[Slater]

I've tried a few different solutions for non-stock cables for the M500. 2.5mm cable adapters, a few different 2.5mm plugs, possibly modding it for 3.5mm or even mmcx. So far nothing has worked yet.

The way KEF integrated the stock 2.5mm jack through the yoke hinge itself (and deep) does not make it easy to mod a solution.

I'm still working on possibilities, but I'm confident I'll eventually come up with something. If and when I do, I'll be sure to share.

 

[maxngck]

I've tried a few different solutions for non-stock cables for the M500. 2.5mm cable adapters, a few different 2.5mm plugs, possibly modding it for 3.5mm or even mmcx. So far nothing has worked yet.

The way KEF integrated the stock 2.5mm jack through the yoke hinge itself (and deep) does not make it easy to mod a solution.

I'm still working on possibilities, but I'm confident I'll eventually come up with something. If and when I do, I'll be sure to share.

Hi

Glad to know that you are working on a mod for this and hope you will success soon. I was thinking if there is any aftermarket ready made cable which i can just buy off the shelves.

I am sure that if we can interchange with some better cable, M500 can sing even better.

 

[Slater]

Hi

Glad to know that you are working on a mod for this and hope you will success soon. I was thinking if there is any aftermarket ready made cable which i can just buy off the shelves.

I am sure that if we can interchange with some better cable, M500 can sing even better.

There are 3rd party cables that have 2.5mm, but they don’t fit the M500.

What makes the M500 difficult is that 1. the stock plug is 2.5mm and 2. right angle and 3. due to the very deep recess of the stock female socket the plug requires a really narrow and long shoulder.

It’s possible to find plugs and cables that are 1 or 2 or 3 by themselves. It’s even possible (although the options are extremely limited) to find plugs and cables that are 1 and 2, or 1 and 3. But absolutely nothing exists that is 1 and 2 and 3.

The M500 needs all 3. That’s why I’m thinking of changing the rules, and modding the M500 to change the 1 or 2 or 3 above. This will me more aftermarket options (such as converting from 2.5mm to 3.5mm, or right angle to straight). But the design of where and how KEF integrated the stock 2.5mm female socket into the headphone does not make it easy in the least bit.

 

[maxngck]

There are 3rd party cables that have 2.5mm, but they don’t fit the M500.

What makes the M500 difficult is that 1. the stock plug is 2.5mm and 2. right angle and 3. due to the very deep recess of the stock female socket the plug requires a really narrow and long shoulder.

It’s possible to find plugs and cables that are 1 or 2 or 3 by themselves. It’s even possible (although the options are extremely limited) to find plugs and cables that are 1 and 2, or 1 and 3. But absolutely nothing exists that is 1 and 2 and 3.

The M500 needs all 3. That’s why I’m thinking of changing the rules, and modding the M500 to change the 1 or 2 or 3 above. This will me more aftermarket options (such as converting from 2.5mm to 3.5mm, or right angle to straight). But the design of where and how KEF integrated the stock 2.5mm female socket into the headphone does not make it easy in the least bit.

If u look at this 2.5mm connector, the shoulder portion is actually tapered. I roughly measured the shoulder tip os abt 3.9mm in diameter. I m now searching for 2.5mm to 3.5mm adaptor which the connector shoulder can fit into the headphone hole. So far did not come across any right agle type which can fit. High chance will be a 2.5mm straight plug. However, this may become a bottleneck.....

I just found a seller using straight plug with diameter of 3.8mm. He made the cable using klotz sq414. He said this can fit into our M500 but the outlook of this cable do not look good especially the connector portion. Not sure if i wan to take the risk to try it.

 

[Slater]

If u look at this 2.5mm connector, the shoulder portion is actually tapered. I roughly measured the shoulder tip os abt 3.9mm in diameter. I m now searching for 2.5mm to 3.5mm adaptor which the connector shoulder can fit into the headphone hole. So far did not come across any right agle type which can fit. High chance will be a 2.5mm straight plug. However, this may become a bottleneck.....

I just found a seller using straight plug with diameter of 3.8mm. He made the cable using klotz sq414. He said this can fit into our M500 but the outlook of this cable do not look good especially the connector portion. Not sure if i wan to take the risk to try it.

I’ve already tried 3 different types of plugs with no luck:



They are still not long enough to fit all of the way in. Not all of the conductor terminals make contact. They could maybe work if the plug is sanded down more.

The other option is to drill the hole in the M500 frame larger. But this is risky, because the hole to the female socket is integrated into the yoke hinge. And the walls are very thin, which leaves very little room to open it up. If the walls are thinned out even more by drilling (or worse it breaks through all the way), then you would be totally screwed because the ear cup would fall off.

Also, for any hope of a balanced, you would need a 2.5mm TRRS. And from what I’ve found, a 2.5mm TRRS does not exist that also has a narrow shoulder that will fit. All I can find is mono and TRS (as I show in the photos above).

I’m probably going to just make a direct-wired pigtail, one that hangs out the headphone a short amount and is terminated in a female 3.5mm plug. Basically like some Superlux models (except female not male). Then I can terminate it any way I want - 3.5mm, balanced, or whatever.

