Taking Koss Portapro to the Limit (cool mods).

This is not a step by step guide but a collection of mods floating around head-fi tweaked for my own needs and taste. Some might find my impressions useful and get encouraged to perform their own.
The thing is that the portapro driver is awesome, but it can do much better if modded. Most ppl here perform the Kramer mod or the quarter hole mod(to release some detail and tighten the bass) and think they are pretty much done. Some add 75ohm resistors (to tame the highs and lows) and re cable their cans. But those are just tweaks.
Another mod is mounting reversed vintage Sennheiser Hd414 pads on the Koss driver. Pair this with the Kramer mod and the phones start to shine. That got me going for a while..

A year ago I purchased a vintage Koss SST/5 cans from another head-fier, which are sort off a Portapro's bigger brother. They were twice as big and.. twice as ugly So I took em apart and grabbed their most valuable part- the ear cushions..
I had no clue that ear cushions can make so much difference! The hd414 are good, but not THAT good!


First thing I noticed that the volume went up by a couple of notches with the SST/5 cushions. So i had to turn it down a bit. I guess what happens is that the cushion captures the sound and nothing is escaping so it goes directly to your ears. I assume that it didn't happen with the stock and hd141 cushions because they are made of foam.

Second major change was in the bass department. No more bloat! Just tight and punchy awesomeness The beautiful thing is it's not less, just better.

Then comes the soundstage and instrument separation... Let's just say that those bad boys sound like a proper can now.

As for the highs, well, they can be a bit sharp. I guess it's because of the driver distance from the ears coupled with the Kramer mod [drilling holes in the driver grills (you can see that on the left side of the pic)].
It doesn't bother me much. Depends on the type of music.
What can be done to fix this is to put back a piece of the original foam

One might ask- wouldn't that defeat the purpose of the Kramer mod?
IMHO it's better to go with the drill mod plus the foam (if the highs are to sharp for you) then going with the stock driver + foams with a quarter hole since plastic blocks more sound then foam. That way you get all the detail you want but with less dominant highs.

Here things went a little crazy..

..mounted some unused hd212pro (lousy cans) ear caps on top of the sst/5 caps plus hd212pro headband cushion on top of the sst/5 leather stripe.
The main goal was comfort but then i discovered that the additional ear cushions widen the soundstage even more and tames the bass a bit. Which would suit classical music and ambient when you just wanna relax.

I encourage anyone who has the Portapro's/KSC75/35 to experiment with the mods. Those drivers are capable of so much more for so little money.

Post pics of your mods in here even if it's just a re cable.

Kramer modded pp's with leather ear cushions, SPC recable and 75 ohm adapter awesomeness!

Just put them into decent enclosure. I put KSC-75 drivers into Senn HD 457 enclosure and added 650 cable. They're equal to my Hd 555 now, with more bass.

Same here. took the 75 driver and clipped it into an HD201 enclosure. Then I just dampened the cups until the sound signature was perfect for my ears and bingo--a pair of closed phones that I'm quite happy with. (Evidentally, my mother likes the sound signature as well because she stole them from my room while I was out and plans on using them on airplane rides.)

I might do something like this next year. I really liked their sound but the clip-on was horrible to my ears. Don’t know which headphone I’ll take to mod with these drivers yet though.

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Pics or it never happend!
Sounds awesome. I allways wondered what's the role of the enclosure in open headphones and how it affects sound.
I mean i can understand why it's important in closed phones but what's the deal with open? Does it metter?

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You might wanna try putting them in the AKG k412p (same as k24p) like this guy did.
Personally I would try to fit the k26p earpads on them but I don't know if they fit. Maybe someone can confirm this?
KSC75 + k412p mod

Also I wonder if this Sennheiser PMX200/PX200/PXC150/PXC250 ear cushions fit the koss driver... Retail 2002
Maybe someone who has both can comment.

Hey people, very interested in those cushion pad mods. How did you guys did it

Mod on! That's just nuts, very nice. I also dig the soundfrog in the picture.

I have a strange feeling that the Lifetime warranty here has been VOIDED!!

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Rofl, i have that exact same frog!

Now THAT is taking PortaPros to the limit. LMAO.

Yeah.. the limit of your budget

I bet mine sounds better

I have some donut earpads on mail from ebay. Gonna see if they fit. Then i'll order another pair of portapro drivers an mount them on that el cheapo headband from partsexpress.com.
Maybe recable them later.

Lets see if I can beat the stock portapro sound ones again. Only this time it should be from parts available to anyone.

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damn

how is this possible? What changes did you make? did you just changed the enclosure?

omg so nice.i bet they are comfortable

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Don't say that you'll make me wish I hadn't bought my HD-555s

However, I think my HD-555 + Fiio E5 combo would have somethin to say bout that

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that is at the same time the greatest and dumbest thing that i've ever seen