[RamblinE]

I'm not currently experiencing too much bass bloat with the AKG K240S' I just got today. Driving them off of a Headroom Micro Amp. They sure aren't perfect. Detail, resolution and seperation can't hold a candle to my K701 and K550. 
 
However these are a much more laid back and easier listen. 
 
In stock form, I'm honestly, and surprisingly, impressed! 

 

[Punnisher]

I actually did reverse my modification. A bit too lean for me. I prefer them with shure srh-840 pads. A nice combination.

 

[troymadison]

I just did this mod on one of my monitors. I used the stretchy material from my earplugs to plug the holes on the drivers. I like the outcome with the sound.

 

[mrrDUDE1]

So I'm here again.
I bought a soldering a week ago for guitar stuff and remembered about this mod.
I found that I was able to do it without desoldering any wires.
There was enough wire for me to stick in pieces of dental wax on top of the little arcs in the drivers.
I removed the stickers by using a toothpick in the little indentation on the cup, and used a couple screwdrivers laying around. I also used dental wax that I had leftover from my braces.
I made sure to roll up a nice sized ball so it'd be easy to remove in case I didnt like it.
And I didn't like it. It killed my bass. Like nonexistent now. Im going to open them back up and try covering half of the holes now? Maybe that will make a difference.


EDIT: I'm an idiot.
I just did a/b ing for about 30 mins and couldn't hear the difference anymore. I was listening on my phone. I'm guessing the phone didn't drive the 'phones enough for deep bass, so I thought it was the mods fault. It wasn't.
Giving a listen through a headphone amp shows a CLEAR difference in clarity. No more flab on the low end.

So my advice? Sharpen up a pencil or grab a toothpick, (both worked) get under that sticker and peel it off, remove a couple screws, carefully pull on the gold ring of the cup, slowly so as to not rip one of the wires out of place, and cover up that little arc on the back of the driver. Put the cup back together and repeat for the other ear.

Don't try to do what I did and cover up 'half' of the bass port. One side was noticeably warmer than the other because it had a few more millimeters of wax covering it
Cover the whole thing on both ears and it makes the headphones much CLEARER, and still have bass. And always use a headphone amp for these.
YMMV

 

[Jiminmuncie]

I know this post is 5 years old, but I just wanted to say thanks for leading me to the fix for why one of my old K240 phones went belly up. In my very small home studio, I try to use the old K240s exclusively because years ago when I was setting up my headphone amp, I wanted all the same phones and chose three of the 240 monitors which have served me well - until one set developed a problem. (It took me a while to find three!)
 
All of a sudden the highs were down and the lows up; a muddy mess. I read your post about the driver holes and people preferring more bass, etc, which led me to removing the pads and having a look as opposed to retiring them, which I really hated to do, anyway.
 
Long story short, I never got to the "holes" issue. In removing the coil cover fabric I found that some of the foam backing had deteriorated and pieces had fallen through the grill onto the coil in both the right and left. A few seconds with my vac and pc attachment and I was back in business with the audio clarity I'd come to expect.
 
Had it not been for your discussion, these old warriors would be hanging in my repair parts area instead of in the studio.
 
Thanks very much. I hope THIS, too, helps someone in a similar fashion.

 

[tansand]

I just wanted to bump this thread to report this is a very good mod.

https://www.head-fi.org/threads/k-240-monitor-to-df-modification.416858/page-3#post-9443827

tansand said: So I did this mod to my K240 Studio. I didn't unsolder anything. I just unscrewed a side at a time, and carefully pulled the gold cylinder to ease the wires through the hole and not pull on them. I covered the arc shaped hole with a piece of electrical tape slid in from the side. Everything the guy says is true, very satisfying sounding headphone now. Tonally similar, but much smoother, better imaging too. (I took the tape off the vent holes on the back of the cups I had put on earlier.) Be sure to fit the two pegs into the two holes underneath when you put the gold cylinder back down.You should keep the pads and foam on throughout this procedure, there are more detailed instructions in the linked thread. Rock on .

The imaging improvement alone is worth doing this mod, but there is also a big improvement in smoothness and lack of resonances. I think the hole was whistling.

 

[tansand]

Update after three weeks. Good mod, really enjoying these headphone a lot more than I did before. I have some Shure 940 velour pads on too now, much more comfortable. I peeled the foam layer off the fabric/foam in the center of the pad.

