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OSSC Noisy Output

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This topic contains 8 replies, has 5 voices, and was last updated by  marqs 2 weeks, 4 days ago.

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  • #12170

    SV001
    Participant

    Hello,

    I am testing my 0.76-aud firmware, OSSC v1.5 unit with a self-installed HDMI Audio Upgrade and am noticing a lot of noise (scrolling horizontal lines) with the following settings:

    Input: 240p
    Type: Scart & Component
    Output: Passthru & Line2x

    Input: 480i
    Type: Scart & Component
    Output: Passthru & Line2x(bob)

    Input: 480p
    Type: Scart & Component
    Output: Passthru & Line2x

    I messed around with all the settings on the OSSC and only increasing/decreasing the H. samplerate has any effect on the noise.

    I have tested the following NTSC consoles with the OSSC: SNES via Scart, PS1 via Scart, Saturn via Scart, PS2 via Scart & Component, and Original Xbox via Component.

    I have tested with three different computer monitors, a Samsung LED HDTV, and a Vizio LCD HDTV via DVI and a basic DVI to HDMI converter, all with the same results. I have also tested the OSSC at two different locations. I am using the PSU that the OSSC came with as well as high quality cables for the consoles.

    There is no noticeable noise when I use Line3x-Line5x with 240p input. When I hookup the PS2 and Xbox directly to the HDTV’s via component, there is no noticeable noise.

    When I received the unit, I did some basic testing mainly with 240p Line3x-Line5x output, but not with 480i or 480p sources. I did successfully install the HDMI Audio Upgrade board and have no issues with the audio.

    Is the noise normal? Am I being overly anal? I do not believe that I damaged the OSSC with the HDMI audio upgrade installation, I was very precise. I confirmed that there were no shorts made and all the soldered connections have appropriate continuity. I appreciate any assistance offered!

    Pictures of my HDMI Audio Upgrade Installation:
    Photobucket – HDMI Audio Upgrade Install

    Poor quality examples of noise:
    240P 2x PS1 Scart
    480i 2x PS1 Scart
    480P Passthru PS2 Scart
    480P Passthru PS2 Component

    #12184

    BuckoA51
    Keymaster

    Could be that you got a bad PSU, did you buy one from us or are you using your own?

    #12187

    Harrumph
    Participant

    I am using the PSU that the OSSC came with as well as high quality cables for the consoles.

    #12188

    paulb_nl
    Participant

    That is certainly not normal. Since you have ruled out everything except the PSU and the OSSC, I would try another PSU.

    #12192

    SV001
    Participant

    I also tested the OSSC using a PSU that output 5V 2.0A that I got from Amazon after I noticed the noise with the PowerPax 5V 1.2A PSU.

    I hooked up my Sega Genesis Model 2 and rgb modded N64 to the OSSC via scart today for the first time and encountered the same noise.

    Any other troubleshooting ideas? Downgrading the firmware made no difference. I am starting to second guess myself; would it be worthwhile to uninstall the HDMI Audio Upgrade? I want to reconfirm that I was not overzealous with the knife when cutting the traces between the I2S, WS and SCK solder joints.

    #12206

    marqs
    Participant

    All your problematic modes (with default samplerate) use ~27MHz sampling clock. I wonder if some interference is picked from 27MHz oscillator (used for different purpose), especially when one unshielded wire gets hooked from there to audio board. You could try temporarily disconnecting audio board clock and power wires to see if that makes any difference.

    #12225

    SV001
    Participant

    I disconnected the audio board clock and power wires and the noise completely disappeared. I reconnected the wires and the noise reappeared. I shortened the wires and tried wiring it similarly to user Kabloui’s pictures. The noise was greatly reduced, almost negligible, but I cannot seem to completely remove the noise with the HDMI Audio Upgrade Board connected. Any suggestions? I am currently using 26 gauge Kynar for the power and clock.

    #12252

    BuckoA51
    Keymaster

    I tested a new PSU with an audio board installed OSSC yesterday and looked very closely for noise, I couldn’t see any, so that’s a mystery. Have you tried a different power outlet? Long shot I know.

    #12270

    marqs
    Participant

    A coax wire for the clock with shields grounded on both ends might help if that is causing the noise.

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