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Everything posted by ChrisM

  1. If the woofer is 4ohms and if the coil is 2.3mH then the crossover WOULD be around 250Hz. A 100Hz crossover would require about 6.3mH or so. All I have is a photo of an Xa crossover but it has 2.3mH printed on top of the coil. Explaining marketing is beyond me.
  2. That rear shot of the woofer looks familiar. I recently rescued a set of Advent Prodigy II speakers. I had to re-foam them and the woofer looked essentially identical to yours except I think the Advents had a bigger magnet. The Advents at that time were made by Jensen. I got the surrounds from Rick Cobb, a well known purveyor of surrounds. https://www.ebay.com/str/looneytune2001 It sounds like these would be good "lab rats" to experiment on. Good Luck!
  3. Reminds me of a KLH 32 but it looks like a 6.5" woofer. The crossover cap isn't one of the really terrible ones but I'd change it out. Unless the vinyl is really bad I wouldn't go to the trouble of re-veneering them. They may be decent speakers but they aren't "classic" speakers. If you really like the veneer idea, I'd do the re-foam and recap first and see if I liked them that much.
  4. That first one does look very nice and no doubt the second one will be just like it. I would like to caution you though about something I just noticed. Kent's woofers had no markings on them and your photos show none so we don't actually know which Peerless woofers they are. I was admiring the photos of your finished one when I noticed that the surrounds appear to be shiny and smooth. I then went back and looked at your earlier photos of the woofers. It is quite possible that these Peerless woofers have surrounds made of PVC. If they do, it is imperative that you keep the grill covers on. There is a lot of evidence that sunlight causes the PVC surrounds to degrade. At first their parameters start changing but it is so gradual people don't notice any changes in the sound. Eventually they shrink up and lose their shape thus wrecking the driver. They also lose their shiny "plasticy" look. Once this happens, that's it. So far no replacements for PVC surrounds have been found so repair isn't possible. Heat and humidity may also affect them but the main factor appears to be sunlight. This also affects neoprene surrounds to a much lesser degree and butyl rubber the least. It is somewhat ironic that people who spent more money to get higher end speakers back in the 70's and 80's left the grills off to admire the drivers and because in general they sounded better with them off and now their surrounds are bad. Obviously the Soprano's were voiced with the grills on since they glued them so there should be no sound penalty to leaving them on.
  5. Sure go for it. As I said, I'm not a member of the "bypass" church but it won't hurt and it's sort of authentic. It looks like the originals were both polyester so either that or polypropylene for an upgrade.
  6. Since you're not doing a "purist" restoration, I'd say just use one high quality cap. Solen makes a 6.2uF for about $5. I forgot. In that previous post when we were discussing the crossover, I mentioned it was about 3KHz. I got that number from assuming an 8ohm tweeter and a 4ohm woofer system. The coil would have to be more like .4 something uF for 3KHZ with an 8ohm woofer system.
  7. Probably. two 8ohms in parallel. Back when, most of the drivers were 8ohms. I know Mr. Kloss made some 4ohm ones but the vast majority of commercially available ones were 8. In Paleolithic times, 16ohm drivers ruled the land. 16ohms makes tube amps happy.
  8. Good question. From photos floating around the interwebs it looks like it is a foam surround or half-roll cloth and it was a acoustic suspension system. If you look at the 1976 driver price list they show the same woofer for the III, the 5 and the 7 which doesn't seem right. The early III woofers were Jensen and then CTS. The mini III is a CTS and probably the other "little" Rectilinears.
  9. Well...... Your picture of the sad looking crossover is interesting because the larger(6uF) cap looks like an electrolytic. It looks like metal end caps which to me says electrolytic but it might be a paper in oil. The one in Kent's picture definitely looked like a Mylar or polypropylene. The simplest answer to the parallel cap question is that they wanted a 6.3uF cap. If these were really that fancy a speaker, they would have measured the caps for exact value. Having said that, it is also true that a 6db per octave series crossover isn't that critical of values. This isn't an LS3/5a crossover where values really are critical. Some people are also big believers in using super high quality small value caps to bypass larger caps. I am not one of them. So not only did they use different tweeters but different caps. We will need some pictures of your rebuild so we can learn more about these speakers and to cheer you on.
  10. The woofers being Peerless explains why I didn't recognise them (not British). I think a lot of people made their own versions of the KEF B110. It is also interesting that the ones you worked on had the big Audax tweeter and the 6moons review ones had the 1" dome Seas tweeter. The Seas units are very good tweeters and were used in a number of commercial speakers one example being the Boston Acoustics A200. Those tweeters do sound nice. I know because I have a pair. Mine are currently sitting on the shelf but I have plans for them.
