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Little Dot MK III slight channel imbalance

post #1 of 7
Thread Starter 

I'm 2 weeks into ownership, got it new from David. I have a slight imbalance, until the volume hits 7 o'clock (6 or 7 on the grading) the right channel overpowers the left one. Even at zero volume, i can still hear the treble from the right channel. Very fade, but i hear them. Opening up the volume, the right channel picks up while left is waaaay behind. Around 4 or 5, the left channel starts to catch up and around 6 or 7 i think they're balanced.

 

I wrote David, he said it's normal. It doesn't sound normal to me, so I'm asking for your opinion: should I send it back (still under warranty)? Or is there a quick fix?

 

I'm using a pair of HD-650, gain 5 (middle setting).

 

Thanks for your time.

post #2 of 7

This is normal for many volume pots at low volume settings. I am not sure if I follow the rest of your issue. You can try to switch the driver tubes and see if the volume imbalance follows. Only a stepped volume attenuator has perfect balance between channels at very low volume settings.  

post #3 of 7
Thread Starter 

I appreciate your reply. I switched the tubes, still the same thing. What about the stepped volume attenuator, is that something I can buy and install? Do you know of anyone that did this for a Little Dot and could provide some advice?

 

Thanks

post #4 of 7

The Little Dot MkIII uses an ALPS-16 potentiometer which supposing has less channel imbalance.There is another thing you can do is the check the jumpers for the gain at the bottom of your Little Dot and make sure that they are tight and on the right pins. You could also see if the jumpers could be moved to a lower gain setting so that the potentiometer  could be operating in a more linear range. I have heard in a few cases that the jumpers are loose and not making the best contact.  A stepped volume attenuator is quite expensive to put in and you would have to check to see if there is room and have the right value and would void your warranty.     

post #5 of 7
Thread Starter 

The jumpers are fine, and I'm already on the lowest gain, so i get to turn the knob a little bit more. Bummer is I have sensitive ears and I listen to low volumes so the imbalance bothers me.

 

The question remains: is this a reason to send it back?

post #6 of 7

That is something you need to decide and work with David. A good quality potentiometer  is not cheap.  I found this thread about the same issue you are having. I believe that the  potentiometer   on a MKIII is mounted on the case and wires go to the circuit board.

 

http://www.head-fi.org/t/136251/replacing-pot-in-an-amp

 

 

I wanted to add that even a $3K headphone system H2+ as reviewed by Head-Fi TV has some channel imbalance issue as stated with the transformer volume control unit. 


Edited by john57 - 9/7/11 at 10:12pm
post #7 of 7
I have no imbalance on my MKIII but another Chinese head amp (using 12au7s) with the same pot has a right channel that is slow to catch-up with the left channel. I suspect that the pot is really a "Chinese version" of the alps! I have not experienced any significant imbalances with verified Alps manufactured pots.

Also, I can tell you from experience that getting the PCB out of the MKIII chassis is nearly impossible. It's really stuffed in there. In fact, an electrolytic power cap got "skinned" when the manu. put the pcb in and at 100 hrs bare metal made contact with the chassis! The 60 Hz scream didn't sound good through my AKG K702s! Had to pull everything out and tape over the bare metal on the cap....might want to look in the larger holes in the chassis bottom where you can see if your power caps are "skinned"....
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