General Forum

Re: Penta High End! A project

Bulgarien — Tue, 15 Nov 2011 09:38:04 GMT

Thank for your help and replay to my tread

Your description of the NEW SOUND i our Penta is fantastic. Specially the treble is a weak point in the Penta and Im but glad to hear that new cap fixed that problem.

Re: Penta High End! A project

tournedos — Sat, 12 Nov 2011 06:24:44 GMT

Well done and glad you like the results! It is sometimes hard to convince people that replacing 15+ years old crossover caps in complex speakers like the Pentas WILL make a difference audible to anybody, while tweaking things like interconnects is mostly just that, tweaking...

The treble level is obviously a very personal taste; I was happy with mine the way they were designed. Did you read the other thread where Die_Bogener described his mods? I think it was either shorting a resistor or altering a cap, but in any case you can make them brighter if you'd rather keep the Beocenter at +/-0

Re: Penta High End! A project

Chrisreunion — Sat, 12 Nov 2011 04:12:58 GMT

I'm digging out this thread to say that after one year with my PentaVox speakers, I decided to follow other members' advice & replaced all capacitors on midrange & bass-treble filters, with :

Mundorf electrolytics 68 uF/100 VDC (none was available in 400 V to match the original dimensions)

Audyn Cap MKP polyprop. 5,6 uF/400V

Jantzen Cross cap MKP 8,2 uF/400V

Jantzen Cross cap MKP 22 uF/400V

Jantzen Cross cap MKP 27 uF/400 V

Although they were all larger/bulkier than the originals, I managed to solder them all on the boards, and after the first 10 minutes, playing music with the new caps, the 3 of us in the room were in awe...That cost me EUR 75 for the caps, and was worth every cent!

The Pentas sound alive again, the treble level adjusted to +3 on my BeoCenter 2 went down to +2 (I didn't replace the original tweeter, but admit that if set to 0, the treble sounds like the original Penta of course, which means " a little bit behind" the rest of the range).

The "new" sound is really full, my speakers are 3.6 m apart from each other, and there is a real wall of sound, the bass is still impressive, but now the mids are lifelike, and treble are..treble!

The most impressive change was in the stage that is no longer "left/center/right", but much more "far left, left, mid-left,center,mid-right, right and far right" when you're playing good recordings & classical music. So I can only highly recommend this cap upgrade, especially on the Pentavoxes & Mk 1 BeoLabs of course.

Now that the mids have been refoamed, back connectors soldered with silver, all caps replaced, what's left to do technically speaking? Replace the treble unit? Or simply adjust the treble level on the BeoCenter/Sound like I'm doing now?

My next step for the final touch will be cosmetic: I need to replace the frets! They are 25 years old, after all!

Re: Penta High End! A project

Bulgarien — Mon, 09 Aug 2010 08:43:50 GMT

Thanks. A modern tweeter will be my next shot :-)

http://www.impactaudio.co.uk/product.asp?ref=546

Visaton DSM25FFL

Uploaded with ImageShack.us

Re: Penta High End! A project

Chasepoes — Sun, 08 Aug 2010 18:00:56 GMT

Chrisreunion:

Chasepoes, have you done any mod to the treble filter section after replacing the tweeter itself?

[...]

Yes I have. I've shorted a resisitor (I think it was R3, have to check that) It's the only resistor in the high-section that is placed in series with the tweeter. This brightens the overall sound of the Penta (Even with the original tweeter).

Have now placed a Visaton DSM25FFL tweeter in my Penta's and it sounds great. Mounting it is very easy. Just remove the frontplate from the Visaton unit and use the screws from the original tweeter to fasten the membrane...Put it in and voila!: A set of Penta's with a metaldome tweeter!

Re: Penta High End! A project

Chrisreunion — Sun, 08 Aug 2010 08:07:11 GMT

Chasepoes, have you done any mod to the treble filter section after replacing the tweeter itself?

