Hello everyone,

I have just purchased a mint Beomaster 6000 with remote, manual, box, even original invoice !

It was fully revised in 2004 by a B&O center, and it works nicely.

The only thing is that the volume is a bit spitty in operation. Should I consider:

-a defective electrolytic (which I know by experience produces this, but what about the BM 6000, and where?),

-a bad pot (rare enough)?

What else should I know?

Thanks in advance.

The volume control potentiometer is operated by a motor via a belt!

Search the forum and you should find suggestions. Apparently a new belt is really hard to come by, but people have fixed this by cutting ~5mm off the old one and supergluing it back together. Just cleaning the old belt and pulleys with isopropanol might be enough as well. Lubrication of the pot could help.

Hi Chartz,

Good choice... I love my 6000!

Had the same issue with the volume, drove me a bit crazy for a while always getting jammed, not able to go higher and sometimes lower... Mika is right I fixed mine with the isopropanol now works a dream... just take the belt off the pully the clean with the isopropanol and its done... i would try this first.

Can look at this thread which covers both the options Mika suggest.

http://forum.beoworld.org/forums/p/25762/198693.aspx#198693

Good Luck.

Laurence.

Thank you, Laurence and Mika.

How would you qualify the BM 6000 sound?

My problem is the pot cracks, like a grinding or static noise in the speakers, as if it lost contact or some DC is passing through.

The belt is not the problem. How do I clean the pot if it comes to that?

I recently sold my Beomaster 6000 under duress, as I moved somewhere smaller and could not find a place for it as I kept my Beomaster 8000. The sound is clean, bright, detailed and very easy to listen to. I used mine briefly with a CDX, BG8002, BC8004 and either some MC120.2s or some Beovox Pentas. It was a great amp in this set up, and if I had chance to own one again I would, but the 8000 would always shade it for me and as they look so similar, I doubt I'll ever have chance to squeeze one into my collection again.

I'm sure you'll be happy with yours :)

I have problems hearing one amp from another... but it sure isn't supposed to sound like cracking & grinding

Looks like removing and reinstalling the pot would be a bit of work, not to mention dismantling it for cleaning. I'm not a big believer in contact spray but I'd try it first - if the pot started crackling from lack of use, it might be enough to fix it for a long time. Don't overdo it.

Yes, thanks. This is what Martin recommends too. What product shoudl I use then? Not WD40 I guess :-)

No, preferrably not WD-40. It's great for polishing the valve covers of a V-8, though

I once heard a long time service guy telling that he never uses anything but LPS-1 on potentiometers, but it looks more like the WD-40 category to me...

I use Kontakt 61 myself. It should have the nice property of not leaving conductive piles of gunk behind it after the volatile ingredients have gone.

Thanks Mika. What's the difference between Kontakt 60 and 61?

Should I use both respectively, or then just 61?

They are promptly available everywhere, but I can't make up my mind.

The manufacturer says  60 cleans electric contacts and remove oxidization, and  61 is supposed to keep them lubricated and conductive.

Jacques

I suppose the general idea is to use both, but plain 61 has worked for me... (according to the safety information, half of it is isopropanol and it also contains naphta, so it will dissolve as well). Anyway, for potentiometers and sliding switches you will want some lubricants to be left behind, and that's the 61 and similar products.

Right. I shall of course keep you informed.

Hello,

My Beomaster 6000 from 1982 is in mint condition and was serviced by B&O in 2004.

After extensive listening tests, here are my humble conclusions.

I compared it to my all valve set-up (Le Tube, Ampliton TS 3000/6CA7), a Luxman LV-111 (nothing special) and a Revox A76 for the tuner section. Beogram CD 3300 and Pioneer DV-717. Beogram 6006, new SMMC20EN.

Speakers were Arcam One.

The sound of the Beomaster 6000 is laid back with much less treble detail and finesse than my usual valve set-up displays. Image depth is a bit disappointing too, because I am used to the deep, deep and large scene my usual system provides for. It is a bit flat, two-dimensional by comparison.

Bass is lightweight, and my 20 watt valve amp seems to have more power reserve than this.

The tuner section is almost as good as the Revox, a bit less sensitive maybe (with a simple dipole aerial), which is a good surprise, notwithstanding the above-mentioned reservations as to flatness of image.

Lots of people look up to this Beomaster. It is very nice to listen to, don't get me wrong, but I feel it's nothing to write home about. One man's opinion then (but 30 years of hi-fi passion!).

Grab a cap kit and replace the lot ...

Martin

Tell me more please!

Is it a matter of changing all these 2,2 μF electrolytics  (10 caps) in the preamp (RIAA, tone adj.) circuit?

Circuit n°3 seems a pain to get out!

It's the electrolytic capacitors in general.
The ones in the preamp, obviously, but also in the amplifier section and power supply.
I am not saying that it will make it sound better then the ones you compare it to but it has been a long
time since the last time I saw a Beomaster (of any type, really) with good original caps and many owners
are surprised after a recap.

Martin

Funny, that. The sound is really okay today, yesterday it was cloudy and lacking in the treble area.

Any clues to why it's so temperamental? My ears? Atmospheric pressure?

THE CAPS?

Hello,

Now the sound has settled for good. Was it not optimal because it wasn't used for a long time?

Is this the sign of half-bad passive components?

Thanks for your thoughts...

The insulating barrier in electrolytic caps is a thin oxide layer that builds on one of the metal plates from the electrolyte once a correct polarity voltage is applied. If the caps stay non-used for a long time, the oxide layer gets thinner and thinner, compromising the insulation properties between the capacitor plates (you can still think plates, even though they for obvious reasons have been rolled up in most modern caps )

Therefore a neglected capacitor can leak an amount of DC current through until the insulating oxide layer has reformed. This can lead to rectifiers blowing and other damage in very old equipment that has sat unused - reforming the oxide should then be done in a controlled way. This mostly concerns equipment that may have been in the attic for decades. Your Beomaster probably got past this danger the moment you first plugged it in and the power supply filter caps got charged.

