I'm sure you will find that most signal path caps are still fine, strange as it may sound.
If you will have to replace some, I would suggest mounting electrolytics again.
The ones most prone to failure are the three large cans (Power supply and the speaker outputs).
Note the polarity of the power supply cap, the Beomaster 1000 has positive ground !

Martin

Thanks Martin

The power supply cap appears to be bad and I suspect the 2 outputs also.

I have noticed this unit has more axial electrolytics than most.Some in the PS and quite a few in the MPX section.These all appear to be very bad,having obvious blow-out at the ends.Can't wait to hear this thing with some good caps in it.

Paul

Hi,

I can confirm what Martin says, electrolytics on the signal path are fine. I changed my BM 6000 caps with identical types (not Chinese ones though!) and the sound is perfect. Blind tests have shown little or no difference in sound quality when you install "better" caps. I tried polyprops in the phono stage but reverted to original caps, because I couldn't hear the difference, and I have a looong experience in hi-fi, believe me, having tested transistor and valve. When you spend money on expensive components your brain tells you they are better, but are they? Methinks this is a placebo effect. 

Jacques

Thanks Jacques

It is nice to hear some voices of reason on this subject.Glad to hear it,the polyesters are a bit hard on the wallet.I have heard much about the "evils" of electrolytics in the signal path,especially tantalums.I was always a bit skeptical,considering some fine sounding B&O gear is loaded with normal electros and tantalums.I do believe in the value of a good quality cap though,for longevity,if nothing else.My main concern at the moment,is that I heard the tantalums tend not to just slowly wear out but actually explode unexpectedly.Any thruth to this?

Paul

Well I wouldn't know really. I have 70s ReVox and B&O gear still running on their original tantalums... I think engineers knew what they were doing. It would be very presumptuous to question their choices, wouldn't it? Some do get noisy though.

Anyway I have never seen exploded ones so far. But I'm sure someone more experienced like Martin or Tim Jarman would enjoy telling us such stories!

Well, obviously, if you can see (or measure) that they are bad, you should of course replace them.
Leaks and blow-outs are clear signs that they would like to be replaced.
I would mount new electrolytics rather than polyesters.

The large power supply filter capacitor CAN explode and it's a terrific experience.  😂

Martin

Oh yes, we had fun (?) making reservoir caps or diodes explode when I was a student! Yellow papery substance everywhere! How stupid we were then... But this kind of experimentation learns a thing or two, doesn't it?😂 And I guess trying that with tantalum would be nice too!!

Jacques

I have seen several exploded tantalum caps in old computer boards and some very old Telefunken / Philips Tape machines.

Tantalum explodes like a firecracker und burns like a candle, leaving only two burnt wires on the board... but all these were used in power supplies, not in the signal path. In the signal path there is not enough power available to burn.

Tanatlum has pretty bad acustic characteristics. If you replace them by MKT/MKS types, the sound will change a lot. The old fashioned sound will get lost to a more clearer sound. It will sound more modern.

I would not change every electrolyth caps to a MKT type, it's way to expensive and in most cases not necessary. There is no sense to replace them in a power supply, only if it becomes really hot the MKT will extend lifetime.

I have replaced a few tantalums that basically had turned into smallish value resistors. I guess these were those that would've exploded if they had been power supply filters/bypasses - never seen that happen, though.