Total bescheuert, da hatte ich einen Gedankenfehler. Den Hochtöner muss ich mir morgen noch einemal anschauen. Was ich aber nicht verstehe: die 6631 waren meines Wissen nach, die letzte Ausführung, oder?

Ich werde morgen mal versuchen die Kondensatoren auszutauschen und dann einmal probehören, bevor ich weitere Änderungen mache.  

@Dillen

Now I'm a bit confused.

The picture from stereomensch are the newest (with the Blue electrolytic capacitors).

My Board is the older one?

Stereomensch said, That the newer with the updated tweeter sounds more „modern“ and the highs are brighter? The older (mine) sounds softer.

Zu den Hochtönern:

Beide sind von dem norwegischen Hersteller SEAS.

Es war wohl so, dass Seas den mit der Plastikkappe eingestellt hat. B&O musste dann einen anderen

Hochtöner aus dem Sortiment nehmen. Mir hat ein B&O Insider erzählt, dass deswegen die Weiche eine Neukonstruktion ist.

Die Nummern beziehen sich meines Wissens nach eher auf das Display und das Baujahr.

Ahh Okay, das macht dann auch Sinn. 
Ich werde die MKPs morgen einsetzten und schauen ob es an den Kondensatoren lag. Ansonsten folge ich den Mods von die_Bogener.

Dillen wrote:

Those blue radial Maxcap capacitors will be bad by now.
The boards are largely identical to the ones in the first post, - they can have either radial or axial capacitors fitted.
To preserve or reachieve the original sound I suggest you fit new electrolytic capacitors instead of the old electrolyctics. No MKPs or other film capacitors.
In the best of cases there won't be any discernible difference from electrolytics, in the worst of cases the speakers will end up sounding
"modern" (some owners may like that), but they can end up sounding far from intended - sterile and wearing on the ears compared to the
original soft and pleasant (B&O-) sound of the electrolytic capacitors, to the point of relief when switched off.
Electrolytics was also what B&O chose to use for the Pentas.

Martin

Hello there,

may I jump in and curiously ask where that change of mind comes from or what happened? I can very well remember that in the older threads, where Die_Bogener first suggested all those modifications, you were full of praise and claimed quite different things. Or am I getting something wrong here?

Greetings,

Kai

I don't recall praising the use of film capacitors in crossovers in particular.
At first I thought it was a great idea to replace electrolytic capacitors with film capacitors. Mainly because they (at least in theory) should last forever.
I even made capacitor kits containing film capacitors for several of the larger B&O speaker models.
But many buyers reported back, that they didn't like the sound of the speakers after the rebuild to film, and a few
even asked me to revert their speakers back to electrolytics.
I wondered about that, but also had to admit never listening seriously and for longer periods of time to speakers rebuilt
with film capacitors, so I sat down and did exactly that. My conclusion was, that they were right, - the sound was wearing on the ears.
Where I could listen to "original" speakers for hours without experiencing any fatigue, I grew tired of listening to
the ones rebuilt with film capacitors fairly fast. In the best of cases I honestly couldn't tell any difference from electrolytics, but in the worst of
cases I felt a relief when switching off.
I also came to the conclusion that the speakers, filters and everything was designed for using electrolytics, and
if any other type of capacitor would've made them better speakers, B&O would've used that.

I no longer provide film capacitor kits.
Feedback from buyers made me aware, and I feel that the, at times very steep, prices of the film capacitors can't be justified.
As mentioned earlier, some owners may actually like the sound of the film capacitors, - a sound that I like to refer to as "modern",
because it seems that's where many speaker producers are heading, but it's not the typical and well-known "B&O-sound", - it's not
what B&O intended and it's not the original and warm sound, I prefer myself.
Another thing is, that the film capacitors are often quite bulky in size and rarely fit particularly well in the filter boards.
This alone can be a challenge to some DIY'ers.
Some film capacitor types are so big they need to be placed elsewhere inside the speaker cabinet, which again requires extended lead lengths = not good for cap specs.

What I recall praising was Die_Bogeners modifications to the amplifier section of Beolab Penta.
A few coupling capacitors and some OpAmps are replaced for newer types.
This is not done to improve the sound reproduction as such, - actually the sound isn't colored notably, but it dramatically
improves the signal/noise ratio, an area where the active Pentas with their "volume control" constantly at max can use all attention obtainable, and
it also takes care of certain older OpAmp types that are notorious for injecting their own noise into the signal, so is absolutely worth doing.
These modifications also got included (with Die_Bogeners accept) in the amplifier rebuild kits I make.

But it's all a matter of taste.
If you like the "modern" sound then by all means go ahead and fit film caps (keep leads short and fasten everything so nothing rattles or breaks their solder joints), but if you want the original sound I recommend staying with electrolytics.

Martin

Hey Dillon,

I have now equipped the right speaker with the MKPs and hear what you mean.

the warm sound goes away and it gets very sterile.  is that possibly at the depths?  I'm still considering to equip the left because otherwise I have no complete system.

I have compared moded and unmoded examples of speakers and amplifiers. I have never made that experience. The mods Die_Bogener suggested clear things up, increase bass and treble. But obviously it also depends on who does the work and not only on the components used. Die_Bogener himself only delivers perfect work and honestly, from a theoretical point alone, his suggestions make much sense. The practical result lives up to that, although, of course, no wonders are to be expected.

I do not really buy that "B&O knew what they were doing" argument. Sorry, but although the Pentas were a very expensive to manufacture speaker and top of the range at the time, times where B&O tried to excel sonically were long over by then. The Penta turned out to be a mass product and costs obviously did play a role. Some of the components used were mediocre or even below that. Just look at those cheap resin enclosures for the midrange drivers - a disgrace to anybody who knows what some of the older spearkers looked like. Some of the electronic components definitely also were not the best (although drivers were still pretty decent). Beogram 4000, Beolab 5000, Beomaster 4400, even the Quad system, and some others - those were the times where costs did not matter to an equal extent. And you can tell. An overhauled Beomaster from that time paired with Beovox M100 will give any modern system even when paired with Beolab 5s a run for its money.

I prefer the moded systems sonically and electronically since they will last as you also highlight. Higher quality compomnents with better specs used in a savvy way won't hurt. One last remark: Die_Bogener knows his stuff. He, from my point of view, is one of the most knowledgable guys when it comes to Beosystem 4500 - 7000, Beocenter 9500, Beolink 7000, Pentas, RLs, but also the TVs and VCRs of the time.

Greetings,

Kai

Hey Manbearpig,

I have just installed the MKPs in the crossover and, if the sound stays that way, I have to agree with Dillon.

I do not know if the capacitors need time to burn in. But if they stay that way, the warm sound is gone. 
Unfortunately, I do not know much about the mods of Die_bogener, but an increase in heights does not seem to make sense to me now. I do not want to doubt it, what I read seemed thought out to me.

Best
Kaya 

Du kannst mit Manbearpig auch Deutsch reden, ist schließlich seine Muttersprache 🙂

Hast du denn jetzt nachgeguckt, was für einen Hochtöner du hast?

Wenn du zu den Bogeners Kontakt haben willst, schreib mal Ulf Kiener an.