Thank you all very much for your answers and tips! I'm a little worried indeed.
Yeah, that's the case for me with my 800s, a minor background noise. Just a little more noise with the Clears (that doesn't disturb the music plays), but with the 109pros the humming background noise is
very loud, to the point it's not at all pleasing to use these headphones with the WA7.
I use the stock usb-c cable connected to my Mac mini or to my iPad Pro. But the problem can't be the usb cable because the noise is present even with the usb cable detached from the wa7
Thanks for the tip
yes maybe it's the tubes...
The headphones cables are very good quality : I use meze silver cables and sometimes hart audio cables.
The 109pros, with those cables, work flawlessly with my Mojo2, pitch black background.
Yeah the hum arrives to both ears.
The amp is fairly new (I received it by the end of January 2024). I've used it around 20 hours, mainly with the 800s and clears, for the reasons explained above.
Thanks for the tube recommendation! I'll take a look! But I think I'm going to contact Woo Audio to discern the problem before spending on high quality tubes
The FAQ on woo audio website mentions the possibility of "light hums/noises" in the point 22 of the page :
"22: What to do when my amplifier developed a light hum/noise?
Noises can come from many different places. e.g. power source, audio cables, environmental EMI. To test, please try the following.
- disconnect all cables from the amplifier.
- install ALL stock tubes.
- move amplifier to another area of the house. e.g. living room, kitchen countertop, office, etc. (This is important to isolate the amplifier from other components).
- keep cell phones, WiFi routers, powered hard drives and other high EMI devices away from the amplifier.
- connect AC power cord directly to a wall outlet (no conditioners or power strips).
- connect headphones to the amplifier and set volume to 11 o’clock position.
- listen through headphone. Do you still hear the hum?
If you still hear the hum, try a ground-lift adapter (for testing ONLY). If the hum goes away using the adapter, you have a ground-loop issue in the house. You can use a device called HUM-X."
I've tried from another area of the apartment and I still hear the hum...
What puzzles me is that the noise, being very light with one headphone (hd800s), is like ten times stronger with another (109pros). And it varies in intensity when I turn up the volume. And that happens even with no music and even with the usb cable detached...
I love the wa7 with the 800s and Clears, it sounds really great, but at this moment I can't use it with my Mezes