Works really well.

 

[Coug]

Really old thread, but I thought I'd give an update of what I've found. I recently got a pair of DFs for cheap, sold as parts, but just needed a re-cable, one cardan snapped back in place, and both lids snapped back on (and the usual - new elastic, new foam (front and back) and new pads). After that they're in great shape, and sound great. Love 'em, especially with live music.

So I have two sets of monitors, one ANIB, and one well worn. I remembered hearing about modding the monitors to sound like DFs, found this thread and gave it a try on the used ones. Plugged the bass sport next to the red lead with some blue tack and,... Nope. Sounded bad. Bass and mids were messed up, soundstage was missing. I went back in to remove the blue tack but, hmmm. I didn't remember which direction the red lead faced - front?, back? one front and one back? Decided to put everything back together with the red lead and covered port facing back on both sides. That did it, they sound really close, if not just like the DFs.

EDIT - more A/Bing on a the Crack gave less bass than the DFs, which really opened up with the Crack -

If anyone else tries this, make sure of orientation when putting everything back together - RED LEAD AND PLUGGED PORT TOWORDS THE BACK.

 

[Coug]

OK, lets put this one to bed. I finally decided to open the DFs back up after finding the difference when "properly(?)" driven (BH Crack). Here are photos of the DF and Modded Monitor right drivers. As can be seen the DFs have several more ports than the Monitor. Also driver orientation is moved about 30 degrees counterclockwise.

The DF (left) has one port on each side of the red and white leads (one red covered), Moving clockwise from the covered port CW about 60 degrees from the covered port are two ports, Then one port an each side of the white lead (four holes but only only those closest to the lead are through), then two more ports (180 degrees opposite the other twin ports), and then finally the open port near the red lead (again appears to be four holes, but the uncovered side shows only one through).

The monitor (right) has only two ports, one near each lead.

They really sounded very similar off an Asgard 2, but the DFs really got the bass moving with the Crack.

LP DF


LP Monitor

 

[Coug]

Man, here I go again.... Mea Culpa.

I'll now say, it depends. I just got another set of Monitors in ($25 shipped, no badge plates, and the headband is a rock). This time EP, Sextett baffle plates with black and white fabric acoustic covering. I took them apart to clean, and low and behold, the same drivers (almost) as my DFs (LPs which have the single paper acoustic covering, but 1/4" plug, and ribbed cable). Couldn't resist. Covered the red CCW port again on these, put them back together with new parts. Success! There is a slight difference with the modded EP Monitors being a little easier to drive (a little...). Just the driver, different baffle covering? The difference in the drivers are the orientation (white at 12 O'clock, red at 6 Monitor, white at 1:30 and red at 7:30 on DF), and tabs on the Monitors at 3 and 9 O'clock that align with tabs on the plate. There may be differences I just don't notice, but they are so close I can't tell the differnce. So EP Monitors, likely a go. LP Monitors, no.

One thing to remember, AKG indicated the DFs came with carefully matched drivers as well (what ever that means and whatever effect that has overall).

EP Montior


For a little more info, here is a 240S driver and a Sextett Driver.

K240S Sextett

 

[Precaud]

New member, rules say 1st post has to go into an existing thread, this one looked like an appropriate one.

This week I happily discovered the dynamic headphones that I bought in the 90's, that I thought had been stolen in a breakin/burglary three years ago (long story). Turns out they took the stats but left the dynamics. Among them an old K240 set. When I bought these, I didn't know anything about the difference between the various K240 versions. I knew I wanted a 600 Ohm set, and found these used locally in roughly 1995 for cheap, because they were missing the side covers with the model # but worked well. I used them occasionally, even bought new pads and foam/cloth inserts from AKG (still have them), then set them aside. 20 years later I need cans for a project so they're getting called into duty again. Would like to know exactly what model they are.

I would insert some pics but I don't see how to do it, do I have to host my own photos? Other than the missing emblems, they're in pretty decent shape - original pads and foam inserts. I'm guessing they're DF's (black trim, ribbed cable, 3 black & 3 white fabric-covered ports), would like your input.

 

[Coug]

Black trim sounds like DF, white and black fabric would be early production (later would be smaller ports covered by paper). Last indicators would be the color of print on the headband. Silver- DF, gold-Monitor, and on the lids (large plastic ring on the outside ear cup) "Studio Monitor" is printed on the DF, and blank on Monitors. But black trim was only DF, and it seems from what I know, only one driver type was used.

