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I always thought electrolitic should not be used in speakers. I have just opened my S80 and there are 5 capacitors all original the 22mfd and 33mfd at first looked to be electrolitcs and all original. The printing is very faded and in the crimped / grouve end the I can just about make out Bipolar ( B p ar ) actualy. I can now understand how someone made the mistake when he recaped a Beovox on another thread recently. These are the yelow / orange ones and look identical to the Electrolitics that were used in 1980s Beocenters ect.
John.
Your S80 should have more than 5. My M70s had 10 before I replaced them with Solen polypropylene.
I have never found any red or orange caps in any of my crossovers, always gray bipolar.
The S80 should have 3 pcs. 6.8 uF, 1 pcs. 15 uF, 1 pcs. 33 uF, you can download the service manual if you sign up as a silver or gold member.
Or order a set of caps from Martin (Dillen) on this forum. If you order from Martin give him speaker type and serial number, there may be differences.
Collecting Vintage B&O is not a hobby, its a lifestyle.
S80 has only five capacitors and they are all bipolar electrolytics as in most factory made speakers, apart from smallish, typically < 4,7 µF values.
The values are 3 x 6.8µ, 15µ and 33µ. You should be able to tell which is which simply from their physical size. The full service manual is available on site for silver/gold members, though, but still doesn't show component placement. Use caps rated to at least 63V if you replace them (which I very much recommend, but regular fresh bipolar electrolytics will be fine).
EDIT: Søren's recommendation is very much valid
--mika
What am I thinking of? The S75?
Rich: What am I thinking of? The S75?
Once in a while it just clicks to the wrong side
Several of my Beovox's have a gold color. Here is the before (top) and after (bottom) recap picture of one my MS150 crossovers (new caps via dillen). My S55 speakers also had gold color electrolytic caps. Note that there is one of the reddish-brown polarized electrolytics on the protection circuit...that one is like some of the Beomasters.
-sonavor
Warning - thread hijack.
Why the need for the protection circuitry on the later (and larger) Beovox? Was this "idiot-proofing" on B&O's part? Can it be bypassed (or defeated) if desired? Does it affect sound quality?
Inquiring minds want to know.
Small amplifiers distort easy.Distorted signals contain a lot of harmonics (high pitch doubles and quads etc. of the original frequencies) witha lot of energy.If not protected, this will pass through the filters and burn the tweeters.
Ideally smaller speakers should also have protection but if you look at the circuits involved it can't really be justified.
No, it doesn't affect sound quality. In most cases, it merely activates a relay when needed.
Martin
Dillen: Small amplifiers distort easy.Distorted signals contain a lot of harmonics (high pitch doubles and quads etc. of the original frequencies) witha lot of energy.If not protected, this will pass through the filters and burn the tweeters. Ideally smaller speakers should also have protection but if you look at the circuits involved it can't really be justified. No, it doesn't affect sound quality. In most cases, it merely activates a relay when needed. Martin
I actually had to do an experiment back in college where we graphed a clipping amplifier (gain vs input voltage) and then measured the distortion. Overdriving underpowered amplifiers is the death of tweeters, for sure. Just wondered why B&O made the business decision to add the cost to their products.
On a semi-related note, I own many an NAD receiver (and one amplifier) with "soft clipping" circuitry.
Rich:Why the need for the protection circuitry on the later (and larger) Beovox?
From the amount of burnt crossovers we have seen on the forum, many people seemingly like to play loud & long enough to create a need!
Purists would probably cringe at the protection circuits, because it usually means that at least the tweeter feed is going through an extra relay contact (or even because the speaker uses some of the incoming audio energy to power up the sense circuit). Shouldn't matter anything in practice, but the contacts can oxidize enough to audibly ruin the sound.
You could of course easily bypass the relay (and disconnect the sense circuitry), but you'll be sorry you did if you eventually manage to burn a driver. The protection isn't fool proof though, so it can be done with the circuitry still in operation as well