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Post by boomzilla on Jun 26, 2020 17:29:14 GMT -5
COMPONENT LIST: DC HDD = External hard drive in cradle containing music library AC MINI = Mac Mini computer running Roon streaming software AC DAC = Black Ice / Jolida FX Tube DAC DC VOLUME = Passive Remote Control Volume Device AC LOKI = Schiit Loki equalizer AC POWER AMPS = Emotiva PA-1 mono block amplifiers The order (top to bottom) indicates the physical layout of the signal chain. The only two components that can physically swap places are the volume control and the Loki equalizer. Since the Loki has output buffer amps and the volume control doesn't, it was my assumption that the power amps are better driven by the Loki than by directly from the passive volume pot. Is that a correct assumption? |
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DYohn
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Post by DYohn on Jun 26, 2020 17:53:51 GMT -5
What does AC and DC mean in your graphic?
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Post by boomzilla on Jun 26, 2020 19:25:33 GMT -5
What does AC and DC mean in your graphic? Components marked DC - ... have "wall wart" transformers and are fed by DC power wiring. AC is similarly descriptive. My initial plan is to run all power wiring along the plane of the shelf that the components sit on. Power wires will run "front to back" on the shelf. Any USB or RCA interconnects will be routed by self-adhesive wire hangers from the bottom of the next shelf above the components. Interconnects will run from side to side on the bottom of the shelf above, and at right angles to the incoming power wires. Hopefully, this architecture will minimize induced hum in the interconnects. The reason I put the components in the order that I did was that I hoped that the output buffer amps of the Schiit Loki would provide the best interface into the long interconnects to the power amps. Yes, No, Maybe? |
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Post by thezone on Jun 26, 2020 22:11:21 GMT -5
I have a faint but notable hum in my lowest sub ( I am running 4 through a 4 way cross over) I have tried using a completely different power socket from a different part of the room but didn't help its clearly coming along the audio signal path, I even tried a passive 25hz high pass filter but the hum is still there!
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Post by boomzilla on Jun 27, 2020 0:43:18 GMT -5
Hum can be from a different ground resistance between components or picked up from interconnects. Ground loops are best cured by plugging in all components to the same electrical socket or else using "star grounding," where only one component is grounded to the electrical system and all other components are grounded through their interconnect signal grounds to the one ground source. Interconnect hum is solved by keeping interconnects away from AC cords and transformers. Cable boxes are notorious sources of hum that can be isolated by using only TOSLINK optical connectors.
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DYohn
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Post by DYohn on Jun 27, 2020 8:43:04 GMT -5
Power is one source for hum but by no means the only source. Do you have hum in your system now that you are trying to eliminate? Also, the Schiit Loki is wall-wart powered, although it is 16VAC out of the wart. What is the "Volume" item in your list?
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Post by boomzilla on Jun 27, 2020 10:56:00 GMT -5
Volume is a MCM 50-8394 IR operated, remote-control, stereo passive volume pot.
Actually, there is very little hum in the system at all now - but I'm sensitive to it since I listen at lower volumes. I'd like to get it all out.
I knew that the Loki used a wall wart, but since its output is still AC, I still considered it a potential source of hum.
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DYohn
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Post by DYohn on Jun 27, 2020 12:49:06 GMT -5
The biggest potential source for hum is actually not in the power but in the signal side side to ground loops through the RCA interconnects. If you don't hear any then you have it licked.
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klinemj
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Post by klinemj on Jun 27, 2020 14:21:46 GMT -5
What does AC and DC mean in your graphic? Components marked DC - ... have "wall wart" transformers and are fed by DC power wiring. AC is similarly descriptive. My initial plan is to run all power wiring along the plane of the shelf that the components sit on. Power wires will run "front to back" on the shelf. Any USB or RCA interconnects will be routed by self-adhesive wire hangers from the bottom of the next shelf above the components. Interconnects will run from side to side on the bottom of the shelf above, and at right angles to the incoming power wires. Hopefully, this architecture will minimize induced hum in the interconnects. The reason I put the components in the order that I did was that I hoped that the output buffer amps of the Schiit Loki would provide the best interface into the long interconnects to the power amps. Yes, No, Maybe? Ooooohhhhh!!!! I thought you meant this... Mark |
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Post by vcautokid on Jun 27, 2020 18:58:42 GMT -5
Or just one of these.  |
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Post by Gary Cook on Jun 27, 2020 23:41:18 GMT -5
It’s been 30+ years since I had any ground/earthing hum. Keeping in mind we are on 220/240 volts @ 50 hz here in Oz. Each house has an earthing rod embedded into the ground and since the 80's we have used what is called a TN-C-S earthing (Terrestrial Neutral Combined and Separated), also commonly called MEN (Multiple Earthed Neutral). This is the same as the UK PME (protective multiple earthing) and in the USA MGN (multi-grounded neutral). From my limited understanding in the USA since the 60's wiring in new construction required a separate grounding conductor connecting all non-current carrying parts of an electrical installation. Portable appliances with metal cases (eg; audio equipment) use a conductor (in the power cord) that connects them to the distribution system ground. The neutral is also connected to ground at the service entrance panel and no other connections from neutral to ground are allowed This is different to other parts of the world. My guess (and it's only a guess) is that's why ground loop hum is more prolific in the USA.
