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发表于 2004-10-24 10:35:47
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Opening the Grado Earcups (SR-60)
Method 1 (Skippy): Pour boiling water onto a cookie sheet (about 1/8-1/4" deep) and put the Grado earcups grill-side down into it. Keep them there for about a minute, and then remove them. The glue softens and the earcup sections should slide apart.
Method 2 (Skippy): Insert a small screwdriver (a jeweler's screwdriver will do) into the crack between the 2 halves of the earcup and carefully pry. Insert a second small screwdriver a bit to the right of the first one. Carefully pry. Take the first screwdriver and insert it a bit to the right of the second one. Pry carefully. Repeat this process, going around the cup until the seal loosens. Finally pull the cup apart.
Method 3: (Beagle): "Blow dry" the plastic enclosures with a hair dryer for about 1 or 2 minutes. Point the hairdryer at the sides of the enclosure, not directly at the front or back. If you fire from 3 or 4 inches away and take a little more time, you get the same results with no risk of affecting the plastic diaphragm. This softens the glue, and you can they pry or twist the enclosure apart.
Note: Beagle says that this method has also worked to open the earcups of his SR-325 headphones, but NOT to use a screw driver: "The aluminum actually conducts the heat better so you have more time to work. Don't use the screwdriver method as it would make marks on the housing. I heat the sides of the air chambers, then use the pull/twist method to extract the driver portion. I remove all the original glue and use my gluegun to re-seal. This glue is easier to soften if I need to go in again."
Method 4 (Mole): Thanks to the collected Grado mods page I got the courage to take apart my Grado SR125s. It was nerve wracking to say the least, because none of the suggestions on how to take Grados apart seemed to work. First I tried prying with a small screwdriver, but I didn't have the heart to do that much damage to the housing. Then I tried lowering the grilles in hot water. No effect. Still couldn't twist the cover off.
Finally I came up with another idea: I found a teaspoon with a sort of tapered handle that I used as a wedge to gradually ease the two parts of the cans apart. You keep the handle of the spoon pressed flat into the crack between the two halves of the Grados using your thumb, and then you pull on the "bowl" of the spoon so that the wider part of the handle forces the two halves apart. You start of where the handle is narrow enough to fit and then force the halves apart. It's all a matter of finding a teaspoon with the right shape.
One of the reasons I think the other methods didn't work was that the SR125 has some kind of rubbery superglue applied where the edge of the transducer half meets the grille. From what I understand other Grados (SR80, SR60 etc) have superglue applied BETWEEN the two halves of the housing, so by prying them apart the glue will "snap". I also doubt the rubbery stuff (somewhat like Liquisole used for repairing shoes) is affected by moderate heat in any substantial way.
Instead of resealing with a glue gun, I placed a strip of black electrician's tape along the inside of the grille part to make the fit nice and snug. That should make it easier to take the cans apart again if the need should arise. (I'm planning on applying the "mini-phono jack" mod in the future.)
Removing the Transducers (SR-60)
Method 1 (Skippy): There are little bumps on the back of the earcup that serve as clips to hold the transducer in place. Sand the bumps down just enough to take out the driver, so that they can go back into position with a bit of force. If the bumps are sanded down too much, the driver will not stay in place when reinstalled. Beagle wrote that he glued them in place. When I installed the submini jack for the replaceable cable (see below), the jack pressed against the back of driver and holds it in place.
Note: the voice coil wires are fragile. Be careful when removing the transducer to avoid breaking a signal connection.
Method 2 (Beagle): Using a medium size screwdriver, going in from the back of the driver, insert the screwdriver along the edge between the driver and the plastic housing. Turn the screwdriver with a slow wiggling motion, gently attempting to "pry" the housing away from the driver. Do this every 1/4 inch or so. You should hear a cracking sound as the glue (probably superglue) lets go.
You may get the driver itself loose or the driver with the perforated cap still attached. If the cap is still attached, the driver should come out through the front of the plastic enclosure. If you have pried just the driver loose, you will either have to remove the plastic bumps on the enclosure and bring it though the back or try prying the driver cap from the enclosure. Use your judgment.
Fixing the Rattle Noise in the Diaphragm (SR-60/SR-325)
Method (Beagle): One of my SR-60 drivers developed a "rattle" on bass notes at somewhat high volumes, and it also caused a channel imbalance. Since they were out of warranty, I decided to try and fix it myself. I think the "wrinkle" occured when the diaphragm was hit with a sudden or prolonged low bass resonance at high volume. I know that his was indeed the case with the SR325, while I was playing the HDCD remaster of Mike Oldfield's "Tubular Bells". There is a lot of low bass energy and extreme dynamic range from quiet sections to loud. I think it is probable that the energy caused the diaphragm to snap back suddenly and retract a tad too far.
Once I got in view of the diaphragm, I could see a "collapse wrinkle" on the diaphragm. Using a small piece of duct tape, I VERY CAREFULLY applied a small area of the tape VERY GENTLY on the affected area of the diaphragm and pulled up slowly and gently. A couple of attempts and the diaphragm "snapped back into place" i.e. the "wrinkle" was gone.
I then used the hair dryer (held about two inches away) to "cure" the diaphragm by "stretching back" the plastic. I applied the heat for about 15-20 seconds. Before gluing everything back together, I placed the driver back in the enclosure, placed the rear enclosure on and gave it a listen. I used superglue to adhere the drivers to the housing and glue gun to hold the enclosure halves back together. This method worked to fix a similar problem with my SR-325 a few months back.
Reattaching the Transducer's Signal Wires (SR-60)
Method (Skippy): A voice coil wire broke underneath the diaphragm of my SR60, so I peeled off the diaphragm, and extendend the wire to repair the driver. The transducer consists of the diaphragm, the coil, the magnet assembly, and the big plastic cup part. The coil is glued to the diaphragm, and the magnet assembly is plastic cup. the magnet assembly consists of a circular magnet in the center, and a metal ring (more like a cup actually) surrounding the magnet. the voice coil sits inside the gap in between the magnet and the ring.
First, I applied some masking tape to the diaphragm to keep it from ripping or stretching during the operation. The shape of the diaphragm isn't flat, so one big circle just doesn't work. I put little strips in a radial fashion overlapping a lot. And I put some ring-shaped pieces on top of those, and then some more just X-ed all over the place - a lot of masking tape. It is very important to use masking tape; The adhesive on other tapes would cling too strongly to the diaphragm, and you'd probably ruin the diaphragm removing the tape.
The diaphragm is stuck on to the big plastic cup part using glue. This glue isn't too strong, around the same adhesiveness as scotch tape. I used a pin to separate the diaphragm from the plastic cup - moving very slowly and very carefully.
I slowly peeled the diaphragm off, exposing the voice coil. Carefully, I unwound a loop of wire from the coil. Then I replaced the diaphragm back onto the transducer. The glue residue was still sticky enough to hold the diaphragm without using any extra glue. That part was hard, but it gets harder.
I couldn't dissolve the enamel coating on the wire. Usually I scrape the stuff off, but the Grado wire is so thin and fragile that any scraping would rip the wire to shreds. Unfortunately, scraping the enamel was the only method I had left. I shredded the wire many times and almost had to remove the diaphragm again to unwind another loop, but I was finally able to scrape off the enamel without breaking the wires.
Soldering those wires is hard because they're so thin and fragile. I couldn't even hold them with tweezers without snapping them. I ended up using the tip of the soldering iron to control the wire. It actually worked very well.
Note: the wires that connect to the transducer are uninsulated. When the cord moves around the uninsulated wires brush up against each other, causing clicking sounds. A little electrical tape fixes this easily. |
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