But anyway, it is quite possible that this same phenomenon affects the audible qualities of caps that are not related to the power supply, and they will take longer to reform since the energy levels they pass are so low. The more complex B&O receivers usually have a silly number of electrolytic capacitors directly on the signal path. It really might improve after some use.

However, the normal aging of capacitors that leads to increased ESR (higher impedance in higher frequencies) is a different, non-reversible process - it will not sound like new until those caps that directly affect the sound have been replaced with new ones that perform to original specs (or better).

Thank you Mika. I'm inquiring about Black Gates at the moment. An American company called Sonic Craft appears to have some in stock. I have a whole stock of new but plain capacitors, but I'm worried they'd badly affect the sound. In the past I have always replaced electrolytics with plastic types for the sake of good sound, but there is no room in the Beomaster to do that!

Would anyone have the instructions to remove PCB n°3? There is nothing in the service manual and it seems quite complex.

I know I will get it when Dillen sends me the cap kit, but I'd like to study it in the meantime. Thank you in advance!

Beware of snake oil...

I have recapped many B&O and as long as you use low ESR 105 degree C capacitors you will be fine.  For coupling capacitors of value 4.7uF and below you can also opt for WIMA non electrolytic capacitors.  I tried these when I replaced the tantalums in a BM3400 quad (user mahnem recommended) and I think you can hear the difference; it somehow appears a cleaner sound.

Just my 2 euro cents worth...

Thanks. I know what snake oil is, believe me. I normally use Wima or Ero caps wherever (more than whenever!) possible, especially with valves.

With everybody just telling me the Black Gates are great, including audio mags, I am possibly wrongly biased. If Martin and yourself tell me they won't make any—or little—difference on B&O gear, well that's enough for me.

Now the Beomaster has settled down and it really sounds great, albeit I find bass a bit lightweight (zero setting): could it be a problem in the tone circuit?  The rest of the audio band is very sweet, treble is amazingly delicate and clear. So much so that I wonder if a recap is still necessary. I need your unbiased opinion.

By the way I have built and repaired audio and video equipment (transistor and valve) for 30 years now. But apart from a great Beovision 8800 in the 80's this is my first B&O equipment.

By the way, spraying the volume pot (I used Bardahl) has worked nicely. No more annoying noise.

Thanks for the tip!

From experience, I can't tell the difference between fancy Black Gates and Panasonic FM, FC, or Nichicon KT's.

I must add that I am over 50, and my hearing may have been slightly damaged from over 20 years of flying noisy aeroplanes, so maybe I am not a good candidate for BlackGates!!!

(I'm not knocking BlackGates, Oscons or any of the other high-end caps, but they are just not widely available, and more expensive)

But I pass my hearing test every year, so I guess that I can still appreciate good sound.

My standard applications, as RichToy stated, are Wima MKS2's for 4.7uf and lower - credit must go to Martin Schmitt (die Bogener) for introducing me to these.

For 105degree caps above 10uF - in the signal path, I use Panasonic FM or Nichicon KT, and in the power supply, Panasonic FC or Nichicon HE.

For the big Power Cans, Panasonic TSHA.

The reason for my choices are simple - firstly - widely available and inexpensive from Mouser and Digikey; secondly - although I really like the FM, it is an aqueous cap, and less stable in circuits which heat up (even though they're 105 rated) - ie power supply, so I keep them for low-power signal path. The FC and HE are non-aqueous, so they are perfectly suited for power circuits which heat up. The KT is Nichicon's new 105 Audio cap - really nice.

If you use these types, you will be more than satisfied with the clarity and musicality in the sound. Of course, there are many more caps on the market, these are just my choices, using them for many years, and just being good-old plain satisfied, so I keep coming back for more!

I regularly show off my restored BM3400 with 4 BV S45's, and nobody can believe the sound-quality which comes out of it, but to be fair, it has been highly modified beyond a simple cap swap. I still love to see all these modern fancy digital boys' jaws drop, when they hear the sound.

Menahem

Hi everyone,

I've now finished re-capping and testing the Beomaster 6000. I used Elna Silmic (genuines!) and Nichicon Muse throughout.

The printed tracks are so fragile though!

Everything works great, the sound is superb. The most significant gains were in the bass department in in treble clearness and information retrieval.

It is now my main amp! I use it with a Beogram 8000, a CD 3300, and a newly fixed (thanks Jeff, IOU) Beocord 6000 which is surprisingly brilliant!

But I have to say the difference isn't night and day. The old Philips caps had all held their values, and so had, against all odds,  the red ROE ones! They really were quality items, as used by Revox for instance. But then my BM had seen little use I suppose ;-)

It's true: the 6000 is quite an amp, and I've heard so, so many in the last 30 years! Even the so-difficult-to-design RIAA preamp surprises me! The only thing it lacks is a "tone defeat" switch (as per BM 4400). How would it then sound?

Hi Chartz,

To check if an electrolytic capacitor is OK, the primary and most reliable method is ESR (Equivalent Series Resistance), not Capacitance. 99.9% (this is my very subjective number here ;-) of defective electrolytics still show acceptable capacitance, but if you were to check them again with an ESR meter, you'd confirm that they are all ready for the trash-can.

B&O's old Philips and ROE caps from that era are NOTORIOUS for being wholesalely useless after 30-odd years, in fact, I don't know any manufacturer's caps which would still be good after 30 years.

Menahem