Little Dot MK8SE / MK6 Super Mods (All verified mods are on first page)

Discussion in 'Headphone Amps (full-size)' started by redge78, Sep 26, 2015.
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  1. gug42
    Or another option ?
    Caps-4-pins-Wiring-Other.PNG

    Well sorry to ask .. i'm a little lost ...
     
  2. baronbeehive
    Hi gug42, my guess is that the second pic is correct as you suggest, except that the negative terminal of the blue cap should go to ground which is the other terminal to the one in the pic I believe. However I'm not certain, you must PM one of the others to confirm before you go ahead, I'm sure they will give you a quick answer.
     
  3. gug42
    Hello,

    Thank you to have take time to answer me.
    I have ask on a french forum too. I will pm people if no more answer :)

    Thank you.
     
  4. baronbeehive
    That's ok. See here: https://www.head-fi.org/threads/lit...erified-mods-are-on-first-page.782183/page-70
    (Second post down the page)This shows how I did it with the WIMA caps which are non polarized, with RIFA bypass caps which are also non polarized. I think your square caps are non polarized also? But the round caps are polarized by the looks of it and that's why I wasn't sure.
    Sorry I can't be more help.
     
    Last edited: Dec 27, 2017
  5. gug42
    Hey,

    Thank you ! exactly what I m looking for :)
    For sure the round one is polarized, I manage it. Don't focus on it for the picture !

    So great I connect the legs like i was guessing. Thank you :)
     
  6. baronbeehive
    Yes, and if you are not sure about the square cap just test the pairs of legs with an ohmmeter, and connect the 2 lets that have zero ohms, ie no connection, if they are at opposite ends of the cap then there will be an ohm reading.
     
  7. gug42
    I repost the link for quick reserch about wima cap wiring : https://www.head-fi.org/threads/lit...re-on-first-page.782183/page-70#post-12402649

    Thank you.

    Oh well of course, obvious but wasn't thinking about this trick :)
     
  8. gug42
    Connection of the blue MKP cap confirmed on a french forum.

    By the way some electro caps have special 4 pins connection. Note the case for mkp.

    Thank you again.
     
  9. baronbeehive
    Good glad that's sorted!

    Just mine to fix now. As I've said the problem with the faulty circuit was fixed due to a bad solder on the WCF cap. Both gauges read the same at about the right current, all appears well, except for no sound.

    I've been re reading this forum and I noticed that others had had a similar problem. Mogus had problems with his transistors, fixed them then had no sound and eventually traced it back to his faulty pot. I haven't touched the pot so I'm now wondering if the problem is more than just the headphone protection circuit kicking in. If this happens does it correct itself because I still have no sound and am wondering if it is anything more now.
    Before this happened everything was working perfectly so it can only be an effect of the problems associated with that faulty circuit that I had before it was fixed.

    Any ideas guys.
     
  10. gug42
    Follow the track with a multimetters ? First in Ohmeters ? No need of power for this.
     
  11. baronbeehive
    Thanks, I might have to do that, I already did it for the problem connection. What I really need is someone who has experience of this type of problem to point me in the right direction otherwise it is difficult to know where to start.
     
  12. gug42
    Sorry never face this type of problem .... perhaps in a near futur but not now.
    Hope you find it quickly
     
  13. SonicTrance
    So the problem you had before with one bias meter reading was off, was caused by a bad solder joint on one of the WCF caps?

    Do both meters read about 60mA now? And you have no sound in any channel?

    Don't really remember but I believe if the protection circuit kicks in, it shuts the B+ off so you wouldn't get any meter readings at all (meters at 0 mA). This is not what happens I assume?

    Was the amp working flawlessly after you repaired the bad solder joint and then just stopped producing sound, without you fiddling with the amp?
     
  14. baronbeehive
    ....thought you might be sitting in front of your latest creation drooling!!!

    You may remember me way back getting the amp back from the engineer and firing it up and enjoying it for a day or so...... until I rearranged the parts inside and aggravated a bad solder connection in one of the WCF caps which no longer had contact with the board trace, resulting in one meter reading 40mA and the other reading 80mA. Prior to this everything was working perfectly with both meters reading around 60mA. Well when I noticed the bad connection recently, I fixed this and the 2 meters now read the same, however they both read around 80mA. Then when I plugged in the headphones there was no sound in either channels.

    I now think it is not the protection circuit because that should switch back on I think. I think that when there was a faulty circuit it might have affected something giving rise to the no sound problem.

    I have had no sound since I did the repair. I can't remember if there was sound the first time I switched on the amp after I did the rearranging of parts inside, tying up the caps etc. This was when I noticed the meters giving different readings therefore I may have switched off the amp straight away I don't know but before this it was working flawlessly.

    I'm using 6AS7G's.

    Edit: I had the board out again to check the trace on the back but I was super careful when I put it back to make sure the wires were OK first so I'm confident nothing happened there.
     
    Last edited: Dec 29, 2017
  15. baronbeehive
    Just soldered the switch back again to see if it made any difference, but it didn't.
     
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