Hi!

I have bought myself a Beosystem 7000 and are now looking for some Beolab Penta's to go with it.

There's one pair for sale here, but they have some cosmetic damage... The seller sent me some pictures:

The seller says that it isn't noticeable, but it looks to me like the one on the base is quite visible (and quite irritating).

I have never seen a pair of Pentas in the flesh, so I don't know what the base is made of or whether it's exchangeable...

What do you experienced guys say? Is it fixable? Does the flash emphasize it or will I be annoyed every time I look at them?

Thank you!

The base is metal covered with plastic of some sort.
It may be possible to polish the scratch away, or at least make it less obvious.
It depends on the depth of the scratch.
It may also be possible to find a replacement bottom plate from a donor somewhere.

Martin

If that mark is their only problem then you should live with it. There are not many, if any, mint pairs around by now and how many of those are in Norway????

You can possibly still buy replacements from B&O!!

joeyboygolf:

If that mark is their only problem then you should live with it.

I agree with that... the surface of the pedestal is soft, and as they live practically on the floor, they collect the heaviest, most abrasive dust. Thus they are very easily scratched by normal cleaning, you can't just go and wipe them clean without blowing the dust off in advance!

You might be able to fade the large scratch a bit by polishing, but risk getting the surround of it all milky in the process and then it'll look much worse.

Thanks for the insight! I bought the speakers and they arrived today - the scratch is much less visible in real life than in the photos!

One of the top panels got a dent in transit though, but that's life I guess...



BUT! One of the amps makes a bzzzzzing noise when turned on. It's not there when the amp is cold - it comes on after a few hours of playing, but the amp doesn't get particularly hot (the other amp seems hotter)... What could that be?

Not cheap postage but as luck would have it there's a PENTA FOOTPLATE on ebay US as we speak.

I agree with graham - I could easily live with it as is.

Not sure what's causing the buzzing though. It could be the transformer plates vibrating which isn't unusual in older equipment.

Chris.

mhw:

One of the top panels got a dent in transit though, but that's life I guess...

You can still order these from your B&O dealer

Thank you very much! I have ordered a new top panel (or I think so, these B&O dealers aren't very fast to respond to emails!).

One more quick question; I think the MMC2 on my Beogram 7000 have seen better days. When it's at its recommended stylus pressure, I have to have my finger on it for the sound to be good. When I turn up the stylus pressure it is enough for me to just touch it once and the sounds becomes good. I'm guessing it's time for a trip to Axel at Schallplattennadeln?

I will surely come back with more questions later when I have more time, because the bzzzing is very annoying when playing movies or listening to quiet music and the speakers "pop" when I turn off the lights in another room!

I think you should get those pentas recapped and readjusted! I remember seeing pictures here of a near exploded penta amp power supply that had a buzz and the owner had just kept using it. Your buzz and the pop when you use the light might indicate a PSU running on its last bit of legs. Maybe Dillen can supply a capacitor kit?

A recap will improve sound too by the way, especially if you do some mods that are suggested here (search for penta high end or something)

http://forum.beoworld.org/forums/p/14509/111394.aspx

Yep; typical suspension degradation problem.  Either Axel or Sound-Smith can rebuild it, with Axel being less costly.

Premiumverum:

I think you should get those pentas recapped and readjusted! I remember seeing pictures here of a near exploded penta amp power supply that had a buzz and the owner had just kept using it. Your buzz and the pop when you use the light might indicate a PSU running on its last bit of legs. Maybe Dillen can supply a capacitor kit?

A recap will improve sound too by the way, especially if you do some mods that are suggested here (search for penta high end or something)

http://forum.beoworld.org/forums/p/14509/111394.aspx

 Thought that was more like a hum than a buzz? And the amp doesn't get very warm... But I guess it's a good idea non the less - I will contact Dillen! Thanks!

And thanks to you too mediabobny - I will send it to Axel!

mhw:

 Thought that was more like a hum than a buzz? And the amp doesn't get very warm...