I soldered the mid & treble driver wires/connectors with silver, and as mentionned before, couldn't hear any difference. My technician friend replaced the bottom speaker cable connectors with gold platted connectors, and I could'nt hear any difference either..

Re: Penta High End! A project

tournedos — Tue, 27 Jul 2010 03:17:58 GMT

I'd start with recapping the crossovers before thinking about the tweeters (or anything else for that matter). I didn't see / hear any need of further modifications after that.

Re: Penta High End! A project

Chrisreunion — Tue, 27 Jul 2010 03:04:23 GMT

Wow, thanks for the info on the tweeters, I simply adjusted the treble level on my BeoCenter 9000 as the linear treble response was quite ...poor, especially compared to the bass response of the Pentas. I'm going to have a look at the specs of the tweeter you chose, being no technician, I haven't touched anything in the filters yet.

Keep renovating ...

Re: Penta High End! A project

Chasepoes — Mon, 26 Jul 2010 16:27:35 GMT

What I do know for sure is that if you order a new driver from B&O, you get a HEAS unit.

I'm currently in the proces of fitting a pair of high quality metal-dome tweeters in the Penta's, which is surprisingly easy. I'm now calculating the modifications I have to make to the cross-over. So far (no mods to the filter) the high's are much more detailed and brighter. Putting the Penta's in a very different playing field.. The tweeters I'm using are a pair of Visaton DSM25FFL's.

Keep you posted!

Re: Penta High End! A project

Chasepoes — Mon, 19 Jul 2010 17:40:11 GMT

As far as I know, the original OEM manufacturer used to be HEAS. My Penta's have unit's with exactly the same label on the back. It's identical in every aspect, except for the brand name, which is ITT in my case.

Re: Penta High End! A project

tournedos — Mon, 19 Jul 2010 11:05:12 GMT

As "Made in Western Germany" hints, they must be pre-1991, and "4086" means probably week 40 in 1986.

Nokia used to own TV factories in Germany as well before concentrating on mobile phones, and this "SEL" speaker factory might have been something Nokia bought out at some time, and the name was changed. Anyway it was probably just an OEM product made to B&O's specs and it might have been manufactured by several sources.

Re: Penta High End! A project

Chrisreunion — Mon, 19 Jul 2010 10:14:58 GMT

Someone in the first messages on this post showed pictures of the "original" Nokia midrange drivers, and guess what? Mine are not Nokias!

They were made by a German company called SEL, I couldn't find any info about them on the net..see for yourself:

Re: Penta High End! A project

Chrisreunion — Thu, 15 Jul 2010 07:07:43 GMT

Well, I've just completed refoaming one of the Pentas, didn't expect it to be so easy, once you know what to do and where to glue, it's like making pancakes, only the first one is a mess, then the others are great!

The sound improvement is obviously noticeable, now I'm going to silver solder the filter wires and keep working on these beauties..Just finished cleaning the frets as well, now they start looking great!

Re: Penta High End! A project

Chrisreunion — Tue, 13 Jul 2010 14:45:37 GMT

Hi, I've just received the new rubber rings by mail today, so tomorrow being a bank holiday in France, I'll start refoaming the midrange drivers and hopefully at the end of the day I'll discover a better "Penta sound"

Re: Penta High End! A project

Chasepoes — Mon, 12 Jul 2010 15:38:35 GMT

tournedos:

resistance between different connectors is not constant. I'm not claiming that would be audible either, measurable just perhaps...

Ok. I thought the soldering was done to improve the sound. Simply disconnecting and reconnecting them again will make them have perfect contact again.

tournedos:

But the Penta displays need power to work. It will not come over Powerlink, you have to supply it from somewhere else if the Penta amp is left out of the equation. So not quite as simple as "hooking them up".

Your right. I just thought that the previous poster intended to mount some Beolab 200's. The auxilary power is not necessary in that setup.