View original (French)

RCA input to Jack problem

MyPixxel Posted messages 116 Status Member -  
MyPixxel Posted messages 116 Status Member -
Hello, I’d like to broadcast on a radio with My Radiomatisme. I have a MIDI controller with USB and RCA ports. I therefore bought a RCA-to-Jack adapter to make the main output (master) of my turntable act as a kind of microphone that can pass into My Radiomatisme. So it works, I can be heard by the microphone input on my turntable and play jingles on the software. But there is a sound problem: the sound (master) from my turntable is very bad and accompanied by a horrible background noise... I’ve checked everything and redone the connections but the problem persists! I should note that this problem does not occur when I plug the RCA cables into speakers (without going through the adapter)

Does anyone have a solution to this?
Thanks in advance for your help!

2 answers

  1.
    georges97 Posted messages 14579 Registration date   Status Contributor Last intervention   2 924
     
    Good evening,

    RCA phono plugs are generally high-impedance outputs (let's say around 15 kilohms). The micro/line input of a PC is a low-impedance input (about 600 ohms to 1 kiloohm).

    The result is saturation of the input due to this impedance mismatch, in addition to a output level (in millivolts) that is too high since it is intended for a line input of an amplifier or recorder (tape deck, cassette player).

    If you have a headphone output on the controller, that is the one you should use with the appropriate cables: a mono-block stereo mini-jack female to 6.35 mm stereo jack adapter + a stereo mini-jack male-male cable (1).

    Otherwise, you plug your mini-jack/RCA cable into a line, tuner, or tape input of a hi-fi amplifier and come out via the amplifier’s headphone jack using the cable described in (1) to enter the PC with a mini-jack.

    Of course, you’ll need to set the headphone output to a moderate level and have a way to listen to the mix (headphones on the PC’s headphone output?).

    Best regards
    1
  2. MyPixxel Posted messages 116 Status Member 31
     
    Thank you for your help!

    I just tested it and the same result for the headphone output of my controller: always background noise and distorted sound.
    For passing from an amplifier, impossible because there is no headphone jack on a large 250W speaker...

    I also know that it is possible to go through an internal method but I would have no way to intervene by talking with a microphone since the mic option of My Radiomatisme will already be taken by the controller. It is also possible to go through Virtual DJ's diffusion mode but again, the delay is too great to manage to time the jingles correctly...
    0
    1. georges97 Posted messages 14579 Registration date   Status Contributor Last intervention   2 924
       
      Have you lowered the output level on the headphone jack as far as possible, if there is a possibility to do it with a volume button, because the output level is sometimes far too high, even at the start of travel. As for the background noise, if it is a "buzz" (a low sound like snoring) it will indeed be difficult to adjust because you need to search in the circuits for what causes this stray sound and either provide shielding or connect the grounds of the different components. It is, in any case, a job for an electronics technician. Sorry I couldn't be of more help.
      0
      1. MyPixxel Posted messages 116 Status Member 31 > georges97 Posted messages 14579 Registration date   Status Contributor Last intervention  
         
        I climbed from the lowest level to the highest level and it does exactly the same thing as directly connected to the master of the controller.
        And for the background noise, it is rather high-pitched because I have a very good sound card, it should not come from the...
        0