maty
Major Contributor
You know, every day the mains are more and more noisy. Cheap chinese SMPS chargers (or not).... and now cheap dimmers with cheap LED lights.
I wonder if it means anything here because all my gear has SMPS.You know, every day the mains are more and more noisy. Cheap chinese SMPS chargers (or not).... and now cheap dimmers with cheap LED lights.
My 230Vac-main-out to my hifi is isolated from the rest in our house.. i.e. seperat ground ect....You know, every day the mains are more and more noisy. Cheap chinese SMPS chargers (or not).... and now cheap dimmers with cheap LED lights.
Ron Texas, the problem are the cheap SMPS like telephone chargers and others and many other cheap electronic hard that is imported from Asia and that do not meet the strict EU standards in this respect.
Others machines that inject DC at mains is the other problem.
KNielsen, you know! But, remember, electrical grid outside your house is also dirtier every day.
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Yes. That's why I paid my electrician to find a solution, so I didn't have to listen to my refrigerator .. it's a new build house, but just in case!Ron Texas, the problem are the cheap SMPS like telephone chargers and others and many other cheap electronic hard that is imported from Asia and that do not meet the strict EU standards in this respect.
Others machines that inject DC at mains is the other problem.
KNielsen, you know!
Yes. That's why I paid my electrician to find a solution, so I didn't have to listen to my refrigerator.. it's a new build house, but just in case!
Regards
haha good one!KNielssen, you can not be less than Nelson Pass I have seen the RF/EMI inlet filter just now! Btw, thick aluminum walls.
Pass Labs HPA-1 headphone amplifier: http://6moons.com/audioreviews2/passlabs2/3.html
More off topic, sorry.
Refrigeratorrrrrrrrrrrrrrr
I suffer from a terrible electrical mains in my house. After research I managed to drastically reduce the interference, noise and DC, but I still noticed the sound improvement after 8 pm on weeknight. And the weekend too.
Last Friday I changed the old refrigerator and it improved the sound! I suppose the engine had to inject DC. And not little. It could have been chance, for the weekend, so I had to wait until Monday. Verified, the amplifier heats up less (EI transformer side) and sounds better. In the main system, the same.
The main hum injection point I see is the incredibly long ribbon cable to the volume control that goes right by the power supply section.KNielssen, you can not be less than Nelson Pass I have seen the RF/EMI inlet filter just now! Btw, thick aluminum walls.
But, remember, electrical grid outside your house is also dirtier every day.
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EMI/RFI Filter Response (bi-directional, wave tracking): With 50 ohm Rg load: 3db at 5kHz; 26dB at 100kHz; 38dB at 300kHz.
I think that at that time, William Snyder, former design manager at Krell, was involved with Mondial, the company that was responsible for Acurus and Aragon. So, modded or whatever, it was a good 'un to start.I have an old Acurus A250 gathering dust. It was $995 in 1994 or so when I bought it.
Here's someone who measured his: https://insta-stalker.com/post/BtrlP4QBEyP/
It says "modded" but still...
"My rebuild/moded Acurus A250, measurements: Pic1: Full load just before clipping, 2 x 320watts @ 1KHz, THD+N 0.013% with a 6.6ohm load (average load of an 8ohm speaker). 1 channel driven: 349watt. Voltage drop at PSU is only 3V between one channel load or both channels driven, so the transformer is doing it's job pretty good. Maximum THD+N measured were 0.076% @ 10KHz. Also look at the harmonic distortion after 1KHz and up, looks pretty good! Under normal operation the noise floor were close to the limit of our scope.. that's under THD+N 0.01%!! "
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"Pic2: Noise floor; 50Hz hum from the transformer is now completely eliminated with the new starground. Also the 100Hz from the HexFred-bridges is at a level where it really can't be any better then this... we wouldn't be able to hear it anyway."
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"Pic3: A 10KHz square wave: Yellow is the target curve, Green is the amplifiers output. To come closer to target I could go lower on C13/14, but they are 220pf now, it's minimal how much this would change selecting a smaller value, as the transistors has an internal C itself, open/close time... anyway! - this test was also OK."
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I'd rate mine perfectly adequate. Somebody else's picture:
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