Seeking info about physical comparison of KOSS Portapro and KOSS KSC75 drivers
Mar 8, 2017 at 12:02 AM Thread Starter Post #1 of 33

JamesWJ71

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Hi all!
I am a newbie here as I am sure you can tell.
 
I have been reading stuff from this forum for a while now but, even though I have found a lot of good information I have never found quite the info I need.
 
Here is my situation:
I have a pair of "KOSS by Ford" headphones which I have been told are basically the same as the KOSS Mac-5.
As I am sure many of you know. the actual electronics of these are very good but, being that the headband is made entirely of plastic that tends to rot over time they are not the best for longevity.
 
I have had two sets of these KOSS headphones which my brother had found in cars (he works in auto salvage). The first pair wound up going bad in one side on top of the plastic band breaking.
 
The second pair has lasted me much longer although the band did break numerous times. I glued it and even used J-B Weld to repair these breaks until I decided to switch the cups to an old Radio Shack band that I had saved from years ago. They aren;t pretty but they work....mostly.
 
Now one side seems to be going bad.
 
There is a buzz at times in the right side that seems to be from bass even when there is not a lot of bass or from too much volume when the volume is not that high.
 
For the record, I do still have the one good side from the other pair of these headphones I had but, it seems to have more of a buzz problem than the one that is currently going bad.
 
I had contacted Koss about the possibility of purchasing new drivers (I know they are the same drivers as in the Portapro) but, they only suggested sending them in for warranty repair.
 
I e-mailed back explaining that these are beyond simple warranty repair since the band is gone which is why I asked about just purchasing the parts I need (I did not mention to them that these were found items rather than purchased which could complicate warranty issues anyway).
 
As I said, I know these are the same drivers as in the Portapro and KSC75.
 
Portapro drivers would be a simple fit as they are physically no different in size or shape from the original driver. I know that the specs for the KSC75 are the same as the Portapro other than that they have titanium coated membranes.
 
I am considering buying a set up KSC75's to pop into the cups but they are physically different from the drivers that are in there and the Portapro drivers in that the plastic housing on them has that domed back side.
 
This is where I need your help.
 
Does the round back on the KSC75 driver make it significantly bigger that the Portapro driver? In the center area I think there is more leeway but at the edges if the rounded back makes it too much thicker they probably would not fit.
 
I have watched videos and looked at countless photos but. I cannot find anything that gives me the view I need to know for sure if I could fit the KSC75 driver into my Mac-5 cups.

The only other option I have found is to buy replacements from Aliexpress which LOOK like the KOSS Portapro drivers but reviews say the sound is not as good. If I wanted a lower quality or lower volume driver I could mod a pair from some other old headphones I have from other brands (one Panasonic and one Sony).
 
The parts from Aliexpress are the cheapest I can find for replacement parts in general and the only replacements I can find that are specifically made to match this driver (even if I decided to try the warranty repair, shipping costs would be more than the $10 the drivers cost on Aliexpress).
 
Option two came to me recently when I realized I had accumulated enough "gift card" cash (THANK YOU ONLINE SURVEYS!) on Amazon to buy a pair of the KOSS KSC75's....I'd have to pay the shipping but that'd be no more than $7 which is cheaper than any other option and faster too.
 
The KSC75 drivers would be the easier way to go since I would not need to solder the cord from the original parts...unless I just want to retain the extra length (about 4 more feet from  what the KSC75's have). The original cord has a 1/4-inch plug which I prefer but the convenience would trump that.
 
So, can anyone tell me if the KSC75 version of the driver would fit the MAC-5/KOSS by Ford ear cup?
 
I am really hoping so since I would only need to take off the ear clips and remove the foam pads then pop them into place.
 
If they won't fit does anyone know what the quality of those replacements on Aliexpress is?
 
Thanks gang!
 
Mar 8, 2017 at 1:29 PM Post #2 of 33
If I were you, I'd just buy different headphones, especially since these cost next to nothing.
 
My ranking of Koss headphones I have owned is something like:
 
KTXPRO1 > UR40 > KSC75 > UR55 > Porta Pro
 
I have found that the enclosure matters more than anything else, having swapped some drivers.
 
Oh, and here's a popular headband for the KSC75:
 
http://www.parts-express.com/parts-express-mini-stereo-lightweight-headphones-with-4-ft-cord--240-015
 
Mar 8, 2017 at 2:37 PM Post #3 of 33
  If I were you, I'd just buy different headphones, especially since these cost next to nothing.
 
