specialidiot
Break Glass, Smoke Lucky
A couple of weeks ago I won an ebay auction for a pair of KLH Model 17s. The price was quite cheap, and the seller charged actual shipping so my cash outlay was about $45 shipped. Unfortunately, the speakers sounded like crap when I gave them their first listen. No highs at all, what sound was there was quite muddy. To make matters worse, the seller taped directly to the cabinet and they looked like crap. Luckily there was no cabinet damage and to my surprise were built from solid walnut.
A quick check on the AK forums indicated that they were definitely worth rebuilding. So began my first speaker renovation project.
I used to work as an electronics tech in the early 80's, and my wife generously assesses my tinkering around the house skills as "handy", so I looked forward to this effort.
The first step is to approach the speaker in a confident manner. Here's the subject:
Remove the KLH badge and set it aside for later
Carefully remove the grill. Mine was fastened by velcro, I've heard of them being glued on too. The grill is a thin piece of fiber board - like peg board without the holes - that has the speaker openings cut out and the grill cloth stapled to the back.
I used a 1-1/2 inch flexible putty knife. Use a towel where the knife meets the cabinet.
Once you can get your fingers under an edge, just start lifting it out
remove the screws from the tweeter
catch a fingernail under the tweeter and lift it out. Yep, that's fiberglass insulation in there!
Label the wiring as you remove it. Failure to do so could cause some head scratching later
remove the wirecaps, set them aside for later, unsolder the leads, and put the tweeter in a safe place. I tested mine out with a sine sweep file provided by spkrdood. Make sure you put a 10MF cap in series with the positive lead of the tweeter to block the lower frequencies. Thankfully both of the tweeters worked great.
Remove the 8 screws holding in the driver and pull it out
One thing I forgot to take pictures of and thanks to AK'r neilsvanm2, I've added this part in. The drivers have cloth surrounds, not foam. The good news is that cloth doesn't disintegrate like foam, but it does need to be re-sealed. I used some standard household latex caulk, thinned with 2 parts water. I used a glue brush and real lightly coated the surrounds. I then set the drivers aside for a couple of days as I waited for my parts to come in.
There is a piece of black fabric under the woofer, looks kinda like a shroud to me. Remove it and set aside for later. Label and unsolder the red and black wires
Here's the cabinet with the tweeter and driver removed, wires labeled.
Put on some gloves and remove the blocks of insulation. A paper shopping bag is large enough to hold the stuffing for one speaker. Put the "shroud" in the bag too.
When you get the stuffing out, you can see the crossover (XO) mounted to the back of the cabinet.
Remove the tape holding the XO together, make note of how the caps are connected. Note that these are some type of dual caps. The black lead is common, and the red lead goes to each side of the 2 pole switch. The switch lets you set how much high frequency you want to pass to the tweeters.
Part two coming up
A quick check on the AK forums indicated that they were definitely worth rebuilding. So began my first speaker renovation project.
I used to work as an electronics tech in the early 80's, and my wife generously assesses my tinkering around the house skills as "handy", so I looked forward to this effort.
The first step is to approach the speaker in a confident manner. Here's the subject:
Remove the KLH badge and set it aside for later
Carefully remove the grill. Mine was fastened by velcro, I've heard of them being glued on too. The grill is a thin piece of fiber board - like peg board without the holes - that has the speaker openings cut out and the grill cloth stapled to the back.
I used a 1-1/2 inch flexible putty knife. Use a towel where the knife meets the cabinet.
Once you can get your fingers under an edge, just start lifting it out
remove the screws from the tweeter
catch a fingernail under the tweeter and lift it out. Yep, that's fiberglass insulation in there!
Label the wiring as you remove it. Failure to do so could cause some head scratching later
remove the wirecaps, set them aside for later, unsolder the leads, and put the tweeter in a safe place. I tested mine out with a sine sweep file provided by spkrdood. Make sure you put a 10MF cap in series with the positive lead of the tweeter to block the lower frequencies. Thankfully both of the tweeters worked great.
Remove the 8 screws holding in the driver and pull it out
One thing I forgot to take pictures of and thanks to AK'r neilsvanm2, I've added this part in. The drivers have cloth surrounds, not foam. The good news is that cloth doesn't disintegrate like foam, but it does need to be re-sealed. I used some standard household latex caulk, thinned with 2 parts water. I used a glue brush and real lightly coated the surrounds. I then set the drivers aside for a couple of days as I waited for my parts to come in.
There is a piece of black fabric under the woofer, looks kinda like a shroud to me. Remove it and set aside for later. Label and unsolder the red and black wires
Here's the cabinet with the tweeter and driver removed, wires labeled.
Put on some gloves and remove the blocks of insulation. A paper shopping bag is large enough to hold the stuffing for one speaker. Put the "shroud" in the bag too.
When you get the stuffing out, you can see the crossover (XO) mounted to the back of the cabinet.
Remove the tape holding the XO together, make note of how the caps are connected. Note that these are some type of dual caps. The black lead is common, and the red lead goes to each side of the 2 pole switch. The switch lets you set how much high frequency you want to pass to the tweeters.
Part two coming up