High pitched background noise, around 2340Hz (anyma phi)
AndyHornBlower last edited by AndyHornBlower
I've been meaning to mention that my anyma phi has a high pitched background noise, most of the time, wavering slightly, around 2340kHz (maybe 2343Hz) - that frequency is according to ClearTune on my iPad 3, connected with an iRig, and it identifies it as roughly D7. It sounds above the top C that I can play with an "empty" patch, but within the range that I can bend that note up to.
It's present on the headphones socket and the left audio out - I assume that's what I should use for mono. I expect it's the same on the right audio out, but I haven't checked. It's largely independent of the volume knob - I hear it as clearly with the anyma phi's volume knob turned all the way down.
It does it whether I'm using DIN MIDI or USB MIDI via the USB Host socket. It does it with headphones plugged in directly, or when taking the output of either the headphones socket or left line out to something else.
I've been working around it by using a FiiO E06 headphones amp from the output (either from the headphones socket or left line out), by turning the gain on that low enough so I can't clearly hear the noise, and turning the volume full up on the anyma phi, to get a better signal to noise ratio.
If I switch to the original factory patch 7 (a piezo patch that has audio in turned full up), I hear the same sort of sound, but louder.
At one point, I was able to get the sound to get louder and softer by turning the LED brightness up and down - I did it a few times in a row and it seemed consistent. I can't get it to do that reliably though. Once when I did that, it suddenly stopped, or got much quieter so I couldn't really hear it any more (still via the headphones amp, with less than unity gain, so it might just have got quiter). I've heard it suddenly get louder when changing patches too - to ones without audio In turned up, and no envelope follower.
Is there a way to turn the LEDs off all together, so I can hear the difference? Since they can be faded, and the colour mix can be adjusted, I'm guessing they're driven by PWM. Is the frequency I hear the PWM frequency, by any chance, or maybe an octave either side of it?
It would be good to be able to turn the display off too, to check if that's being picked up.
On a maybe not directly related problem, I've also been hearing a metallic ping or pling, not unlike the sound that the built in piezo might make if something small and hard fell on it. It's intermittent - it can go quite a while without making the sound, then do it a few times within a couple of minutes. I was hoping that was a bug, maybe from CPU overload, but it does it even on an "empty" patch.
Are these known problems? I thought I'd read about noise on the outputs, but I can't remember who said it.