USB noise help -- SOLVED!

[atticusGoldman]

Hey guys,

Kind of new to this stuff. Got a lot of headphones and a few DACs so I just got my first dedicated desktop amp (Garage 1217 Project Polaris) and I love it but I'm having a bad day lol. My Sabaj Da2 DAC just died after I discovered that the Polaris is indeed a quiet amp but I was having massive USB noise issues.

My original assumption that with such a powerful amp IEM use was probably a no go but it actually works fairly decently even without the attenuator cable I got with it. The real problem has actually been on the other end of the chain, the source XD.

I just got an Earstudio ES100 and it's been a revelation for me. I thought my amp was having noise issues with some of my more sensitive headphones but then I realized it sounded more like RMF noise, since my PC is in an open frame case, and sure enough problem solved by moving to another room. But then I realized just having the ES100 on Bluetooth fixed the problem even with the computer on and running right next to the amp which is also open frame.

So then I tried my other small usb DACs (dragonfly style dacs) and they all had noise as well. But plugging them into my phone's USB also eliminated the noise.

I have a pretty high end motherboard with isolated audio circuits and special clean DAC USB ports all of it noisy. Interestingly the line out from the motherboard also has the same exact noise when plugged directly into the Polaris. It's a static hiss with high frequency overtones and it changes frequencies correspondeing to the PC doing stuff so it's definitely the PC. But all the DACs in question and the line out on the PC are all super clean when driving headphones directly but the noise kills it when they are plugged into the amp.

I plan on getting an Enog 2 which uses optical and has its own power supply so that should solve the issue but I really would like to be able to use my ES100 over USB with my amp.

Anyone have any ideas as to what in the heck is going on and what the best solution would be other than ditching USB? I have heard of USB noise before but I also thought it was either just cheap low end PC components or way overblown as to the severity. Or do certain amplifiers hate USB sources?

 

[tomb]

It sounds to me like your issue is with the amp, not the USB connection. Your test with Bluetooth is converting directly to a digital stream, so I'm not certain it's a valid test. Plus, you lose S/N, etc. when using Bluetooth, so it's possible that Bluetooth is simply masking the sound due to its inferior performance.

I would be more concerned about the open case amp, not the open case PC, although that's potentially a bad actor in your environment.

Many, if not most, USB cables are shielded and should not be affected by any of this. If you have very cheap USB cables, you might check this and get some that are shielded. That said, my guess is that your issue is in the amp, not the cables or PC.

 

[atticusGoldman]

Your test with Bluetooth is converting directly to a digital stream, so I'm not certain it's a valid test.

Yeah that's what I was thinking so I ran all the DACs off USB from my phone and once again problem solved. Also it seems to be the same noise I heard through my sub woofer until I got a more shielded cable. I also get the noise through the line out on the PC. However plugging the amp directly into my phone also fixes the problem. I hate the way my phone sounds but I now realize its much more the amp in my phone than the DAC that I dislike, the Polaris actually makes my phone sound pretty good. I have emailed the guy that makes the amp just in case who is said to be very helpful and I haven't really heard too much negative stuff about his amps unless they just aren't your style so I doubt there's something wrong with the amp. I thought it was just a high noise floor at first but upon turning it up its definitely digital noise which again is not there when plugged into anything other than my PC. After fiddling with it for a while the noise is just barely audible when the volume is turned up to top end of my listening range. So its not that bad but on an aux cable from a phone the amp is dead silent all the way up vol pot.

 

[Monsterzero]

It might be dirty electricity too. Diagnosing the source of noise can be a challenge. I lost my mind when my system all of a sudden began to produce noise. I bought all new interconnects,tore the system down multiple times,all to no avail. I finally bit the bullet and spent my Auteur funds on a high end power conditioner and that solved the issue entirely.

Try changing inter-connects,electrical outlets,power cables(if you have spares). See if the noise level raises or lowers during certain hours of the day. If possible try and split up the outlets you use for the computer vs. your audio gear. See what works and what doesnt.

TL;DR
Its a process of elimination.

 

[tomb]

Yeah that's what I was thinking so I ran all the DACs off USB from my phone and once again problem solved. Also it seems to be the same noise I heard through my sub woofer until I got a more shielded cable. I also get the noise through the line out on the PC. However plugging the amp directly into my phone also fixes the problem. I hate the way my phone sounds but I now realize its much more the amp in my phone than the DAC that I dislike, the Polaris actually makes my phone sound pretty good. I have emailed the guy that makes the amp just in case who is said to be very helpful and I haven't really heard too much negative stuff about his amps unless they just aren't your style so I doubt there's something wrong with the amp. I thought it was just a high noise floor at first but upon turning it up its definitely digital noise which again is not there when plugged into anything other than my PC. After fiddling with it for a while the noise is just barely audible when the volume is turned up to top end of my listening range. So its not that bad but on an aux cable from a phone the amp is dead silent all the way up vol pot.

