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Doug G.

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  1. If the two 8uF caps are connected together, each end to each end (in parallel), that equals 16uF so either Advent did that or whoever did work on them later, most likely the latter. The only real reason to get another Masonite woofer and another "cageless" tweeter is for originality and so the two speakers are the same. Soundwise, it won't matter. That being said, it would bug me they aren't the same. In fact, it bugged me on one of my pairs that, when they were refoamed, in the past, whoever did it put different diameters of dust caps on the woofers so I had to match them up. It still bugs me a little bit that they are too large a diameter for original Advent woofers but I had to cover up the old glue line. Of course that they are porous caps results in no change to the sound. The Masonite woofers had the surrounds installed inverted (roll poking away from you) to avoid any possible interference between the roll and inner edge of the Masonite ring when the cone moves in and out. The all-metal woofer doesn't have that possibility, of course. Again, soundwise, it makes no difference. Doug
  2. The tweeters originally had virtually no protection from being pushed in. In the first attempt to alleviate the field issues, Advent placed a window screen type grille directly into the tweeter opening in the Masonite grille frame. Then, they mounted an extra block with Velcro right under the tweeter to keep the grille, itself, from being pushed in. Finally, they put the cage type grille right on the Masonite frame of the tweeter. This proved to be effective although Advents still show up with the cage type grille pushed into the tweeter dome. This all happened in a relatively short period of time and by the end of 1971 or early 1972, they had the cage type grille on the tweeters. Advent even offered the grilles, free of charge, to owners of earlier speakers, to mount them themselves if they wanted. The crossover was changed, more as an effort to ease the tweeter from having to reproduce the lowest frequencies of its range as there were problems with owners blowing them in the field, too. Also, it was to make the integration of the woofer and tweeter smoother at the crossover point. A 16uF-16uF combination was first used for the two electrolytic capacitors and that was changed to a 16uF - 8uf combination in 1975. The resistor was changed and the inductors beefed up, too. The best place to see the differences is Pete Basel's site, here: http://baselaudiolabs.googlepages.com/ADVENT_LA_XO.html Doug
  3. Hi Patrick, Those are early Advents with those serial numbers and before Advent standardized the "A" suffix. They would have come with Masonite woofers and tweeters like the one on the left speaker, without and grille/cage on the front. The left tweeter and right woofer are probably original and the left woofer and right tweeter, replacements. As to what to do with them, if you want to be absolutely original, you would want to get a tweeter without the grille for the right speaker and Masonite woofer for the left speaker. Soundwise, it doesn't matter as the drivers were always made to sound the same, regardless of iteration. I have a pair of very early ones also and they both have Masonite woofers but the woofers are not original. I have the original woofers but the previous owner had replaced the original cones with plastic cones so I am waiting to find original type cones to rebuild the original woofers. Whether I ever actually do it is a separate issue. I have the original "cageless" tweeters, too, but one of them has a broken lead right where it goes into the voice coil by the edge of the dome. So, they both currently have later tweeters with grilles/cages. I don't let it bother me too much. More important to have them operational. So, as far as how they sound, as long as you have real Advent drivers in them, they'll be OK. As far as the crossovers are concerned, the only way to tell is to see them and test the capacitors and verify that the resistors and inductors are OK. I am of the opinion that even capacitors don't automatically need to be replaced if they check out OK. Others replace them just because of age. That's your decision. If you do replace them, I would just use modern equivalent non-polarized electrolytics. Good luck. Doug
  4. Doug G.

    First Large Advents

    As I stated on AK, the only discrepancy is the serial numbers and driver dates. The drivers are definitely later ones as the tweeters have the black tape only going part way across the Masonite and the stamped dates, of course. Earlier (pre 1975) ones have the tape going all the way across. So either somebody stuck newer drivers in older cabinets or the paperwork was missing and they found older examples to stick on there. Who knows? Also, as I said, the tweeter cone colors make no difference as long as the magnets are the same size. Another thing I just noticed - the glue holding the Masonite ring on on the one woofer is dark. Is it reddish? The usual was a light tan, mastic type glue. I have seen other examples with the red clue, however. Doug
  5. They look well-made and have gotten great customer reviews on Amazon. Doug
  6. Yeah, beautiful! And, you're not alone. I am re-restoring (I originally did it in the mid seventies) an old Hallicafters shortwave radio my late father-in-law had and I got when he passed away in 2015. Even though it needs several parts replaced, particularly the old paper capacitors (it's from the nineteen fifties), and needs to be realigned. I restored the appearance first. Doug
  7. If they are Advents with the metal plate for the crossovers, the caps are most likely 16uF. Those are very early units. Some research shows Advent may have originally used the `16uF/8uF combination in some of the early ones but it is unclear. Regardless, there were only 16uF and 8uF caps used in the original Advents so you would be safe buying some of each. It's not like they are expensive. Doug
  8. Just for reference, it should not be all black when you get inside. Doug
  9. In my post above, I indicated that the gray plastic trim pieces will always be gray. However, with age, they can discolor on the front edges and appear yellowish. This has happened to a couple of mine. I imagine sanding that edge may restore them but I haven't tried it yet. Doug
  10. After Advent started putting tweeters with the large magnet in the Smaller Advent, they may have been trying to zero in on the perfect values of capacitors and 1975 is when they made the magnet size change. It's kind of like when they were settling on the values for the original Advents. In any event, the 3 ohm resistor indicates the tweeters will have the large magnet. It was needed to tone down the tweeter a bit to match the woofer efficiency. The original Smaller Advent did that with the smaller magnet and only needed the 1 ohm resistor. Doug
  11. The New Advent and Advent/1, however, use the same woofer. The difference is the cabinet size. Also, the Masonite woofer and all-metal woofer would not be considered identical since the Masonite woofer has a bit longer excursion (Pete B. has measured them) but, in all practicality, they are the same. Same cone. Doug
  12. And sometimes, an Advent employee used a black marker but it means the same thing - positive connection. Doug
  13. Doug G.

    OLA's I Just Bought

    Yes, the optical illusion is common with the Masonite woofers where they look like the rolls are poking out when they are not. There are subtle clues to tell. Doug
  14. Doug G.

    OLA's I Just Bought

    Masonite ring woofers have inverted roll surrounds, all of them, or SHOULD have. The later all-metal woofers have standard mount with the roll poking out, or SHOULD have. The only way they get switched is if a subsequent owner changes them or a "professional" changes them. Doug
  15. Doug G.

    OLA's I Just Bought

    Yup, get 'em fixed up so they sound new. Those are probably from 1973 or so, with those serial numbers. Doug
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