1.     Don't be a dotard!
    Read these "rules" AND introduce
    yourself     before your first post
  2. A healthy approach to understanding measurements
    Being true to what the artists intended
  3. After being asked for the 308th time, Merv lists top 5 headphones
    (opinion / entertainment piece)
    Dismiss Notice
  4. $1000 to the first to design a headamp using discrete components with better measurements than Magni 3+
    Dismiss Notice
IMPORTANT: New Members Read This Don't Be a Measurement Fascist Merv's Top 5 Headphones - 2023 Edition $1000 Challenge

OP amp SO-8 to DIP8 adapter

Discussion in 'Modifications and Tweaks' started by badf00d, Feb 28, 2016.

  1. badf00d

    badf00d Friend

    Pyrate
    Joined:
    Sep 28, 2015
    Likes Received:
    55
    Trophy Points:
    28
    Location:
    Ohio
    I''m trying to help a friend do some OP amp rolling with a Creative X7. Bought a pair of TI OP 827 SO-8, and some SO-8 to DIP8 adapter boards and some header pins. Soldered everything up, and it looks pretty good. Plugging in the adapted chips results in just a faint buzzing sound, no music. Putting the original chips back in works fine.

    Does anyone have any suggestions on how to figure out what's wrong? I'm fairly confident in my soldering skills, but zero on troubleshooting. Any help is much appreciated.
     
    badf00d, Feb 28, 2016
    #1
  2. purr1n

    purr1n Desire for betterer is endless.

    Staff Member Pyrate BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    89,999
    Trophy Points:
    113
    Location:
    Padre Island CC TX
    Aren't the X7 opamps JRC2117 dual opamps? The OP827 are singles if I remember correctly. EDIT: Nevermind, I guess you bought a dual singles to dual adapter gizmo. Attach pix of top and bottom for us?
     
    purr1n, Feb 28, 2016
    #2
  3. ultrabike

    ultrabike Measurbator - Admin

    Staff Member Pyrate MZR
    Joined:
    Sep 25, 2015
    Likes Received:
    8,960
    Trophy Points:
    113
    Location:
    Irvine CA
    I'm looking at the Creative X7 amps pics:

    [​IMG]

    Amps in view are the NJM2114 and the LME49710.

    I would guess the LME49710 is used for voltage amplification. It is a single channel device.

    I would guess the NJM2114 is used as a current buffer. The device is dual channel and possible they are connected in parallel, since there are two ICs in the board.

    If all of the above assumptions are true, I would guess one can replace the TI OP 827 with the LME49710, but not with the NJM2114. The pin outs look compatible and the supply ranges also look somewhat compatible:

    OP827: http://www.ti.com/lit/ds/symlink/opa827.pdf
    LME49710: http://www.ti.com/lit/ds/symlink/lme49710.pdf

    Verify that the correct op-amps were replaced in the correct socket.

    It is also possible that the OP827 device you have is defective or damaged due to placing it in the wrong socket or similar issues. They can be also defective from factory. This happened to me some time ago with a Flip-Flop.

    EDIT: corrected links
     
    Last edited: Feb 28, 2016
    ultrabike, Feb 28, 2016
    #3
  4. badf00d

    badf00d Friend

    Pyrate
    Joined:
    Sep 28, 2015
    Likes Received:
    55
    Trophy Points:
    28
    Location:
    Ohio
    Thanks for the quick feedback guys. Here is a picture of what we soldered - standard phone picture caveat. Maybe the chips are bad. I bought them from Mouser and wouldn't think they would both be bad, but I guess it's likely they are from the same batch.

    EDIT: Forgot to mention, it's possible we didn't have them inserted far enough. The header pins really don't want to work their way into the sockets. The DIP is so much easier.

    [​IMG]
     
    Last edited: Feb 29, 2016
    badf00d, Feb 29, 2016
    #4
  5. purr1n

    purr1n Desire for betterer is endless.

    Staff Member Pyrate BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    89,999
    Trophy Points:
    113
    Location:
    Padre Island CC TX
    Just to confirm, you are replacing the LME49710 chips and you have the pin 1 orientation correct?
     
    purr1n, Feb 29, 2016
    #5
  6. badf00d

    badf00d Friend

    Pyrate
    Joined:
    Sep 28, 2015
    Likes Received:
    55
    Trophy Points:
    28
    Location:
    Ohio
    Yes, and as far as I know. :) Although you can't tell from the photo, the print on the chip reads in the orientation shown.
     