There's nothing wrong with the amp, per se - except that an open case style offers very little in shielding from RF. With headphones, we are in the business of amplifying very small signals. If there's any extraneous signal that can be picked up, it probably will be.

The cable suggestion from Monsterzero is also good. With the environment you describe, you should not be using any interconnects that are not shielded. That said, there is little to any shielding in an amplifier except for the casework. Even then, most casework is aluminum and it provides little shielding anyway. Just reviewing your photos again, I think you are tempting fate by locating the amplifier directly under your monitor. The electronics controlling the screen are probably getting picked up from your amp. There are very few tube amps that can be located very close to a smartphone, for instance. I would try to get more separation between your amp, your DAC, and the PC equipment.

 

[atticusGoldman]

It might be dirty electricity too. Diagnosing the source of noise can be a challenge. I lost my mind when my system all of a sudden began to produce noise. I bought all new interconnects,tore the system down multiple times,all to no avail. I finally bit the bullet and spent my Auteur funds on a high end power conditioner and that solved the issue entirely.

Yeah interconnects make a difference. New interconnects I got actually just failed and strangely caused an error with my ES100 it absolutely would not play anything other than a loud buzzing noise with the cable in question. I did get a bluejeans cable for my sub because I was definitely getting RF noise since the cable runs directly behind my exposed motherboard. This^^^ is actually what I'm trying to avoid. I lover tinkering with things but having to spend hours switching out stuff on my system and wasting money is proving rather frustrating. I'm wondering if a USB cable with a ferrite bead would do anything. I can't believe I don't have one laying around. I believe USB is notorious for being a very dirty power source but I just really want to understand why the tiny amp circuitry in the little USB DACs isn't sensitive to it but the big amp is. I wonder if its actually there in the USB DACs but its just never audible with the lower power output they have.

There's nothing wrong with the amp, per se - except that an open case style offers very little in shielding from RF. With headphones, we are in the business of amplifying very small signals. If there's any extraneous signal that can be picked up, it probably will be.

That was my very first thought. Already had to get a shielded cable for my sub. That was the only reason I tried it on bluetooth to begin with. I brought it downstairs to the dining room away from any electronics and that seemed to work. But then when I brought it back upstairs put it in the same exact spot, didn't switch back to USB, and it still sounded great, no noise, dead silent. I know the quality of bluetooth is questionable but with the ES100 I can't tell the difference at all when its running on the LDAC codec and its my favorite sounding DAC so far. Also it works just as well when the DAC is fed from an Android phone as the USB host. So phone plugged into DAC plugged into AMP both sitting directly on top of the amp right underneath the monitor with that monstrosity of an open PC on the other side of the desk and ZERO noise. So now I'm doubting if it really is RF interference lol. And its actually a solid state amp the only one Garage 1217 makes. I read from reviews that it didn't have as much interference issues as you'd expect from something with its guts hanging out. There's also a version with aluminum plates or you can buy them later and apparently the board is grounded to the plates to help reduce interference. But all the reviews I saw mentioned a phone could be right by it no problem.

I was kind of taken aback at first by Geshelli refusing to use USB on the Enog Pro 2 but maybe this is why? XD.

 

[atticusGoldman]

Okay I think I got it figured out or at least narrowed down a lot more. I was right it's not RMF interference rather a noisy USB port. I plugged my amp into the line out on my mini cube PC (ITX form factor vs. ATX) and it was noise free then proceeded to hook a DAC up to it via USB and while not completely noise free it's not audible at my normal listening levels and overall is much much better. Interestingly when I first plugged in the DAC it was through a USB hub and once again super noisy. So it's definitely the motherboard on my ATX rig. I would say it's just a noisy USB port but I get the same sound out of the line out and it's also the same noise that was introduced to my sub cable running up the wall to my Vanatoo's directly behind the motherboard. Kind of pisses me off since the board in question is supposed to have ultra clean DAC specific USB ports and pretty decent onboard audio with isolated circuits and a fairly powerful amp (It doesn't sound half bad, not that I'd use it). And on top of it the DAC ports are JUST as noisy. Okay I am now a believer in optical. Or at least USB with its own power supply. I'd imagine that would fix it too but I would have to try to be sure. I've heard elsewhere of there being ground loops in the USB interface itself causing noise and I'm not sure if that would impact the digital signal. The Enog doesn't have usb. Maybe I should get a Modi 3 just to try it out and it looks like it has optical as well (I thought it was USB only but I guess that's the Modi 2). I could switch between optical, self powered USB, and USB powered to compare.