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Realistic Minimus-7W Crossover capacitor

H

Hifibythekg

Super Member
Hi.
I have a pair of Realistic Minimus 7’s, walnut veneer, model no:‘40-2039B’

(Currently powered by a Yamaha A-1.)

Want to have them working at their best, although they’re very enjoyable in their current state.

A simple service/upgrade would be to replace the single capacitor in the crossover, a 4.7Uf 100V bipolar electrolytic.

My question is, what would be the most ideal cap for this particular speaker?

a) Simply a good brand bipolar electrolytic replacement.

b) A film (poly) cap of the same value?

If anyone should recommend ‘b,’ a film cap, please could you recommend a specific model as I’m somewhat overwhelmed by the options. Ideally it should be able to fit within the existing space.

Please feel free to recommend anything else for me to consider.
Many thanks.
 
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I used the common Dayton polypropylene caps on my 7s. They work fine, sound fine, and are cheap enough. I never considered anything extravagant for those little speakers, which usually show up for roughly the same price as the caps.
 
Biggest improvement you can make to the Minimus 7 is this.
92430ab850e823b6135e7dd07085d234 (1).jpg

Replace them with the Canton Plus S, everything the Minimus 7 wishes it were.

Don't get me wrong, I like the Minimus 7 and why I have 6pair including the W's, but they will never be contenders to the Cantons no matter what you spend on them.

If you must have wood veneer the Plus S has you covered, mated to the Plus C passive sub and they're giant killers. The Plus C also works well with the Minimus 7, and other small rat shack speakers like the Optimus Pro X77.

image.jpeg

subwoofer_plus_c_1800259.jpg

Optimus Pro X77
images (17).jpeg
 
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Sgt Shultz said:
Biggest improvement you can make to the Minimus 7 is this.
View attachment 2678579

Replace them with the Canton Plus S, everything the Minimus 7 wishes it were.

Don't get me wrong, I like the Minimus 7 and why I have 6pair including the W's, but they will never be contenders to the Cantons no matter what you spend on them.

If you must have wood veneer the Plus S has you covered, mated to the Plus C passive sub and they're giant killers. The Plus C also works well with the Minimus 7, and other small rat shack speakers like the Optimus Pro X77.

View attachment 2678585

View attachment 2678586

Optimus Pro X77
View attachment 2678587
Click to expand...
Thanks for the tip!
Yes, which model are these?
Very well reviewed, people love them.
A bit harder to come by in the UK for some reason. Are they as good at rendering vocals and convincingly handling the more delicate aspects of music?
Thanks again.
 
Hifibythekg said:
Oops, hadn’t read all of your post @Sgt Shultz
I think you’d already answered my questions, my apologies.
Click to expand...

No problem, and as Canton are a European manufactured (Germany) speaker I would think easier to find and cheaper in the UK than here in the States. Not many here are familiar with Canton due to their rarity here but I've never heard anyone who has heard any of their speakers say they didn't like them.
 
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There's only about a 7mm gap between crossover assembly and rear of woofer magnet in model 40-2039B. A larger film cap will need to be fitted inside the cabinet to one side of the assembly. A spot of glue would fix it to the cabinet wall and prevent rattling. Though the terminal cup could no longer be extracted in the usual way without first freeing or disconnecting the capacitor.
 
Hifibythekg said:
These are readily available to me...
Presuming that some are appropriate, could anyone recommend the likely best choice please?
https://uk.farnell.com/webapp/wcs/s...8142,251224762,85754481,64855413&pageType=PLP
Click to expand...
Three from this list have tighter ± 5% tolerance.

Two of these are metalized polypropylene, which is held in high regard by many:

The Vishay with its axial leads lend flexibility of installation. Its 41.5mm length is surprisingly large for a 160VDC cap. That's longer than typical 4.7µF PP axial caps of similar diameter rated up to 400VDC.

The Kemet would also work well in this application. Its shorter radial leads will likely need wire extensions, but that's a small effort. It is much less pricey than the Vishay.

The Panasonic, though metalized PET rather than PP, is still superior to original NPE. This might be easiest to install with its straight radial leads. Though note that its leads are not as long as the product photo makes them appear to be:

Panasonic 22nF.jpg

This pic just represents the ECQE series and actually shows a tiny 22nF cap. They all have 20mm lead length, but this cap body is much smaller than 4.7µF with 1/3rd the lead spacing.

From those you've listed, I personally would use any of the three above in a Minimus-7.

.
 
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Thanks so much @Stuart Pedaso for doing the hard work of looking up the charts and providing a nice selection, and explaining the reasoning too. Really appreciated.
Seems like you have some experience with the Minimus 7..
The Kemet cap mentions 'pulse' in its description, I don't know what this means but presume it isn't an issue in its intended application.
Also, with the crossover rig in my Minimus speaker I think all of the above will, as you already pointed out, be just a little bit too big.
By my reckoning the space I have to play with is : 15mm x 16mm x 29mm
But that's just how it is I guess and one has to lengthen the leads and stick the chosen capacitor to the inside of the cabinet?
Not sure of the function of the black plastic post to the left of the cap, can one just cut it down to gain some real estate?
also.. the cap is actually embedded in the plastic of the crossover I think.
 
I would use a bipolar electrolytic in those. To be honest. Since your set is made in Japan, they're probably nearly 40 years old, so the capacitors likely have elevated ESR. Now it is certainly true that film capacitors help you squeeze the last drop of performance out of higher end speakers, but I think it's a waste of effort with tweeters like those in the M7. I'm not saying the M7 is a bad speaker, just that I don't see the upgrade as likely to accomplish much.
 
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