Custom AKG K1000

A really, REALLY beat up K1000 meets a kid with way too much time on his hands

Some people who browse the 'Bay regularly may have noticed a severely mistreated AKG K1000 up for sale. Absolutely filthy, with only one working driver, no cable, no strain reliefs, no headband pads, and a severely stretched out headband. $199 starting bid, free shipping, put up for a week, still no bidders five days in.

Now I personally have been ogling the K1000 for quite some time now. It may seem odd, but I also greatly enjoy restoration projects. The idea of owning this headphone, especially one that must have been tossed off the side of the empire state building and straight into the nearest open manhole, was absolutely exhilarating. So, I did what any irresponsibly ambitious person would do. I jumped on it like stink on shit. The auction ended at $308... and it became mine.

I am currently still waiting for the headphone to arrive in the mail, so before I can start any teardown/restoration, I'm gonna throw down some thoughts about my plans for it.

Cosmetics

PAINT:

I have several color schemes in mind if I end up being unable to repair the stock drivers. However, before I get into those, I need to figure out how I'm going to paint it. I'd like to do a professional powder-coating job, but unfortunately, I do not have access to a paint booth. I plan on contacting Custom-Cans and Colorware to see if they will help me out, but for now I'm operating under the assumption that they will not. (If anyone else knows someone who could do this for me, please let me know via PM.)

What I'm looking for is an attractive finish. Not necessarily cheap, but something that I can do myself without any training or experience. Yeah, fat chance, I know. One thing is certain: no matter what color scheme I end up going with, it's going to be a matte finish. After a bit of looking around, I found a few options:

• Plasti Dip: Yeah no, glad I looked around about this stuff more before buying it. Maybe usable for making new strain reliefs, but I doubt it.
• Nextel: The spray-on variant of this product has been discontinued for a while, and I can't figure out where to look to order it. Yay for me.
• Krylon: Self-explanatory. Probably won't look nice enough, but conversely probably the only one I can do myself.

So yeah, if anyone knows someone with a paint booth that would be willing to do a custom job, let me know. >___>

As for the color patterns themselves, I'm working on a basic model of the K1k I can use to make test renders and play with colors. Yeah f**k that, it'll take too long to make an accurate model. Might do it later. For now, here's some photoshop bullshit instead. Vote in the poll(no polls?! what kind of 90s BBC forum IS this?!?!) or post comments about the different colors. I personally seem to leaning more towards 4 and 5. Idk, I think I'm gonna do the model instead, it's a lot easier to do colors with that.

1: [IMGhttps://dl.dropboxusercontent.com/u/34404748/noDel/K1k/col/1.png[/IMG]
2:
3:
4:
5:
6:

CABLE:

Before I choose the final cable, I ordered a cheap Monoprice 1/4" to RCA cable to cut up and wire to the headphone for testing. If I can fix the stock drivers, I might have to stick with this cable for the final product unless I make my own with high-spec wires. Lots of power will be running through this headphone.

I'm considering a Zy HD800 cable as well as HD800 sockets on the headphone side, which you can order from chinese manufacturers (but for some reason no one has any HD600 sockets... f'ing dumb. If anyone knows what that connector is called, let me know; it is NOT a Sennheiser proprietary design).

More on the cable later.

Sound

I have three plans on what to do with this headphone sound-wise.

PLAN A:

My first course of action is obviously going to be to try and repair the broken driver. If I can get the driver working, I just got myself the best deal on a K1000 anyone will ever see, ever again. Yay. Except I know the likelihood that the driver isn't completely f'ing shot is quite low. So, after I'm done exercising my tolerance for futility, I'll be moving on to...

