your issue only happens in mono. If you are using the burm mono adapters then the wiring should be fine unless by any chance you are erroneously using the bi-amping adapters in which case the wiring will be different.

I realise I haven’t been of much help but if you need any person within Burm to speak to do PM me. Alternatively, speak to Rocco on this forum who has much more experience than I of Burmester and should be of help. Rocco was the one who connected me to the person in Berlin who was very helpful.

Cheers

Sujay

 

[JaapV8]

Ok, I will try this (I hope there are

Also I read that Burmester uses a different pin hot configuration on their xlr connections....that’s probably why there was no sound.

This should only be an issue when you go from a normal polarity device to a Burmester or other device with inverted polarity I think. If u go from inverted to inverted like in this case , it shouldn't be a problem.

While I am not an expert I think you have two options- send the amps to the dealer for opening up and checking. Or send the amps to Berlin ( preferred though arduous). It sounds to me like a gain issue but it’s an amateurish guess at best. If your preamp can adjust gain, would suggest going all the way down and checking.

I currently have a pair of 911 amps in mono with the 088. They work beautifully and I only have a very low, normal level hiss at the tweeters when I put my ears against them. I drive Rockport Aviors @ 89.5 db sensitivity which are very close to the B&W 800’s sensitivity in my view.

The amps are fine, they both work like a charm seperately. As I mentioned before, when I hook up the 111 with one 911 (regardless whicch one) there is no problem at all.
That leaves 2 options; the adapters, I think if they accidently sent me bi-amp adapters , it wouldn't work at all bc the mono wiring is totally different form the bi-amp configuration. Besides they would have made that mistake twice, first when the dealer assembled them themselves and after when they sent me originals.

You mention you have an 088, which also has a 24 volt output, this thursday the dealer will come over with a 088 for a test, I'm very curious about the results. If it's better, it would confirm my voltage theory, if not , I can focus on the adapters, or adapter/extension combination.

I have had contact by email with Burmester regularly, the first time when I bought my first set which came without packaging and invoice, to check the serial numbers to have the age of the devices confirmed and if they were not registered as stolen. I was pleasantly surprised by the quick and kind responses (usually within a day). Lately however, the responses are tediously slow. My first email in which I extensively described the problem and the measures I had taken to try to solve it, along with some questions was only replied after 2 weeks, with just the message that 'according to the techs, it should work'. The next email I sent with the questions that remained unanswered (now 3 weeks ago) still hasn't been answered.

PS. I got rid of the tweeter hiss/noise problem. by swapping the 1350 euro Furutech power distributor for a regular 25 Euro Brennenstuhl block!

 

[Anatta]

I think the problem is the 911s are not really fit to drive bridged the 800D difficult load so they sound worse than single stereo (you should never bridge amps to drive 4 Ohm loads or lower). Are both amps MK3 versions? Since you bought them used I'd send them to Burmester for a checkout and see if they're within spec, maybe they need some bias adjustment.

There is no issue with the preamp output voltage; the 911's input sensitivity is high at 770mV (only 0.77 volts needed from the preamp for full power output).

 

[bonzo75]

Hi, I'm new to this forum so I will introduce myself before going into the subject.
I'm Jaap, 48 years and working in the entertainment industry as a stagehand/stagebuilder. I'm also a part time photographer (who isn't these days ;-)

Although music is my life (and my job), and I have always had a decent installation in both my car and at home, I only recently got into the 'high end' audio.
In fact it started at a photography job I got at a MBL demo in a high end audio store in Belgium. They had multiple setups , up to the giant reference set (with the ugly black/gold components, matter of taste I presume) and the huge omnidirectional speakertowers. While doing my job as a photographer, I also joined the lsitening session and was impressed. I never heard music like this , apart maybe from live accoustic sessions, So I decided to get my own high end set.

I already owned a pair of B&W 802N's, driven by two Vincent 331's in bi-amp mode. According to some reviews, the Vincents should sound as well as amps way above their price level but when I started my search for better amps, I found out that this claim was exaggerated, and not even mildly.

I listened to many systems; Krell (KAS 2), Pass Labs 250.5, temporarely owned a pair of Mark Levinson's 20.6 monoblocks (with which I had a hard time finding the right preamp for them), I found many differnces in sound signature, and price levels of course and wasn't able to find a set I both loved and could afford. Until one day I was visiting a friend who had the same B&W speakers and had borrowed a set from a friend to put up for sale. This set was a Burmester 061, 035 and a 911MK3. I was immediately sold. This was definitely the soud I was lookig for and although the price was still above my budget (or rather what I wanted to spend), the price was a bargain compared to the new price (10.000 euro for the whole set ,which was 6 years old). So I didn't hesitate and bought it.

