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  #1  
Old 7th October 2018, 11:50 AM
Black Stuart Black Stuart is offline
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Default recapping speakers

It's time to recap my Heybrook Sextets, getting into active x/overs will have to wait.

The original caps are IWC and Alcap. The IWC are an easy replacement using K73-16 and potentially I can use 22uF/63V + for the bass.

Should I stay with Alcap for the 60uF bipolar for the mid?

The x/over is as per the Mk 1V and I intend to externalise the x/over, the wiring will be changed later for air cored, staying with quality copper solid core.
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  #2  
Old 7th October 2018, 01:32 PM
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Phil Y Phil Y is offline
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Default Re: recapping speakers

Hello Stuart.

Bipolar electrolytic caps sound poor anywhere in crossovers in my opinion. Obviously a 60uF film cap would be huge, I would go with a new 47uF 'lytic and then make up the difference with film caps of your choice.

Phil.
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Old 7th October 2018, 03:17 PM
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Default Re: recapping speakers

Yep, high value polypropylene caps are not cheap and large. I ‘ve just rebuilt my KLS3 Mk3 (Peter Comeau revision) crossovers. Total of six 50uF caps. Ouch! Needed a big box for external application as well. Phil’s suggestion is a good one. You could even parallel polyprops to achieve the needed value and save space and cost. I recently bought from this company who stock the widest range of clarity caps I have found.

https://www.lautsprechershop.de/index_intro_en.htm
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Old 8th October 2018, 10:57 AM
Black Stuart Black Stuart is offline
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Default Re: recapping speakers

Thanks for the replies.

I've looked in detail at the recs. from the Serbian on the Heybrook thread and it's worth trying his idea about lowering the values on the mid. His assertion that 250V caps are not required opened up the real possibility of using the 22uF/63V K73s. They are not large caps, quite the opposite.

Re. the K73-16 thread on diyaudio,years ago I got a PM from an American who made speakers commercially. He did'nt dare comment openly on the thread because it could have cost him a lot of business, many Americans being brainwashed about COMMUNISM or anything to do with it.

He bemoaned the fact that the large value K73s he used in the x/overs had all dried up and he only had enough for a few dozen speakers. So, he approached a well known American cap maker and they said they could replicate them - he was awaiting the price.

I totally agree that the mids are a bit veiled, is that down to the values on the mid section of the x/over or is it the caps used?

For those that don't have any aural experience of these K series mil. spec caps they are as transparent as Z foils are as resistors. So, if I maintain the values of the tweeter caps I can easily make that value with two K series caps and form the mids I could do as Phil suggests use lytics beefed up with 2 x 6.8uF K caps. I have a lot of the 22uF already so experimenting won't cost an arm and a leg.

I bough12 W Mills rs to replace the existing 8.2 Ohm ages ago, always a good investment.

If air cored i/cs are so good I see no reason why the beefier signal speaker wiring should'nt benefit also.
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Old 12th October 2018, 04:01 PM
Black Stuart Black Stuart is offline
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Default Re: recapping speakers

Anyone use the F&T caps?
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  #6  
Old 13th October 2018, 01:49 PM
Black Stuart Black Stuart is offline
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Default Re: recapping speakers

How about Roderstein caps?
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  #7  
Old 14th October 2018, 01:28 PM
Black Stuart Black Stuart is offline
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Default Re: recapping speakers

Thought about trying bipolars and bypassing with 2.2uF K73-16s. reason being the bipolars are cheap and having used the Russian caps for bypass i know they work.

So saw that the parts Express bipolars get some heads up I thought I might as well take a look - 100uF/100V @ $1.59 a piece, I'm going to try bipolars in the D/V 336 as well.

Could'nt believe the cheapest shipping from P/E @ $37 - this is for 4 caps. Just unbelievable.

I may well shell out for some polyprops but not sure using multiple caps in x/overs is a good idea sonically. If I did try that idea I could always multiply some 22uF K73-16s to give me 100uF - 120uF for not much money and i do know how good they are.
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Old 14th October 2018, 05:55 PM
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Default Re: recapping speakers

I have no personal experience but I noticed a while back that Mundorf do bipolar electrolytics for crossovers, 2 types I think. If you wanted to stay with electrolytics they might be worth a look.

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Old 14th October 2018, 07:36 PM
Chris Chris is offline
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Default Re: recapping speakers

My first speaker diy kit was KEF constructor, the crossover used the Alcap capacitors. It's worth keeping an eye on the tolerance as 5% could make a possible difference of 10% so on a 100uf one could be 10uf difference between the speakers..If you have a way to measure the uf values this could be easily corrected.

Chris.
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  #10  
Old 15th October 2018, 11:49 AM
Black Stuart Black Stuart is offline
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Default Re: recapping speakers

Chris,
for x/overs or coupling caps i think measuring is hugely important, so always do that. I've seen an NOS cap that looks interesting - ROE EGT 100uF/63V bipolar, problem is the seller will not match, which means taking a chance or shelling out for more to ensure a good match.

I use bypassing with reluctance i can well see the problems that can arise, especially using different types of caps.

I need to change the Chinese o/put caps in my D/V and want to up the value from 30uF per side to 100uF. I would rather use (1) cap per side instead of 3, problem is that the voltage must be at least 100V - be nice to find a cap that would suit both.

There is a K73-11 that has the voltage rating I need and on the big K73 thread on diyaudio the thread starter said he had used these and other K caps and said there was little difference. They are not expensive so I think I may take a pop at these. If they are good I will let the forum know, they have the advantage of being bipolar like the K73-16 so could be very useful for x/overs. - vamos a ver.
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