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SOTA Pyxi Initial Impressions

Cell phones or local cell transceivers cause this also. They have to occasionally register with the local tower, even when not actually in use, and that can occur every 30 minutes or so, depending on a variety of local conditions.
If I was there with my test equipment, I could determine the character of the noise and hence the nature of the source, but if wishes were horses...
 
I don't think this is OP's problem, but while we are at it: Another potential source of this type of noise can be ethernet over power lines, e.g. "Powerline". I've come across a couple of cases where customers of mine had an interesting warbling highish frequency noise from their turntables, which disappeared when they disconnected their powerline networks. Pretty obvious, when you think of it – their entire idea is about injecting a high frequency noise into the power lines of one's house. Turntables, especially with lomc carts should be extra sensitive to this.
 
wyn palmer said:
Cell phones or local cell transceivers cause this also. They have to occasionally register with the local tower, even when not actually in use, and that can occur every 30 minutes or so, depending on a variety of local conditions.
If I was there with my test equipment, I could determine the character of the noise and hence the nature of the source, but if wishes were horses...
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Yeah. In today's urban environment, we are bombarding with a TON of RF, UHF, VHF, microwave, etc EMF noise. To sort all of them out would prolly take a team of experts and expensive equipment.

Maybe, a Faraday cage is the real answer. :idea:
 
Well, I am playing an album using the Pyxi with the lights off right now. In about 30 minutes my daughter is taking her lunch break, and I will unplug the master WiFi node and turn off my phone (usually on my desk near my gear rack) to see if the noise persists. I am all about removing variables to troubleshoot and I still have the Pyxi, so why not...
 
The large gap/somewhat aperiodic nature of the issue is certainly a clue. That's why I suggested the cell phone possibility as it's the right frequency range, and has the correct coarse temporal characteristic. To be more sure I would need to look at the waveform envelope. That's how I diagnosed prior wifi issues at home.
 
tothmes said:
I don't think this is OP's problem, but while we are at it: Another potential source of this type of noise can be ethernet over power lines, e.g. "Powerline". I've come across a couple of cases where customers of mine had an interesting warbling highish frequency noise from their turntables, which disappeared when they disconnected their powerline networks. Pretty obvious, when you think of it – their entire idea is about injecting a high frequency noise into the power lines of one's house. Turntables, especially with lomc carts should be extra sensitive to this.
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Hadn't heard of this ethernet over powerline. I use wi-fi.

Of course, if you are injecting HF noise into a line. It's just like a noisy refrigerator, computer, or TV. ;)
 
tothmes said:
I don't think this is OP's problem, but while we are at it: Another potential source of this type of noise can be ethernet over power lines, e.g. "Powerline". I've come across a couple of cases where customers of mine had an interesting warbling highish frequency noise from their turntables, which disappeared when they disconnected their powerline networks. Pretty obvious, when you think of it – their entire idea is about injecting a high frequency noise into the power lines of one's house. Turntables, especially with lomc carts should be extra sensitive to this.
Click to expand...
Hi! The Pyxi will be available for purchase in the EU. SoTa have added a choice on their purchase page for non-North American purchasers.
 
So I got to start my additional troubleshooting a bit early. Shut down everything in the office including lights/cell phone and unplugged all wifi nodes throughout the house. Played some music and let the system sit at idle for awhile, no noises. Started turning things back on at 5-10 minute intervals until everything back on. Still no noise. After a few minutes I put on some music. After music, let the system sit idle for a few minutes - there is the noise pulse.

So not real conclusive, and only one of the three potential causes (lights) are realistically resolvable. I was going to do some more testing with the cell phone off to see if the noise returned to test Wyn's hypothesis of the cell phone, but I got an email from Christian at SOTA with my RMA number (and I actually have some work to do this afternoon). So, I will pack this up and regretfully send it back. Hopefully my efforts are helpful here, what I learned from this is that modern technology puts a lot of **** in the air, and at least in my system that is impactful. From the sounds of it I am in the minority, and fortunately my SUT cures all ills. Thanks to those who followed the journey and offered suggestions and provided help, it is much appreciated!
 
Interference from a cellphone communicating with the tower actually on a commercial recording. Starts 2:07. It's quite noticeable.
 
So I've gone a bit over 3 hours with cell phone turned off (which has been great!) and the Pyxi powered up (a mix of music playing and idle). Have not had any unexpected noises during the quiet times or anything out of the ordinary with music playing. Had the LED lights off most of that time as well (wifi and computers have been on the whole time), just turned the lights on about 15 minutes ago. As soon as the current record side is finished, I am going to let things sit idle for 10-15 minutes, then turn the cell phone back on and see if the excitement starts...

The Pyxi is not in the exact position it's been in (next to my tube preamp) its about a foot away on top of my rack as I set it up quickly for this test. Also, the cables from Pyxi to pre are not the Morrow's I've been using, I used the cables (Mogami microphone cable with Neutrik ends) from my DAC to another preamp input as I didn't want to dig around behind the rack to get things set up. I don't think any of these things are making a difference as I tested the Pyxi yesterday in a similar location with the phono input disconnected to validate nothing was wrong with the Pyxi.
 
mprince said:
So I've gone a bit over 3 hours with cell phone turned off (which has been great!) and the Pyxi powered up (a mix of music playing and idle). Have not had any unexpected noises during the quiet times or anything out of the ordinary with music playing. Had the LED lights off most of that time as well (wifi and computers have been on the whole time), just turned the lights on about 15 minutes ago. As soon as the current record side is finished, I am going to let things sit idle for 10-15 minutes, then turn the cell phone back on and see if the excitement starts...

The Pyxi is not in the exact position it's been in (next to my tube preamp) its about a foot away on top of my rack as I set it up quickly for this test. Also, the cables from Pyxi to pre are not the Morrow's I've been using, I used the cables (Mogami microphone cable with Neutrik ends) from my DAC to another preamp input as I didn't want to dig around behind the rack to get things set up. I don't think any of these things are making a difference as I tested the Pyxi yesterday in a similar location with the phono input disconnected to validate nothing was wrong with the Pyxi.
Click to expand...
It really is starting to "sound like" the cell phone. If so, how do you want to proceed?
 
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