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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

    DIY Supertweeters

    Thank you all for the positive comments! In the first ones I experimented a bit with the values. I had planned to do 1uF and 2uF, like the MicroStatics, but the effect was too much, so I replaced the 2uF with a 0.47uF. But I think the issue wasn't the crossover point, it was the volume. So with the attenuators in place I went back to the 1 & 2uF layout but I adjust the volume for a more subtle enhancement. Nice hefty tweeters but no printing on the backs.
  2. JKent

    Ar-3a Capacitor Advice

    I did 2. For the first I recapped the original boards but for the second, shown in the previous post and now powering my 3a's, I used Musical Concepts http://www.musicaldesign.com/Haf_pwrmods.html I used the PA4 boards because they were on closeout for $209. Now they're up to PA6 so you can get the PA5s at a nice reduction ($279 vs $499 for PA6). The Musical Concepts boards do have DC offset adjustment. There are extensive instructions but I found them somewhat confusing at times. The owner, John Hillig was very helpful when I needed support. I used some parts from ebay seller qua-co (Fantasia Audio) https://www.ebay.com/str/QUA-CO-AUDIO?_trksid=p2047675.l2563 He's a former Hafler employee, located here in NJ. For the first one I used his Hafler 200 semiconductor repair kit, inrush limiter, and bridge rectifier. I bought new caps for the boards as well as the big 22000uF caps from Mouser. Added new gold RCA jacks and binding posts. I see qua-co now has "HIGH END AUDIOPHILE UPGRADE KIT TOSHIBA JFET CASCODE TOPOLOGY" for the 200 AND for the 500. Those may be a good alternative to the Musical Concepts boards. They're $249 OBO (!) and include RCAs and binding posts. If I were doing it again I'd buy the big output caps from him too (I think his price is about the same as Mouser). I have NO connection with qua-co, just a satisfied customer. The seller, Ed Fantasia is a good guy and provides fast email support. Kent
  3. JKent

    Ar-3a Capacitor Advice

    Amen to that. And it's fun to experiment. I'll admit to using bypass caps in several applications even though I don't believe I hear any difference. The vishay roederstein mkp1837 or Russian PIOs only cost about a buck apiece, so why not? I even "cascaded" some bypass caps on a recent Hafler 200 rebuild (shown below--that's a 22000uF Nichicon 'lytic, 10uF film, 1uF PIO and 0.01uF mkp1837). And I may try those Mundorf E-caps. But there's a point of diminishing returns that each must decide on for himself. When I see 1uF caps "sale" priced at $107 (marked down from $214) I gotta wonder. But I have the same attitude about cables. Dirt-cheap no-name cables are questionable but Monoprice has good cables, cheap. BlueJeansCable has very good cables for a little more. Beyond that, IIMHO (and YYMV) it's a waste of money that could be spent on music. Remeber what Carl used to say: "It's all about the music."
  4. JKent

    Ar-3a Capacitor Advice

    Yes. You did 😉
  5. JKent

    Ar-3a Capacitor Advice

    An LCR meter can be a good investment. They start at $30 on Amazon, even less on ebay. In fact, the ones that look like a kid's science kit and sell for about 10 bucks are quite good and test a variety of components. My technician, who owns thousands of dollars' worth of test equipment bought one and was impressed. Those even test ESR so if you're fanatical about using the "right" capacitor you can address that issue. And besides testing your Spragues, it's not a bad idea to test new caps before installing them. btw--I tend to use inexpensive caps. Bought a bunch of those 10uF surplus caps whan Madisound had them for ).60 each and otherwise use Carli or Dayton. BUT if you want good quality "esoteric" caps for the 150uF value, Madisound has 155uF ClarityCap ESA series on sale for $59 each. PE has the Audyn 100uF 400V for $26 each. Add a 50uF Dayton @ $15 and the 150uF is $41. The most bang for the buck may be to use NPEs for 50 and 150uF and film caps for 6uF. Carlis are $1.80. Clarity PX is $6.20. Solen is $3.90. I'll admit to splurging a little on mine because I didn't want to ever have to re-do them. I used Dayton 100 + 50, 50 and Clarity PX 6uF. I only used the Clarity because I had them on hand. I'm sure I can't hear the difference. I've recapped KLH Model Fives with everything from all NPE to a mix of NPE and film to a mix of surplus and Carli caps to one I did with all ClarityCaps SA series (the older red ones). I couldn't hear any difference. The room, furnishings and signal source will have far greater effect. -Kent
  6. JKent