While very happy with the sound, after a while I wanted more (of course). So I upgraded my speakers to a pair of 800D's, this definitely improved the bass and depth of the sound. Then after reading many fora and reviews I learned that an extra 911 would be the way to go next. So I did.
I found a pre owned 911 at a Burmester dealer and bought it together with two mono adapters (original Burmester silver) to bridge my stereo configured 911's.

That is when the problems started. Yes, I got more power, bigger soundstage, even more bass and depth but somehow the balance in the sound seemed off. Also the dynamics seemed to suffer. Where before I turned the volume to listening level and never felt the need to adjust it (unless I changed the CD of course). Now suddenly the louder parts in a song made me run for the remote to turn it down. Mainly because some oversteering seemed to happen in the high frequency range. I also noticed that some hiss/noise (no hum) was coming from the tweeters when no music was playing. Before there was also a slight hiss, but only audible when you put your ear right next to the tweeter.

After discussing the problem with the Burmester dealer (he even visited me), he concluded that my preamp was causing the problem. And while I was selling off my surround gear anyway bc it didn't add much to the great sound I got from my stereosystem, he made me a great deal, all my surround stuff + my 035 and 061 (and some extra cash) for a brand new Burmester 111!

When I got it and installed it (together with the dealer), the problem remained. The dealer could hear it too, but the only solution he could think of was a problem with the power distribution so he gave me furutech power distributor in exchange for a pair of (now obsolete) Burmester silver interlinks. Again, a good eal but it didn't solve the problem.

Because the dealer couldn't provide an explanation for the problem , I tried to do some research myself. Problem is, although I work with professional audio, I have no technical education or background so most terms and specs have little or no meaning to me. What I did notice however when I compared the spec sheets of the various Burmester preamps is that while the 088 and 077 which are often used in combination with 2 911's in the reviews have an output voltage of 24 volts, the 035 and 111 provide only 12 volts of output (even though the 111 has an 077 built in). I wonder if this might be tthe cause of the problem. I mailed Burmester about this but they claim it shouldn't be a problem at all and that they use this setup regularly in demo's.

Does anyone here know what might be the problem with my system and/or is my theory about the voltage output right?
My setup is as follows; Burmester 111 connected to 2 911's mono bridged by Burmester silver mono adapters with a Burmester silver XLR extension interlink to the Burmester 111.

BTW , I also tried bi-amping with regular XLR splitters, which reduced the problem but at the cost of the power, definition and other benefits I had with the dual mono. The only real solution so far is connecting the 111 to one 911. Which gives me back the sound I loved with my initial configuration, the balance and dynamics are back and more defintion (I think) probably bc of the superiour preamp/dac of the 111 compared to the 061 + 035. But hardly justifies my expensive upgrade path.

I compared a burmester 911 mk3 with symphonic line Kraft on B&W 802'D3 with burmester 077 pre. The Kraft was better by quite a bit. It is also a popular pairing in Germany with this speaker. Used price is good, 10k euro for the 300w version.

 

[Gregadd]

My apology for you having been led down the primrose path to audiophile nirvana. With predictable results I might add. I have only heard the Burmester in un-bridged version at audio shows. You might want to contact Gary Koh via PM. He was a big fan of Burmeister before designed his own amp.
It has been my experience that when buying used many people have expensive products shipped directly to factory for evaluation. The mere fact that the amp is playing does not mean it is not malfunctioning. I am sad to say many people dump their equipment rather than pay for repair.
I do find it strange that Burmeister left you hanging. It appears as though they would want to avoid bad publicity.
P.S. It is always a good idea when buying expensive used equipment to get the serial number and call the factory to ascertain if the product has any "history."

 

[sujay]

Hi Anatta,

The 911 mk3 is designed to be run in bridged mode. They are designed to drive 4 ohm speakers. I drive Aviors with them with no issues. The amps output around 1.2 kw on 2 ohm loads from what I know. So the problem is elsewhere. Someone else did say though that they don’t pair well with the B&W speakers for reasons unknown, which is quite possible. Not all amps pair well with all speakers.

