JKent

I'd contact the seller and tell him you want a refund because that's not an AR-4x. Any problem, you can file a complaint with ebay but most sellers are honest and will correct a mistake. There are two listings for real 4x tweeters on there now, $49.99 each (I have no connection with the seller) Kent

Well, Henry Kloss is said to have remarked that he "finally got it right" with the Model Six. So I think he was pretty proud of them. BUT beware (and I should have mentioned this earlier) early Sixes have epoxied-in drivers, making them a royal PITA to work on. Guess Henry was so sure he's gotten it right he didn't want anyone inside. If the Sixes you're looking at have the epoxied drivers, I'd stay away. The Twenties are fine if your amp can handle the 4 ohm load. I added 5-way binding posts to the ones I worked on. The Six was a bigger speaker, with a 12" woofer. The Twenty had a 10" woofer (actual sizes of all KLH woofers were less than stated). Kent

Beats me. The 20 was part of a system, 4 ohms and with an RCA jack fo hookup. The 17 was the 8ohm stand-alone version. Get the Six.

Two problems with those: First, they are the wrong value. You need 15 Ohm, those are 30 Ohm. Second, like the expensive Ohmite pots, those are open in the back and you would need to construct some sort of enclosure to keep the fiberglass out. If you check the For Sale section you'll see some pots I'm selling. https://community.classicspeakerpages.net/topic/13225-potentiometers-for-ar/ PM me if interested. Postage to the UK is $26 USD for the 4 pots you will need. Kent

Still available

"Before" it was filthy, grille cloth was faded, cord was stiff and a knob was missing. Pretty now but needs work.....

Nice radio but full disclosure: I don't have a lot of technical expertise. I just bought one in similar condition--nice cosmetics but not working. Mine's a 21/II. I replaced a dried out power cord and the 2000uF filter cap but still no go, so it's off to Tim at Bristol Electronics. He'll have it good-as-new. btw, don't just go by appearance on that fuse. Check the continuity. Good luck and keep us posted. Kent

Welcome Jason Are they the highboys or the lowboys? https://en.wikipedia.org/wiki/Rectilinear_Research_Corporation Show us some pics! Either way, pretty special (although I have not heard them, I did have some III Minis that were very cool). Definitely keep if you have the room. Or put them on the curb in my neighborhood 😉 I would recommend replacing the capacitors. Mine had black caps with red ends--those are notorious for drifting. You can use NPE for the 90uF and film for the 2uF. Kent

Sorry I missed this. Hot glue “may” damage caps. Use something like E6000 or tie wraps on bases.

Nice. I think you will be able to refresh those cabinets when you have a chance. Meanwhile, the caps should make a significant improvement. Do you have the grilles?

Doesn't matter a bit so long as it's 100vdc or more.

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.

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.

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.

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

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/

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.

Most electrolytics are aluminum. I was typing while you were so see previous message

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.

I have never worked on the AR-6 but it is not unheard of for an 8 Ohm system to have a 4 Ohm tweeter. Try to find 8 inch 8 Ohm AR woofers. Kent

I did a search and found some discussion on AK. Try this search: KLH thirty-eight speaker site:audiokarma.org Looks like the classic Thirty-Eights (as opposed to the CT-38) came in 2 different versions. One with a naked tweeter and one with fiberglass over the tweet. Otherwise basically the same as all the 2-way KLH speakers of that era. Nice cloth-surround woofers. You definitely need new capacitors. I saw a photo in one thread with the notorious Temple black caps with red ends. One 4uF per box. Those leak over time. Kent

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.

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

Just a note for other members who want to use real pots. Please see the For Sale section: https://community.classicspeakerpages.net/topic/13225-potentiometers-for-ar/

The AR-91 is essentially a slightly more modern, floor-standing AR-3a. I got a great deal on a pair 10 years ago: These are my "reference" speakers but some day I'd like to try stacking the AR-3a's on top.