Author Topic: Furutech GT40 noise when recording  (Read 3554 times)


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Furutech GT40 noise when recording
« on: February 22, 2014, 10:21:48 am »

I recently bought a Furutech GT40 and I've been trying to record music from my Yamaha clavinova using Vinyl Studio. Unfortunately, all my attempts to record come with an annoying humming noise which changes frequency when there's some input coming in (it sounds like a weird corrupted digital signal).

My setup is clavinova to GT40 input via 2 x RCA, GT40 to my laptop via USB, and I've set the switch on the back (MM/MC/LINE) to LINE. When I set the switch on the front of GT40 to Phono/Line any sound I play on my Clavinova sounds perfect, undistorted. However, when I try to record and the ADC comes into play I get this noise. The really weird thing is that when I slightly poke the usb port on the back of the GT40 while recording, the frequency of the noise changes.

I noticed this warning on the GT40 website which I thought was related:

The TENOR chip used in the GT40 has a bandwidth limitation of 12Mbps (USB 2.0 full speed operation), and due to this limitation only one I2S input or output can be set for 24bit/96KHz application at one time. Therefore, under this condition, for simultaneous multiple-channel applications other I2S interfaces must be configured at 16-bit/48KHz or 16-bit/96KHz. In other words, when recording it is necessary to set the audio Input on the computer to 24bit/96KHz (PC-Sound application; MAC-MIDI application), but do not set not the audio Output to 24bit/96KHz. The Output should be set to a lower 16bit resolution until recording is done. Then when you want to playback your 24bit/96KHz files through the GT40 you need to reset the output to 24bit/96KHz and reset the input to a 16bit resolution."

I noticed that Vinyl Studio has a specific setting for this on the output device which I enabled. I also changed the quality settings of the input and output devices on Windows (through the control panel) when recording to match these guidelines. Unfortunately, I still get the noise.

I thought it was my laptop introducing the noise when connected to power, so I tried it on battery too and it still happens. I also tried a different USB cable which didn't help.

Any suggestions? I can record a sample of what the noise sounds like if it would help.

Paul Sanders (AlpineSoft)

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Re: Furutech GT40 noise when recording
« Reply #1 on: February 22, 2014, 11:37:42 am »

Can you send me a sound sample please?  Please record about 30 second's worth of audio, including a section of silence, and save it as an Ogg file to keep the filesize down.  Then email it to:

p DOT sanders AT alpinesoft DOT co DOT uk