They are excellent amps (to me) and I would take them over most SS amps including the Vitus which I have heard on the same setting. Haven’t heard the symphonic line though and they may well be great but at this level i haven’t found the differences earth shattering.

 

[Anatta]

I bet the distortion is higher in bridged mode than in stereo when driving 4 Ohm loads or lower; just because they work with such loads doesn't mean is ok to do it. And there's no way a 911 could give 1.2kW @ 2 Ohm when the amp only has a 750VA transformer.

There's a reason for the 909 existence; 2x911 =/= 1 x 909. If you want to drive 4 Ohm loads or lower it would be better to get a single 909 instead of two 911.

 

[sujay]

I am not here to argue or prove anything. I have checked the power output with Burmester. If you don’t believe it’s possible, so be it! I just feel the problem is elsewhere.

 

[sujay]

And I didn’t say two 911 are equal to one 909.....I haven’t used the 909 myself so can’t comment.

 

[sujay]

And in case if it wasn’t clear I meant 1.2kw at 2 ohm per channel run as bridged mono

 

[JaapV8]

Thank you all for the replies. Instead of waiting for my dealer to show up (he mailed me today that he will come over with a 077 at the end of the week), I found a good deal on Ebay for a pair of used Sonus Faber Stradivari. Although they are huge, I love the looks of them and read many good reviews. The rated power is 30-300 watt at 4 Ohm, so I was afraid that my dual 911 might be overkill, Yet I read elsewhere on this forum that these speakers are very 'power hungry' and Stereophile also tested them with powerful monoblocks.

I picked up the speakers with a friend, who is also a music lover (or audiophile, who also couldn't believe that the 911's sounded awful on my B&W800D's. Until I showed him)
Anyway first installed the Strads on 1 BM911. Sounded good (if not great). Then I connected both 911's... And...What a sound! The sweetness, the joy! We spent all night listening to music, first to check if I could find anything wrong, playing the tracks that gave me problems with the B&W's. But although sometimes highs could sound sharp, never unpleasantly sharp. Again I could turn up the volume to frightening levels without any sign of oversteering or running for the volume control. For the first time since my upgrade by adding a 911 I enjoyed listening again. Again I enjoyed familiar tracks in a different, more enjoyable way. Just as when I bought my first Burmester amp. Were they perfect? No, the lower bass frequencies were less tight then with the B&W's and some minor issues, most of which I solved quick enough by adjusting the placement.

In fact, they sounded exactly like most reviews described them. They are not the most refined, detailed or perfectly layered speakers, but especially voices sound amazing, the soundstage and depth is great and now I understand why some people find B&W's sound 'analytical' and label the SF Strads as 'Musical'.

Still, I have already decided to exchange the 111, mainly bc I dislike the looks and the app interface (and maybe because this machine has caused me too much frustration) Yet I want to stay with Burmester. So will it be the 077 with external PS or the 808 MK5. I like the looks of the 808 much more, but it has no DAC ,the current 077 comes standard with the DAC module built in. I'm a bit afraid that by using an external DAC (from another brand) I might lose my favoured Burmester sound. So with the 077 I can experiment with external DAC's while always being able to fall back on the built in DAC. With the 808 I have no such option, or I could buy the 113 external DAC with the silly tooth. Or add a 151, so I have my player/streaming options back with a good BM DAC, but no way to connect my TV or other external digital sources to it.
luxury problems... ;-)

Happy listening to all!

 

[sujay]

I would take the 808 with the power supply

 

[JaapV8]

I would take the 808 with the power supply

Why? (I haven't heard neither of them, but I''m curious about your opinion). All I read so far is that many people love the 808 bc it sounds 'neutral'. Now I don't exactly know what they mean by that or if that's something I want.

I remember experimenting with my former setup (061 + 035 + 911 + BW802N), I also had an Oppo UBP 205 for playing Blu-Rays. Since this device was also praised for it's great DAC and 'Audiophile' sound reproduction I tested it with both the surround throughput of the 035, using the volume control of the Oppo and connecting it as a source device using the 035 controls. While the first option didn't sound bad, I definitely preferred the 2nd. It was like bypassing the 035 pre didn't give me that engaging Burmester sound I loved.

I know that part of the 'audiophiles' are of the opinion that a preamp is or should be nothing more then an input selector and/or a volume control, while others consider the pre as the device where the magic happens. I think I belong to the latter group.