That is true of course, but the pop when switching lights made me think the PSU capacitors don't have a lot of reserve left. Anyway, a recap is never a bad idea, how old are the pentas?

Another possibility: a bad solder joint or connection somewhere that starts acting up when the amp gets hot. Bad joints are pretty common in pentas I believe!

Maybe Dillen can shine his light on this case?

Premiumverum:

mhw:

 Thought that was more like a hum than a buzz? And the amp doesn't get very warm...

That is true of course, but the pop when switching lights made me think the PSU capacitors don't have a lot of reserve left. Anyway, a recap is never a bad idea, how old are the pentas?

Another possibility: a bad solder joint or connection somewhere that starts acting up when the amp gets hot. Bad joints are pretty common in pentas I believe!

Maybe Dillen can shine his light on this case?

I was hoping he would

They're from 1998, so not the oldes pair around...

Capacitors, yes.
The Pentas are not as old as most other B&O's with capacitor problems but the
majority of capacitors used in the Pentas are 85deg types and since they work in a
warm environment, they don't last very long.
The available capacitor kits contains 105deg capacitors with a slightly higher voltage
rating in selected areas (power supply) so should last a lot longer.
The kit also contains the upgrade (originally suggested by Die_Bogener), consisting of WIMA MKS-2
foil caps and Burr-Brown Opamps in the preamplifier signal paths.

The best places to find cracked solder joints in the Penta amplifier is at the
driver transistors and the long row of solder joints at the front, next to the front panel connector
(I don't remember what it connects to).

Martin

Another thing is that not all link cables are equally good.
Some cables will introduce a background buzzing from the speaker.
Often, the amplifier (which works at full volume all the time) will also produce a buzz
if no signal cable is attached.
If in doubt, pull out the signal (link-)cables and insert an RCA plug that you can short.
If the buzzing disappears when the RCA plug is shorted, the problem is not in the amplifier.

Martin

My Penas had new caps and the update Martin mentioned. Both of the speakers have a faint buzz when they are on. The distance to the listening place is about 2m and I can hear the buzz there (very faint and easily lost in music but still) - is this normal or is there still something funny going on? The cables I got with the speakers, they are self-made but look-and-feel pretty solid, I checked the solderings on both ends. Source is my Beocenter 9000. Perhaps I should try the RCA-shorting -trick to see what happens.

Also one of the speakers makes an audible pop when it switches off, the other one doesn't. 

I'm pretty certain that the buzzing is from the amp itself, and not the speaker elements... And it's still there in LINE mode!

I will check if the thump from the lights are still there in LINE mode tonight!

Finally checked it out some more tonight: The thump from the lights is not there when the speakers are in LINE mode (and switched on), BUT when I connect some chep computers speakers to the Beomasters headphone socket they make the same noise... Sounds like the Beomaster may need some work too!

Just an temporary update if somebody finds this thread in search of help with similar problems:

The MMC came back from Axel working as it should and is now sounding very good!

The Penta amps came back from the shop today, after a full recap (Martin's kit) and supposedly re-soldering any bad solder joints. They sound very good! But it did not fix the buzzing problem - it's still there, maybe a little quieter, but still annoying.

The thump is still there, and seems to get louder if I have more stuff plugged in to the Beomaster (with only one speaker and my iPhone plugged in, it's barely audible, but with all the other stuff plugged in it's quite loud).

I will report back when/if I find out more!

Very good!

The thump seems to be coming from the beomaster, have you had that recapped/serviced too?

Just went over all the replies again, concerning the buzzing: have you already checked it is not from the cable, by swapping the powerlink from the left and right speaker?

Thank you very much for the help!

The Beomaster have not been serviced, so it's probably something dodgy there. It pops when I turn it on from cold aswell, so I guess it's about time to have it serviced!

About the Penta: It's definitely not the cable; I plugged it out and tried with a line source, and it's still there. It reminds me of the sound from high voltage lines and it's coming from the amp itself, so my guess is the transformer... I will bring it to the shop tomorrow!