Realistic Minimus-7W Crossover capacitor
- Thread starter Hifibythekg
- Start date
A simple recap with a 4.7uf poly in the Minimus 7W will get you a very nice improvement in sound. That's what I did to mine using Dayton's. For the cost of two caps you can't do any better. Don't be fooled, the dome tweeters RS used in the Minimus 7 line is good enough to benefit from a cap upgrade. An electrolytic cap will give you what they sounded like from the factory. A poly cap will let your speakers sound better.
z-adamson
Addicted Member
Pretty sure in stock form the cap is only part of the tweeter crossover. The woofer runs full range.
Anything other than an NPE of similar size to stock is going to be much larger. Even cutting off the unused plastic posts won't yield enough space to mount a film cap onto the terminal assembly and clear the woofer magnet and/or pass through the cabinet opening.
An audio grade NIchicon DB series NPE, as suggested by @WizardWG4 is available through Digi-Key UK. At 10mm x 21mm it would fit into the stock location after cutting the glued-in stock cap out.
If entertaining the extra labour required to fit a film cap, you might consider a Solen on offer at Falcon Acoustics. They also stock a Low Loss ALCAP that claims superior performance over regular NPE's. Though at 13mm x 32mm it approaches the size of film caps and would need to be similarly mounted.
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alteclipsch
Super Member
Mine have an inductor in the circuit.
Though probably true in principle that physically displacing box volume with larger components could alter bass response in this acoustic suspension system, Zilch measured Minimus-7 comparing PZ crossover assemblies mounting inside vs outside the box and found no significant difference in bass response. The PZ-2.1 crossover mod assembly is much larger than stock assembly.
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Hifibythekg
Super Member
Very impressive, a shelf up from my efforts!
Hifibythekg
Super Member
Thanks again everyone for the very helpful contributions.
Lavane
Lunatic Member
I agree with this. Unless your comfortable with repositioning a big film cap to get it to fit. You can use a Wima stack film cap as long as you get one with the right lead spacing. Sometimes you have to get creative using a film cap.
I replaced radial electrolytics with film caps in a pair of speakers I have and the crossovers are built into the terminal cup. The polypropylene film caps were axial and much bigger.
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AudioAvarice
Super Member
I found Jantzen 'standard' series caps work well with these kind of speakers, and they tend to be smaller than other brands. If your in the UK https://www.hificollective.co.uk/ is a good supplier, just be aware their prices are listed without VAT.
z-adamson
Addicted Member
The cap is for the tweeter, but what does that have to do with bass extension?
The woofer is has an inductor.
RTally
Speaker addict
The tweeter has a second order filter, that is, the cap and inductor are in the tweeter circuit. The woofer runs wide open.
https://www.diyaudio.com/community/threads/modify-minimus-7.314621/
As for bass extension, a large cap occupies a significant fraction of the small cabinet volume, potentially affecting the response of the woofer. As Stuart Pedaso notes above, testing found that reducing cabinet volume with the crossover has little impact on the FR.
z-adamson
Addicted Member
Hmm, somehow I remember the woofer having an inductor. I must remembering incorrectly.The tweeter has a second order filter, that is, the cap and inductor are in the tweeter circuit. The woofer runs wide open.
https://www.diyaudio.com/community/threads/modify-minimus-7.314621/
As for bass extension, a large cap occupies a significant fraction of the small cabinet volume, potentially affecting the response of the woofer. As Stuart Pedaso notes above, testing found that reducing cabinet volume with the crossover has little impact on the FR.
It looks like some have managed to fit mkps into that cabinet somehow. But I'd recommend the UES or UDB electrolytic bypassed with a small 0.01 - 0.1uF cap using a superior material like mkp, mkp/oil, paper in oil, polystyrene, teflon etc. Or, I'd look into a 4.7uF 100V CBB polypropylene capacitor as it will be smaller than all the other MKP options. The bypass cap is of course optional, but would allow you get some of that 'film flavor' if that sort of thing is important to you, while still maintaining a smaller 'mass' internally within the cab. which gives more cabinet volume and better bass response as previously mentioned. Will any of this be noticeable if you choose one option over another? Who knows, but technically, it "should".
I purchased a complete, upgraded Minimus-7 crossover board upgrade kit and soldered it into my pair, but have since given the speakers to a friend and that upgraded crossover board listing is no longer available or being sold.
I purchased a complete, upgraded Minimus-7 crossover board upgrade kit and soldered it into my pair, but have since given the speakers to a friend and that upgraded crossover board listing is no longer available or being sold.
Bicyclist
Super Member
The cabinet is effectively larger with a physically smaller cap