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Sansui SP-L500 Capacitor Change

Discussion in 'Exclusively Sansui' started by larry777, Oct 10, 2018 at 7:52 AM.

  1. I would like to change the capacitors in these speakers at the same time new upgraded binding posts are installed (spring clips getting weak) , as I will be soldering on the crossover board to install them. Each speaker has 3 capacitors as follows : 1 x 2.2uf 50v.......1 x mp125 WVAC 8.2uf u-con 1977.l........ and 1 x mp125 WVAC 2uf u-con 1977.l
    I am confused as to what WVAC means although I think the AC stands for alternate current and the u-con 1977.l may not mean anything important. But what does the mp125 mean ? A voltage rating does not seem to show on the cap unless the 125 # means something about that. I think all speaker caps are Bi-Polar meaning Non polar but correct me if I am wrong. The caps also have 2 leads coming out each side but when I search for caps a lot of the time I will see caps with 2 leads coming out the bottom like those used in amplifiers. Are speaker caps a certain type like Bi-polar mentioned above and would automatically give the 2 lead wires coming out each side so the caps can lay flat on the board ? I assume I would look for audio grade caps but would that be correct or would their be another type ? Thanks for the help and direction.
     
    Last edited: Oct 10, 2018 at 8:04 AM

     

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  2. tnsilver

    tnsilver AK Subscriber Subscriber

    Messages:
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    Location:
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    MP=metalized paper (the dielectric material) and WVAC = working voltage AC, which in the case above is 125.
    Capacitors with two leads coming out one end are called "radial" vs. one lead out of each end, which is "axial" and it's just a different physical configuration.
    Electrolytic capacitors in speakers XO networks are typically bi-polar (AKA none-polar) and are usually a cost effective compromise for the alternative much larger
    (and more expensive) film capacitors that are always none-polar. FWIW I've used Mundorf's bi-polar AC "E-Cap" series capacitors and their "M-Cap" film capacitors with great results on Sansui
    speakers in the past.
     
  3. Thanks tnsilver. So 125 volts for the 2uf and 8.2uf caps. Is the MP metalized paper type important when I order ? Or just use one of the cap examples you show above for the proper uf and volts ? If I can't find 125 volt samples, can I use a higher voltage ?
     
  4. The Mundorf's look good but I couldn't find the three that I need ( 2uf 125V, 2.2uf 50V and 8.2uf 125V ). I searched elsewhere on line
    like Parts Express and Digikey and Mouser but don't seem to be able to find all three with correct uf and volts from the same place. Someone must have them in Canada. Anyone have any ideas ?
     
  5. It seems that to get the higher 125v capacitors that I would have to go with Metallized Polypropylene types instead of Non Polarized Electrolytic. The electrolytic caps that I found only have a voltage rating up to 100v. I also read some comments that if polypropylene are used in speaker crossovers that you should use a film and foil bypass cap with them to eliminate glare and brightness that comes from poly caps. Is this a true statement ? The caps that I saw also show a voltage rating as VDC ( Direct current ? ) rather than VAC ( Alternating current ) so does that mean they are not suitable as well ?
     
  6. tnsilver

    tnsilver AK Subscriber Subscriber

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    Location:
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    A cap is a cap regardless how the voltage ratings are marked. For a cap rated 125VAC of working voltage you'd need a VDC rated replacement that's roughly 1.4 time higher (V(rms) * √2) plus some ample margin like commonly 250VDC.
    Speaker XO networks are fed AC so some mfgrs state working voltage in AC for their speaker designated caps. It's still the same capacitor as if it was marked in DC. Mundorf M-Cap MKP Polypropylene capacitors come in the capacitance and voltage ranges that you need. They're a mainstream German mfgr, so google a distributor that will ship to your location. By-passing a film cap is an audiophile trend that's kinda controversial. In electronics the capacitance of two caps in parallel is the sum of the individual caps. Bypassing a 99% crap capacitor with a 1% magic capacitor still yields the sum of both capacitance values, only it performs 1% magic and 99% crap. You can always experiment with low capacitance bypass caps after your XO is complete in the traditional way.
     

     

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  7. Thanks Tom for taking time to respond again to my questions. Things are a lot more clear now and less confusing. I feel better about searching for the correct caps for the SP-L500 speakers. They are very very rare Sansui speakers and I don't want to screw something up by putting in the wrong caps. I will search more for those Mundorf MKP caps that you suggest.
     
    Last edited: Oct 11, 2018 at 6:46 AM
  8. Leestereo

    Leestereo Super Member

    Messages:
    2,090
    Location:
    Ottawa, ON
    Speaker crossover parts can be ordered from Solen.ca

    For consumer-level speakers, crossover capacitors rated 100V are more than adequate (this voltage is ~1250W into 8 ohms).