My ranking of Koss headphones I have owned is something like:
 
KTXPRO1 > UR40 > KSC75 > UR55 > Porta Pro
 
I have found that the enclosure matters more than anything else, having swapped some drivers.
 
Oh, and here's a popular headband for the KSC75:
 
http://www.parts-express.com/parts-express-mini-stereo-lightweight-headphones-with-4-ft-cord--240-015

+1
 
Mar 8, 2017 at 7:05 PM Post #4 of 33
Yes, I know about that headband. Came across it in my search for info.
 
The reason I want to "repair" these is that I like the sound quality and that they are light on my ears rather than covering them completely like higher-end headphones.
I would actually end up paying more for the Parts Express headphones than to just get the KSC75's on Amazon since I have $15 in gift card credit on Amazon. I would just need to pay the shipping. With Parts Express I would pay double what I would for the KSC75's.
 
I really just want to know if there is a major difference in the size of the plastic casing that holds the drivers.
 
Mar 8, 2017 at 11:38 PM Post #5 of 33
I should have been more clear.
 
I know that these are inexpensive headphones. Yet, they are damn good headphones for the price.
On top of that, the band I transferred the cups to when the original Koss band rotted fits my head better than most headphones to.
 
Yeah, if I just wanted a cheap pair of replacements I could spend 5 to 10 bucks at Big Lots. The problem is that the headphones they have tend to have flimsy bands that don't hold the drivers to my ears enough. This tends to happen when they make items cheaper and when, like me you have a larger than average head.
 
I am not looking for high-end stuff. If I were I would not be asking about the KSC75. I am just asking about them because I know they are the same drivers as are originally in the headphones and I wish to keep that level of quality without spending a ton of cash.
 
I mean I could send them to Koss and see what they say but, it would cost more to deal with that than  to get the KSC75's since I have $15 in credit on Amazon. So, basically the headphones would be free and I would just pay the shipping.
 
I do appreciate the input though.
 
Mar 8, 2017 at 11:48 PM Post #6 of 33
The KTXPRO1 has a headband with good clamping force, and, to my ears, it's the best-sounding of the semi-open budget Koss headphones. It's an alternative to buying the KSC75, which I don't like as much aside from its sparkly treble and soundstage. But it would be simple enough to buy both and experiment. Sorry I can't say for sure whether the KSC75 and Porta Pro driver housings are the same. (I had the KSC75 before I got the Porta Pro.) From memory I'd guess they're slightly different.
 
Mar 9, 2017 at 4:04 PM Post #7 of 33
Well, thanks for the info.
 
I know they are "SLIGHTLY" different. The Portapro is flatter while the KSC75 has a domed back. They are the same size around.
 
I know that the KTX Pro has the same driver as both the PortaPro and KSC75 but, it should be closer in sound (if not identical) to the KSC75 since both have the titanium coating.
 
Since the ear cups of the MAC-5 are not very deep it is the domed back of the KSC75 that is my concern.
 
I like my "Franken-phone" set up. The band I have is comfortable even if I have had to replace plastic parts with some scrap wood. I also had to replace the vinyl on the underside of the band with tolex that I had removed from an old guitar amp when I recovered that with canvas to have a more vintage look.
 
I have found micro speakers online but, most seem to be too small and would need a screen of some sort to protect the diaphragm.
 
The "Porta Pro" replacements I found on Aliexpress would physically fit I am just not sure about the quality of sound or the durability.
https://www.aliexpress.com/item/Replacement-headphone-parts-Speakers-drivers-sound-speaker-for-KOSS-pp-portable-portapro-porta-pro-headset-headphones/1688860607.html
 
There is also a rather long window of time for delivery if I buy from Aliexpress.
 
That is why I am thinking of the KSC75 since it is the same driver design (other than the titanium coating and the domed back). As long as the housing of the driver is not too much thicker in size it would be a direct replacement and save me the need of having to swap the original cable from the original drivers to the replacements.
 
I do understand that, a lot of people take the view that, "if you need to replace something then why not upgrade?""
 
I am a person that does not like change. I have a diagnosis of Asperger's Syndrome. An aversion to change is one of the traits (it is among the traits I saw in myself that made me seek a diagnosis).
 
I have considered the KTX Pros just as a new pair but; A- they cost more and I am cheap, B- you have a ton of people online saying they are the same drivers as the KSC75's and C- did I mention I am cheap? I am a person that likes to repair things rather than replace if I can.
 
