NEED HELP CHOOSING DRIVERS ...

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audioengr

Re: NEED HELP CHOOSING DRIVERS ...
« Reply #20 on: 9 Apr 2019, 05:45 pm »
If you want to make these sound great, replace the inductors with air-core ribbon inductors from jensencapacitors.com.

The large capacitors can be replaced with Black Gate non-polar types.  Search them on the web.  Partsconnexion may have some left.

The middle-size-range caps can be replaced with Multi-caps, up to about 1uFd.  Let me know what you need because I have some of these left from a project.

The small caps should be replaced with V-Cap Teflons if not Duelunds.

This will turn these speakers into real audiophile quality, assuming that the tweeter is a good one.

Steve N.

S Clark

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Re: NEED HELP CHOOSING DRIVERS ...
« Reply #21 on: 9 Apr 2019, 06:33 pm »
Deulands??? on this thing?  A pair of caps would exceed the value of the speaker itself!!!  For the price of 4 you could go buy a really nice set of speakers, or one hell of a kit. 
Sorry, just can't agree with this advice. 

tomchr

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Re: NEED HELP CHOOSING DRIVERS ...
« Reply #22 on: 9 Apr 2019, 07:20 pm »
If you're still looking to refurbish the crossover in these speakers, I suggest replacing the electrolytic caps (light blue cans) with film caps. Polypropylene dielectric would offer the lowest distortion. I see no need for fancy caps in this (or any) application. The fancier caps tend to measure worse. Wima MKP would be great. Solen has a bunch of options as well.

Tom

SCM

Re: NEED HELP CHOOSING DRIVERS ...
« Reply #23 on: 10 Apr 2019, 12:57 am »
If you're still looking to refurbish the crossover in these speakers, I suggest replacing the electrolytic caps (light blue cans) with film caps. Polypropylene dielectric would offer the lowest distortion. I see no need for fancy caps in this (or any) application. The fancier caps tend to measure worse. Wima MKP would be great. Solen has a bunch of options as well.

Tom

 Yes, I want to recap the crossovers.
Can I ditch the 8 daisy chained Nichicons and put a single cap in instead ??     

tomchr

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Re: NEED HELP CHOOSING DRIVERS ...
« Reply #24 on: 10 Apr 2019, 02:47 am »
If the caps are connected in series or parallel, you can replace them with one cap. Finding a cap of the right value might be a challenge. That could be why the caps are currently "daisy chained".

If you can draw a schematic of the crossover and label it with the parts values, I'll be happy to help.

It looks like the inductors are air core, which is nice.

Tom

jules

Re: NEED HELP CHOOSING DRIVERS ...
« Reply #25 on: 10 Apr 2019, 06:14 am »
Quote
Can I ditch the 8 daisy chained Nichicons and put a single cap in instead ??

Given the rats nest of wiring in the crossover it might seem impossible to figure out what's going on in there, but to answer questions like the one above, your best chance is to carefully follow all the wires and connections and draw up a wiring diagram of the thing as John suggested on page 1. To do this isn't rocket science, it just takes patience and some careful drawing.

SCM

Re: NEED HELP CHOOSING DRIVERS ...
« Reply #26 on: 10 Apr 2019, 05:25 pm »
If the caps are connected in series or parallel, you can replace them with one cap. Finding a cap of the right value might be a challenge. That could be why the caps are currently "daisy chained".

If you can draw a schematic of the crossover and label it with the parts values, I'll be happy to help.

It looks like the inductors are air core, which is nice.

Tom
Ok...I tried to map it out and what a mess (my schematic ability) I think it would be much easier just to focus on swapping out the old Nichicon caps. At least I know what and where they are.

I can easily post close up pics of all 12 caps and they are all the same value: 100uf 50v

Can we give this approach at try ??

Thanks
Steve

WGH

Re: NEED HELP CHOOSING DRIVERS ...
« Reply #27 on: 10 Apr 2019, 06:32 pm »
First off, how do you know the caps are bad and need to be replaced? I would snip out a cap and take it to an electronics repair shop to test it. Replacing all the caps for some nebulous idea that new caps will "improve" the sound is somewhat misguided. Those old speakers are probably not the last word in detail retrieval so in all likelihood it would not make a difference.

But it sounds like you are on a mission. I suggest you modify one speaker at a time, that way you always have a reference as to what goes where. Plus you can compare the finished improved speaker to the original. Hint: keep all the old parts in case the magic is gone.

SCM

Re: NEED HELP CHOOSING DRIVERS ...
« Reply #28 on: 10 Apr 2019, 07:01 pm »
First off, how do you know the caps are bad and need to be replaced? I would snip out a cap and take it to an electronics repair shop to test it. Replacing all the caps for some nebulous idea that new caps will "improve" the sound is somewhat misguided. Those old speakers are probably not the last word in detail retrieval so in all likelihood it would not make a difference.

But it sounds like you are on a mission. I suggest you modify one speaker at a time, that way you always have a reference as to what goes where. Plus you can compare the finished improved speaker to the original. Hint: keep all the old parts in case the magic is gone.

That does make sense but isn`t 33 years a long time for those caps ? they also sat unused for these last 8 years too and some feel from what I`ve read that that`s the worst thing to do.
The drivers were/are of ok quality not too awful bad from what I`ve gathered.

