[Dolman]

On a similar note: I've skimmed most of this thread and has anyone out there found a good impedance adapter (~75ohm) that is 1/4" and not 1/8"?

 

[Big Mother Goose]

Do the Audio GD OPA's Sun, Moon and, Earth work in this ?

 

[mitchb]

My MkV has a ground hum in the right side if I use inputs 1 but has a ground hum on ther left side if using input 2. I like the sound of this amp but the ground hum, although not very loud, is enough to make me use another amp. If I could cure the ground issue then this amp would be perfect. Any advice or help would be appreciated.

 

[Neil27]

The MKV looks like a great amp, but I was wondering if anyone could let me know their experience of this amp with high impedance phones such as DT880 600ohm's as I am looking for a good solidstate amp to go with them. Can it drive these well, or is it worth spending a bit more?

Thanks.

 

[Currawong]

I'd say it doesn't have enough gain for them. Depending on your source you might find yourself turning the volume up to maximum quite a lot.

 

[Radical_53]

After reading this review I had to get an MK V myself. I was lucky to find a used unit which got here last week and I've been toying around with it since then.
I haven't been too lucky so far and couldn't solve some of the problems that occured to me, not even after reading the whole thread.
As I'm using some low impedance, 35 ohm Ultrasone phones I had to get an impedance adaptor to get rid of the constant hiss the amp produced. With an additional 120 ohms, this problem went away.
Two problems that still exist though seem to be related to my dedicated source which is a PC, to be more exact an Auzen Forte 7.1 sound card.
The first thing is that I can hear the mouse movement or the HDDs spinning up as soon as the amp is connected to the PC. The volume of this sound is annoying and doesn't change with any volume setting I can adjust, neither on the PC nor on the volume knob of the amp. I do not have this problem when I connect the phones directly to the card or use a different amp (a Meier Headsix in my case). Both are dead silent and give an absolutely "black" ground level.
The second problem is gain. So far I haven't been able to use the pure, un-amped line out of the card as the amp doesn't deliver enough gain to do so. Only when I use the built-in headphone amp of the card I can use the MK V to listen at a decent level.
So far I tried different interconnects between amp and card, snap-on ferrite cores, different power cables and power outlets.
All inputs the card has are already disabled, muted and set to "zero" volume. No other cables are connected to it but the one lead leading to the amp or the headphones, depending on what I'm using.
I also tried to move the USB devices around to see if there was a difference and I made sure nothing wireless would contribute to this kind of noise. When I turn off the PC the noise is gone completely, as soon as I turn it on the noise is back.

Is there anything I could use to filter the input and to increase the gain setting?

 

[EddieE]

I feel really bad about this as I'm the one who sold you this amp!

Really sorry it's not working out.

The problems (mouse moving giving odd noises) happens on my work computer when I plug phones straight into the hp out. The sound card's heapdhone out is crap and it's also getting interference from the computer itself is my guess.

At home I don't have these issues as I use a DAC between the computer and amp, have you tried using one with it?

EDIT: There are some inexpensive options like the AUNE dac and some others can be picked up used for the same sort of price in headfi classified.

 

[Radical_53]

You certainly don't have to feel bad about this

You sold me the amp at a great price and I'm sure it's not defective in any way. So that's what I wanted to have, a revealing and powerful amp. I'll just have to find a way to "fix" the ugly things it reveals or make them go away

The funny thing about the headphone out of the sound card is that I don't get any intereference there, at all, when I plug in the headphones directly or use the Meier amp.
I had intereference there before I muted/deactivated the mic in of the card but even then this intereference was much more quiet than with the Little Dot.
I don't have an external DAC as I don't use any mobile players and planned to only listen to music, movies or games on my PC.
To me the question really is why this amp picks up all kinds of noise the other two devices can't "see" and if there's a chance to get rid of it without sacrificing the sound quality.
The hiss was annoying as the amp was rated to be suitable for these phones and certainly isn't without the adaptor, but this is something different and I hope it can be solved.

 

[EddieE]

Thanks Radical 53,

You say you use the headphone out to the amp from the computer - maybe double amplifying to this extent shows up interference that was too quiet to hear on the portable amp or the headphone out itself? Just guessing here, I'm no expert.