 

[maxngck]

I’ve already tried 3 different types of plugs with no luck:



They are still not long enough to fit all of the way in. Not all of the conductor terminals make contact. They could maybe work if the plug is sanded down more.

The other option is to drill the hole in the M500 frame larger. But this is risky, because the hole to the female socket is integrated into the yoke hinge. And the walls are very thin, which leaves very little room to open it up. If the walls are thinned out even more by drilling (or worse it breaks through all the way), then you would be totally screwed because the ear cup would fall off.

Also, for any hope of a balanced, you would need a 2.5mm TRRS. And from what I’ve found, a 2.5mm TRRS does not exist that also has a narrow shoulder that will fit. All I can find is mono and TRS (as I show in the photos above).

I’m probably going to just make a direct-wired pigtail, one that hangs out the headphone a short amount and is terminated in a female 3.5mm plug. Basically like some Superlux models (except female not male). Then I can terminate it any way I want - 3.5mm, balanced, or whatever.

Wow u have tried so many already. I am really impressed by your knowledge .

Stock connector is 4 poles. Wonder 3 poles connector lile in the photo will work? I need to ask seller about the shoulder diameter n length though.

 

[Slater]

Stock connector is 4 poles. Wonder 3 poles connector like in the photo will work?

I’m not sure if 3 poles would work or not. It all depends on the pinout configuration of the stock 2.5mm female socket. I have not taken apart the headphone to do the pinout analysis yet, but I plan to in the near future.

 

[maxngck]

Hi

I am currently working with some seller on the upgrade cable. Most of the seller using afteramarket (diy) cable which is made for B&W P9/ P7. Seller said the 2.5mm jack should be ok to insert into our M500.



I found another site which diy the cable using similar connector. I do not have the detail or information on the jack which they using.



Hopefully it can be used.... still searching for suitable cable material. Do u think should go for silver or copper cable?

 

[Slater]

The end doesn't look particularly sturdy or reliable long-term. If you do end up getting a cable like that, I would be very careful when inserting or removing it.

 

[maxngck]

The end doesn't look particularly sturdy or reliable long-term. If you do end up getting a cable like that, I would be very careful when inserting or removing it.

Yes, after further communicating with different seller n others, they mentioned with such cable the connection may broken. So i may just put off this kind of cable. Instead i am thinking of the below adaptor 2.5mm male to 3.5mm female type. Then get a better 3.5mm aux cable.

 

[Slater]

Yes, after further communicating with different seller n others, they mentioned with such cable the connection may broken. So i may just put off this kind of cable. Instead i am thinking of the below adaptor 2.5mm male to 3.5mm female type. Then get a better 3.5mm aux cable.

Yup, that’s what I had determined.

Basically, IMO the 3 most realistic M500 options are:

1. A short 2.5mm male to 3.5mm female pigtail adapter made out of all new parts, assuming a compatible 2.5mm plug could be found (preferably a 90 degree one).

2. A short 2.5mm make to 3.5mm female pigtail adapter, made out of the stock cable.

3. A short 3.5mm female pigtail made out of all new parts, with a hard wired connection soldered directly to the headphone (similar to Superlux headphones).

The other options I’ve kicked around involve significant/riskier modifications to the headphone (drilling, grinding, converting to dual plugs, relocating sockets to elsewhere on the headphone, etc).

 

[maxngck]

Yup, that’s what I had determined.

Basically, IMO the 3 most realistic M500 options are:

1. A short 2.5mm male to 3.5mm female pigtail adapter made out of all new parts, assuming a compatible 2.5mm plug could be found (preferably a 90 degree one).

2. A short 2.5mm make to 3.5mm female pigtail adapter, made out of the stock cable.

3. A short 3.5mm female pigtail made out of all new parts, with a hard wired connection soldered directly to the headphone (similar to Superlux headphones).

The other options I’ve kicked around involve significant/riskier modifications to the headphone (drilling, grinding, converting to dual plugs, relocating sockets to elsewhere on the headphone, etc).

I would choose option (1). However, i have enquire many seller and they have not seen a 90 degree connector. Even straight one is hard to find with such a small step. Most of them ask me to give up the idea snd either stay with stock cable or upgrade a new headphone .

I wouldn't wanna take the risk to modify on the headphone side. It seem that hole portion is quite fragile. Any mistake made then really gotta upgrade new headphone .

Straight connector which able to plug into the hole will look weird as it is long..... still very hesitating to gety previous post adaptor. Seller said i will look like teletubbies with that...

 

[Slater]

I would choose option (1). However, i have enquire many seller and they have not seen a 90 degree connector. Even straight one is hard to find with such a small step. Most of them ask me to give up the idea snd either stay with stock cable or upgrade a new headphone .

I wouldn't wanna take the risk to modify on the headphone side. It seem that hole portion is quite fragile. Any mistake made then really gotta upgrade new headphone .

