[ericj]

In my continuing effort to be a cheap person, here's how i made my own K-501's!

I started out with a pair of K-301's i got off the 'bay for about $16, and some varimotion drivers i found on the 'bay for about $21.

All it takes is some dremel work! And the willingness to ruin a dremel grinding bit.

The original K-300/301 baffle disc looks like this:



It appears that the mold for this baffle is a modification of an earlier design that used 42mm drivers like the K-501, with an additional inner ring added to fit snugly around the 38mm K-301 driver.

So i got out the dremel and turned it into this:



Fits perfectly!



Sounds pretty good too. There is some harshness in the high end that I'm hoping can be remedied by carving up the baffle some more to let the driver breathe as well as it does in the real K-501 baffle disc.

I considered ordering genuine K-501 baffles from AKG, but if the cardan configuration is different, then I'll have spent $20+ on worthless parts. Plus I'm a cheap person, and i have half a dozen K-30x baffle discs.

I also need to see about damping or sealing some or all of the ports in the baffle. Since there's so much crap sticking out of the disc on the back side, I'll probably have to work from the front. I have some nonwoven fabric here (the stuff they line the bottoms of couches with), I'll cut a few donuts out of it and try gluing them on.

Edit: The technical name of the nonwoven fabric in question is "cambric". It's about twice as hefty and air-blocking as the stuff in my DT-880 Studio's, and about half as hefty and air-blocking as the stuff in my K-141 M's. But yeah, it's the stuff on the bottom of your couch.

 

[facelvega]

nice project. Be careful with damping the baffle holes, though: too much and the bass will go through the roof into muddy, while handily killing the soundstage at the same time. But I guess it should be easy to get a good balance through the simple process of trial and error. Make sure to cover any gaps where the driver actually attached to the baffle: holes here will be seriously problematic for backwave.

Another way to take on that shrillness is to simply seal off some percentage of the baffle holes and add a little wool or cotton matting in the earpiece. That can rapidly get dangerous too though, as necessarily tends to turn an open phone into a closed-sounding one. Let us know how it goes!

FV

 

[ericj]

Alright, further modifications done. Dremel shaping burrs work a lot better than grinders for this, now that I know I'm just cutting 99% of the plastic out of the area.

And of course, I'm using the most exclusive of AKG earpads. Can't be more than about 3 or 4 of you out there who've even seen these!



Quote:

Originally Posted by facelvega Be careful with damping the baffle holes, though: too much and the bass will go through the roof into muddy, while handily killing the soundstage at the same time. But I guess it should be easy to get a good balance through the simple process of trial and error. Make sure to cover any gaps where the driver actually attached to the baffle: holes here will be seriously problematic for backwave. Another way to take on that shrillness is to simply seal off some percentage of the baffle holes and add a little wool or cotton matting in the earpiece.

Yeah, I'm beginning to experiment with blue painter's tape.

I'm considering trying blue thread locking compound between the driver and the baffle. I'll have to be pretty careful to keep it off the diaphragm, though.

 

[ericj]

So i spent last friday night repairing the foam surrounds on an old pair of Boston loudspeakers i found at a thrift store by painting over the cracks (and indeed the rest of the foam) with this neat stuff - Permatex Flowable Silicone.

Basically this stuff is clear silicone sealant, consistency of honey, cures in about an hour. It has two neat properties.

1: It has a tendency to wick into small spaces, such as leaky windshield gaskets, and deteriorating foam rubber.

2: It's not really a glue, so the excess can basically be rubbed off of non-porous surfaces with your fingertip.

I'd noticed a slight honkyness to my frankenphones, and today i started thinking about how this might relate to the repeated admonishments I've had from wualta and facelvega to ensure that the drivers were perfectly sealed to the baffle, and i had to consider that my dremel work had to have left the baffle surface more than a little rough.

So i sealed in the drivers by laying a very thin bead of flowable silicone on the baffle, laying the driver on it, and then painting over the seam with more flowable silicone.

Honkyness gone!

You can find this stuff at AutoZone. It's probably good for other "Why is this rattling" or "how can i make this seal better" headphone mods.

 

[tropalander]

Do the K 501/401 Earpads fit on the K 301 housing, or is there modification neccessary? The size looks quite similar and both pads have 4 mounting clips, right? Anyone tried that?