New caps

[silver faced]

Hello Everybody , Well i finally got re-capping done on one each of two different sets of speakers. First was my Pioneer CS-66 E , The original caps were pretty close in tolerence but did them anyhow. The reason for doing only one of each was to do a comparison the pioneers took 3 caps, 2uf 3uf 5uf . The result was clearer mid , deeper lows . Will wait a couple weeks to do the other to see if sound changes.
Next were AKAI SW-155s , 3 caps , 16uf 28uf 0.4uf but when checking tolerences one was way off The results were above the rim . Same as Pioneers will wait a couple weeks to compare. End result if you have speakers 50 yrs old do them you will not be sorry. Mind you if they were super ratty i would of sold them But both are in above average shape perfect surrounds and mint grills

 

[Freddymac2]

The audible difference, after replacing non polar and polar electrolytics that were 35+ years old was staggering. I used Polypropylene Solens and Axions. Some do say that doing this will ruin the original voicing of the speaker. IMO my 5 way speakers have been improved more than I could have imagined. Try it you will like it!

 

[starcopy]

Hi again, Freddymac2.

I'm about to order new caps for my Boston HD8s. We exchanged posts in another thread RE caps some time ago. Supposedly, the stock HD8 woofer caps are 8.2uf and 50V. And the stock tweeter caps are 4.7uf and 50V.

One of the well-known parts places has Solen 8.2uf (but 400V) polypropylene caps, and 4.7uf (but also 400V) polypropylen caps. I know you are a Solen fan. Would these work, despite the very different voltage ratings?

Cheers.

 

[StimpyWan]

Hi again, Freddymac2.

I'm about to order new caps for my Boston HD8s. We exchanged posts in another thread RE caps some time ago. Supposedly, the stock HD8 woofer caps are 8.2uf and 50V. And the stock tweeter caps are 4.7uf and 50V.

One of the well-known parts places has Solen 8.2uf (but 400V) polypropylene caps, and 4.7uf (but also 400V) polypropylen caps. I know you are a Solen fan. Would these work, despite the very different voltage ratings?

Cheers.

Match the capacitance. But, you don't want to go to a lower voltage; equal or higher voltage is fine. That will help with power handling too.

As far as which brand, Solen and Axon are fine. They're basically the same capacitors, as they're made in the same factory. Parts Express Dayton 1% and 5% caps are good. Mundorf MKP's, and ClarityCap PX are good as well, and not too expensive. Pretty much any poly cap will better an original NPE. So, don't stress about what to get. They'll all be an improvement to stock, at least in my experience.

 

[starcopy]

Terrific. Thanks so much, @StimpyWan. Admittedly, I am/was a bit apprehensive -- have never recapped anything before and don't want to screw this up, especially with the cost of new (quality) caps and the shipping. Can I assume that the 400V versions are not any bigger in physical size than the original 50V caps?

 

[RTally]

Terrific. Thanks so much, @StimpyWan. Admittedly, I am/was a bit apprehensive -- have never recapped anything before and don't want to screw this up, especially with the cost of new (quality) caps and the shipping. Can I assume that the 400V versions are not any bigger in physical size than the original 50V caps?

The 400V caps will be huge in comparison to the original 50v caps. If you are buying from Parts Express, they specify dimensions. For example, the Solen 8.2 uF at 400V have " Dimensions: 24 mm Dia. x 38 mm L." That is about 1 inch diameter by 1-1/2 inch long. For point-to-point wiring as you have in your pics, size is usually not a concern. I always position the caps so the value is visible when installed.

 

[toxcrusadr]

I'm not sure why those guys make their crossover caps 400V. It's bad enough the Daytons are 250V, even they get pretty big over about 10 uf. 400V seems gratuitous. I guess you can use them in tube amps too but there are a lot more speakers out there than there are tube amps.

I would think 150-200V is plenty for crossovers.

Anyway the premise of this thread is spot on - if they're ancient, recap them. And don't forget that even if the capacitance is still pretty close, the ESR may be way off. Somewhere I have a link to a page where a guy did impedance sweeps of new and old caps and it was staggering how much resistance was in those old things at some frequencies, even if the capacitance was not that far off when measured with a meter. I have such a pile of links I can't find it right now but it really bolstered my opinion on recapping, especially old electrolytics.

 

[starcopy]

Thanks for jumping in, @RTally and @toxcrusadr. I might have otherwise ordered and made a bad purchase. To me it sorta makes sense that a higher-voltage cap would be physically larger than a lower voltage one.

This is essential info for people like me who have loved great analog audio for many years and are now getting deeper into restoring receivers, amps, speakers, etc. (beyond giving everything a deoxIT shower LOL).

So, for replacement caps I (1) need to stay with the same or slightly higher value, and (2) a same or slightly higher voltage. BUT I also need need to consider the size of the new cap. (Sounds like caps with identical values and identical voltages usually vary in physical size?)

Another option to doing all this research (cap type, capacitance, voltage, cap size, vendor, cost) is to take the lazy, but trusted, way: Just follow the advice of a fellow AKer who has successfully recapped the identical piece of electronics. But that's cheating, right? I have at least 10 vintage receivers, amps, preamps, and receivers that are on my upgrade list. I'm gathering schematics and learning on the fly. Anytime I can take a well-devised shortcut and arrive at a successful conclusion it's a win. Thanks for sharing.