The question then is how is your residence connected, if it's MGN then its probably an individual components problem. But if it's a single ground to neutral at the service panel then that is the ultimate source of the hum. The former you can fix the single component by removing (isolating) its earthing. The latter you may need to remove (isolate) the earthing from multiple components.
Cheers
Gary
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Post by gus4emo on Jun 27, 2020 23:57:19 GMT -5
Does that really work? Meaning, does it keep hum away? |
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Post by vcautokid on Jun 28, 2020 1:53:18 GMT -5
Hello Gus4emo, it is situational, but more often than not. Yes it does work. We used to keep one in stock when I was doing custom.
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Post by audiobill on Jun 28, 2020 5:33:23 GMT -5
Components marked DC - ... have "wall wart" transformers and are fed by DC power wiring. AC is similarly descriptive. My initial plan is to run all power wiring along the plane of the shelf that the components sit on. Power wires will run "front to back" on the shelf. Any USB or RCA interconnects will be routed by self-adhesive wire hangers from the bottom of the next shelf above the components. Interconnects will run from side to side on the bottom of the shelf above, and at right angles to the incoming power wires. Hopefully, this architecture will minimize induced hum in the interconnects. The reason I put the components in the order that I did was that I hoped that the output buffer amps of the Schiit Loki would provide the best interface into the long interconnects to the power amps. Yes, No, Maybe? Ooooohhhhh!!!! I thought you meant this... Mark Beat me to it!!! |
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Post by thezone on Jun 28, 2020 5:37:26 GMT -5
It’s been 30+ years since I had any ground/earthing hum. Keeping in mind we are on 220/240 volts @ 50 hz here in Oz. Each house has an earthing rod embedded into the ground and since the 80's we have used what is called a TN-C-S earthing (Terrestrial Neutral Combined and Separated), also commonly called MEN (Multiple Earthed Neutral). This is the same as the UK PME (protective multiple earthing) and in the USA MGN (multi-grounded neutral). From my limited understanding in the USA since the 60's wiring in new construction required a separate grounding conductor connecting all non-current carrying parts of an electrical installation. Portable appliances with metal cases (eg; audio equipment) use a conductor (in the power cord) that connects them to the distribution system ground. The neutral is also connected to ground at the service entrance panel and no other connections from neutral to ground are allowed This is different to other parts of the world. My guess (and it's only a guess) is that's why ground loop hum is more prolific in the USA. The question then is how is your residence connected, if it's MGN then its probably an individual components problem. But if it's a single ground to neutral at the service panel then that is the ultimate source of the hum. The former you can fix the single component by removing (isolating) its earthing. The latter you may need to remove (isolate) the earthing from multiple components. Cheers Gary Sorry to Hijack your thread. I live in Australia and I have a low (faint) throbbing hum from my lowest sub, it started when I plugged it into the sub output of a 3 way active cross over. So briefly I have 4 subs, running in mono, with 3 connected to the 3 way outputs and 1 connected to the sub output. If I connect just the 3 to the 3 way outputs there is no hum, its just the sub output that introduces hum. This is a fully balanced unit with a fully balanced line out coming from the XMC-2 but all 4 subs are unbalanced. Redback A5350 |
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Post by Gary Cook on Jun 28, 2020 6:24:34 GMT -5
You need to eliminate the possible causes. I assume you have tried all 4 subs connected to the sub output, do they all hum or only the one? Next test, try a 2 pin power plug (Ie; no earth pin) on the sub on the sub output, That will confirm if the problem is the earthing in the active cross over (or not).
Cheers
Gary
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