I repaired the original plastic band a few times before I gave up and swapped it for the old Radio Shack band. Mostly because I have used the radio Shack band before and it is hard to get it to hold ear cups that were designed for a completely different band. I took more time when I did the swap this time


I may just order the KSC75's and take my chances. I just thought I would use this forum as a resource since it would be silly not to. I mean if you can gather info about a product before buying it's typically a good idea to do so.
 
The price can't be beat since I only have to pay for the shipping. I do online surveys where I can earn Amazon gift cards and I have $15 which covers the price of the headphones. I "could" wait until I can get enough credit to cover the shipping too but, it can take a while to build up the points in the survey system.
 
Mar 9, 2017 at 4:46 PM Post #8 of 33
But, the KTX Pro and KSC75 are the same drivers. Both are titanium coated versions of the driver used in the PortaPro.
 
I had considered the KTX Pro but, I am the kind of person that prefers to repair things if possible before replacing them.
 
I am not a person given to change. I was finally diagnosed with Asperger's Syndrome a few years back and one of the traits that I have that led me to seek a diagnosis was my aversion to change.
 
As I mentioned I have these headphones on an old Radio Shack band but I did not move them to it the first time the original Koss band broke. I repaired it 3 or 4 times before I swapped to the Radio Shack band. Like I said I prefer to fix things if possible. Of course there is also the fact that I used the Radio Shack band on my first pair of Mac-5's and it was difficult to have it hold the ear cups without them popping lose.
 
This time around I spent the  time to bend the Radio Shack band to better grip the smaller ear cups.
 
Yeah, it's a set of "Franken phones" but I kind of like that aspect. The band has had plastic parts replaced with scrap wood and one side of the vinyl covering for the padding has been replaced by tolex that I removed from a guitar amplifier when I recovered it with canvas to get a more vintage look.
 
I have been 80% sure that the KSC75's will fit my application. However, when you have a resource like this forum it is silly not to use it which is why I have not simply ordered the KSC75's.
 
Initially I was going to order replacement drivers on Aliexpress that LOOK like PortaPro drivers. They list them  as PP driver replacements but some of the customer reviews have me a tad "iffy" on them. They say the sound is not as good and so on. Granted they do not claim them to be Koss parts so the quality should not be assumed to be the same. And of course the shipping from the sellers on Aliexpress can take quite a while.

I have found micro speakers on sites like Parts Express but they are too small to fit and even if they were the right size I would need to fashion some sort of covering to protect the diaphragm.
 
That's why I am looking at the KCS75's. The have the same diameter and are the same driver according to virtually every source I have found other than having the titanium coating.
 
I may just order them and take my  chances.
 
I have accrued $15 in Amazon gift card credit (I do online surveys where I can earn stuff like that). I would just need to pay the shipping. The price can't be beat....unless I wait until I can get enough Amazon gift credits to cover the shipping as well. However, it takes a while to do enough surveys to get an Amazon gift card.
 
The KTX Pro would have more of a draw for me if it had a longer cord. That would seem to be the one down side to swapping drivers unless I want to do some soldering. It seems unless you get high-end headphones or ones meant for studio work you are lucky to have a 4-foot cord. The original cord I have is more like 8 feet. Not that I NEED such a long cord but, as I said, I don;t like change.
 
Yes, I could  swap the cord anyway but to do unnecessary soldering can lead to issues. That is part of the appeal to using a new set of Koss headphones for donor drivers rather than buying new drivers from  Aliexpress, Parts Exress or any other source. The fact that I won't need to do any soldering.
 
I learned long ago that it is all to easy to screw up a driver when soldering.
 
Mar 9, 2017 at 5:08 PM Post #9 of 33
  But, the KTX Pro and KSC75 are the same drivers. Both are titanium coated versions of the driver used in the PortaPro.
 
The KTX Pro would have more of a draw for me if it had a longer cord. That would seem to be the one down side to swapping drivers unless I want to do some soldering. It seems unless you get high-end headphones or ones meant for studio work you are lucky to have a 4-foot cord. The original cord I have is more like 8 feet. Not that I NEED such a long cord but, as I said, I don;t like change.

 
What point are you trying to make? That they sound the same? Because they don't; not even close. To be fair, though, the enclosures have more of an influence than the drivers do.
 
