Sony MDR MA900 Impressions Thread
Apr 14, 2020 at 4:34 PM Post #2,566 of 2,632

Maxx134

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I completed the mods
IMG_20200414_162119.jpg
:)
IMG_20200413_215209.jpg
:)
( front material removal, resistor removal & balanced rewiring), and that certainly elevated the unit to erradicate the lack of clarity, and increase the image size.

Also,
I have to say out of all the pads I tried, the Audeze had the most realistic, detailed sound, and excitement, and balanced large size.

The Dekoni ferenstrated pads was second best, having a bit more distanced stage and more relaxed top end.

Now I going to get some replacement stock pads.
 
Apr 14, 2020 at 10:02 PM Post #2,567 of 2,632

Sp12er3

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the audeze pads doesn't look as out of place than other examples ivve seen. would look into that one, thanks for the red.
 
Apr 16, 2020 at 2:55 PM Post #2,568 of 2,632

Maxx134

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This unit now sounds more closer to the top sony mdr- z1r, in signature, than the z7m2.
:)
 
Apr 27, 2020 at 2:44 AM Post #2,569 of 2,632

RedJohn456

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I completed the mods
IMG_20200414_162119.jpg
:)
IMG_20200413_215209.jpg
:)
( front material removal, resistor removal & balanced rewiring), and that certainly elevated the unit to erradicate the lack of clarity, and increase the image size.

Also,
I have to say out of all the pads I tried, the Audeze had the most realistic, detailed sound, and excitement, and balanced large size.

The Dekoni ferenstrated pads was second best, having a bit more distanced stage and more relaxed top end.

Now I going to get some replacement stock pads.

Wow, those are some serious mods! I bet they sound heavenly :) How does one go about getting stock replacement pads? I am hesitant to experiment with 3rd party pads and would love to get a fresh pair of pads for my MA900. Thanks in advance!
 
Apr 28, 2020 at 1:06 AM Post #2,570 of 2,632

Maxx134

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Wow, those are some serious mods! I bet they sound heavenly :) How does one go about getting stock replacement pads? I am hesitant to experiment with 3rd party pads and would love to get a fresh pair of pads for my MA900. Thanks in advance!
I got these to try for closest cheap replacement:
Screenshot_20200428-010442__01.jpg
I will post impressions.
:)
 
May 1, 2020 at 3:55 AM Post #2,572 of 2,632

cottonthemoth

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After elimination of resistor network,
Removal of old wiring, and
Directly wiring new plugs onto driver is best as well.

This will eliminate the built in cross-feed (more obscurity) that the original wiring was setup to do.
@Maxx134
I've had my MA900's since 2013 and used them as my only PC Music/Movie/Gaming headphones-- it took me 7 years but I'm ready for the resistor mod haha! I've got plenty of soldering experience but am a bit hesitant since my understanding of circuitry (and what I'm actually accomplishing electrically) is pretty bad.

These are the best pictures I can find, and I want to make sure I understand them correctly, would you mind confirming a few questions of mine?
https://www.head-fi.org/threads/sony-ma900-resistor-mod.637168/#post-11782176
On the left and right sides, do the ground wires all get moved to the "inside" remaining 1RO resistor (pad closest to the epoxy blob), and can I with relative ease remove both 220 resistors completely? If cutting trace entails digging down into the PCB material by knife or drill, I'd rather not lol.

I think I get it, just wanna bounce that by those who have done it.

For the below foam bits, which did you end up keeping? I've got dogs and an old brick rental house that gets relatively dusty relatively quickly-- would I be sacrificing any protection from damage that could occur from contamination over time due to buildup or anything like that?
1588319272022.png


FWIW the plasticized circumference of my original pads eventually cracked and gave way, so one kept sliding off-- when I'd remove my ma900's the pad would stay and hang off of my ear haha! I tried Brainwavs HM5 Velour Memory Foam model pads and they drastically reduced the overall experience, had to go back to stock. They were very comfy but they ruined the headphone to me. I've been using these current Dekoni-made "for Beyerdynamic" velour ones since June 2019 and they work very well for me, though they collect dust more obviously:
https://www.amazon.com/gp/product/B019QXF2FY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Same ones you bought above, I like em a lot @RedJohn456 -- definitely thicker than stock, my ears make less contact with the driver than the stock ones, but it's never bothered me anyway because it's not like my ears are being crushed or anything. The ultra-chinesium stock replacements they offer on eBay don't look comparable in mesh material to the actual OEM ones so these have been great for me.

I bought these cans October 2013 for $151.99 on Amazon-- I had a gift card :wink: best purchase ever!
 