  11. Kent, take a look at this: https://audiokarma.org/forums/index.php?threads/european-holophone-systems-soprano.915874/
  12. In actual use there isn't much if any difference between the black frame and the silver however I did measure a difference in resonant frequency between them. The black ones have a significantly lower Fs. Neither type has much of a peak at resonance and the crossover is so broad it just doesn't seem to make much difference. The black ones came in the earlier 17's. The change was I believe in late 1969.
  13. Having a quick look at the specs for the Ditton 44's, if you're happy with the Arcam's performance, you should be equally as happy when using it with the IMF's. I would normally say that something with more like 100W per channel would be appropriate but it totally depends on your listening levels and choice of program. It might behoove you to consider recapping both of them as they are older. Also trying to judge whether the Arcam is working well with the IMF's isn't valid if the capacitors in the IMF's are bad.
  14. Hi Larry, Rectilinear III's are very different from most speakers. The main driver is the midrange. The 4 tweeters and Flex-Air woofer just fill in the very top and bottom . This way of designing a system require a really good, really wide range mid-range so Jon Dahquist used a full range driver. No crossover, no phasing issues just a bit of help on the top and bottom. Spendor did the same thing in their classic series 3 ways.
  15. I just meant expensive in relation to an older Sansui driver. If IvanB loves them it's worth it. I've only ever heard good things about Millersound and the prices mentioned are very good.
  16. After the sorry state you got them in, I'm sure the owners will be very pleased. Good job!
  17. I second the Millersound suggestion but the cure may be expensive. If they are really stiff you have little to lose so you might try using a small paint brush to apply a bit of MEK to them. Instead of MEK there is Toluene or Xylol/Xylene. It is hard to say what Sansui used although any of them should work. These were commonly used as solvents to apply the sealant to the cloth which has obviously dried up. Reapplying some of the solvent might loosen it up. Be careful to just apply it to the curved area not the part on the cone or frame. Try a small area on the worst afflicted part and gently prod it to see if it is softening before continuing. Do not saturate it and don't do it indoors. Interestingly enough, I was going to try the same thing on a set of otherwise good woofers I salvaged. If you want to wait a bit, I can try it on mine first measuring them before and after to check how it works.
  18. Kent, what is the black stuff on the coil? Is it some kind of goop or is the coil insulation burned?
  19. Series crossovers are more tolerant of driver impedances. The resistor will change it but less so than a parallel network. Are you going to use velcro for the grills?
  20. It's true, AR's were balanced to sound like you're half way back in Boston Symphony Hall. KLH's put you about a third of the way back. With Advents Mr. Kloss moved you into the first quarter of the audience. Boston Acoustics are about the same as Advents just cleaner sounding. Hard to say what the best balance would be. The owners might like it brighter. The Dayton woofers may not be as efficient as the originals. Because of the series crossover you can't just stick in an L-Pad. Referring to your second drawing of the crossover, I would insert a 3 ohm, 10 watt resistor between the tweeter plus and the coil. If that doesn't make sense let me know and I'll redraw it. I really don't like series crossovers.
  21. Jeez calm down!? I'm 68 and if the corona virus doesn't get me, moving around Altec Valencias and Rectilinear IIIs just might. Sadly, my KLH 22's and 14's just don't sound as good no matter how much I love them.? If anyone wants to donate some KLH Fives to the "save Chris' back" cause it would be welcomed.
  22. Just out of curiosity, are the owners elderly? I was thinking that maybe "those darn kids of ours" nuked them rocking out. Those wouldn't have had too much volume capability. The sound should be close enough with the Daytons if it's been that long since they heard them.
  23. A lot of interesting and perhaps useful information on classic speakers is contained in anecdotes from former employees, people who worked in the industry and even some of the people who were salespeople at the time. Quite a lot of this sort of info is spread throughout the CSP forums. I am sure there is more out there as well but there is no single collection point. I think that maybe there should be a Wiki section to the site for a sort of an oral history. This wouldn't replace the Library which is the repository for tech documents and photos. I suppose an elaborate "sticky'" section would work but a Wiki would be easier. Just a thought.
  24. I looked at Pete's page but didn't see the recommendations. I saw in the picture you posted that you used an air core for L1 (the big one). What was the DCR of the coil you used?
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