PLAN B:

I have always wanted to try a K1000-style DIY headphone. But, an ACTUAL DIY K1000 was something I never thought I'd be able to do. Again, yay. I have several pairs of working drivers on hand from various headphones I've gathered over the years, just begging for another chance to perform. They are as follows:

• Peerless MB 55mm Orthodynamics, 120 ohm (of the breed seen in the B&O U70 and Magnat RT-10)
• Fostex 55mm dynamics, 32 ohm (used in several OEMphones, mostly Audatron gear)
• Pioneer Monitor 10-II drivers, 50mm, 20 ohm

The first two have already proven themselves to be quite nice sounding in a fully-open implementation, such as the one the K1000 would provide (The Magnat RT-10 is particularly exquisite sounding). The Pioneer drivers on the other hand have been needing a shell for a while, and are the reason I was looking for a donor shell in the first place, but I'm not certain how they will sound in the K1000. The driver's distortion is extremely low and the bass lacks any kind of "warmth", which might lead to a VERY thin, unpleasant sound.

I plan on trying all three of these drivers at least once before doing any major repainting or alterations to the K1000 enclosure. However, there is one more course of action I could try...

PLAN C

This is what I would call the "Super K1000" if it works.

You can order Sennheiser HD800 drivers from senn for ~$500 a pair.

Really, do I even need to say anything else?


Cheers, will update later.

EDIT: Sorry guys, chang posts don't migrate well. the pictures can't be resized.

 

Updates from previous post:

1. This project has been taken off hiatus as I've started regaining some money and stopped being lazy.
   
2. Only one of the stock drivers works. The other has several burn holes where someone tried to solder the voice coil and the diaphragm is completely detached from the capsule. Fun.
3. I am now having the headphone painted by Casper over on Head-Fi. He gave me a good offer that I couldn't refuse. I've chosen the blacked-out colorscheme.
4. I'm currently working on the new spider model to house the new drivers. The design I'm doing is universal and should fit any one of the drivers I've listed with ease, including the HD800 drivers.

 

Progress on the new spider 3D model.



The measurements and scale were perfectly replicated using the stock part as a guide. I'm going to punch some holes in the mounting area to reduce production costs and print a prototype from Shapeways. If adjustments need to be made, I will do so.

This will definitely fit all of the drivers I had in mind, which I have on my person. However, I can't be sure the HD800 driver will fit until I have one. It may be too deep and touch the back of the K1000 mesh when mounted. I will also need the driver to get the dimensions required for the cutaways for the cable mount.

Those little pins at the bottom are what hold the clamp tight, which is what keeps the spider on the headband and the meshes attached to the headphone. These pins are only 1 millimeter wide, but the material AKG used for this part is an extremely high quality polymer, so it holds. I'm not sure the nylon that Shapeways offers will maintain durability at such a small mechanical tolerance. I'm not sure the printing will be accurate enough, either.

Time will tell, but I may have to use a different ($$$) material for the job.

 

Finalized prototype spider:



Price quote from shapeways is extremely reasonable: $9.93 USD. Purchasing one for now since this is still a prototype.

Total project investment so far: $317.93.

More to come in a few weeks when the part arrives.

 

In the meantime, here's some proper renders of the part.







The model is extremely high poly: 15,776 tris for something barely 3 inches tall. Didn't take too long to replicate -- approx. 10 hours of SketchUp and a metric ruler. The original part, for comparison:







I left out a couple features for now to reduce cost and chance of manufacturing error, namely the screw holes on the bottom, the cable inlet, and the grid-like raised area where the piece attaches to the headband. I might not add that last one at all actually, as it doesn't appear to be for anything specific.

Also, this showcases an interesting thing about the K1000 driver. The "magnet" is actually a set of machined stainless steel rings, stuck together using enamel, with 16 small neodymium bar magnets between them. Its quite heavy and appears to provide excellent flux density. They might have done this to reduce manufacturing costs, or they might have done it because it offers some sort of sonic benefit. Either way, I thought it was quite intriguing.

 

Updates:

1: The part shipped just now. Almost 3 days early, which I was expecting. Shapeways has always been very snappy and reliable in the past and I'm really happy to see them grow the way they have.

2: I will be ordering these connectors from Aliexpress with my next paycheck. These will be going on the bottom of the earcup where the K1000 cable would normally be attached, onto a custom 3D-printed mount which will attach via screws. This will allow the use of any commercial cable designed for the HD800. Unfortunately, I do need to actually have the connectors before I can make the model, so we won't be seeing the final part for a while. Total investment so far: $347.92.

