Little Dot II Amp issues

sir-les-mp

sir-les-mp

sir-les-mp

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As some of you may be aware i recently purchased a set of Beyer-dynamics DT770 250 ohm Headphones and also bought a little dot II to drive them to thier full potential.

Over the past few days when turning on the Tube amp im getting an annouying buzzing noise from the headphones with a little playing about with the 6.3mm plug removing and replacing it into the socket on the amp i can usually get the buzzing to dissappear.

I have tested the headphones directly into the Asus Xonar U5 external sound card i have and the buzzing is not present. i have also tested out my older Razor Tiamat 2.2 Headset in the amp and the buzzing is present there also.

The only theory i can summise is there is an intermetent issue with the Amp but what is causing it im not aware of.

i'm putting it out to you ladies and Gents here to theorize what could be causing the issue and if it is/should be possible for my to resolve without having to send the unit back for a repair/replacment as for me living on an island this will be a costly and time consuming excersie.
 
First thing to try would be to pull all the valves/tubes and check for oxidation of the pins.

Generally the action of inserting and removing them a few times will clean the pins sufficiently, if not then I've used very fine sand paper in the past with no adverse effects.

If that doesn't cure it (it cured my buzzing) then it will most likely be an RMA as the fault would be internal and that would be covered by the warranty.
 
Try lifting all cables associated with the amp away from any other cables and see if that helps. It could be an interference thing. I had what sounds like the same issue with my Little Dot MkIII. Simply re-running the cables away from data cables helped.
Along the same lines it might be worth powering it off a dedicated wall socket in case you are picking up some power supply noise via a power extender.

If none of that helps I would defer to other answers and then contact Little Dot.
 
I think buzzing is normal on tubes until they warm up ? is it happening even if the units been on a while ?
 
Yes unfortunatley

I have since opened her up and had a good look inside and from my untrained eye there does not appear to be any loose connections or any scortching around any of the componets.

I do have to add that it is more noticeable whilst gaming.
 
C64 said:
I think buzzing is normal on tubes until they warm up ? is it happening even if the units been on a while ?
Click to expand...

Has been my albeit limited experience with tubes that you can get some weird stuff in the first 20 seconds or so, while tubes can be varying degrees of "microphonic" this does sound more like a ground loop type issue.
 
well working on this theory i did move the amp as far away from my pc as possible a good 4feet, and away from as many other electrical componets as i can but to no avail.

so ive went onto the Auction site and found myself one of these

PRO DJ GOLD RCA PHONO GROUND LOOP ISOLATOR TO PREVENT UNWANTED HUM OR NOISE

wasnt too expensive so heres hoping it works.

i also just bought a set of sheilded 3.5mm to rca cable as well
 
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It's unlikely to be EMI as you don't get it through the U5, which is the only part connected to the PC, so a ground loop is certainly favourite.
 
Well i can confirm since the purchase and application of the Ground Loop Isolator i havent had any issues with Humming or buzzing from my Amp.
 
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