Mark Heija Posted July 7, 2021 Report Share Posted July 7, 2021 Hello Classic Speaker Pages Folks, This is my first posting on your site and am excited to be in the company of like minded (or should I say eared) listeners. My first speaker purchase was in the mid-70's and after a lot of comparison shopping (at Pacific Stereo) the AR-11 met my ideal. I remember taking in my Round Records release of "Old and in the Way" into the listening room so I'm sure it was in 1975. Not long after (and with a better paying job) I also discovered the LaScala. I've loved how both have sounded ever since. Recently I've embarked on my first crossover check-up... I have a bit of soldering experience and used a meter to test speakers when I rebuilt four salvaged LaScalas. I'm more of a woodworker than an electrician and have the cabinets already looking like new. I was told I would probably need to replace some (or all) of the capacitors and these are the assumed current component ratings (I see five capacitors so I'm not sure about this list - from a later AR-11 version? -some in parallel?): One 10uFOne 40uFOne 50uFOne 72uF I do see these same numbers on a schematic I found online. I'm hoping to get some advice on how to check the status of these parts and how to proceed iff necessary. Photo attached. Also, included a photo of the plugs I cut to fill some screw holes... had 'em up on steel brackets with added fastener security... living here in earthquake country (San Francisco)! Thanks for any help, Mark Quote Link to comment Share on other sites More sharing options...
DavidR Posted July 8, 2021 Report Share Posted July 8, 2021 Having a capacitor meter is a plus. You could see how much they have drifted over time. The resistors they used back then usually test very close to spec. There are better sounding resistors like Mills but its a personal decision. The parallel caps, like the 2 x 20uF, can be replaced with a single 40uF cap. There are NPE (electrolytic caps), like the originals, or film caps for replacements. You might find that film caps present a brighter sound. When I restored my 10Pi speakers I used NPE but added a small 'bypass' film cap in parallel to the base cap on the series caps only; not the shunt caps. Looks like the earlier version and not MkII so I'll attach a schematic for you. Quote Link to comment Share on other sites More sharing options...
AR55 Posted July 8, 2021 Report Share Posted July 8, 2021 Note that the AR-11 schematic provided by DavidR has an error. The 72uF & 50uF capacitors should be shown in parallel. In the second generation AR-11B, AR changed these to a single 120uF capacitor. A capacitor that size isn't that common, so you may need to go with 2 - 60uF capacitors in parallel. I used Dayton Audio capacitors from Parts Express, but others have their own favorites. Quote Link to comment Share on other sites More sharing options...
AR55 Posted July 8, 2021 Report Share Posted July 8, 2021 My mistake - the schematic is correct. It does show the 72uF & 50uF capacitors in parallel. Quote Link to comment Share on other sites More sharing options...
Mark Heija Posted July 8, 2021 Author Report Share Posted July 8, 2021 Hey Folks, many thanks for your input. I'm not sure if the meter I have works for capacitors (photo attached) and if it does, also not sure how to test with it... but ready to give it a go. Quote Link to comment Share on other sites More sharing options...
JKent Posted July 8, 2021 Report Share Posted July 8, 2021 Welcome Mark! Nice job on the plugs. When I restored some 11s for a friend I got 8 Erse 39uF caps, 2 3uF, and 2 10uF. Used a 39 for the 40 and 3 39s + a 3uF for the 120 (as AR55 pointed out, AR later changed the 72 + 50 to a single 120uF). https://www.erseaudio.com/Products/PulseXAll/MPX25-03-39-00 I had actually ordered the cheaper ones: https://www.erseaudio.com/Products/PEx250v/39uF-250-volt-Metallized-Polyester-Mylar-Film-Capacitor but they must have been sold out so Erse sent the more expensive ones. Either would do fine IMHO. I had the 10uF Carlis on hand but if I hadn't I would have used Erse for those, too. An LCR meter is nice (your Elenco is not an LCR) but for speakers this old and this valuable, my recommendation is usually to replace those NPE caps BUT the pink (?) Compulytics have a reputation of being very good and long-lasting, so I might be tempted to leave those.. Good luck with the rest of the restoration. Kent Quote Link to comment Share on other sites More sharing options...
Mark Heija Posted July 8, 2021 Author Report Share Posted July 8, 2021 Hello JKent, Thank you for clarifying my meter question, and for the parts recommendations. Fortunately, I just found out that metal shop director at the maker's space where I volunteer (teaching an intro to wood shop) is also an avid vintage HiFi enthusiast. We have an electronics bench with test equipment and he's also the resident expert in this area. I be visiting with him today to ask about an LCR meter. As you appreciated my plugs, I'm attaching some photos of a project I did with the teens at the Boys & Girls Club (I've recently retired after 43 years of running their Industrial Arts & Crafts studios). We found these cabinets being thrown away just around the corner from the Club. With some fantastic guidance from the Klipsch Online Community and parts from a wonderful gentleman Bob Crites (who recently passed) the project was a success. One pair was sold and the proceeds covered all the costs for materials and parts. The second pair is now in the Social Recreation room with a large screen TV. The kids can now really hear what audio should sound like;-) Quote Link to comment Share on other sites More sharing options...