    The increased "brightness" from replacing electrolytic capacitors with film types is due to the lower ESR of the replacements. To compensate for the lower ESR of film capacitors, a small value (e.g., ~0.5ohm) resistor can be added in series with the capacitor; however, since the Sansui SP-L500 speakers have L-pad controls for the midrange and treble response, it is not necessary in this particular case.

    Here is a crossover restoration project that may provide useful information for you: Restoration And Upgrade of AVID 103 Crossovers
     
  9. tnsilver

    tnsilver AK Subscriber Subscriber

    Messages:
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    Location:
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    If you can't get the Mundorf's, I've used Parts Express's house Dayton PMPC capacitors on some JBL projects in the past with great results.
    I've experimented with Audiocap PPT Theta bypass caps for the large values.
    It seemed to have recreated and pronounced the original west coast sound but I can't swear it was the bypass. I was happy nevertheless.
    so if you're not doing resistors and coils you can be done with a real TOTL recap for about $40 (sans shipping)
     
  10. Thanks guys for this information as it will be very useful and I already have some items in my cart from Solen.ca. But I thought that I better supply a picture of the crossover for review before I submit my order ( after removing the 12" base speaker and having another look at it ), as the 8.2uf 125v and 2uf 125v caps are larger metal types and not like the 2.2uf 50v smaller blue cap. The 8.2uf and 2uf caps are also held on the board by metal clamps as you can see in the picture and they have 2 leads coming out of one end only, rather than each end like the 2.2uf cap. Are these a different type of cap ( polypropylene ? ) and should they still be changed due to age ? And with the same options discussed above but not Axial ? Sorry for any confusion as this is all new to me.
     

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    Last edited: Oct 11, 2018 at 12:44 PM
  11. Leestereo

    Leestereo Super Member

    Messages:
    2,090
    Location:
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    Considering the 1977 date code and the large physical size of the can capacitors relative to their capacitance and voltage ratings, these may be oil-filled capacitors. The U-CON capacitors look similar in size/capacitance/voltage rating to these Jensen capacitors. Film capacitors in the late 70s were usually physically smaller than the U-CON capacitors that the OP posted.

    1201682-jensen-10uf-aluminum-foil-in-oil-speaker-capacitors.jpg
     

     

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  12. If they are in fact oil filled capacitors should they still be changed due to age ? And would I look for Polypropylene types with both leads coming out the same end as they now are on my crossover board ( they look like solder lug on my crossover board )? And would they still be considered Non-polar with no negative (-) or positive (+) post marked ?

     
    Last edited: Oct 11, 2018 at 1:32 PM
  13. Leestereo

    Leestereo Super Member

    Messages:
    2,090
    Location:
    Ottawa, ON
    As mentioned by tnsilver, if the PIO capacitors test good for capacitance and ESR, you can consider keeping them. If you do not have an LCR, replace with polypropylene film types; you can use the axial or radial lead configuration, doesn't really matter. Yes, PIO capacitors are non-polar.
     
  14. I have a multimeter, can I measure with that ?
     
  15. Leestereo

    Leestereo Super Member

    Messages:
    2,090
    Location:
    Ottawa, ON
    You can use your multimeter if it can measure both capacitance and ESR.
     
  16. I don't think it measures ESR, so maybe the best thing is to replace all these caps at the same time. The good news is that the larger Polypropylene caps will likely fit right into the existing clamps.
     

     

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  17. I was able to find out a little more information about these caps from the sales pamphlet I got when these speakers were purchased. It says in the Network and Level Controls Section of the pamphlet the following : We've selected expensive metalized paper capacitors for the crossover network because they exhibit less phase distortion and less current loss for improvements in tonal quality. So they seem to be paper with oil as you pointed out Ben. Thanks for the help and I will be ordering from Solen.ca as you suggest
     
    Last edited: Oct 12, 2018 at 7:52 AM
  18. Thanks tnsilver these are the caps I will likely buy from Solen.ca, minus the bypass caps based on Leestereo's comments regarding the L-pad adjustments already on these speakers.
     
  19. Leestereo

    Leestereo Super Member

    Messages:
    2,090
    Location:
    Ottawa, ON
    I suggest that you measure the capacitance of the PIO capacitors and if within spec, just replace the electrolytic and have a listen. Or replace the electrolytic and PIOs in one speaker and compare to the other to see you have a preference. After all, since you will have the replacements on hand, you can always replace at a later date.
     
  20. Good idea Ben and I think that's how I will proceed when the caps arrive. Nothing like a good comparison with the stock speaker (If the caps are still good ) and one that had the caps changed. That way their will be no doubt as to which one sounds better.
    I
     
    Last edited: Oct 13, 2018 at 2:06 PM

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