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About JKent

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    Advanced Member
  • Birthday July 14

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  • Location
    Appalachian Mountains of NJ
  • Interests
    KLH Model Eight radios, classic American Hi-Fi, Miles Davis, classic rock, C5 'vette

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  1. JKent

    Heathkit AS-103a Restoration questions

    Those surplus Russkie pots show up once in a while on ebay. I bought 2 but have not used them. Other members have tried them and may chime in. They appear to be well made but like the Ohmite pots they are open and therefore must be put in some kind of enclosure to keep the fiberglass out. From my experience with Ohmites I can tell you it's a PITA. But some members have made them (Ohmites) work. Here are 2 pics of Ohmite installations. CSP member Xmas111 did a beautiful job, using an enclosure made of wood and Masonite. My XO is less beautiful. I used a standard project box. Best solution IMHO is to follow the instructions in the AR-3a Restoration Guide and use L-pads (from PE or Madisound) with 25 Ohm 10w resistors on the mids. Also use resistors on the tweets if you go with Hi-Vi or Chris's rebuilds. One more thought. I've never worked on the Heathkit version but I can tell you based on working on KLHs--that metal plate can be a problem. Be SURE no metal parts touch it and if you remove the terminal screws for any reason observe how they are insulated and be sure to replace the insulation. KLH used 2 rubber washers on each screw; a flat washer and a shoulder washer so the screw was isolated from the plate. -Kent
  2. JKent

    Another AR-3a restoration

    Finished the 2nd xo (2nd one always goes faster). Scraped gobs of duct seal off one woofer and cabinet. Cleaned the woofer flange with alcohol & Scotch Brite to prep it for PE foam gasket tape. Also soldered leads to woofer terminal tabs. Woofer will be easier to remove if needed.
  3. JKent

    Another AR-3a restoration

    Finished one xo. I had forgotten how tight it is working inside that box but itโ€™s all wired up. You can see the 3 original inductors across the top in this photo. Below those are the 6uF cap, Tweeter L-pad and Mid L-pad. Both have resistors installed per the AR-3a Restoration Guide. Then in the lower area are the 50+100uF bundle and the single 50uF cap. Some of the wires are new but I kept the original color coding. On to the other one, probably tomorrow.
  4. Glad things are working out. Looks good. Yes--you should be able to use a single strand of copper. Be sure to tin it. The blue plastic insulator is a wire nut. It's meant to splice 2 wires. So if you soldered them there's no need for the nut. Things sound brighter because of the crap pots that were in there. If you don't feel you get enough modulation with the pots install a 25 ohm 10w resistor on the Mid pot (refer to the AR-3a resto guide). And speaking of the guide, in there John suggests 28-count crinoline to replace the crumbling paper Kimpac. However, Roy made a brilliant (IMHO) recommendation for my current 3a restoration: Low loft poly batting from Walmart. A crib-size piece is under $4, in the fabric dept. Good luck. Kent PS. This stuff: https://www.walmart.com/ip/Morning-Glory-Low-Loft-Batting-1-Each/19397503 or from JoAnn's https://www.joann.com/poly-fil-low-loft-bonded-polyester-batting-crib-size-45inx60in/7145667.html
  5. JKent

    AR22BX Woofer Drivers

    Welcome Meerkat! Why not refoam them? It's pretty easy. If you "love the tone in the room" any non-original replacement will disappoint you. I believe your woofers were made by Tonegen (by the TNG in the part #). If you are not up to the task yourself, contact Bill LeGall http://www.millersound.net He'll make them good as new. -Kent PS: You did not say where you are. The 22BX was (also?) made in England. If you're on that side of the pond Bill can't help you.
  6. Agree with Adams. Some other options: Contact CSP member RoyC to repair the leads Contact CSP member Chris1This1 to repair the leads Install Hi-Vi tweeters with inductors as described in Restoring the AR-3a. You can always sell the old tweets (even with a broken lead) on ebay. -Kent
  7. Yeah David, I feel your pain. Those tinsel leads are maddening. They are way too brittle and break easily. When I refurbished an early pair like yours I ended up replacing the tweeters (which were both dead) with later 2ax tweets. So I have NO experience repairing the aluminum tinsel leads. Those crimps were John O'Hanlon's recommendation. John is no longer active on the CSP. This is just speculation but maybe you could make your own crimp from very thin aluminum tubing, sold at hobby shops. There such a thing as aluminum solder but I understand it is very tricky to use. There is also, as mentioned in the resto manual, "conductive glue". Bill LeGall http://www.millersound.net/contact-bill-legall-millersound.html is known for repairing woofers but it may be worth a call to ask if he can repair the leads on your tweeters. Good luck. The early 2a's are really beautiful speakers and worth repairing. Kent
  8. See page 20 of Restoring the AR-3a
  9. JKent

    BOSE 901 SERIES V - speaker rot question

    Welcome Charlie Don't play the speakers until they've been repaired. Foam surround rot is common to ALL speakers of that age, not just Bose. As dxho says, you can replace the surrounds. It's not difficult and people here can help. Here's a good source for repair kits: http://www.speakerworks.com/bose-801-802-901-902-speaker-repair-kit-p/swk425bose.htm One kit will repair 9 drivers. Each speaker has 9 drivers. If 4 of the surrounds are shot, the others will soon follow. Parts Express sells "Bose 901style" drivers for $20 each but they're not really Bose and replacing the drivers when only the surrounds are shot is foolish (I know this from experience. Live and learn). If you absolutely can't do the surrounds yourself (sometimes life intrudes on our hobbies) you might let us know where you are and maybe another member can help you out. OR contact Bill LeGall. He's the acknowledged master speaker repair shop and a good guy http://www.millersound.net You can give him a call. Nice score on your part but don't rush into playing them without replacing the surrounds. It is possible, given the distortion you hear, that one or some drivers are already damaged but it's very likely just the surrounds. btw, after all the drivers are working you may want to think about refurbishing the EQ. Just a thought. -Kent
  10. JKent