JKent Posted July 8, 2021 Report Share Posted July 8, 2021 Wow! Beautiful! Regarding the LCR meter, that's for Inductance (L), Capacitance and Resistance. You only need the "C" part but the meters are often multimeters. If there's one on the bench, use that. You don't really "need" one since most speaker restoration involves putting in new capacitors, simply because electrolytics only last about 30 years +/-. Of course, some do last longer but anything in a classic speaker is on borrowed time. But as I said, those Compulytics were very high quality and "may" still be good. Quote Link to comment Share on other sites More sharing options...
Mark Heija Posted July 12, 2021 Author Report Share Posted July 12, 2021 Hey Folks, I have decided to replace all the capacitors but... I've been looking at a number of capacitor suppliers (Parts Express, Mouser, Digikey) and not doing so well. Trying to come up with varying combinations to arrive at 10, 40 & 122uF Electrolytic (Aluminum?) 100v non-polar (10%D.F. or 6%D.F.?) has been more difficult than expected... most are Back Ordered / Out of Stock. If you can address the Aluminum & D.F. questions and possibly how close to these numbers do I have to be, i.e. (120 for 122, 39 for 40). With this information I think I may try calling customer service to see if they can help with my order. I did find the 10uF in stock at Parts Express!Thanks again for help, Mark Quote Link to comment Share on other sites More sharing options...
JKent Posted July 12, 2021 Report Share Posted July 12, 2021 Remember that if you use electrolytics they MUST be non-polar. You won’t find much at Mouser. Use Parts Express or Madisound. PE definitely has poly Dayton caps in 40, 100 and 20uF. They also have electrolytics if you want to save money on the 120uF. Quote Link to comment Share on other sites More sharing options...
Mark Heija Posted July 12, 2021 Author Report Share Posted July 12, 2021 Hi JKent, Non-polar (check)... can you clarify D.F.% for me? or including Aluminum in description? Thanks Quote Link to comment Share on other sites More sharing options...
JKent Posted July 12, 2021 Report Share Posted July 12, 2021 Most electrolytics are aluminum. I was typing while you were so see previous message Quote Link to comment Share on other sites More sharing options...
JKent Posted July 12, 2021 Report Share Posted July 12, 2021 OK. At the computer now so it's easier to type. I don't know what D.F. is but here's an explanation of sorts https://www.illinoiscapacitor.com/pdf/papers/impendance_dissipation_factor_esr.pdf If ordering from PE: 10uF: https://www.parts-express.com/Audyn-Cap-Q4-10uF-400V-MKP-Foil-Capacitor-027-118 OR https://www.parts-express.com/Dayton-Audio-DMPC-10-10uF-250V-Polypropylene-Capacitor-027-428 OR https://www.parts-express.com/Jantzen-0264-10uF-400V-Crosscap-Capacitor-027-932 (I'd use the Jantzen but the others are good too) 40uF: https://www.parts-express.com/Dayton-Audio-DMPC-40-40uF-250V-Polypropylene-Capacitor-027-442 120uF: This is trickier. You could use NPEs to save money but most values are back-ordered. Odd. This 100uF film cap is $35,https://www.parts-express.com/Jantzen-0290-100uF-400V-Crosscap-Capacitor-027-956this 20uF is $12. https://www.parts-express.com/Jantzen-0271-20uF-400V-Crosscap-Capacitor-027-939 That's $47 per speaker. Too much. I'll check Madisound and Erse and get back to you. Quote Link to comment Share on other sites More sharing options...
JKent Posted July 12, 2021 Report Share Posted July 12, 2021 Madisound 10uF: https://www.madisoundspeakerstore.com/m.d.l.-xpp-poly-capacitor-250vdc/mdl-xpp-polypropylene-10mfd-250v/ 40uF: https://www.madisoundspeakerstore.com/solen-capacitors/solen-40-mfd-fast-cap-400v/ 120uF: https://www.madisoundspeakerstore.com/m.d.l.-electrolytic-capacitor-100vdc/mdl-100-mfd-non-polar-electrolytic-capacitor-100v/ AND https://www.madisoundspeakerstore.com/m.d.l.-electrolytic-capacitor-100vdc/mdl-22-mfd-non-polar-electrolytic-capacitor-100v/ Quote Link to comment Share on other sites More sharing options...
