About: Computer Audio
General Stereo articles
So my Accuphase DC-37’s USB input was damaged a while back. It was broken, but it’s fixed now.
Cannot remember what the exact message was, but neither Windows nor Linux can detect the Accuphase DC-37’s USB input. The Snakeoil OS logs returns an error message with the error code of -110.
So what have I done to damage the USB port?
On the day, I had a problem with my PS Audio P5 - it refused to turn ON. To try and get the P5 working again I had to power on/off several equipment multiple times. By the time the P5 is working, the Accuphase DC-37’s USB port is dead.
In the Linux world the code -110 means an I/O READ error; but what is the problem, and the cause?
A colleague of mine (Steve) has kindly helped me out on this matter. He has diagnosed the problem, fixed the USB and modified the board to prevent this from happening again. Here’s a review of his findings, note that as I’m not a tech, everything is likely lost in translation!
Some audiophiles prefer to defer to machines and equipment to override humans cognitive senses. This never made sense to me. 121 months and a small redundancy paycheck later. I hope I am a bit qualified to say something about measuring equipment.
The more sensitive the measuring gear, the more noise it is susceptible to. Trying to identify what is noise, and what is data is part of the quality analysis, and that itself is part of something bigger called quality control. Reason for this is noise is subjective - there can be background noise, and also things like you are measuring some effect from something else (i.e. you are measuring something else you’re not expecting). These quality checks are part and parcel of splitting up what is data and what is noise!
The more important thing, as mentioned previously, measurements are doing physical measurements. Humans when we listen are doing this via cognition. The two systems are not even close to being the same. Saying measuring gear is more sensitive than humans is akin to asking a measuring machine how good tasting a dinner from the best restaurant is. There are some things in the world where you simply have to experience yourself - and remember nobody will ever share the same experiences from the same event. At best, machines can only tell us what is common, at worse data from measurements are completely useless.
Here is something you can try at home. Next time you are charging your mobile phone with your wall wart USB charger, put your ears right up to the charger.
Do you hear a high pitch whine?
I do, and one can hear this from up to 1 meter away. This is a video recording of me trying to capture the noise on my mobile but this is probably not working. At least I do not think I can hear the same hum when playing back this video on my aging notebook computer.
Do not panic if you can not hear this whine, your hearing is fine.
This whine may well be connected to the home electrical supply and the same charger that whined can be dead silent when use in somewhere else. The exact cause is still unknown to me at this stage.
This noise is similar to a 50 Hz transformer hum/buzz. Where it differs from a traditional 50 Hz hum is this high frequency will not blend into the background noise. You should still hear it when music is playing (hence why the recording couldn’t pick it up is a surprise for me).
Some other things I’ve noticed about this whine:
- As the device gets to full charge, more often than not the volume of the whine gets louder
- When you power off the charger, the volume of the whine gets louder and louder and pitch goes higher and higher. And then everything fades off
- All my USB chargers exhibit this whine. Seems as they age, the noise gets worse
This is a short video of my Marantz setup playing “Eternal” from a Japanese group called Rin’ (Album: Jikū 時空 Track #11).
My listening room is tiny - almost a cube at 2.4 m (W) x 2.6 m (L) by 2.4 m (H). The speaker placement can be best described as an equilateral triangle - speakers on two points and the sweet spot making up the three points of a triangle. The speakers are only slighly toed in, so while the distances between the speakers and myself are equidistant, if you draw a line from the tweeters projecting towards the sweetspot, the two lines will only converge behind the sweet spot.
The reason for the gentle toe in is to give the illusion of an expanded front stage, i.e. sounds that you perceive are coming from the extreme left of the left speaker, and extreme right of the right speaker.
The computer is running stock version of 0.1.4 of the Snakeoil OS, the only changes I’ve made is to restrict the output to no more than 96 kHz (maximum the KillerDAC can handle), and custom priority levels for certain processes (e.g. USB 2.0, network, squeezelite and so on). Music is streamed from a NAS (FreeNAS running on HP MicroServer Gen8).
This setup is far from being what is commonly known as a “high end” system in audiophile circles. Every equipment selected for this system is reasonably priced. The room while small and claustrophobic for some has a very big sound. The speakers completely disappear and any sound from the recording just pops up in freespace and is localisable (i.e. your brain is telling you there is a person standing at this spot, or there is a violinst at that point and so on). Done right this can send your brains into a frenzy as your ears are telling you something is there but your eyes are contradicting it. This state of confusion can often give you a high, and this high can be very intoxicating.
So what’s the best feature of this setup? It allows me to enjoy the music hidden in highly compressed music (99.9% of most modern music).