M100-2 crossover capacitor values

[TheFinisher]

Hi guys ,

had a little bit of time this weekend to check over my M100-2’s speakers, the previous owner did mention that he had recapped the crossover ( and maybe the coils )

now I have a concern as none of the capacitors on the crossover match a schematic that I have , which do I trust ?
does anyone have a photo of their crossover please?

 

[TheFinisher]

Update!
now I’m even more confused as I count 11 capacitors on my crossovers but there are 16 according to the schematic

[Glitch]

It looks to me that there are 10 bipolar capacitors on the schematic and “10” on the actual crossover board. I’m assuming that the two capacitors to the right left of the “50” on the board are wired in parallel and should be counted as one.

The other caps are (likely) the white boxes, yellow components and the electrolytic on the bottom of the board.

Glitch

 

[TheFinisher]

Hi Glitch , thanks for the reply. There are 2 soldered together to left of the 50 , thing is none of them match the values of those on the schematic.

[Glitch]

The former owner may not have been able to find the exact values and substituted the next closest values.  Piggybacking the capacitors in parallel is one way of getting a value closer to the original.

Post a table of the installed values versus the schematic values. This will make it easier for those that want to help to give better advice.

Glitch

 

[TheFinisher]

I’ll do that thanks

[TheFinisher]

So it would appear that you are correct.

is it ok to do so ?
they do sound very good , I mean end game speakers.

Surely the wrong values will have some effect on their performance?

Schematic               Capacitors currently installed

C2 16uf                     2x 8.2uf

C3 50uf                     47uf

C4 5uf                        4.7uf

C5 8uf                        8.2uf

C6 50uf                      47uf

C7 16uf                       15uf

C8 8uf                         8.2uf

C9 12uf                        15uf

C10 50uf                     47uf

C11 4uf                        4.7uf

 

[premiumverum]

This is fine. The original caps have values that are not available anymore. Tolerances on these 1970s caps were +/-10% probably so e.g. 47uF instead of 50uF is close enough. Everything the previous owner installed is within spec.

Proof of the pudding is in the eating, as you said they sound very good. Close em up and start enjoying!

[TheFinisher]

Done just that , and saved over £100 by not replacing ?

 

Thanks

[Glitch]

premiumverum wrote:

The original caps have values that are not available anymore.

This is not completely true. A quick check of part-express.com will show that you can still buy capacitors that are marked the same as the original caps. One would have to measure the caps that were received to be sure.

There are a few other manufacturers of higher end caps that would likely have the original values (but you might have to wait a while for them to come into stock). The tolerances on these caps are very close to design, but are much more expensive.

In many of the other capacitor brands or product lines they will only make the values similar to what you have in your crossover.

I generally agree with premiumverum about the tolerances (assuming that the original caps were +-20% parts) and the sound.

I’d leave them alone if you like how they sound. Unless of course, that you like tinkering with things as much as listening to music.

Glitch

[AdamS]

Normally I’d have said all you need to do if you have any concerns over the caps in your M100-2s, or their performance, would be to head to Beoparts and buy the correct capacitor kit for them.

However, Martin doesn’t appear to do one for them that I can see.

 

 

[Evan]

TheFinisher wrote:

they do sound very good , I mean end game speakers.

You’re making me want a pair of M100s even more. Why do you tease us!!

[TheFinisher]

I did enquire some months ago and they can supply with the replacement caps .

[TheFinisher]

Well if you’re ever passing MK you’re more than welcome to have a listen.

[TheFinisher]

I do wonder how these would compare to the legendary Tandberg studio monitors

[ajames]

I bought the kit from Martin a couple of years ago and they transformed my M100-2’s – he boards when I had finished looked similar to the ones in the photo here and I had to double up some capacitors. I managed it with Martins instructions.

Congratulations on your speakers – I love mine, they are superb.

[TheFinisher]

I agree, fantastic speakers.

[Author]

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