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May 1, 2020 at 3:45 PM Post #2,573 of 2,632

Maxx134

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I with relative ease remove both 220 resistors completely
Yes, but I have two checking a few different tutorials I realized that the wiring was placed reversed for ease of installation...
Screenshot_20200501-152644__01.jpg

So you Will find your wiring may be the same as those pics which are actually incorrect (!) and opposite for one speaker.
I correct:
Notice the green positive wire, placed reversed on the negative side!
Screenshot_20200501-151931__01__01.jpg

They have the series resistor wired incorrectly, at the end of the circuit, because of this...

Incorrectly reversing the green and the ground wires!
Lazy b*stards, as you can see from this picture:

Grounds around the opposite side, and all the positives are on the other side..
Screenshot_20200501-160104.jpg
Which I believe this to be correct.

So it is reverse of this diagram I show you a picture of both how I did it.
Do not solder wires close to those center blob.!

You wire the positive on the opposite side of one resistor and the negative all the way on the other end, as shown.
Don't want to miss up near the voice coils in the center, so you solder at the furthest point.
Screenshot_20200501-153945__01.jpg
Notice I remove both resistors, which are garbage and not needed.
Don't believe anyone who tell you different.
The resistors are useless and mess with the mid-range clarity.
I can prove it in my measurements, a 2-3db drop.




For the below foam bits, which did you end up keeping?
Nothing...
All the frontal material acts as an air resistance to the sound.
tech2.png

Take all off and just leave the dust cover back..
 
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May 1, 2020 at 6:34 PM Post #2,574 of 2,632

cottonthemoth

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Do not solder wires close to those center blob.!

You wire the positive on the opposite side of one resistor and the negative all the way on the other end, as shown.
Don't want to miss up near the voice coils in the center, so you solder at the furthest point.

Notice I remove both resistors, which are garbage and not needed.
Don't believe anyone who tell you different.
The resistors are useless and mess with the mid-range clarity.
I can prove it in my measurements, a 3db drop.

Nothing...
All the frontal material acts as an air resistance to the sound.
Take all off and just leave the dust cover back..
@Maxx134
How are you getting at those foam layers, just tearing all of the foam layers from here where the driver faces?:
IMG_20200501_170453.jpg



I do not plan to mod in 3.5mm female adapters like you did. The following are my stock wirings, unaltered

Left Side:
IMG_20200501_170555.jpg


Right Side:
IMG_20200501_170602.jpg


I understand what you meant about switching the left driver's positive wire over to the grounds, in your example, and will avoid doing that. My question is, which wires need to get moved after the resistors are removed, keeping in mind I'm leaving my stock 3.5mm cable alone. It looks on your right driver you soldered the positive cable to a pad where the 1RO resistor was previously. Should I do this?

Once I complete this mod I'm going to complete diagrams/instructions for others to be super clear for others in the future.
 
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May 1, 2020 at 7:18 PM Post #2,575 of 2,632

Maxx134

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How are you getting at those foam layers, just tearing all of the foam layers from here where the driver faces?:
you have to carefully peel from the edge and then it all comes off...
do not try to tear the foam.


My question is, which wires need to get moved after the resistors are removed

your headphones are wired correctly.

All you have to do is remove the resistors...
and on the left speaker (where all the wires are), you simply move your positive wire over to the other side of the "removed" resistor..
Screenshot_20200501-192126__01__01.jpg

The closer pad to the center.
Remember remember to remove both resistors..
 
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May 1, 2020 at 7:23 PM Post #2,576 of 2,632

Maxx134

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I updated my post with a picture..
Do the same thing to the positive on both speakers...

you move over to that positive wire, to the resistor pad that used to have resistor (once you remove)

Remove all resistors on both sides of both speakers...
 
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May 1, 2020 at 9:52 PM Post #2,577 of 2,632

cottonthemoth

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I got it done! I got all 4 resistors out, swapped the left driver's positive wire to the 1RO terminal, and then messed up the very last wire-- iron was on too high and probably warmed up enough by that point, and I didn't have the wire positioned right--somehow burned through the whole damn contact point so had to scrape away some plastic to expose some fresh trace! I'm a bit rusty, but it's all back together and sounds good.
1588384225829.png


Above picture is the scraped away PCB to show where I ended up having to solder my right driver's positive (white) wire to. Could have gone neater but it worked out!
 
May 5, 2020 at 8:59 AM Post #2,578 of 2,632

Maxx134

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very comfy but they ruined the headphone to me. I've been using these current Dekoni-made "for Beyerdynamic" velour ones since June 2019 and they work very well for me, though they collect dust more obviously:
https://www.amazon.com/gp/product/B019QXF2FY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Same ones you bought above, I like em a lot

I did some initial listening with those new velour pads, and it sounded more open and involving, as it also closer pad, so I was excited to have them on...
Then later I realize therr is a bit of treble suck out, so I will have to measure them, and post here later..
:)
 
May 16, 2020 at 11:16 PM Post #2,580 of 2,632

Sp12er3

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I do have them both, but mine is stock so the impedance compensator assures it basically is good running it from basically anything.
 

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