SMSL C200 Humming on standby

[AudioBozo]

Hi Guys!

I purchased an SMSL C200 to pair with my HD 600's as my entry pairing and I am loving it! In operation the unit is perfect and I have nothing but praise however I have run into an 'issue' when the unit is in its standby state.

One of the reasons I picked up this unit is its low power consumption especially in standby mode however there is a low electrical hum in this state around where the power lead connects to the unit which I am unable to ignore in quiet conditions, i.e winding down for the evening. Doing a bit of research on technical jargon it seems that when the unit is operating slower the vibration frequency of the coils reaches hearing levels, I tested a new power cord and moving the device location to an isolated/dedicated socket and I get the same so I can rule that out. Is this just a trade off of cheaper great sounding devices? The internal PSU may also be a contributing factor in this instance. Given its connected as part of a desktop setup I am currently resorting to switching everything off in the evening to avoid the hum which kind of defeats the point of buying it for its efficient standby mode. Is there anyway to alleviate this? Or in the very least tips to avoid it in future from a design perspective? I may just get used to it but currently its grating, I am within my return window but I otherwise really like the unit.

Any insight from other owners would be beneficial to confirm whether its at least 'normal' as I have been reviewing the product reviews for it and haven't seen much mention, whether this is because its considered expected or because my unit is unique in this regard I am unsure. I suppose an option is to leave it on constantly instead but this was not my intention when buying. I am in the UK if that makes a difference power wise.

Any insight is appreciated,

 

[Reddoc]

It's probably just bored. I do the same thing.

 

[TimW]

I have had this issue with power amplifiers that had toroidal transformers. The solution was an Emotiva CMX2 which is a DC offset eliminator. From what I read at the time, DC offset can exist on your AC mains and cause hum with some transformers. I believe there are a few products on the market that can solve this but I can't recommend any others.

 

[AnalogSteph]

I'm pretty sure the C200 has a SMPS though. It's probably in burst mode at this point. The exact amplitude may be subject to sample variation depending on transformer luck of the draw as well.

 

[AudioBozo]

I'm pretty sure the C200 has a SMPS though. It's probably in burst mode at this point. The exact amplitude may be subject to sample variation depending on transformer luck of the draw as well.

Believe you are correct on the SMPS. Reading a few bits on SMPS units and the 'burst mode' you mention I am 99% sure this is what I am hearing rather than anything else. Although this doesn't indicate a technical issue with the device, I wonder where mine would sit on the scale of 'normal' to 'bad' in regards to noise. In the quiet I can quite easily hear it in the opposite corner of my room, I would roll the dice on another unit just not sure if its worth it if others experience the same.

Options are:
1. Carry on as normal switching it off when I would otherwise use standby.
2. Leave it on all the time
3. Roll the dice on a replacement unit, since it does not seem 'faulty' in a technical sense however I am not sure if this would be the most ethical course.

Clearly I care about this more than the average person so I was wondering how I could best avoid this in future, just stay away from SMPS units in general? One of the main pros of SMPS units seems to be their low power consumption, so it makes sense that this type correlated with my purchasing decision.

Thanks!

Edit: I am now looking at purchasing a switched extension lead, so I can turn off the amp individually. There are power cable extenders with toggle switches on Amazon/Aliexpress however I am skeptical of them looking at reviews of the toggles breaking/not working, a switched extension lead sounds like the better option in my case.