And, yes I was looking at Parts Express, among others.

 

[RTally]

Thanks for jumping in, @RTally and @toxcrusadr. I might have otherwise ordered and made a bad purchase. To me it sorta makes sense that a higher-voltage cap would be physically larger than a lower voltage one.

This is essential info for people like me who have loved great analog audio for many years and are now getting deeper into restoring receivers, amps, speakers, etc. (beyond giving everything a deoxIT shower LOL).

So, for replacement caps I (1) need to stay with the same or slightly higher value, and (2) a same or slightly higher voltage. BUT I also need need to consider the size of the new cap. (Sounds like caps with identical values and identical voltages usually vary in physical size?)

Another option to doing all this research (cap type, capacitance, voltage, cap size, vendor, cost) is to take the lazy, but trusted, way: Just follow the advice of a fellow AKer who has successfully recapped the identical piece of electronics. But that's cheating, right? I have at least 10 vintage receivers, amps, preamps, and receivers that are on my upgrade list. I'm gathering schematics and learning on the fly. Anytime I can take a well-devised shortcut and arrive at a successful conclusion it's a win. Thanks for sharing.

And, yes I was looking at Parts Express, among others.

There is a big difference in recapping speakers and recapping electronics. All crossover caps are non-polarized. That is not true for caps in electronics. The information in this thread relates to speaker caps. A good general rule is to replace electrolytic caps in speakers that are more than 20 to 30 years old. Caps for electronics have their own rules and things to know. I suggest posting in the other sub-forums about recapping electronics.

For speaker replacement caps you want a capacitance value as close as possible to the original value. You can wire capacitors in parallel to reach the correct value, for example a 6.2 uF and a 6.8 uF in parallel equals 13 uF. It is also important to remember that there is a tolerance to cap values. Many old caps had a plus or minus 20% tolerance. Newer ones are typically 5%, such as the inexpensive Daytons. If 5% of a new cap is within 20% of the original specified value, then you are good. Don't sweat it.

With speakers, there is always room to install larger caps. You may have to add jumpers to extend the lead to make a connection, but they will fit in the speaker cabinet. It is going to be very difficult, if not impossible, to find crossover caps with the same 50 V voltage ratings that were used 40 to 50 years ago. Currently, the standard voltage ratings are 250 V and 400 V. The new caps are larger than the old, 50 V caps. The only requirement for voltage rating is that speaker replacement caps must have a voltage rating at least as much as the original cap.

 

[starcopy]

Right now I'm concentrating on three sets of speakers: Boston HD8s; AR TSW-210s; and EPI 200Bs. New surrounds + new caps for all. Unfortunately, I have not heard any of these speakers -- acquired them all with bad foam so a before/after comparison won't be possible. Yes, I could refoam, then listen, THEN recap later, but once I'm inside....

However, replacing caps in electronics is a whole different ball game -- not ready for that yet. For one thing, caps in electronic equipment can hurt me LOL. I have basic soldering skills, but need more info such as how to safely short a cap, how to read a schematic, etc.

I really appreciate you providing such a detailed explanations re speaker capacitor selection. I now have all the info I need to make smart speaker cap choices. And I'll certainly be able to handle the soldering/upgrading of the crossovers.

Have a great holiday season.

 

[toxcrusadr]

I am not sure when all those sets of speakers were made, but for example just looking at pics on the web, the Boston HD8 looks like a very modern bookshelf speaker and is almost certainly loaded with film caps. OK I looked it up, 1989-94 vintage. This would be on my list as 'probably used good caps to begin with, age is not so much that they would automatically be suspect, recapping optional.' Very much like a pair of Klipsch I have from the same era. When I eventually did recap, I found 'good' quality films in there but since it is a very simple crossover with only two of them, I replaced them and heard a slight improvement.

As opposed to a 70s or 80s speaker with electrolytics that are expected to be shot even if they were never played.

So if you're prioritizing, I'd look at what's in there and consider quality, type and age of the stock caps before deciding where to invest time and $ first. Just my two cents.

 

[starcopy]

@toxcrusadr, you bring up a good point: Don't just assume that every vintage speaker needs new caps.

Funny you should mention, but one AKer posted that he recapped his HD8s and didn't notice much difference -- was disappointed. Another did his HD8s, plus replaced the "pillow foam" with R-13 insulation and they are now his favorite speakers. Maybe I hold off recapping the Bostons. I'd need four caps. Plus there is a resistor in there that may or may not need replacing. Add in the cost of the new surrounds and those HD8s better sound good considering the money/time invested.

I'm a huge EPI fan. Love that East Coast sound. The EPI 200-series speakers were built from 1977 through 1980. My 200B version has a tweeter, 8-inch woofer, and large passive radiator. Cabinets with real walnut veneer. Crossover features a 3-position tweeter level switch with two 5-ohm power resistors wired to it and a 10uF capacitor in series with the switch and the tweeter. That's it. Could be an "easy" recap?

And the Acoustic Research TSW-210 speakers were made from 1987 through 1989. "New" by vintage standards. Not sure what's inside. Maybe new enough to not need a recap? But they sure need surrounds.

Thanks for your keen insight.