Could you perhaps borrow a DAC from someone local to see if it would solve the problem? It will give you a lineout signal from USB or SPDIF so it would be impossible (I think) for mouse movements and internal noise to come through to the amp.

Might be worth a go at least to exclude it from your investigation.

I have to say personally, adding a DAC to my set up brought a huge improvement to the sound quality. It's certainly something to try.

 

[Radical_53]

That's the question, why isn't it audible with the two other configurations even if I use the same "listening volume" or the same output volume of the card.
They all use the same type of connection also so I can't use the output itself as an excuse.
I would love to use the un-amped line out from the card but the amp has not enough gain to use it. It's even worse as the background/intereference noise is even more annoying there due to the lower listening volume possible.
An external DAC with optical input might solve the issue but I could sell the card then anyhow as its "better quality" components woulnd't be used then at all anymore.

I'm no expert in this but it's hard to understand why I can't hear any of the intereference with the two "less powerful" combinations. Not even at max volume of the card there's a faint hiss or noise from the system, no intereference or any PC-like sound even when both the card and the small Meier amp are turned up all the way to max.
I even get this intereference with the Little Dot when the card's output is muted! Always the same kind of sound (depending on PC activity) but it stays at one volume no matter what I do, turn up/down the amp or the card. Just when one of these two is turned off it goes away

 

[TabooPc]

Just got this amp new yesterday! This review hits the nail on the head about its details!

I was shocked at how much bass was improved. Grados benefited from this amp more than expected.

Great buy!


Beware: Audiophilechina.com is a unauthorized middle man from little dot, buy directly from little dot and your package will be faster.

 

[EddieE]

Radical 53

I've heard dfkt say before that (before he got the arrow) the only portable amp he had tried that didn't hiss with extremely sensitive phones was the head six, which is an interesting bit of trivia but I don't think that is the route of the problem. I could be wrong, but it doesn't fit.

The sound of the HDD drive moving and the mouse movements seem unrelated to amp or headphones and very much to do with the sound card. Yeah it's a puzzle why the headsix did not suffer the same, or the headphones on their own. Maybe these more powerful amps are just more sensitive to such things? I don't know.

But it absolutely will be cured by a DAC; there is no conceivable way I can imagine of that these interferences could be there with a DAC.

One way or another you need to get a clean line in signal into that amp, even if that isn't the issue you are facing, you won't get the best out of the amp until you do.

When I first got that amp I was using the hp out on my S9, and it actually sounded fantastic and I didn't get any hiss or noise, but I remember when I first involved a DAC in the chain, it was like someone had just pulled cotton wool out of my ears. The increase in clarity was one of the biggest single advancements of my audio journey to date.

EDIT: Hold on I just had a thought... what is the noise like? Could it be ground loop? If it's a laptop try pulling the power out and see if it stops...

 

[Radical_53]

It's a desktop PC, so yes when I pull the cord the noise is gone

How could I describe it, kind of a "screaching" sound? I can provoke this with the other two combinations also. If I remove the electric tape around the PCI bracket of the card I can hear it with my phones, if I don't mute / deactive / set volume to zero the inputs (mic and mic fp) I can hear it with the Meier.
I haven't found the solution yet to silence the Little Dot. What I thought was strange is that this noise doesn't change in tone or volume no matter what I change on one of my devices. To me it would have been more logical if it did change somehow, for example depending on whether I use the amped headphone out on the card or the unamped line out.
A DAC would most certainly solve the problem with background noise, yes, but I'm afraid I would also loose most of the features I used this card for (5.1 to 2.0 downsampling for positional audio for example or hardware accelerated audio).
Sadly I don't know anyone who could borrow me a nice DAC with optical inputs to try this out.

 

[Gomoo]

Did anybody test the MK V with DT 770/250?
I'm interested if these two will be a good combination.

 

[Radical_53]

Even though I hadn't found a solution to the noise problem I thought about rolling opamps. Thought, I had to take a look. Strangely I found a temporary solution to the problem this way:

Can someone explain to me why the intereference and noise is compeletely gone when I pull the PCB out of its case on this amp?
When I close it again the intereference comes back. I also get some sort of hum as soon as I touch the volume knob, it's silent again when I let go of it.

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.