    badf00d, Feb 29, 2016
    #6
  7. ultrabike

    ultrabike Measurbator - Admin

    Staff Member Pyrate MZR
    Joined:
    Sep 25, 2015
    Likes Received:
    8,960
    Trophy Points:
    113
    Location:
    Irvine CA
    What's the PN of that SO-8 to DIP-8 adapter? (hard for me to make heads or tails of the pin connections w/o it)
     
    ultrabike, Feb 29, 2016
    #7
  8. badf00d

    badf00d Friend

    Pyrate
    Joined:
    Sep 28, 2015
    Likes Received:
    55
    Trophy Points:
    28
    Location:
    Ohio
    I bought it on Amazon here, after trying one from eBay that never arrived.
     
    badf00d, Feb 29, 2016
    #8
  9. ultrabike

    ultrabike Measurbator - Admin

    Staff Member Pyrate MZR
    Joined:
    Sep 25, 2015
    Likes Received:
    8,960
    Trophy Points:
    113
    Location:
    Irvine CA
    I'm not certain, but I think the dot is incorrect on the side you are using. Ohm out pin 1 of the device to pin 1 of the adapter.

    EDIT: Actually I think it's correct. But ohm out all pins anyway just to be sure (i.e. make sure there is a short between the device and the pins using your multimeter).
     
    ultrabike, Feb 29, 2016
    #9
  10. badf00d

    badf00d Friend

    Pyrate
    Joined:
    Sep 28, 2015
    Likes Received:
    55
    Trophy Points:
    28
    Location:
    Ohio
    I'll have to check it when I get home after work with access to a multimeter. Pin 1 on the chip is lower left (relative to silscreen text), from what I can tell? There is no physical dot molded in the package, so I had to make an educated guess based on the lame silkscreen and limited info in the TI PDF.

    Just touch that pin on the chip, and pin 1 on the header? I think we tried that before we soldered, but I'll confirm tonight.
     
    badf00d, Feb 29, 2016
    #10
  11. ultrabike

    ultrabike Measurbator - Admin

    Staff Member Pyrate MZR
    Joined:
    Sep 25, 2015
    Likes Received:
    8,960
    Trophy Points:
    113
    Location:
    Irvine CA
    Try all the pins just in case. Double check for shorts too (check the pins are not connected to more than one leg of the device - also with the multimeter).
     
    ultrabike, Feb 29, 2016
    #11
  12. badf00d

    badf00d Friend

    Pyrate
    Joined:
    Sep 28, 2015
    Likes Received:
    55
    Trophy Points:
    28
    Location:
    Ohio
    Checked all the pins, and 1 (lower left) maps out as hoped, and the rest seem to be correct, with no shorts. So either both chips are no good, or we didn't insert it far enough. Maybe sand down the squared pins, or would this create a corrosion problem or make them too weak or something?
     
    badf00d, Feb 29, 2016
    #12
  13. ultrabike

    ultrabike Measurbator - Admin

    Staff Member Pyrate MZR
    Joined:
    Sep 25, 2015
    Likes Received:
    8,960
    Trophy Points:
    113
    Location:
    Irvine CA
    What are the supply voltages (V+ and V-) when the LME49710 is in place?
     
    ultrabike, Feb 29, 2016
    #13
  14. badf00d

    badf00d Friend

    Pyrate
    Joined:
    Sep 28, 2015
    Likes Received:
    55
    Trophy Points:
    28
    Location:
    Ohio
    I assume you mean checking it with the multimeter? I'll have to learn how to check it without frying anything.
     
    badf00d, Feb 29, 2016
    #14
  15. ultrabike

    ultrabike Measurbator - Admin

    Staff Member Pyrate MZR
    Joined:
    Sep 25, 2015
    Likes Received:
    8,960
    Trophy Points:
    113
    Location:
    Irvine CA
    Yup. Multimeter. I would plug the LME49710 device in and make sure things are working properly with it. Then I would put the multimeter in DC voltage mode and put the positive to V+ and the negative to V-.

    It should measure somewhere between 5V to 34V me thinks.

    Then repeat with the OP827 device and see what I get.
     
    ultrabike, Feb 29, 2016
    #15
  16. badf00d

    badf00d Friend

    Pyrate
    Joined:
    Sep 28, 2015
    Likes Received:
    55
    Trophy Points:
    28
    Location:
    Ohio
    Ok, good news. Was able to get over to my friend's house. We tweaked the pins a bit and reseated the adapters in the chip socket. Success!

    It looks like Creative uses a socket that expects round pins, and the header pins are the typical squared variety. Not sure where to buy better pins, but it's working and he's happy.

    Thanks for all the help!
     
    badf00d, Mar 7, 2016
    #16

Share This Page