In my case the major offender turned out to be my kitchen under-cabinet lights. Even though they are on a different circuit, turning these off reduced the noise on my dedicated audio line from 200 to 35mVp-p.
Measuring power line noise with the TriField EM100, and the impressive effect of Shyunyata products
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Interesting. I've sent an inquiry to Pi Audio. I take it this plugs into a different circuit in the house and somehow filters the RF noise in parallel with the audio system?
Vlad graciously lent me his TriField.
Interesting numbers:
In my music room I have an outlet in the back with 50, one next to my main outlet in the front with 75, but unfortunately the outlet for the system itself measures 90. It goes up to 110 with dimmable light switch in the kitchen on! So definitely worth turning it off. Yet there is one hooray, which is that the reading of 90 (with kitchen light switch off) stays the same if the 14,000 Btu air conditioning unit in the second floor is off or on!
Now comes the weird thing. The measurement of 90 was on my wall outlet for the system. Measuring after thick extension cord and thick power splitter cord (i.e., what the system sees), the noise drops down to 35-40! How do you explain this?
Great:
The outlet of my TrippLite Isolation transformers (for digital front end only) gives reading of 11and 10, respectively, for transformer 1 and 2.
Interesting numbers:
In my music room I have an outlet in the back with 50, one next to my main outlet in the front with 75, but unfortunately the outlet for the system itself measures 90. It goes up to 110 with dimmable light switch in the kitchen on! So definitely worth turning it off. Yet there is one hooray, which is that the reading of 90 (with kitchen light switch off) stays the same if the 14,000 Btu air conditioning unit in the second floor is off or on!
Now comes the weird thing. The measurement of 90 was on my wall outlet for the system. Measuring after thick extension cord and thick power splitter cord (i.e., what the system sees), the noise drops down to 35-40! How do you explain this?
Great:
The outlet of my TrippLite Isolation transformers (for digital front end only) gives reading of 11and 10, respectively, for transformer 1 and 2.
Have we been able to relate meter readings to sq? I have not yet metered mine so this is a bit of a rhetorical question...
Al, did you do any listening and see if you could actually correlate what you heard with what the measurements tell you? It would be very interesting to see what threshold measurement from this device is audible. You, Tasos, and Vlad have not said anything about audible results correlated with measurements. I’m just curious.
I don’t know how to explain the noise figure drop after your extension cord and splitter, but I have heard of improved sonic results with some power cords that are thinner gauge and longer length then one would expect when comparing with shorter thicker power cords. My thinner gauge in wall wires sound better than the thicker gauge audiophile wires that I used to have in my wall.
EDIT: I see I was posting at the same time that Solypsa was asking the same question.
I can definitely correlate lower noise with better sound. Tasos has amply documented his experience with the Denali’s effect on SQ in a separate thread, and my experience has been similar to his.
The latest improvement - turning off my noisy under-cabinet lights - is also noticeable, even though the system is all already connected to the Denali via Sigma NR PCs. With this last change, there’s was a small but palpable increase in the sense of ease, transparency and lack of grain. And that’s from an already pretty good baseline.
I guess every little bit helps.
Vlad, I was not asking about the effect of the Denali and whether or not you prefer it. I was asking specifically if you could hear the differences in your three respective systems between the measured noise level readings as reported in the photos. When one of you reports the noise goes down as indicated on the device when you turn the dimmer off, how does the system sound different when the dimmer is off compared to when it is on? How much noise is require for you to hear it? What do the numbers actually mean in terms of audible effect through your systems.
Al has the extension cord and splitter. It lowers the noise out of that wall outlet. How does it sound different? Is it audible? Has he actually done the listening comparisons? Don't we all want to know how the measurements correspond to what we are hearing? Is that an unreasonable request? That is all I'm trying to understand here. We all agree that noise is unwanted. Do you all hear differences when you turn off one dimmer in the house? If you have already reported on correlated listening to measured levels, please point me back to the right posts. I am just trying to understand what the measurements mean. Solypsa seems to be interested in knowing also. Thank you.
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I just ordered one of the EM100's to test the noise level of my electricity. I will test that against my 512 Engineering Symmetrical Power Supply. Larry
I'm no expert, but from I've heard from people that are, the readings from this Alpha Labs/ Trifield meter don't mean much when it comes to sound quality. Particularly when you're talking about tiny differences like 90 mv to 50 mv. There is no way you're going to hear that!
Yes I did, Thank you Vlad. It is still not clear to me what the measured noise levels were for you to hear the difference. I'm trying to figure out what the numbers mean.
Also, it is going through the Denali both times. If the Denali lowers noise, and you still hear the difference between the light being on and off, then I am trying to get a sense of what the Denali is doing. I guess it is still allowing some noise to come through but does lower the level as confirmed my the measuring device.
I am more interested in what Al hears in his system without the Denali as he compares measured noise levels with what he hears and specifically the audible difference the extension cord makes. He can see different noise measurements with the meter, but I am curious about audible differences with and without the extension when the lights are turned on and off and what measured noise level can be correlated to what he hears.
For those of us who don't have the Denali to improve the sound and lower noise, I'm trying to see if going around my house turning lights on and off can be heard. So far no, but I don't have the measuring device to know if the noise at the system is going down with the lights off. Thank you.
I don’t doubt that the meter is not particularly accurate, but I think that does not preclude its being useful in showing relative differences, I.e., the noise becoming lower or higher after a particular change to the system.
As to the audibility, you may be right. But personally I’m wary of overgeneralizing here, because this probably depends on the particulars of the equipment (how vulnerable or immune to AC noise your components happen to be), the resolution of the system (a highly resolving system may be more able to reveal a lower input noise level), as well as one’s hearing etc.
But I agree that my own correlation of the turning off of the under-cabinet lights with better sound is just anecdotal evidence, but in that regard, it’s no different from every other post in this forum
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Sounds like the cords absorb noise, or they may be shunting it to ground with a capacitor; more measurements would be required between hot and ground. There may also be a very small possibility of high resistance in the wires, and that can also be measured.
Based on our private conversations, you've gone back and forth using the TrippLite... is that correct? And the latest I think I recall is that you put it back on, long before the now low-noise measurements and in spite of them. Did you still hear improvement with the TrippLite and what are your thoughts now after these measurements? Do you hear any improvements with and without right now?
Yes, I've gone back and forth. I now only use the TrippLite isolation transformers for the digital front end (DAC on one transformer, CD transport/re-clocker on the other), because having the preamp on one of them robs the music of energy. I had planned at some point to again perform a comparison with/without, but I will now wait until I have fixed my in-wall wiring. I plan to have that done relatively soon. Who knows, maybe trying a Denali v2 is not out of the question after that (in that case, the TrippLites would be out).
If you are using an isolation transformer, the rule of thumb is do not exceed 50% of the rating of the transformer. Otherwise it will produce significant distortion.
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