b4nt
Addicted to Fun and Learning
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wonder if Topping D90SE has galvanic isolated USB GND to Analog GND , My NAIM DAC have different architect , you can read about it here https://www.naimaudio.com/sites/default/files/products/downloads/files/naim_dac_august_2009.pdf, upload it even here too ,I just wanted to know if it does anything so we can evaluate if that's doable.
These are analog switches to mute the outputs.
Smps can whine, transformers hum....
?The 'whine' should be at the supply switching frequency, hence inaudible. The fact that it's audible is a mystery as to what's causing it.
There are various ways coil whine could exist under various conditions. You can't just think switching frequency is higher than 20khz then it would be inaudible.SMPSes switch/operate at much higher than 20kHz frequencies hence should be inaudible.
As being said, if the coil whine is too loud too tolerate one can just ask for a replacement unit.I was actually considering purchasing the D90SE or the D30/A30 Pro combo, but I have to admit I am a little hesitant considering the "shrug of the shoulders" reaction to various reports of coil whine on these units. Knowing myself, I would not be able to tolerate any audible coil whine coming from any of the devices that reside on my desktop. While I understand what @JohnYang1997 was saying about linear power supplies also having issues with the mains hum and vibrations, I have never experienced 60 Hz hum that is clearly audible and intrusive from any of my desktop DACs and amplifiers. I have seen it with power amplifiers, but they are not designed for desktop use and deal with much higher current.
I would like to know what the official position of Topping is to this type of phenomenon. Is it considered a defect that will warrant a replacement? Is the issue being looked into to ensure that future revisions of these products with SMPS PSUs do not exhibit audible coil whine? I am not desperate to buy right now but would like to know if a fix is coming. It is fine if you are considering this normal as well, since Sony does for their PS5, and they have sold 9 million of them.
The only inconsistency I see here is that this is a flagship device in every other sense of the word - it would seem bizarre to me to have a marvel of engineering in every aspect except this one.
As being said, if the coil whine is too loud too tolerate one can just ask for a replacement unit.
About the hum of transformers, how often do you put their ears close to the unit and listen to the hum? Same here, many only reports coil whine when seeing others report it and listen for themselves. Most wouldn't notice otherwise. Otherwise our customer service would be bombarded with complaints.
Not really that simple. And not often the case shown here. There are different types. Under heavy load. Light load. Coil, transformer, or ceramic capacitors. Subharmonic, skipping mode etc.
Agreed. It is a very difficult and frustrating issue to diagnose and fix. For example, the PS5 coil whine shows itself under heavy load only. My LG OLED is the exact opposite - it only emits coil whine in standby mode at very light load. I’ve had phone chargers that worked silently for months only to develop loud coil whine buzzing all of a sudden. I’ve had PSUs for led lamps that would sing only when the light was partially dimmed. And so on. I do not envy any company that has to troubleshoot this.Not really that simple. And not often the case shown here. There are different types. Under heavy load. Light load. Coil, transformer, or ceramic capacitors. Subharmonic, skipping mode etc.
Using the higher output voltage setting also puts a bit less gain that has to be delivered by your preamp. In some preamps that could result in less output noise.Thank you for your answers! - The thing is that the 5v sounds better through my amp. The 4v seems too quiet. But I was wondering if the 4v measures better or worse than the 5v using RCA's in DAC only mode. (No preamp)
Transformer should have so call vacuum varnish or potting with epoxy which make them noiseless and viberation free , it is very common method , it cost extra . I made a lot of such transformer and they are dead silent.There are various ways coil whine could exist under various conditions. You can't just think switching frequency is higher than 20khz then it would be inaudible.
It is viberation between wire in transformer, they did not make so call vacuum varnishing coating on transformer, it is very common method.