I believe the drivers are all slightly different shapes and they may even have slightly different materials. I read that the KSC75 is round-backed while the KTXPRO1 is flat-backed. I didn't pay enough attention when comparing it myself.
 
The cable of the KTXPRO1 is longer than the listed 4 feet. I guess they only list the part below the inline volume control. If I hold the headphones up and let the cable go down to the ground, it's almost as tall as I am.
 
Mar 9, 2017 at 5:44 PM Post #10 of 33
Small differences can affect what we hear quite a bit.
 
The KSC75 is more "open" than the KTX Pro. I would suspect that the difference would be less if you compared them with both on the same headband (assuming you could put the KSC75 onto the KTX Pro headband).
 
According to what I have found Koss even has some over-ear headphones that use the same basic drivers but being that they let in less environmental sound they would not sound exactly the same as the on-ear models even if the drivers are identical.
 
The in line volume control of the KTX Pro doesn't appeal to me. I have two sets of headphones with inline volume control and I typically just leave it wide open. I find it to be a potential point of failure. This is my opinion based on the experience I have had with inline volume.
 
I am not saying that everyone would have the  same issues or that inline volume is not useful. For me personally I can live without it.
 
Mar 9, 2017 at 5:49 PM Post #11 of 33
  Small differences can affect what we hear quite a bit.
 
The KSC75 is more "open" than the KTX Pro. I would suspect that the difference would be less if you compared them with both on the same headband (assuming you could put the KSC75 onto the KTX Pro headband).
 
According to what I have found Koss even has some over-ear headphones that use the same basic drivers but being that they let in less environmental sound they would not sound exactly the same as the on-ear models even if the drivers are identical.
 
The in line volume control of the KTX Pro doesn't appeal to me. I have two sets of headphones with inline volume control and I typically just leave it wide open. I find it to be a potential point of failure. This is my opinion based on the experience I have had with inline volume.
 
I am not saying that everyone would have the  same issues or that inline volume is not useful. For me personally I can live without it.

 
The KSC normally rests away from your ears, which does add to the openness. However, it is easy to push the drivers against your ears. They sound very different.
 
I believe the UR40 may have the same drivers despite being larger. I had that one too, but prefer the KTX.
 
Yeah, I understand not wanting the inline volume control. It is kind of annoying sometimes. Every once in awhile, when I move the slider, it can make one of the drivers cut out...but that's 'cause mine is getting old.
 
I guess the most likely solution for you to try is the KSC. You can return it if it doesn't work out.
 
Mar 9, 2017 at 6:05 PM Post #12 of 33
What I mean by "openess" is the fact that they do not rest as close to your ears. You have more surrounding sound getting in. Also the design of the back of the driver is less "solid."
 
Mar 9, 2017 at 8:00 PM Post #13 of 33
Please keep in mind that my initial post was asking about the PHYSICAL properties of the KSC75 driver (thickness, width, etc.) compared to the PortaPro driver.
 
I have already seen various info and opinions on the differences of how they sound.
 
I understand that others would just get a new set of headphones. However, for me at this time I would prefer to just get new drivers regardless of the source. Preferably staying as close as possible to how my headphones sound now but, losing the buzz in the right side.
 
I am not a person to take change easily but, beyond that there is the fact that any set of headphones I may be interested in are quite a bit more money that just getting the KSC75's which I hope will fit the Mac-5 ear cups.
 
Mar 9, 2017 at 11:40 PM Post #15 of 33
Slight differences are fine. The truth is it is possible for 2 of the same model of headphone to not sound exactly the same.
 
Since I am swapping both sides it won't really matter if there is a difference between the new and the old.
 
Now, if I were going to replace JUST the one that is starting to buzz it'd be a different story.
 
What would make me happiest would be if I could find a way to stop the buzzing. It's weird because it isn't consistent. I have played stuff that is louder and has more bass that doesn't cause the buzz and then I can be using them to hear during a video chat with a comfortable level and they buzz up a storm.
 
It may seem stupid, especially since these were "found" headphones rather than some I bought. I mean I have paid more for headphones at Dollar Tree (where everything is $1) than I paid for these.....unless you count the replacement pads I bought.
 
But, like I said, I prefer to fix things if I can rather than replace them. Granted there are times that replacing makes more financial sense. Technically I am replacing these but, I am keeping elements so that part of my brain that hates change won't be screaming so much.
 
Picture the Frankenstein monster when he goes "Fire BAD! RRRRR!!!!" Just replace 'fire" with "change."
 
Welcome to my brain.
 

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