JKent Posted July 12, 2021 Report Share Posted July 12, 2021 Erse 10: https://www.erseaudio.com/Products/PulseXAll/MPX25-03-10-00 40: https://www.erseaudio.com/Products/PulseXAll/MPX25-03-39-00 or TWO of these https://www.erseaudio.com/Products/PEx250v/20uF-250-volt-Metallized-Polyester-Mylar-Film-Capacitor 120: https://www.erseaudio.com/Products/NonPolarElectrolyticAll/ANP10C-05-100-0-PB AND https://www.erseaudio.com/Products/NonPolarElectrolyticAll/ANP10C-05-20-0-PB Or to stick with film, you could bundle 3 of these 39uF (close enough) https://www.erseaudio.com/Products/PEx250v/39uF-250-volt-Metallized-Polyester-Mylar-Film-Capacitor Quote Link to comment Share on other sites More sharing options...
Mark Heija Posted July 12, 2021 Author Report Share Posted July 12, 2021 Thanks so much for helping me navigate the maze of these websites! When the description includes "poly" and "film", it was suggested these change the original sound, "brighter". Should this be a concerned about this? Quote Link to comment Share on other sites More sharing options...
JKent Posted July 12, 2021 Report Share Posted July 12, 2021 Erse is the most economical by far. If those were my speakers I'd use Erse film caps. Electrolytics are OK and that's what was originally in there but film lasts forever. I used Erse film caps in the 11s I did for a CSP friend, as pictured in my first reply. The black ones are PuseX, the more expensive ones, but the yellow PEx are fine and actually closer in ESR to the original NPEs if I understand things correctly. Quote Link to comment Share on other sites More sharing options...
JKent Posted July 12, 2021 Report Share Posted July 12, 2021 6 minutes ago, Mark Heija said: Thanks so much for helping me navigate the maze of these websites! When the description includes "poly" and "film", it was suggested these change the original sound, "brighter". Should this be a concerned about this? I don't know if it makes them brighter. There are so many other factors and there's always the level controls on the back of the speaker. Quote Link to comment Share on other sites More sharing options...
Mark Heija Posted July 12, 2021 Author Report Share Posted July 12, 2021 Got it! I'll let you know how things progress. Oh, one more question. Is that Hot Glue that holds the parts in place? Is that what I should use? Quote Link to comment Share on other sites More sharing options...
JKent Posted July 12, 2021 Report Share Posted July 12, 2021 There are different varieties of film caps. Most common are polyester (mylar) and polypropylene. There's nothing wrong with non-polar electrolytics (aluminum) aka NPE but they can drift over time and eventually wear out or go badly out of spec. Film caps will last and if you want to pass the 11s on to the next generation, use film. 11s are excellent. More modern version of the illustrious AR-3a. Quote Link to comment Share on other sites More sharing options...
Mark Heija Posted July 12, 2021 Author Report Share Posted July 12, 2021 I also see variations in voltage... what should I watch for? Quote Link to comment Share on other sites More sharing options...
JKent Posted July 12, 2021 Report Share Posted July 12, 2021 6 minutes ago, Mark Heija said: I also see variations in voltage... what should I watch for? Doesn't matter a bit so long as it's 100vdc or more. Quote Link to comment Share on other sites More sharing options...
Earthnz Posted July 14, 2021 Report Share Posted July 14, 2021 Very informative discussion for people, like me, jumping into a AR-11 restoration... Thanks 👍👌 Quote Link to comment Share on other sites More sharing options...
JKent Posted July 14, 2021 Report Share Posted July 14, 2021 On 7/12/2021 at 5:29 PM, Mark Heija said: Oh, one more question. Is that Hot Glue that holds the parts in place? Is that what I should use? Sorry I missed this. Hot glue “may” damage caps. Use something like E6000 or tie wraps on bases. Quote Link to comment Share on other sites More sharing options...
Mark Heija Posted August 10, 2021 Author Report Share Posted August 10, 2021 Hello JKent, Sorry for the lapse in communicating... It's been that my hesitancy to plunge into snipping out the old and soldering the new that gives rise to my tendency to procrastinate. Not that I'm ignoring the project, on the contrary, I've been finding all sorts of side projects to keep me busy. 1) Used a cool online Trig calculator to determine the exact downward angle for the speakers to face the cross room listening chairs (used string to create a right triangle). This angle was translated to wood platforms, later felt lined. 2) Built risers to get the speakers high enough to clear a door in one corner of the room, as well as placing them within the cove of the ceiling (good for sound dispersion?) and on swivel platforms for fine tuning. 3) Designed a "garage" for a Sansui where when opened the door slips out of the way. 4) Fabricated cradles to adhere the capacitors to the speaker bottoms. Here's where I have some questions: Do I need to worry about the wood cradles creating an insulation that may help generate too much heat? In soldering the two capacitors (100uf & 22uf) in parallel, is there a preference as to which might attach to which? Also, cut my own foam tweeter surrounds and built some bracing to attach a circular omnidirectional FM antenna outside the window. I am starting the recap this week for sure, after I run new speaker wire along the molding 😉 Thanks again for your help, Mark Quote Link to comment Share on other sites More sharing options...
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