    Another AR-3a restoration

    Quick update: The original owner tells me these were never opened, but the 2nd one is also light on stuffing. No matter--I'll put in all new. The big 150/50 brick measured 222/70. The 6 measured 7.76 uF. The mid is fine but the tweeter, although working, is extremely weak. Time for a rebuild. My PE order just arrived. Now the fun starts!
  11. JKent

    AR3a grills

    The resto guide mentions gel contact cement ("Goop"). I think the adhesive on your Velcro just isn't strong enough. It also specifies a power stapler. They specifically mention Sears "chisel point" staples but I don't believe they are available. Personally, I use Arrow Monel (stainless steel) for grilles because they're, well, stainless. Kent
  12. JKent

    AR3a grills

    der, Could you tell me what the issue is with Velcro? I'm restoring a pair of early 3a's and the owner asked for Velcro. Restoring the AR-3a does suggest 6 small Velcro tabs but also says "contact cement alone is not the most permanent method. A 1/4" staple is needed . . ." If your self-adhesive Velcro is pulling off, maybe just add staples. -Kent Thanks, Kent oops. I see Gene already answered as I was typing.
  13. JKent

    Another AR-3a restoration

    Hey ra.ra And I'll look forward to following your resto. To answer your questions, I had a cheap LCR meter and like you was not fully comfortable with it. I'm now using a B&K Precision 810C, which is very good for my purposes and less expensive than a Fluke. OTOH, it doesn't test inductance (L), which is sometimes helpful. Which brings us to your other question. According to p. 17 in the restoration guide, yes. "In late 1969 or early 1970--probably at the introduction of the ceramic woofer--AR re-measured the 3a and increased the woofer inductor to 2.85mH (AR #9 coil)." The guide says to either leave the #7, add a 1.0mH coil in series or replace the coil with a new 2.7uH (closest available off-the-shelf). edit: That passage in the Guide is ambiguous at best. Fortunately we have Roy to set us straight. Latest word from him his there's no need to change the inductor with the alnico woofer. Good. Less work for me ๐Ÿ˜‰ Another bit of advice from Roy: the originals were over-damped at 28-30 oz. I'll use 20 oz. per speaker, which I think is 2 little bags of unfaced Johns-Manville FG. Oh--one other thought about capacitance testing. It may be helpful to also test ESR. I have one of those dirt-cheap no-case LCR meters from ebay. Think they're under 10 bucks, shipped from China. They actually work and they test virtually everything: "Test ranges: Inductors, capacitors , diodes, dual diode , mos, transistor, SCR , the regulator, LED tube , ESR, Resistance, Adjustable potentiometer". You could spend a little more and get it on Amazon, with a case https://www.amazon.com/Multifunction-transistor-Capacitor-Inductance-screwdriver/dp/B071Y5CHPK/ref=sr_1_20?gclid=Cj0KCQjwzunmBRDsARIsAGrt4mu6haKVP97dIgOgpmyVAD2H__8B8LraqC7qqIXNJoO-Y9RWMp9k4-AaAkq0EALw_wcB&hvadid=177795303352&hvdev=c&hvlocphy=9003579&hvnetw=g&hvpos=1t1&hvqmt=e&hvrand=10918808959811123088&hvtargid=kwd-309580207&hydadcr=25905_9903850&keywords=esr+tester&qid=1557840037&s=gateway&sr=8-20
  14. I was asked to restore some AR-3a's. Turns out they still belong to the original owner who bought them from Sound Reproduction in East Orange NJ back in 1969 or 70. That's where I bought my 4x's at about the same time! So my first thought is to adhere to the speaker doctor's oath of "first, do no harm." The cabinets and grilles are perfect! I'll clean the wood and oil them but nothing more is needed. The linen, although undamaged, shows its age so I'll install new linen from 123 Stitch. These are early, with serial numbers in the 31,000 range, so they have the cloth-surround alnico woofers. I opened one today. The woofer is stamped Sep 17, 1969. Masonite on the surround and spider seem OK. The Kempac is intact but old, so I'll replace that with crinoline. The fiberglass is nasty, crumbly stuff. I put it in a bag and weighed it. Only 15 oz. Odd--it should be 28-30 oz and these "look" unmolested. I'll replace it with the correct amount of new, formaldehyde-free FG. Pulled the wax bricks. The 150/50 measured 210 and 69uF. The 6 measured 7.8uF. I'll be using film caps as replacements. All the drivers in this one work but there are lots of dead spots on the pots. I'll replace them with L-pads. Sort of undecided, for now, about what to do with the #7 inductor but there's lots of time to think about that and get input from others. Photos will be posted when I have anything interesting. -Kent
  15. JKent

    KLH Model Twenty

    Yes. The 17s are 8 ohm, the 20s are 4 ohm. Tweeters and crossovers are the same. Only the woofers are different.