1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.

    Dismiss Notice

Millett "Starving Student" hybrid amp

First
 
Back
299 300 301 302 303 304 305 306 307 308
310 311 312 313 314 315 316 317 318 319
Next
 
Last
  1. Juaquin
    You've checked that there is no conductance between the MOSFET tabs and the case, right? [​IMG]

    If you're really obsessive compulsive you can check the resistance of various resistors. They won't necessarily be their rated value (because they are now in the circuit), but resistors in the left channel should measure very close to their counterparts in the right channel. This is of course not necessary but it will catch a wrong resistor value or perhaps a bad solder joint.
     
  2. simwells
    Quote:

    Originally Posted by Juaquin /img/forum/go_quote.gif
    You've checked that there is no conductance between the MOSFET tabs and the case, right? [​IMG]

    If you're really obsessive compulsive you can check the resistance of various resistors. They won't necessarily be their rated value (because they are now in the circuit), but resistors in the left channel should measure very close to their counterparts in the right channel. This is of course not necessary but it will catch a wrong resistor value or perhaps a bad solder joint.




    Yep that was the first thing I checked and that's fine, think I'll just wait til the tubes turn up and see how it sounds then! As long as there's nothing else to check that could damage the amp, phones or source.

    Just need to respray the volume knob to match the heatsinks and it'll be finished.
     
  3. Entropy1
    Okay, there is definately channel cross talk as with only one rca jack connected, I can hear audio on both sides. Testing signal on both rca jacks there is no conduction like it should be, but at the 1/4 headphone jack, everything - left, right and even ground- has very little resistance. I have no idea how this is possible as I have double and triple check how everything is put together. If anyone has any ideas, please let me know. Thanks.
     
  4. Juaquin
    I'm not sure what you mean there - are you saying that when you measure resistance between the left output and ground (and right output and ground), it is near zero? You should be seeing somewhere around 2k (R6/R12) after a few seconds (once the capacitors charge), although I'm not sure how useful that measurement is anyway.

    My guess is still that you've blown the MOSFET in the quiet channel (left, correct?) and it's shorted that signal path to ground internally (even though you have now fixed the isolation issue). Have you replaced the MOSFET(s)? Once you do that, testing will be more conclusive. Pictures would be helpful too.
     
  5. Entropy1
    Okay, I am getting around those readings for the output jack. I expected those to have infinite resistance. i will try to get hold of a camera to see if we can figure out what's going on.
     
  6. Lil' Knight
    Got the kit in the mailbox! Awesome packaging.

    I ordered the Green LED but got the Blue one. Not a big deal though. Can't wait until weekend to start building it.
     
  7. tomb
    Quote:

    Originally Posted by Lil' Knight /img/forum/go_quote.gif
    Got the kit in the mailbox! Awesome packaging.

    I ordered the Green LED but got the Blue one. Not a big deal though. Can't wait until weekend to start building it.




    Uh-oh. I thought I had kept those straight. Send me a PM with your real name and I'll send some green ones out to you.

    EDIT: Never mind. I looked up one of your earlier PM's - I know who you are.[​IMG] I'll get those green LED's out to you tomorrow.
     
  8. UKToecutter
    I'm still waiting for mine, but it's not Tom's fault.

    I just live a long way away and have to wait for 2 delivery companies and a customs check.
     
  9. Llama16
    Quote:

    Originally Posted by UKToecutter /img/forum/go_quote.gif
    I'm still waiting for mine, but it's not Tom's fault.

    I just live a long way away and have to wait for 2 delivery companies and a customs check.




    yeah it does! Trust me on that one. But it's ok, they usually give me a nice and shiny paper when it arrives after all... to pay extra taxes.
     
  10. Lil' Knight
    Quote:

    Originally Posted by tomb /img/forum/go_quote.gif
    Uh-oh. I thought I had kept those straight. Send me a PM with your real name and I'll send some green ones out to you.

    EDIT: Never mind. I looked up one of your earlier PM's - I know who you are.[​IMG] I'll get those green LED's out to you tomorrow.




    Cool beans. Thanks [​IMG]
     
  11. Juaquin
    Quote:

    Originally Posted by Entropy1 /img/forum/go_quote.gif
    Okay, I am getting around those readings for the output jack. I expected those to have infinite resistance. i will try to get hold of a camera to see if we can figure out what's going on.



    I hate to be pushy, but have you replaced the MOSFETs? You haven't said yes or no. If you keep running a (potentially) shorted MOSFET you could (in theory, at least) do further damage.
     
  12. Entropy1
    No, I need to either order some or go digging around at our EE building. I'd like to look for them first as I'm sure a majority of the cost of ordering will be shipping. Thanks for the help and I'll get back to you as soon as I have other MOSFETs to test with.
     
  13. Lil' Knight
    So I spent a couple of hours working on the PCB. My first try ever with the PCB!

    [​IMG]

    The problem is on the back side, there are some solder pads that I messed up and they can't stick solder any more [​IMG] any tips on how to solve this?

    Another question is there is holes next to the caps' legs. Do I have to solder these too?
     
  14. tomb
    Quote:

    Originally Posted by Lil' Knight /img/forum/go_quote.gif
    So I spent a couple of hours working on the PCB. My first try ever with the PCB!

    <IMG]http://farm5.static.flickr.com/4065/4342052612_33e39462f1_d.jpg[/IMG>

    The problem is on the back side, there are some solder pads that I messed up and they can't stick solder any more [​IMG] any tips on how to solve this?




    Are you sure? The pads on the other side are all tied to the ground plane. You need to turn the temp up on your iron to quickly heat the local area around the pad before it starts heating up the entire ground plane, instead. Otherwise, you'll never get the pad itself hot enough to let the solder "stick."

    If you've truly torn up a pad and it was supposed to be connected to the ground plane, then scrape a small portion of the ground plane next to the pad and solder a jumper using a spent resistor lead. However, if your problem was as above, you'll have even more trouble making the solder "stick."

    Quote:

    Another question is there is holes next to the caps' legs. Do I have to solder these too?



    Those are holes for different size caps. Perhaps you noticed that the KW's use different holes than the Panasonic FC's. If there's nothing in them, then don't worry about it.[​IMG]

    How are you going to solder in the green LED's now? Looks like you've finished it.
     
  15. Lil' Knight
    So far this is the only solder joint I think bad, one of the legs of C8. Looks like I didn't put enough heat when soldering it.

    [​IMG]

    About the green LED, I think I'm still able to solder the wires. Pretty tight but not impossible [​IMG]
     
First
 
Back
299 300 301 302 303 304 305 306 307 308
310 311 312 313 314 315 316 317 318 319
Next
 
Last

Share This Page