Headphone amplifier mod recommendation

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Hello DIY'ers!

This is my first post in this forum, so a bit about me. I am a headphone audio enthusiast. My main rig is Mac -> Matrix m-stage hpa-3u+ dac/amp -> hd6xx/HE560. I'm not a bass head, but don't hate it if it's clean. And more important I am not a DIY guy. I know pretty much nothing about electronics.

I am here because my matrix amp used to have a very shitty sound until someone suggested I change the capacitors (in head-fi), suggested I replace input wima caps with Audyn Plus and coupling nichicon with Elna Silmic II as described here. Once I did that, I started digging the sound of my amp. It sounds a little bass light compared to earlier, but really detailed and natural.

I have a second headphone amp, a nuforce ha-200 which i want to check can be improved. I'm not technically competent to know what can be replace easily but I can tell you it has 14 Eelna re3 1000uf/25v caps. It also says (J) in the caps, if that means something. I really don't want to break the bank with this mod, so if the parts are around $50 then I would really love to try out the mods. What I am looking for is a much blacker background (similar to the modded matrix) and better layering.

The reason I would love to improve this amp is because I can get two of these and setup a mono-block config (when I have enough money), which sounds interesting.

I am including a bunch of pics that I took or found elsewhere.

Interieur-11.jpg

VM23aL5b_o.jpg

ksdlcfIx_o.jpg

An externally hosted image should be here but it was not working when we last tested it.


Mods, I have included the link to head-fi in this post because it explains the mod was, since I don't know much about electronics anyway. Please excuse me if I'm not supposed to do so. Also, if this thread has to be moved to a more appropriate sub-forum, please feel free to do so.

Thanks!
 
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The matrix gives a feeling that, between two instruments there's absolutely nothing and gives a nice sense of space and also when there're quite passages there's just nothing there. With this amp I don't get the same feeling. That's what i am describing as a black background; as I don't know a better way to describe it.
Also the amp is a bit relaxed feeling. I want to make it a bit more dynamic and euphonic sounding. The matrix started giving this sound kind of sound once i switched over to Elna Silmic II
 
Getting good dynamics in a classAB amplifier is about getting the power supply noise - at the point of use - down. Looks to me that your PSU is too distant from the amp itself and connected by too thin wires. You could upgrade to thicker cabling and ensure the wires are twisted together to get the lowest inductance. You could also add some local decoupling caps on the amp board itself.
 
No, those blue wires aren't the low-hanging fruit as they are before the regulators. The regulators are those 3pin devices on the heatsink at the top of the board with 14 capacitors on it. I mean the black wires running from that regulator board to the amp board - which is right behind the front panel. Notice how those wires are bunched up with other wires and don't take a direct path from A to B? That extra length isn't good news for dynamics.

On second thoughts leave those wires just as they are and add more capacitance to the amp board directly. This needs to go between pin4 and pin8 of the opamp in the centre of that board (marked OPA2134). You'll need to use 35V rated capacitors.
 
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Got it! I will try replace those cables. Anything else you see that can be changed easily? The reason I don't want to simply give up on this amp is because if I could somehow get to sound it good I can buy another one and run it in a monoblock config, which I guess is rare at this price point.
 
I can't see any of your images - perhaps imgur is blocked here? If you want pics to be seen by all then I suggest attaching them. I meant to connect extra capacitors between pin4 (neg) and pin8 (pos), not to remove any. 100uF is way too small, try something at least 10X bigger.
 
Got it! I will anyway have to take this to a local electronics geek to get the mods done. I can ask him to check introduce a capacitor between those pins. Just out of curiosity, what do you expect the capacitor to do? Will those pins not already be decoupled (if I remember my school electronics right).
 
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