You may want to replace the foam ring under the lid, you can buy them through AKG (phone call), or Full Compass Systems (on-line). It's only about $4 for two. The foam deteriorates and black flecks will fall out the back between the disk lid and housing. It can also eventually get "gummy" and fall into the baffles.

The disk lids can be removed by removing the earpads, then using a thin non-marring tool (think good plastic), insert the tool between the lid and housing and gently pry up on the lid, using the housing as the fulcrum point. You can also slip a piece of thick cloth, thin leather, or rubber between your pry tool and the ornamental ring on the housing. Don't want to mess it up, it's aluminum and will get marked up if not careful. I usually place the headphones over the end of my work table so the side I'm working on sits flat on the table. Don't pry too hard if it's stuck. Just keep steady pressure and use your finger nails to grab the lid where it meets the disk and pull up on the lid at the same time. It should pop off. They can be stubborn if they haven't been opened in 30 to 40 years.

Once loose it can be maneuvered over the headband and out of the way. The left one will need to be maneuvered over the cord as well and the stress relief sleeve will be in the way, but just work it over the sleeve.

Then clean out all the old gunk, and stick in the new foam. Most say the foam has no real sonic impact. The purpose is to keep the housing from bumping into the disk.

You may also want replace the elastic band adjusters (rubber loops). Also available at Full Compass. Unscrew the slider and remove it and it's disk. The rubber loop will probably be stuck to the inner headband. Take note of the orientation of the holes on the rubber loops disc and how they align with the slider. Pop
the rubber loop loose from the headband. Install the new rubber loop to the headband and slider. Now the other end.

Remove the screw holding the housing lid (under where the side plates would normally be), and lift the housing lid off. I'm pretty sure this is when they went to a two screw vs screw in a screw arrangement, so there should be a hole in the center of the housing lid with a screw visible through the hole, and a screw above the hole. Remove the screw above the hole to remove the housing lid. If just one screw is in the center of the housing lid, remove that screw. A larger screw holds the outer headband to the housing (the one seen through the hole, under the housing lid). Remove this screw, pull the outer headband gently away from the housing just enough to pull the rubber loop out. The outer headband is still attached to the cable (left side) or the driver(right side) so be gentle as to not detach the wiring. The rubber loop sits around a round extension on the outer headband plastic mount. Stretch the new loop over the extension, and reinstall the outer headband to the housing. Reinstall the housing lid. Done.

Lots of words, little work.

Attached is the service sheet for reference and parts numbers. Diagram is for modern K240 Studio, so some things are a little different (xlr connector, plates, etc, but should still be useful.

DFs are a unique member of the K240 family, enjoy them.

 

[Precaud]

Thanks for your detailed reply, Coug. And the PDF. Much appreciated. These definitely sound like DF's, then. (They don't have an aluminum trim ring 15b on the housing, though.)

New elastic bands are definitely needed. I don't see the "foam ring under the lid" on the parts list, is there a part number for them?

I just remembered, I had a couple new spare capsules (drivers) that I got from AKG in the 90's, but unfortunately they were in the box with the 'stats that got stolen. Sigh...

I am thinking of experimenting with fibrous fill inside the housing to tone down the upper-mids a little bit (enhancing perception of the bass). I recall that working with some Senns back in the day.

I still don't have an option to post pics, does that come with good behavior at some point?

 

[Coug]

No problem. Silver, gold or black, the trim ring is aluminum (anodized black?).

Foam ring, assembly number 17, part number 2073Z1502.

DFs were purpose built for monitoring/mixing so have a unique signature. Not sure if you can change the sound much without making them not DFs.

 

[Precaud]

Foam ring, assembly number 17, part number 2073Z1502.

Ah yes, there it is. Looks like a solid ring in the drawing, my bad.

I mostly used the DF's for on-location recording. There were no closed-back 'phones I knew of in the 90's that could be trusted.

Something else worth noting is their 'material integrity'. These have sat in storage next to a set of Senn HD560 Ovations for most of the last 20 years. Except for the elastic bands, everything is intact, even the foam disks. A tribute to AKG engineering/design. The HD560, by comparison, are not usable. Earpads are flat. Foam disk totally disintegrated. And Senn doesn't sell those parts anymore.