Review of Little Dot MKV Dual Mono Solid State Headphone Amplifier - Page 48

Quote:

Originally Posted by Radical_53 

Well, on my card (Auzen X-Fi HTHD) the sound changed when I switched OPAMPs. The more sensitive it was the louder this sound got. Different mainboards or PSUs didn't help, switching off some of the energy savers did though (not a valid option for me).

I'd seriously doubt a different card would help much on its own. Some people say it helps to move the soundcard as far away from the graphics card as possible but to me it seems as if the noise came in through the bus connection. Can't do much about that of course other than going back to PCI instead of PCIe.

My soundcard is already as far away from graphics card as possible, but its not EMI shielded.  Also, if its the PCIe doing this, thats good news, because the soundcard I'm planning to buy (Asus Xonar ST) is a PCI card. I'll give it a try, dont have anything to lose, SQ will improve at least.

Let us know how it works out. Sound cards have always been giving me the most trouble out of all PC components.

Older X-Fi cards had problems with PCI latency and bandwidth, the newer cards can get could in PCIe noise coming from the graphics card. Not an easy choice ;)

Quote:

Originally Posted by Radical_53 


PS: I think I just found the solution. There was a small grounding cable in the back of the amp, just one wire with a ring on its end. As soon as I take this off the case and isolate it the noise goes away even when the case is closed. I'm curious if it's needed for something.

Any luck finding out what this cable with a ring on the end does?

I just took my Mk5 back plate off, and I saw that little wire "hooked" onto a tip of the screw.  The wire goes from power socket plug, precisely, from the top middle "metal" tip (2 in the bottom, one in the top) in the power socket, if you know what I mean.

I put the amp back together, and as you experienced, there is no buzzing, humming, noise or any kind of interference whatsoever.  So thats a good thing.  What worries me though is that this little wire is related to power supply of the amp.  What if its important? Some kind of grounding cable or something....

Well, that's just what it is ;) An additional grounding wire. It gives a higher level of safety (as any plug with 3 pins) but it isn't exactly needed (as far as I know ;) ).

Quote:

Originally Posted by Radical_53 

Well, that's just what it is ;) An additional grounding wire. It gives a higher level of safety (as any plug with 3 pins) but it isn't exactly needed (as far as I know ;) ).

Hah...dont want my amp or headphones to get fried or something... :P     I'll ask on little dot forum, maybe they will know if its safe to keep it like this or not.  I definitely like the sound more now, without the constant buzzing. :P

Just use a 2-pin power plug instead of a 3-pin one. You have a ground loop which is causing the buzzing. You could also try changing power sockets, eg, plugging your computer and LD MKV into the same power board.

Quote:

Originally Posted by Currawong 

Just use a 2-pin power plug instead of a 3-pin one. You have a ground loop which is causing the buzzing. You could also try changing power sockets, eg, plugging your computer and LD MKV into the same power board.

I am using a 2 pin power plug already.

The one like on picture underneath, if thats what you meant.   I tried plugging Mk5 into various power outlets, but nothing helped. Even when my PC and amp are connected to the exact same power board, it still was buzzing.  The only thing that helped was isolating this grounding cable.  I will go to a local electronics store and get myself a ground loop isolator and see if that helps.

Take a look at the plug on the left. It has three pins. Disconnecting the small wire inside the amp does the same as isolating the middle pin of that plug. It's just an additonal layer of security.

Quote:

Originally Posted by Radical_53 

Take a look at the plug on the left. It has three pins. Disconnecting the small wire inside the amp does the same as isolating the middle pin of that plug. It's just an additonal layer of security.

Yea i guess so.  I just hope its safe to keep it like this. Still waiting for an answer from Little Dot.

Quote:

Originally Posted by derbigpr 

Quote:

Originally Posted by Currawong 

Just use a 2-pin power plug instead of a 3-pin one. You have a ground loop which is causing the buzzing. You could also try changing power sockets, eg, plugging your computer and LD MKV into the same power board.

 

I am using a 2 pin power plug already.

The one like on picture underneath, if thats what you meant.   I tried plugging Mk5 into various power outlets, but nothing helped. Even when my PC and amp are connected to the exact same power board, it still was buzzing.  The only thing that helped was isolating this grounding cable.  I will go to a local electronics store and get myself a ground loop isolator and see if that helps.

Ahh, that explains much -- you're not in a country that uses US power plugs. Your power plug is grounded, the outer grooves containing what would be the ground pin on US plugs. You don't have any choice but to use grounded cables, unlike many of us. 

Quote:

Originally Posted by Currawong 

Ahh, that explains much -- you're not in a country that uses US power plugs. Your power plug is grounded, the outer grooves containing what would be the ground pin on US plugs. You don't have any choice but to use grounded cables, unlike many of us. 

So its fine if I have the grounding wire in the amp isolated?  I mean, if had it like this for a few days, nothing happened, so I guess I'll keep it like this. I kinda like it without any buzzing. :P

Could it drive an HE-6 loudly from a 2V source without clipping?

Quote:

Originally Posted by cactus_farmer 

Could it drive an HE-6 loudly from a 2V source without clipping?

Probably not, the 600 Ohm 88dB K240DF's sound sharp out of the mkV at louder volumes, I'm sure the HE-6's will too.

nice review!

Does anyone here know what the output impedance is on the headphone output? There is generally very little information regarding this on the producers website and on the web....

I've sent an email to the company regarding this, but after reading about this here on Head-Fi I suspect that they will not answer this question.... Have anyone here gotten any answer or made any measurements themselves?