Audax super tweeter. Polydax dome tweeter.  Audax/Polydax bextrene mid range woofers and an Eminence sub woofer. Not so much on a 'mission' but since I`m this far....

Steve

WGH

Re: NEED HELP CHOOSING DRIVERS ...
« Reply #29 on: 10 Apr 2019, 07:21 pm »
That does make sense but isn`t 33 years a long time for those caps ?

I don't know, nobody knows. People can guess, there are plenty of "Capacitor Psychics" on the internet but without testing....

S Clark

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Re: NEED HELP CHOOSING DRIVERS ...
« Reply #30 on: 10 Apr 2019, 07:29 pm »
Yes, I want to recap the crossovers.
Can I ditch the 8 daisy chained Nichicons and put a single cap in instead ??     
From a quick inspection, not quite.  The section I can see clearly has two 100uF caps in parallel, then in series to another two 100 uF caps in parallel...  then two wires T into the circuit, then repeat the first part?
The first 4 100uF caps all added together equal--- 100uF, if the quick math in my head is right.  So, what was the designer doing to use 4 caps to do the work of one?? The power handling is changed, but there's easier ways to solve that with much less labor. 
Replace each set of 4 with a 100uF 100V (or more) cap.   They range from $.50 to $3.00 at Digikey. 

Or... leave them be, and add a pair of decent bypass caps across each cluster of 4.  1 uF Sonicaps from Sonic Craft at about $8 should work.
,
Or do both, and you are still only out the cost of a dinner out.

But we still don't know what that part of the crossover controls.  I'd start from the tweeter and work backwards to the input, noting all caps directly in the path.  If that's a 4 way design, I'd keep my upgrades simple.   
And one other thing... those are pretty decent driver in this speaker, actually rather highish end for the day.  This could be time well spent.  Good luck.  :thumb:

SCM

Re: NEED HELP CHOOSING DRIVERS ...
« Reply #31 on: 10 Apr 2019, 08:28 pm »
From a quick inspection, not quite.  The section I can see clearly has two 100uF caps in parallel, then in series to another two 100 uF caps in parallel...  then two wires T into the circuit, then repeat the first part?
The first 4 100uF caps all added together equal--- 100uF, if the quick math in my head is right.  So, what was the designer doing to use 4 caps to do the work of one?? The power handling is changed, but there's easier ways to solve that with much less labor. 
Replace each set of 4 with a 100uF 100V (or more) cap.   They range from $.50 to $3.00 at Digikey. 

Or... leave them be, and add a pair of decent bypass caps across each cluster of 4.  1 uF Sonicaps from Sonic Craft at about $8 should work.
,
Or do both, and you are still only out the cost of a dinner out.

But we still don't know what that part of the crossover controls.  I'd start from the tweeter and work backwards to the input, noting all caps directly in the path.  If that's a 4 way design, I'd keep my upgrades simple.   
And one other thing... those are pretty decent driver in this speaker, actually rather highish end for the day.  This could be time well spent.  Good luck.  :thumb:

Thanks. I`d like to start with the subwoofer and midrange drivers then move to the two tweeters, That way I can keep things a bit more manageable (I hope)  Here`s a couple more pictures of the subwoofer and mid range setup.

The daisy chained group of 8 mounted to the side of the cabinet is for the subwoofer.
The other cluster/bundle of 4 goes to the mid range, they are soldered to that green box thing that says 10% and some other parts that look ceramic ?
The last picture gives some perspective as to the layout. You can see the midrange driver in the back ground the subwoofer stuff on the side wall and the floor with some others components.
The orientation is not correct but you can see what I mean.
I have to say these weren`t exactly cheap I still have my receipt from 1985 where I paid $1200 then DUTY FEES on top of that !








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S Clark

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Re: NEED HELP CHOOSING DRIVERS ...
« Reply #32 on: 10 Apr 2019, 09:16 pm »
If you think these are worth up to a $500 investment, contact Danny Richie and have him build new crossovers and reinforce the cabinets.  Instead of screwing around with pictures on the internet and guys like me, Danny is about as good as it gets at crossover design. 
There is no way I'd touch a four way crossover, even if it was in my shop.  They are just too many interactions for amateurs. 
http://gr-research.com/

SCM

Re: NEED HELP CHOOSING DRIVERS ...
« Reply #33 on: 10 Apr 2019, 09:35 pm »
If you think these are worth up to a $500 investment, contact Danny Richie and have him build new crossovers and reinforce the cabinets.  Instead of screwing around with pictures on the internet and guys like me, Danny is about as good as it gets at crossover design. 
There is no way I'd touch a four way crossover, even if it was in my shop.  They are just too many interactions for amateurs. 
http://gr-research.com/

I appreciate you trying to help..Thanks

 

tomchr

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Re: NEED HELP CHOOSING DRIVERS ...
« Reply #34 on: 11 Apr 2019, 02:32 am »
I can't help much with the pictures. The crossover is one of those things you have to get right. Would it be possible for you to draw the circuit on a piece of paper and label the components with their values?

The 2x100 uF + 2x100 uF network forms a single 100 uF capacitor rated at 100 V working voltage. You might be able to find a 100 V or 160 V rated polypropylene cap in that capacitance from Solen.

Tom