statman122
Well-Known Member
Jon,
I have a pair of these, and i'm currently restoring another pair for a customer.
When I first got mine, about 6 months ago (after a 20-year wait!:yes, I was a bit disappointed, remembering what the first set I had heard sounded like. The electronics driving mine are definitely superior to what I was listening to 20 years ago.
Here's how I got the "magic" back, and it's all easy, just labor intensive:
1. Remove the MTM pods, and remove the hatch to the top woofer. After making sure the top woofer is in good shape (the ones in my customer's 104/2 were NOT, but that's a story for another time), check the gasket under the hatch. It probably should be replaced. Pick your favorite method for sealing a speaker cabinet, apply where the old gasket was, and replace the hatch. When bolting it back down, slowly torque the bolts down as if you were tuning a drum head. If you're not sure what I mean, it's similar to tightening the lug nuts/bolts on a car wheel, i.e., first one, then the one ACROSS from it, etc. The main difference here is, drive one bolt in until you start to feel resistance, which will be nowhere near all the way in, then go to the one opposite. Keep going in this manner until the bolts are firmly torqued, but NOT enough to warp the hatch. It may take 3 or 4 times around the bolts to get there, but the end result is more than worth it.
2. Before re-installing the MTM pod, firmly torque down EVERY screw on the back. And I mean FIRM. This may be more important than the woofer hatch even. My KEFs were losing a LOT of energy from the tweeters and the B110s just because of slight leaks, and lost inertia from the loose screws. Replace the gasket on back of the pod if necessary. Make sure you have all the spacers when remounting the pod, and torque the bolts nice and firm against the cabinet, to avoid inertial losses there as well.
3. Repeat the procedure in #1 on the bottom woofer chamber. A BIG hint for getting the bottom panel off in one piece: Leave the feet ON. Take out all the bolts, and use the feet as points to get leverage on for prying if necessary. The feet/spikes only bolt to the bottom panel, not the cabinet.
4. Slight detail left out of #1 and #3: Torque down the woofer nuts. They will only go a certain distance, so don't fight them. The gaskets for the woofers should be fine, don't worry about them at all. Also, make sure the bolts for the force canceling rod are tight. You'll have to find the top one by feel, with a socket extension.
All the above should take care of the sound issues, especially by making sure the new tweeter is air-tight against the baffle.
The B200 woofers in the 104/2 always had inverted rubber surrounds. The only foam part was the annulus, and I've heard rumors on some of those being rubber (seems like we're getting close to some kind of bad joke here, but I will not partake . . . :scratch2
Good luck, let me know if you need more info.
Thank you, BrassTeacher, this deserves a sticky! I followed the directions to the letter. Also got the KEF R1548X replacement tweeters installed today as well. They blend in much better than the Vifa's I was using. Are they $130 better? Hard to say , but I sure am pleased with the sound. Now all that's left is a good coat of Howards and this long project is finally complete. I also found when I had the top hatch removed that the shop that reassembled these after the woofer had been fixed had put the foam padding touching one of the woofers on top so I slid that piece of foam back and it opened up the woofer in that chamber. I now see what the fuss is about these speakers, and I'm glad I decided to restore them. total cost into it was more than I planned on but it's worth it!
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