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Originally Posted by cwell2112 /img/forum/go_quote.gif
As much as the impedance adapter takes care of the noise issue for me, something continues to bother me regarding the MKV. Isn't it true that a properly designed amplifier should be quiet with low and high impedance headphones? Doesn't the fact that there is noticeable noise with low impedance cans mean there is something fundamentally wrong with the design of the MKV? Can anyone (Penchum, perhaps) speculate as to what this design flaw/compromise might be? There has been a lot of discussion on ways to remedy the problem, but no real attempt that I've seen at explaining why it exists in the first place.
I realize this may seem slightly accusatory in tone, but it is not meant to be. I just find the hiss issue slightly troublesome, and I'm legitimately curious as to why it exists in the MKV and not in so many other amps (as far as I know).
Any insight would be much appreciated.
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Hey Cwell,
No problem about the accusatory tone thing.
This low impedance noise issue has many people perplexed, all of them have low impedance phones too.
At the time of the review, the MKV was a "new" concept in super quiet/very dynamic SS headphone amps. The majority of owners were using higher impedance headphones, and the noise issue didn't even come up, until someone matched the MKV up with lower impedance headphones. It caught all of us owners off guard.
What is known, has been talked about in this thread. I put a warning in the review updates, and it appears that LD has told others that the impedance adapters are necessary for lower impedance headphones. I don't believe it is a design flaw. There are several other SS desktop amps reviewed on HeadFi, that have this same trait to them. Considering the MKV was voiced to the Senn HD-580, 600, 650 type of higher impedance headphones, this noise issue wasn't even known at all. I am glad that they are including adapters if you tell them you have lower impedance headphones! That, is excellent customer service!
I would also encourage MKV owners who have lower impedance headphones, to try the MKV with higher impedance headphones. This might change their minds about which headphones they should own. I had to put new driver elements in my HD-650's and then burn them in for 250 hours. When they were matured, I listened to them via the MKV for about a week straight. The results were excellent, and the overall presentation was improved greatly. So, you see, even small things can make a difference. With the MKV, many pre-existing noise issues in a rig, can be heard for the first time, and need to be dealt with. Grounding loop is a popular problem, and so is EMI, RFI from sources near bye. Your rig will benefit from eliminating these noise issues, whether you have high or low impedance headphones connected to the MKV. The fact that the lower impedance headphones tend to show these noise problems more easily, simply means the MKV is a more sensitive high end amp, that should be used in a quiet rig and interference free surroundings. So many users have said they thought their rig was "noise free", then they found out they had some of these noise problems, thanks to the MKV. I guess it is all about perspective.
In my rig, I have taken steps to minimize noise on many levels, prior to purchasing the MKV. Right now, I can hook up my HD-280's (64 ohms) and the background is dead silent, black as you want it to be. Perhaps, the elimination of possible noises in my rig, has paid off in the long run? Perhaps others could follow my lead, get their rigs super quiet and they just might have less noise and a happier rig because of it. This is my best guess on this matter, so far. Amp noise with 24 ohm headphones, is a real possibility with any SS desktop amp. The 24 ohm headphones are very susceptible to outside interference and internal amp noise, so I'm pretty sure they will always need adapting to a higher rating, when used with the MKV. 32 ohms to 64 ohms, may need less adapting with a quiet rig.
So, this whole issue seems to be variable, depending upon the rig and the environment around the rig. If an owner is going to stick with his lower impedance headphones, then it is advisable for them to eliminate all possible noise issues, and adapt their phones to a higher impedance. The ultimate fix, is to eliminate all noise issues, and purchase higher impedance headphones that are liked/loved by the owner.
I've been doing audio for a very long time. Noise issues, are always the worst problems to come up against, and those same noise issues will continue to bother you, until they are eliminated. Every rig imaginable, can have noise issues. Usually, the better the rigs are, the more noticeable the noise problems become. There are some simple steps to go through, that will eliminate a large percentage of the noises, for very little money. Moving a few things, plugging the entire rig into one socket, capping off unused RCA's, are just a few that come to mind quickly. YMMV since this is a variable situation.
But, eliminating the noises is still a smart thing to do, no matter what you do for headphones. IMHO of course.
Just my rather long 2 cents worth!