Straight connector which able to plug into the hole will look weird as it is long..... still very hesitating to gety previous post adaptor. Seller said i will look like teletubbies with that...

If you’re looking for an inexpensive and easy solution that requires no modding the M500, I found something that will work.

I had previously bought this 2.5mm to 3.5mm adapter, hoping it would fit (but it didn’t). They run about $1 each.



However, I discovered that the black body is just rubber, and can be carefully trimmed off to reveal the actual plug ‘guts’ underneath. These guts are literally the exact size needed to fit the stock headphone!







The only caveat is that they are somewhat fragile. They appear to be able to stand up to normal use, but if you’re overly rough with them or put a lot or stress on them they could break apart. However, if I break one who cares, as they only cost $1 each and take 30 seconds to remove the rubber covering. So I figure if I can get a few months of use out of an adapter it’s worth it.

Here it is after adding a small piece of heat shrink tubing. Hopefully, it will provide an extra layer of reinforcement.



Also, the adapters are 4 pole, meaning that they’ll work with a balanced aux cable assuming the 3.5 cable has the correct pinouts. A custom 3.5mm balanced cable may need to be constructed to ensure the balanced pins are mapped properly. But a custom balanced cable would be a small price to pay for such an easy and inexpensive adapter solution.

If you look around, some sellers sell the adapters in qty of 1, 3, 5, or even 10. I recommend buying at least a 3 pack ($3.xx), which will allow you to ‘practice’ removing the black rubber without causing any damage to the underlying plug. That way, if you damage 1 adapter while learning, you’ll still have 2 left. I was able to relive my rubber body with no damage to the guts, but YMMV.

Anyways, if you wanna give the adapters a try, search Aliexpress for the terms “2.5mm right angle”, and you’ll find them. I’m sure they’re also available on Amazon, eBay, etc.

 

[maxngck]

If you’re looking for an inexpensive and easy solution that requires no modding the M500, I found something that will work.

I had previously bought this 2.5mm to 3.5mm adapter, hoping it would fit (but it didn’t). They run about $1 each.



However, I discovered that the black body is just rubber, and can be carefully trimmed off to reveal the actual plug ‘guts’ underneath. These guts are literally the exact size needed to fit the stock headphone!







The only caveat is that they are somewhat fragile. They appear to be able to stand up to normal use, but if you’re overly rough with them or put a lot or stress on them they could break apart. However, if I break one who cares, as they only cost $1 each and take 30 seconds to remove the rubber covering. So I figure if I can get a few months of use out of an adapter it’s worth it.

Here it is after adding a small piece of heat shrink tubing. Hopefully, it will provide an extra layer of reinforcement.



Also, the adapters are 4 pole, meaning that they’ll work with a balanced aux cable assuming the 3.5 cable has the correct pinouts. A custom 3.5mm balanced cable may need to be constructed to ensure the balanced pins are mapped properly. But a custom balanced cable would be a small price to pay for such an easy and inexpensive adapter solution.

If you look around, some sellers sell the adapters in qty of 1, 3, 5, or even 10. I recommend buying at least a 3 pack ($3.xx), which will allow you to ‘practice’ removing the black rubber without causing any damage to the underlying plug. That way, if you damage 1 adapter while learning, you’ll still have 2 left. I was able to relive my rubber body with no damage to the guts, but YMMV.

Anyways, if you wanna give the adapters a try, search Aliexpress for the terms “2.5mm right angle”, and you’ll find them. I’m sure they’re also available on Amazon, eBay, etc.

Wow, it is fascinating to see how you diy the part. I found the 90 degree adaptor as below.



Just to check how to do you cut open the plastic casing? What tool do you use?



Can you help to check and confirm the length of X? As i look at our stock connector the step seem to be very long. Just wanna make sure it is fully inserted. The above circle in red, is the area flimsy? The green circle area the 2.5mm pin is it secure firmly? I worry the pin drop out and stuck in the headphone hole when pulling out the cable



The below circled in red that semi transparent casing is it being cut open when you cut the black outter case? The 3.5mm female adaptor is it firmly secure in the semi transparent case?



Sorry for so many questuons asked

Thank you

 

[Slater]

I used a razor blade to remove the black rubber. You have to be careful not to cut any of the semi-transparent plastic. Only cut the black rubber.

As far as the length, it is the same length as stock. It gets fully inserted. No need for me to measure.

As far as it getting stuck and not being able to be removed, I have inserted and removed the adapter about 10 times so far. It fits perfectly, like it was made for the M500. If you can insert and remove the stock plug, then you can insert and remove the DIY adapter. It has the same dimensions.

As far as the semi-transparent plastic casing, yes it is thin and flimsy. That's why I said in my post above that "The only caveat is that they are somewhat fragile. They appear to be able to stand up to normal use, but if you’re overly rough with them or put a lot or stress on them they could break apart. However, if I break one who cares, as they only cost $1 each and take 30 seconds to remove the rubber covering."

I'd recommend to spend the $1 and get one of the adapters. Then you can check it out in person. When you can see it and hold it with your own hands, I think it would clear up any questions. Photos can only do it justice to a point.