    I Have AR-5's

    Sara, Love your write-up, your journey and your comments. Glad you're enjoying these. Are you still using the Hi-Vi tweets? I'm curious to know your impressions of Hi-Vi vs the Chris1 rebuilds. I'm actually wondering if there is any discernible difference at all. -Kent
  7. JKent

    DIY Supertweeters

    So further experimenting with the "found" L-pads and pots, they work fine. The Clarostat pots were salvaged from a pair of Rectilinear XIa crossovers. Here are the innerds. I used caps that were on hand. For the pair with the Violet L-pads the caps are Madisound Surplus 2uF mylar (with the maddeningly short leads) and Russian 1uF paper-in-oil. For the pair with the Clarostat pots the caps are 2uF Carli and 1uF Russian PIO. And for these 2 pair I used brass threaded rod and acorn nuts. Back of one shown below. Push-on knobs from ApexJr.com On the other pair I'll use DakaWare knobs that match the AR-3 etc.
  8. Well I don't have definitive answers but here are some thoughts: Don't know if they designed it but CTS made a lot (all?) of the originals. Phenolic IS plastic DK about any KLH inspiration PE still has them (by GRS). They "had" some nice buyout specials with metal screen grilles but they had different characteristics. Don't know about the other questions.
  9. Welcome kittidat I'm not sure I understand your question. Are you using KLH Model Twelve contour boxes with those Goodmans and Jensen drivers? If so, you may have the contour boxes hooked up wrong. On the back of the contour box there are two terminal strips. The bottom strip has 2 terminals for the connection to the amplifier. They should be painted black and silver. If not, the left one (viewed from the back) is - and the right is 8 ohm (+). The top strip has 4 terminal screws that should be painted Black, Red, White, Yellow. Black is - and common to all 3 drivers. Red is woofer +, White is mid +, Yellow is tweeter +.
  10. JKent

    AR-4X tweeter and crossover upgrade?

    Welcome Harley The Hi-Vi tweeters you linked are great replacements for those in the AR-3a but won't work well in the 4x. The tweeter crossover in the 4x is at 2,000 Hz IIRC. The Hi-Vi's frequency response is 2,500 - 20,000. Your best bet is to use original AR-4x tweeters. Some people (myself included) have reported some success using phenolic ring tweeters like these https://www.parts-express.com/grs-prt-8-phenolic-ring-tweeter-replacement-for-ar-4x-cts-marantz-and-more-8-ohm--270-252 Photo below shows 4x with PRT. This is NOT an "upgrade", it's a "make do" if your original tweeters are shot. IF YOUR ORIGINAL TWEETERS ARE NOT DAMAGED DO NOT REPLACE THEM. Replace the wax 20uF capacitor with a 20uF film cap (leave the original in place and just cut the wires). If you use the PRT tweets, maybe try a smaller value cap as Roy suggested in the linked thread above. Replace the pots with L-pads. The linked thread shows how to wire them. Your 4x's with ORIGINAL drivers, new capacitors and new L-pads will sound great. -Kent
  11. JKent

    Upcoming AR3a project

    I thought maybe he cobbled them together himself. There are photos of the innerds on the ebay listing and they look like coils recycled from old A-P pots. The ad states "I decided to re-manufacture original wirewound controls that were used back in the days." They do look nice on the outside.
  12. JKent

    KLH Seventeen Woofer Cone Lead Wires

    A belated welcome baconbadge I'm sorry but I don't know how to fix that. Maybe glue? Hoping another member would chime in here. If not, Bill LeGall could certainly fix it http://www.millersound.net -Kent
  13. JKent

    How to test crossover on Advent/1

    I'm sure it's an Advent/1 and not an NLA. The photo I posted was an Advent/1 and the OP's sure looks the same to me. But your point, I think, is that the inductor is air core. I think this shot (also "borrowed") shows the construction of the coil better. -Kent
  14. JKent

    How to test crossover on Advent/1

    Welcome greyeyezz I agree. The Advent/1 was produced 1978-1983 so your capacitors are about 40 years old. Electrolytic caps have a life expectancy of 23-30 years or so. Some last longer but they are on borrowed time. The Advent/1 has just one 13uF capacitor. I've never been inside them but here's a photo I "borrowed" from an ebay listing. 13uF is an odd value but you could use 12uF (close enough) or use 2 caps paralleled. Film caps are preferred because unlike electrolytics they don't go bad. These are good, and they're inexpensive: https://www.madisoundspeakerstore.com/carli-capacitors/ If you've never done it before, it's easier than it looks. Plenty of help available here. And how are the woofer surrounds? Foam surrounds deteriorate faster than capacitors. We can help with that too. -Kent
  15. JKent

    Pot vs L pad

    Thanks, Pete