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Multi-Way Conventional loudspeakers with crossovers

Technics  SB-10 Crossover Questions
Technics  SB-10 Crossover Questions
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Old 8th February 2018, 09:02 AM   #21
Mooly is offline Mooly  United Kingdom
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Technics  SB-10 Crossover Questions
20uF is fine for replacing a 20.6uF. Normal component tolerances of capacitors will blur the exact figures in any case.

The 0.47uF that parallels the 47uF is just the designer getting his own way and without the accountants picking it up

Only if the 47uF becomes degraded and 'lossy' might you notice the benefit of the smaller one across it.

Don't be confused

If you are unsure then get some cheap electrolytics and make up the bi-polar equivalents and pop them in. If you think the speaker sounds better then you might want to consider spending more money on better parts. Two 100uF in series will make the 47uF.

Remember plus to plus when connecting them in series and you wont go wrong.

Let your ears decide.
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Old 8th February 2018, 09:39 AM   #22
giralfino is offline giralfino  Italy
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Elko bipolar 47,0 uF - Jantzen Audio (2 Stuck) | eBay
Just to show that a 47uF bipolar for crossover exists, and is inexpensive enough not to build a 50uF one out of two regular 100uF electrolytic.

The 12+8.2uF caps are equivalent to a single 20uF cap once you factor in the tolerances, 0.2uF is a mere 1% of the total. I simply object the fact that the original caps need to be replaced if they are already a film type.

The 330+330uF caps aren't strictly part of the crossover, but are a trick to enhance the bass. If you don't want to replace them, remove them and place a wire across the holes.

Ralf

In order to obtain better answers, amp related questions should be posed on another forum.
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Old 8th February 2018, 11:56 PM   #23
TechnicsSB10fan is offline TechnicsSB10fan
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Thank you Gentlemen your reply's are helping a lot

Mooly, on the bass circuit, if I was to put a polypropylene film 47uF instead of the electrolytic 47uF, would the 0.47 bypass still be necessary? Should it be removed it or would it not matter?
On the midrange circuit might there be some improvement by replacing the two in parallel polyesters with the one polypropylene film of close uf value?

giralfino, I was looking at the Jantzen electrolytics to replace the two 330uF`s in the bass circuit, there is also Mundorf electrolytics 63v would the Jantzen be better choice at 100v? Removing them all together would loose the bass yes? Incidentally that is what the Gentleman in Japan did, he was using a valve amp though. You can check here, his modifications;
Google Translate You can open the links to photos.
The Japanese version speakers and had a different crossover with a 22uF cap in the bass circuit, 47uF was used in the export models like mine.
He has added a Bennic 22uf polypropylene film in place of the 22uF electrolytic.

All great advice and very much appreciated.
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Old 9th February 2018, 07:38 AM   #24
Mooly is offline Mooly  United Kingdom
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Technics  SB-10 Crossover Questions
There would be no benefit at all paralleling a film with another film in a speaker application. It is up to you whether to remove or leave but either way will make no difference.

The polyesters should not show any deterioration so probably no benefit in swapping those.

Sounds like you might try anyway though

The big thing with any modification is something called 'experimenter expectation' and because of that alone you may well feel things improve after swapping parts. The real test would be if you could pick a preference listening 100% blind and with no knowledge of which set of parts was fitted.

We've all been there
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Old 9th February 2018, 08:13 AM   #25
Lojzek is offline Lojzek  Croatia
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Hi Technics, depending on your wherabouts, high quality NPE caps are Erse Audio, Visaton, Intertechnik, Bennic and probably many more that I am not familiar with. I have measured Visaton's and Intertechnik's and the former proved to be better than specified in respect to ESR and labeled capacitance. I have measured ESR not only at one frequency like 1 kHz but in the whole range where this particular cap is likely to alter the signal significantly. So, my studies have convinced me that NPE are very good at what they do, so I would not swap these with any other type than the same.


Would be interesting to see you measure capacitance of your original caps to see how much they have deteriorated already. Without a C meter and not wanting to deal with software+sound card setup, the easiest way to evaluate could be to use a smart phone as a source (amp) of a 1 kHz sine (mp3) and measure voltage drops.
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Old 9th February 2018, 08:40 AM   #26
ICG is offline ICG  Germany
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Quote:
Originally Posted by Lojzek View Post
Hi Technics, depending on your wherabouts, high quality NPE caps are Erse Audio, Visaton, Intertechnik, Bennic and probably many more that I am not familiar with.
Well, for non-polar electrolyte capacitors I would like to mention Mundorf, Monacor (you can get these literally everywhere) and Jensen as further possible alternatives with Mundorf being probably on top quality wise. Bennic was new to me, thanks for the information.
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Old 9th February 2018, 09:00 AM   #27
ICG is offline ICG  Germany
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My advice for what its worth would be to always go for reputable well known commercial brands and not 'boutique' offerings. Look for 105C temperature rating for new electrolytics.
Well, for amps the 105°C spec is surely a good recommendation, for crossover use there is no benefit in lifetime compared to the 85° capacitors. Yes, in theory but not in praxis, the temperature of electrolyte caps in hifi-speakers are rarely (if at all) more than 10° higher than the ambient temperature. That's because of the nature of music, it consists on short, varying impulses and they can dissipate the heat, they simply don't heat up like power supply caps in an amp. That's why it's usually preferred to buy e-caps with a better foil and especally tighter tolerances instead of higher temperature rating.
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Old 9th February 2018, 09:13 AM   #28
TechnicsSB10fan is offline TechnicsSB10fan
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Thanks Mooly, I know you are right. I think it is probably best to do this in two stages, first replace the two 330uF electrolytics with new perhaps better electrolytics. At the same time replace the 47uF electrolytic with a polypropylene remove the bypass 0.47uF polyester. Try it out.
Second replace the remaining polyesters from the midrange and tweeter circuits, replacing them with polypropylene.
Does this sound like a reasonable approach?

Thank you for your patience
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Old 9th February 2018, 01:48 PM   #29
Mooly is offline Mooly  United Kingdom
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Technics  SB-10 Crossover Questions
Replacing the electrolytics sounds reasonable. Personally I wouldn't spend on replacing the others (but don't that stop you doing so)
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Old 9th February 2018, 01:54 PM   #30
ICG is offline ICG  Germany
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Originally Posted by Mooly View Post
Replacing the electrolytics sounds reasonable. Personally I wouldn't spend on replacing the others (but don't that stop you doing so)
I see it the same way. Unless they are (mechanically) damaged, there's no need to change them. These capacitors will likely live a lot longer than the rest of the speakers.
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