MCM_Fan
AK Subscriber
Tagging @Pete B and @Doug G. for their vast Advent knowledge...
I just picked up a pair of (what I think are) New Large Advents in the bullnose cabinets last week and am getting ready to start the restoration process. But first, some questions...
1) Are these actually New Large Advents? As mentioned, they have the bullnose cabinets (roughly 26" x 14" x 11.5") and have the stamped steel frame woofers (no masonite rings). Here's what the back panel with the speaker terminals and High Frequency Control switch looks like:
Unfortunately, the serial number stickers are missing from both.
Tweeters: They came with two different fried egg tweeters - one orange, one green.
I know the Smaller Advents came with the green tweeters, but I also believe those had smaller magnets (2.5" square). Both of mine have 3" square magnets.
I haven't tested them yet, but assuming both tweeters are functional, other than aesthetics, will these two unmatched tweeters cause any problems? I could always sell the green one and try to track down another orange fried egg tweeter, but is it likely to be worth the trouble?
Also, as you can see in the top photo of the tweeters, the metal screens have been pushed in, thus denting the center domes. I plan to use some monofilament fishing line to pull the metal screens back to their original position. Will that likely cause the smushed domes to rebound, or will I need to somehow coax, or suck them out. Are these center domes merely dust caps, or are they part of the tweeter diaphragm? If part of the diaphram, will performance be impacted? Again, should I be looking for replacement tweeters, or are these salvageable (assuming they are functional)?
Woofers: Of course, the woofers need refoamed. As mentioned these are the steel frame (non masonite) woofers. I have already emailed Rick Cobb to get a pair of the correct foams. I will refoam them with the new foams attached to the backs of the paper cones (I have done this on several pairs of JBL woofers).
Crossovers: These have the standard New Large Advent crossovers as shown on Pete Basel's page. As soon as I saw the single 13uF cap in the tweeter circuit I recalled that AXON makes a very affordable metalized polypropylene film cap in this value. I don't see a spec for the ESR for this cap, but I assume it's quite a bit lower than the original NPE. As such, would it be wise to put a 0.56 ohm resistor in series with the 13uF replacement film cap?
I tend to favor Mills wirewound resistors whenever I redo crossovers, but they actually cost more (each) than the 13uF film cap, in this case. How much I am willing to spend on these depends on how well the cabinets turn out (see below).
Fill: These have the original yellow open cell foam fill. The fill looks like new. Should I leave it as is, or replace it? If so with what - polyfill, pink fiberglass insulation from Home Depot?
Cabinets: Unfortunately the cabinets are very rough - especially the tops on both. I'm going to dive into these over the next couple of days and see what I can do. In addition to the legendary sound (which I have yet to hear) a big part of the appeal to be is the beauty of the bullnose cabinets. They would look great with my mid century modern decor. The original grills look great, but as mentioned the cabinets are pretty trashed (cosmetically). One looks like it had hot wax (or some other substance) poured on it which damaged the veneer, perhaps burned all the way though. The other is completely covered with very deep gouges and scratches, some that may have penetrated the veneer. I hope I can make them presentable, and whether I can or not, will determine if these are keepers, or I will end up reselling them.
Thanks in advance for any help!
I just picked up a pair of (what I think are) New Large Advents in the bullnose cabinets last week and am getting ready to start the restoration process. But first, some questions...
1) Are these actually New Large Advents? As mentioned, they have the bullnose cabinets (roughly 26" x 14" x 11.5") and have the stamped steel frame woofers (no masonite rings). Here's what the back panel with the speaker terminals and High Frequency Control switch looks like:
Unfortunately, the serial number stickers are missing from both.
Tweeters: They came with two different fried egg tweeters - one orange, one green.
I know the Smaller Advents came with the green tweeters, but I also believe those had smaller magnets (2.5" square). Both of mine have 3" square magnets.
I haven't tested them yet, but assuming both tweeters are functional, other than aesthetics, will these two unmatched tweeters cause any problems? I could always sell the green one and try to track down another orange fried egg tweeter, but is it likely to be worth the trouble?
Also, as you can see in the top photo of the tweeters, the metal screens have been pushed in, thus denting the center domes. I plan to use some monofilament fishing line to pull the metal screens back to their original position. Will that likely cause the smushed domes to rebound, or will I need to somehow coax, or suck them out. Are these center domes merely dust caps, or are they part of the tweeter diaphragm? If part of the diaphram, will performance be impacted? Again, should I be looking for replacement tweeters, or are these salvageable (assuming they are functional)?
Woofers: Of course, the woofers need refoamed. As mentioned these are the steel frame (non masonite) woofers. I have already emailed Rick Cobb to get a pair of the correct foams. I will refoam them with the new foams attached to the backs of the paper cones (I have done this on several pairs of JBL woofers).
Crossovers: These have the standard New Large Advent crossovers as shown on Pete Basel's page. As soon as I saw the single 13uF cap in the tweeter circuit I recalled that AXON makes a very affordable metalized polypropylene film cap in this value. I don't see a spec for the ESR for this cap, but I assume it's quite a bit lower than the original NPE. As such, would it be wise to put a 0.56 ohm resistor in series with the 13uF replacement film cap?
I tend to favor Mills wirewound resistors whenever I redo crossovers, but they actually cost more (each) than the 13uF film cap, in this case. How much I am willing to spend on these depends on how well the cabinets turn out (see below).
Fill: These have the original yellow open cell foam fill. The fill looks like new. Should I leave it as is, or replace it? If so with what - polyfill, pink fiberglass insulation from Home Depot?
Cabinets: Unfortunately the cabinets are very rough - especially the tops on both. I'm going to dive into these over the next couple of days and see what I can do. In addition to the legendary sound (which I have yet to hear) a big part of the appeal to be is the beauty of the bullnose cabinets. They would look great with my mid century modern decor. The original grills look great, but as mentioned the cabinets are pretty trashed (cosmetically). One looks like it had hot wax (or some other substance) poured on it which damaged the veneer, perhaps burned all the way though. The other is completely covered with very deep gouges and scratches, some that may have penetrated the veneer. I hope I can make them presentable, and whether I can or not, will determine if these are keepers, or I will end up reselling them.
Thanks in advance for any help!