3: I have some Cardas pure silver wires and quad eutectic solder left over from when I recabled my DR-Z6 a year or so back. I will be using these to do the internal cup wiring for the connectors.

4: I cannot afford it yet, but the ZY HD800 cable has more or less been decided on. If anyone else has a better or perhaps cheaper suggestion, let me know, keeping in mind I greatly prefer a plain, flexible, and durable cable as opposed to something like Nordost or Q. Something like the HD650 (but thicker) would be nice. In the meantime I have a test cable I can use instead.

5: Once I have Tyll measure my NAD RP18, amongst some others, I'll be selling it off and using the proceeds to buy the HD800 drivers. Hopefully I'll have the drivers by the end of the month and can finalize both of the models.

6: I need the headphone to be wearable to figure out the angle and position I want the HD800 drivers in for the final product. This means I need new headband pads. While looking around, I saw these on Beyer's headphone spares site. I don't know for sure what size they are, unfortunately, but the chance they will fit is somewhat decent. I bought one to see if it'd fit the bill, since it was only $10. If all else fails, I guess I can make my own. Total investment so far: $357.91.

More to come.

 

Make sure you have the back metal mesh for the HD 800 drivers. It was in an thread back in changstar where marv ripped out the mesh and the bass extension dropped significantly. The mesh seems to defuse the sound and improve the characteristics.

 

First of all, amazing stuff mate!

I have one question, Tak: Why would you willingly pick the HD800 connectors? They are horrible to work with.

Also, definitely consider selling the working driver. I know they fetch something like $100 in certain places

 

^^ That too. I just spent 3 hours today soldering some f'ing 24 gage wire to those overpriced bastards. The clearance between the pins is so small, a fine sowing needle cannot fit through. I barely managed to fit electrical tape around one of the pinouts so I could wrap the pin to avoid shorting the two. If I had to guess, the tape is 1.5x as thick as the clearance between those two pins. It is extraordinarily small, and even more extraordinarily annoying to work with.

 

Marv also ripped the driver out completely and did a bare driver measurement with the drivers suspended about an inch from the ear. Check the thread on chang for the result (it was quite good). This is the type of implementation that will end up in this headphone. I'm planning on either locking the K1000 cup rotating mechanism or simply advising against using it, and angling the drivers inside the cups instead.

It'll take some experimentation, but I'll get the sound right.

 

Ahh yes, true that. Would be very interesting to see the results, I wish you the best of luck.

If I may make one final suggestion, depending on how the ear cups fall on your head, you may want to leave a little bit of swivel room in case you don't build them exactly to the specifications of your head.

 

... Holy shit.

 

troubling, but I have another idea. Can't post it all right now; at work. More to come.

Yikes marv, that driver is way too big...

 

Then move them back....

then build a cabinet...

then add a few more....

 

any progress?

 

Being a bit lazy/busy, I have way too many projects going at the same time

The part came in with three slight errors: the pins were a bit too thin and short on the print to properly close the cup assembly. Otherwise the scale is fine, almost perfect. Second, and I really cant believe I let something this silly slip past my judgement, but I put the recessed area (to mount the driver in) on the wrong side of the spider. So when mounted, it'd be firing out the back. Lol. Finally, the pin holes which mount the spider assembly to the headband, while correctly spaced apart and the correct size, are not centered. So I can't get the piece to mount on the headband yet.

I'm making the necessary adjustments to the part now and should be able to order it tomorrow.

I also got the HD800 connectors in, so while I wait for the HD800 drivers I can get the cable inlets modeled. Yay. Also these things are really f'ing cheap, ugh. Definitely making the slot they mount into solid so they won't break.

As for ordering the HD800 drivers, I'm still too poor for that. Need to get the NAD RP18 sent to tyll and sold off first. I will likely end up ordering them one at a time, as I don't think I need to worry about sennheiser's QC and ordering two will not get me a matched pair I'm sure.

More tomorrow.