Hi BeoWorlders,

I'm looking for the service manual for my PentaVox speakers, I want to recap' the filters but it seems the 1st version has different caps than the Mk 2 and 3.

Thanks in advance!!

The only sure way is to open up one of yours in advance and see what you have on the actual circuit boards. I don't think these ever had a dedicated service manual, they are described in the Pentalab manuals.

Anyway, here's what I found in mine - but don't trust that list either! (pics didn't survive the forum upgrade, but they don't add much to the story anyway.):

Link to the old thread

Thanks Mika, I managed to find a service manual for PentaVox 6611 on the net, and as you wrote, they are in the same manual as the first BeoLabs!

I'm afraid I'll have to open the speakers once again..

Yes, I hate having stuff laying open waiting for parts as well!

But, if you are not going to use some megaexpensive audiophile caps, you might just order all the values you find in the different sources, one of the sets should match. The variation seems to be in the smaller, cheap sizes so you wouldn't be wasting a lot of money.

I eventually opened my Pentas, and found out that the caps on the filter boards were actually similar to the ones listed in the service menu for type 6621 (BeoLab Penta 2) and not those for Pentavox/Pentalab MK1.

My deduction is that the original filters were already replaced once, since my speaker is one of the early types (6611 BeoVox from 1986).

Now I don't know whether I should replace the caps if they are less than 20 years old.. Besides, the only caps I found on Internet, on a (german) website, offer the same performance/specs as the originals. I couldn't find any high-end caps of similar size, they all are much bigger than the originals. Or am I looking on the wrong websites?

As far as I know all Beovox Pentas were the same type 6611. I'm sure they simply put the same crossovers in them that were installed in Beolabs manufactured at the same time, I can't think of a reason why your crossovers would've been replaced later. (The year on the type sticker is just a copyright year for the design, you need to check the serial number for the actual production date.)

If the caps are the original golden Roedersteins, they must be somewhat tired already, and you should hear some improvement even if you replace them with the fresh, same spec bipolar electrolytics.

If you want to use foil caps, they are inherently much larger physically. If you don't go overboard and settle with 160V types they should still fit - you possibly need to nick a piece of plastic from the speaker pedestal to accomodate one of the 68 uF cans, though.

I used Intertechnik MKT caps for mine, Solen is another popular brand.

Thanks for the valuable information, Mika, my Pentas have a serial nr 06398839, does that "0" make them old?. I guess only B&O can give me the production year based on the serial nr, right?

If you're right about the filters using the same type as the PentaLabs, then my speakers should have been made between 1989 and 1992.

Having never heard Pentas before, I don't know if mine sound like Pentas or like old speakers..I owned Lab 4000,8000,3,4 and 2500, and all I can say is that the Penta sound is clearly delivering massive bass compared to all the others, but the midrange lacks realism/presence, and the treble lacks ..treblebut that seems a common remark about the Pentas, I had to set the treble level to +3 on my BeoCenter 2.

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I guess only B&O would know for sure, but here's one thread mapping serial numbers to year of production. That would date your pair to 1989, which would appear to make sense

The Pentas aren't overly bright, that's for sure. Tired caps will exaggerate that, and I believe you would benefit from a cap replacement or upgrade - if the above holds, they are 22 years old now.

You have probably noticed already that the Pentas are quite directional vertically (I think because of the midrange arrangement) - you'll need to sit down to enjoy them! And in the 'voxes the drivers are lower still because of the missing amp.

One property of the Pentas I particularly like is that they sound full at low volume. You can easily enjoy them at levels where most other speakers would have you reaching for either volume up or loudness on; nice for an apartment...

tournedos:

One property of the Pentas I particularly like is that they sound full at low volume. You can easily enjoy them at levels where most other speakers would have you reaching for either volume up or loudness on; nice for an apartment...

That is a nice property to have!  Are the passive Pentas easily driven by a BM2400 or BM1900?

Rich:

That is a nice property to have!  Are the passive Pentas easily driven by a BM2400 or BM1900?

I don't have either; but they sounded fine connected to my Dirigent

tournedos:

Rich:

That is a nice property to have!  Are the passive Pentas easily driven by a BM2400 or BM1900?

I don't have either; but they sounded fine connected to my Dirigent

 

Indeed, the Pentas' efficiency makes them ideal in my setup, you don't have to push the volume too high to enjoy them!

I paired them with a Rotel RB1510, which has the same ICE Power amps as those in the BeoLab 3, and the sound is excellent, no noise at all, like on the Lab 8000 for instance.

My Pentas make a "wall of sound", it's not really 3-dimensional like the Lab 3, but you feel the power in them.

I read in a user guide that they needed at least 3m separation to excell, and since I only have 2.2 m to give them, they can't make miracles. I'll try to find a solution to improve their stereo imaging.

The downside, unlike the newer BeoLabs, is that you think & operate like "normal hi-fi" freaks, finding the right placement, speaker cables, connectors and amplifier for them, and I thank B&O for making our lives easier with BeoLabs and ABL/ABC + "free-wall-corner" settings