Author Topic: PSX-SX900 USB noise in the audio path  (Read 651 times)

0 Members and 1 Guest are viewing this topic.

Offline kampot

PSX-SX900 USB noise in the audio path
« on: June 08, 2020, 10:19:59 PM »
when having PSR-SX900's USB-midi connected to a computer and audio (balanced) outs connected to audio interface (mackie onyx producer 2x2) there is usb noise on the audio inputs and outputs.
the noise also gets recorded onto the audio track. 
using unbalanced audio cables its much louder but using balanced its quieter but still audible.
 

Offline manuel

Re: PSX-SX900 USB noise in the audio path
« Reply #1 on: June 09, 2020, 08:14:38 AM »
Hello

Do you know that you can record Audio in the PSR SX900, no need of external recorder.....why complicate your life?....Then after you record your song in Audio (You can record also in MIDI Besides, of course one at the time), then you can transfer your recorded song into the Computer.....if I am not mistaking, in the PSR SX900 you can Choose to record in MP3 or in Wav.....

My 2 Cents.

Manuel
My 2 Cents

Manuel
 

Offline overover

Re: PSX-SX900 USB noise in the audio path
« Reply #2 on: June 09, 2020, 10:05:31 AM »
when having PSR-SX900's USB-midi connected to a computer and audio (balanced) outs connected to audio interface (mackie onyx producer 2x2) there is usb noise on the audio inputs and outputs.
the noise also gets recorded onto the audio track. 
using unbalanced audio cables its much louder but using balanced its quieter but still audible.

Hi kampot,

first of all, you should use unbalanced (TS) Audio cables only with the SX900. This is because all Audio outputs and inputs are unbalanced TS jacks. If you use balanced (TRS) cables, your Audio interface will receive the plus-phase signal only. The "Ring" contact (on which the Audio interface expects the - phase signal) is not connected inside the SX output jacks. This can cause hum, and the effective incoming signal level on the Audio interface is relatively low, because no minus-phase signal is received.

So, either use unbalanced TS cables or, if using TRS cables, the Ring and Sleeve contacts must me bridged (to get unbalanced cables again).

If relatively long Audio cables (over 3 meters) are needed, I recommend to use a Stereo DI Box (short unbalanced TS cables from the SX900 to the DI Box, and then balanced XLR cables to the Audio interface).

Regarding "USB Noise": In principle, USB is a digital Interface, and this cannot actually produce any noise. However, it can happen that disturbing (usually high-frequency) audio noises get from the computer to the keyboard via the ground connection of the USB cable.

These noises often come from the (switching) power supply of the computer. If you are using a Laptop, please unplug the power adapter to test whether the noise transmitted via the USB cable then disappears.

Another option would be to use a USB Isolator box (to break the direct ground connection between the computer and keyboard).

Hope this helps!


Best regards,
Chris
« Last Edit: June 09, 2020, 01:14:10 PM by overover »
Everyone always said: This is not possible! - Then someone came and ... just did it!
 

Offline kampot

Re: PSX-SX900 USB noise in the audio path
« Reply #3 on: June 09, 2020, 09:25:46 PM »
Hello

Do you know that you can record Audio in the PSR SX900, no need of external recorder.....why complicate your life?....Then after you record your song in Audio (You can record also in MIDI Besides, of course one at the time), then you can transfer your recorded song into the Computer.....if I am not mistaking, in the PSR SX900 you can Choose to record in MP3 or in Wav.....

My 2 Cents.

Manuel

I know but I'm also using it as a midi controller and source for sounds as an external midi device in cubase
 

Offline kampot

Re: PSX-SX900 USB noise in the audio path
« Reply #4 on: June 09, 2020, 09:29:02 PM »
Hi kampot,

first of all, you should use unbalanced (TS) Audio cables only with the SX900. This is because all Audio outputs and inputs are unbalanced TS jacks. If you use balanced (TRS) cables, your Audio interface will receive the plus-phase signal only. The "Ring" contact (on which the Audio interface expects the - phase signal) is not connected inside the SX output jacks. This can cause hum, and the effective incoming signal level on the Audio interface is relatively low, because no minus-phase signal is received.

So, either use unbalanced TS cables or, if using TRS cables, the Ring and Sleeve contacts must me bridged (to get unbalanced cables again).

If relatively long Audio cables (over 3 meters) are needed, I recommend to use a Stereo DI Box (short unbalanced TS cables from the SX900 to the DI Box, and then balanced XLR cables to the Audio interface).

Regarding "USB Noise": In principle, USB is a digital Interface, and this cannot actually produce any noise. However, it can happen that disturbing (usually high-frequency) audio noises get from the computer to the keyboard via the ground connection of the USB cable.

These noises often come from the (switching) power supply of the computer. If you are using a Laptop, please unplug the power adapter to test whether the noise transmitted via the USB cable then disappears.

Another option would be to use a USB Isolator box (to break the direct ground connection between the computer and keyboard).

Hope this helps!


Best regards,
Chris

I used both balanced and unbalanced cables (both 6ft) and ironically with balanced cables noise was significantly quieter.

If i unplug either USB cable from sx900 or audio cables from sx900 the noise stops, so theres something with the ground loop.

what USB Isolator box would you recommend to get ?

 

Offline kampot

Re: PSX-SX900 USB noise in the audio path
« Reply #5 on: June 27, 2020, 10:37:24 PM »
any ideas ?
 

Offline kampot

Re: PSX-SX900 USB noise in the audio path
« Reply #6 on: July 04, 2020, 07:46:27 PM »
More bad news for me.

https://www.electrahealth.com/Premiu...ces_p_159.html

2 of these arrived today.

Tried both of them at once at both usb cables (sound card, and PSR-SX900).

It fried my audio interface, computer can't detect it, and green USB light on interface doesn't light up.

Now even without these grounding cables interface is dead still.

Hopefully it didn't screw up PSR-SX900 too.

Will test PSR-SX900 later, cuz this got me too stressed right now..