ODAC+O2 clipping and other problems

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by Psalmanazar, Nov 6, 2015.

  1. Psalmanazar

    Psalmanazar Most improved member; A+

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    After forgetting to switch back to ASIO or WASAPI for a month I finally remembered to do so. Unfortunately it caused my O2+ODAC JDS Labs combo to start clipping well mastered recordings on 3.5x gain on my newish HD 650s. It clipped the DR10, -2.34 DB peak, -20 RMS keyboard interludes on Morbid Angel's Blessed are the Sick. Could this input clipping damage the HD 650 drivers? Is there any way to stop the clipping other than getting rid of it?

    Edit: It's only clipping in WASAPI and ASIO which are not bypassing the Windows volume control despite the ODAC being set in exclusive mode.
     
    Last edited: Nov 6, 2015
  2. logscool

    logscool Friend

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    It sounds like something is wrong with your player settings you should be able to have the wasapi and asio drivers bypass the windows mixer interface. As for the clipping on the O2 I have heard that if an input gain of higher than 3.1 or 3.1 (can't remember exactly) it will clip the full scale output from the 2v ODAC. This means you should use a lower input gain setting. Clipping your amp will not cause damage to your headphone drivers it will just sound bad.
     
  3. Psalmanazar

    Psalmanazar Most improved member; A+

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    Yeah it's definitely driver related as it's clipping at 1x gain while louder volumes through DirectSound are not clipping and my USB power is randomly good on this Thinkpad T440s. I'll post a list of the settings I have in Windows, the Lenovo laptop keyboard, and foobar when I come back.
     
  4. Psalmanazar

    Psalmanazar Most improved member; A+

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    So it was definitely driver and USB power related. At a meet with my only my Thinkpad and O2 plugged into my surge protector which was plugged into a battery backup surge protector another guy's gear was on, I got no clipping with WASAPI and good USB power and it sounds good.

    At home with a bunch of stuff (USB hub, O2, laptop, external HD drive, external optical drive) plugged into the surge protector plugged into the wall, and the ODAC+O2 on the port on the other side, WASAPI and ASIO clip on any gain settings while DirectSound doesn't.

    Should I buy a Wyrd or a Schiit Uber stack and sell the O2? Could the USB port somehow being overdriven (I am guessing this was the case) have a problem with how much stuff I had plugged into the surge protector? I don't really want to deal with this issue again.
     
    Last edited: Nov 7, 2015
  5. lm4der

    lm4der A very good sport - Friend

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    You probably tried this, but be sure to try it from a usb hub.
     
  6. logscool

    logscool Friend

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    Yeah i would give a powered usb hub a try if you have one.
     
  7. lm4der

    lm4der A very good sport - Friend

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    Even an unpowered one is a worthwhile experiment if you have one on hand.
     
  8. logscool

    logscool Friend

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  9. Psalmanazar

    Psalmanazar Most improved member; A+

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    I finally got the O2 to stop clipping the ODAC on quieter recordings with less sensitive without using DirectSound:

    1. Nothing in surge protector but the O2 wart and laptop plug. Nothing else plugged into the outlet.
    2. Mute everything but the ODAC and foobar.
    2. No ASIO. No ASIO4ALL. This will clip.
    3. WASAPI "push" mode. No "event" mode.
    4. Enjoy the sweet sound of no clipping unless it is on your crappy recordings.

    I don't know if this undervolts the ODAC slightly or prevents overvolting or what as I wasn't overdrawing the outlet before. I tried this at a meet from a probably overdrawn outlet and it worked. Now it works at home. I will definitely be upgrading to a Schiit stack within a month or so. This is getting ridiculous.
     

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