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Advent Repair/Restoration

guptonr

guptonr

Active Member
I picked up this pair of utility cab Advent Loudspeakers (old Large Advent) a couple of weeks ago. (Previous thread: http://www.audiokarma.org/forums/showthread.php?t=292970&highlight=advent+foam). They needed to be refoamed. The foam had been previously replaced but it wasn't the right kind and size and didn't fit well. I got the new foam from R Cobb (looneytune2001 on eBay) as recommended by many AKers and it was a perfect replacement. I recapped the speakers to get them to match. They were of two different production runs. One from 1973 with fiberglass fill and two 16 uf caps and a 3 ohm resistor in the crossover. The other was a 1976 vintage with foam filling a 8 uf, 16 uf, and 3 ohm resistor in the crossover. I put new caps to make both 8 uf and 16 uf. I used Dayton caps from Parts express. I had to use 12 uf and 4 uf caps in parallel to get the correct values (4+4 and 12+4). While I was in there, I noticed some of the sealant on the inside cabinet corners had hardened and was coming loose, so I resealed it too. My next step is to make my fist attempt at veneer. I have some paper backed cherry that I'm going to use. I'll post those pics when I start on that part. Pics of progress in next posts.

One question: Does anyone know how to clean a speaker cone? These are fully functional, but have dirt dust on them that won't come off with a brush.
 
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Vinyl stripped off, foam and fiber glass filling. Also is a picture of the foam filled cabined minus the foam. I noticed what I though was an brace in the one that had the foam. But since it runs up and down each side and is not connected on either end, I figured it was just there to hold the lower chunks of foam down.

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Recapped crossovers. The two pics are before and after pics of the older (1973) Advent with 2 x 16 uf caps. The third and fourth are the more recent Advent (1976) with an 8 uf and 16 uf cap. Both were replaced with 8 ( 4 uf + 4 uf) and 16 uf (12 uf + 4 uf). Each also got new 3 ohm resistors. Both the resistors and caps were much larger than their predecessors so it required some creative placement. Also, the recap was done without removing the crossover from the cabinet. It was fairly east to get to through the woofer and tweeter cut out.

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Is it dirt on the cones or could it be that they are faded?

If it is dirt, you could try and wipe them lightly with a damp cloth but don't bear down too hard or you will damage the paper.

If they are faded, you can dye them with black dye. Don't use paint, though, because you don't want to change the physical characteristics of the cones.

Nice work so far.

Doug
 
I think it may be a little of both dirt and faded. there is some dirt and dust that's worked it's way into the fibers of the cone. I may try some dark gray die, at least the cones and dirt will be the same color.
 
IMO leave them be, I've tried to clean advent cones in the past and it looks obvious. Just get the loose dust off and call it a day.
 
Restore Advent Update

I've finished putting the veneer on the Advents. It was my first attempt at applying veneer and it was fairly easy and turned out well. I highly recommend any of you thinking about doing it give it a try. I used paper backed cherry veneer. The 24"x96" roll was enough to do the top, bottom, and sides of the speakers, but not enough to do the inside lip and face edge. I got a roll of 2" pre-glued cherry edge banding that I cut to length and width. The only I needed were a straight edge, utility knife, block of wood, clothes iron, 3" foam paint roller, and a Band'It edge trimmer (well worth getting one, it made perfect edges.

For a first time veneerer, I found the paper backed veneer easy and forgiving to work with. It didn't splinter or crack when I cut the pieces with the utility knife or applied it with the iron. The pre glued edge banding was very easy also. I applied it with the glue/iron on method. I used the foam roller to apply Titebond Original Wood Glue to the cabinets and veneer, let fully dry, used the iron on the "wool" setting (no steam), and used an old T-shirt between the iron and veneer. I followed right behind the iron with the wood block to press the veneer as the glue dried.

Two words of advice for anyone trying this for the first time: "glue control." I may have a couple of small spots on the bottom that may not take stain (I think I got the glue out with judicious use of a heat gun and acetone). , I started with the bottoms in case I made mistakes. Fortunately, I made most of my mistakes early on and on the first piece. After I applied glue to the first bottom piece, I laid the next piece on the same work surface. The surface had some glue on it from applying it to the first one. I also had a little on my fingers from opening the glue bottle tip. I solved the work surface issue by covering it with fresh newspaper after each piece. Alos, keep a wet rag nearby and always clean your hands before you pick up a piece of the veneer. Near the edges, I only used the roller from middle of the piece to the outside edge (not back and forth) to keep glue from getting underneath.

Pics in next post.
 
Another question

I was looking for some info on in the forums about an internal bracing mod for the Advents. I thought I had read about it before but couldn't find anything. Anyone have any recommendations about bracing Advents? Pro/Con, location, material, etc. As soon as this last coat of finish dries, I'm was going to reassemble and give them a good shake down. I figured if a bracing mod is an improvement, I might as well do it while I have them apart.
 
Progress Update

Here's another progress update: finished with Minwax English Chestnut stain, 3 coats of Formby's tung oil finish (low gloss) with two coats of Formby's high gloss on top. You may be able to see small areas that didn't stain well. That's from the edge banding. The glue stuck to the edge of the veneer and when trimmed off started to pull some of the veneer off the side pieces. Or, when ironing down the edge band, some of the glue came off the back and got on the veneer. I would have been better off making my own edge band from veneer, but I didn't have enough. They didn't turn out perfect, but I think they look pretty good for a first attempt at veneer.

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Well, the speakers are stuffed, reassembled and ready for listening. I've only been able to spend a little time with them.

The woofers weren't marked with a + or - so I had to take a guess (I forgot about the battery test). The tweeters were marked. I remembered it when reading another thread few days ago. When I got back from my trip today, I tested them and sure enough, they were both hooked up backwards. After unsealing and reversing the wires, they sounded much better.

I'm leaning on matching them with my Yamaha CR-2020 instead of the Sansui AU-666. The HPM -100s I had with the yammy made a bright, fatiguing combo. The Advents with the Yamaha sound great so far.

Overall, it was a worthwhile and rewarding project. Final pictures to follow.
 
Finished Project

The black grill cloth came with them. I may keep it instead of looking for something similar to the originals. I sort of like it and it matches the environment.

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You can leave them as is or use "The Wet Look" from Parts Express. I've used it only once, on a pair of Wharfedale 15" woofers. I didn't notice any change in sound one way or the other. But the woofers sure as heck look better.
 
The black fabric is the original underlayment for the burlap-type material.
I think it's a little thin looking for speaker cloth and I prefer more solid looking fabric.
My projects use fabric from www.acoustimac.com (no affiliation, just promoting a GOOD product)
 
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