TOPIC:

entripy wrote:

Power amps should be turned off before preamps are

Agreed but the noise here is coming from the SHD itself, not the speakers.

Ultrasonic wrote:

dbwinter wrote:

I was just surprised by how loud it is in standby, it does slightly worry me or give me a great deal of confidence - although, the SHD in itself when powered on, is at least equal to the SA30 for its streaming/Dirac/preamp abilities, which is obviously a huge positive.

I think this very much depends how loud yours is. You could measure this using your UMIK-1 and REW actually, using the RTA. You could do a measurement at say 50 cm with it on and then in standby to show what the difference is. I could check mine for comparison if you'd like.

I will try this tomorrow evening - the buzz/hum when the SHD is on is negligible. It is only when on standby that it becomes noticeable.

Odd. I never standby mine so haven't noticed but am confused what could cause that.

Ultrasonic wrote:

entripy wrote:

Power amps should be turned off before preamps are

Agreed but the noise here is coming from the SHD itself, not the speakers.

'Would have been nice if he mentioned that to begin with, for crying out loud.
A waste of everybody's time.
Unsubscribed.

Dave.

dreite wrote:

'Would have been nice if he mentioned that to begin with, for crying out loud.

To be fair they did, including the thread title, it's just that everyone's first thought (including mine) was to incorrectly think something else was meant.

Well acoustic and electrical noise both come from the SHD, I managed to skim the whole thread without figuring out it was acoustic. And I'm still wondering how something with a switching power supply hums, they normally whistle since 50/60Hz is so quickly converted to higher frequencies. To an EE hum means 50/60Hz and a buzz has harmonics thereof, neither should really be likely from an SHD.

Does anyone else using standby suffer acoustic hum/buzz?

entripy wrote:

Does anyone else using standby suffer acoustic hum/buzz?

I posted above to say that I do get slightly more noise from mine in standby bat it's much higher frequency than 50 Hz. I partly suggested the OP measure what was going on with REW's RTA to see what type of noise he was experiencing.

Could you try putting your SHD in standby @entripy and seeing what happens for you? The difference I hear is quiet and only noticeable close to the unit, which is why I'd never noticed it (and certainly isn't a problem in my case).

Out of curiosity I had another go at looking for a power usage difference in standby this morning. I can only do this using a device that indicates the total electricity usage for my property at a point in time, which updates every few seconds.

With SHD on a display on this total usage showed 55 W. Once the display went off this dropped to 54 W, and putting it into standby dropped this further to 53 W. Note these total figures include power used by other devices around the house but the differences were repeatable and give an idea of the change in power consumption of the SHD. No decimal places are shown on the display but there is of the order of 1 W saved by going into standby. So it does something but I wouldn't lose too much sleep over someone choosing not to use it.

I won't put either of mine into standby because they go straight into power amps that are permanently on.

As I recall standby was a rather late firmware addition and was caveated as being somewhat limited because it wasn't an initial design consideration. I've never been too clear on just what gets turned off but at 1W (or maybe 2W) saved, not very much I guess.

I find turning the display off useful but standby is of no use to me.

entripy wrote:

I won't put either of mine into standby because they go straight into power amps that are permanently on.

As I recall standby was a rather late firmware addition and was caveated as being somewhat limited because it wasn't an initial design consideration. I've never been too clear on just what gets turned off but at 1W (or maybe 2W) saved, not very much I guess.

I find turning the display off useful but standby is of no use to me.

I'd encourage you to make the change to switching your power amps off when not in use to save electricity.

You're right about the standby function being introduced by a firmware update rather than it being an original feature, and going by my quick test numbers not one that makes a huge difference. Small changes made by everyone do add up though so it's not completely pointless.

My power amps are designed to be left permanently powered on. The output stage requires the sealed box to be self heated for optimal biasing. The warm up time required after turning them off makes power cycling impractical. Compared to my heating, air conditioning and computers (over 50 devices on my subnets) the power amps are an insignificant part of my power consumption. Yes I have done the maths :/

Ultrasonic wrote:

dbwinter wrote:

I was just surprised by how loud it is in standby, it does slightly worry me or give me a great deal of confidence - although, the SHD in itself when powered on, is at least equal to the SA30 for its streaming/Dirac/preamp abilities, which is obviously a huge positive.

I think this very much depends how loud yours is. You could measure this using your UMIK-1 and REW actually, using the RTA. You could do a measurement at say 50 cm with it on and then in standby to show what the difference is. I could check mine for comparison if you'd like.

I tried to capture it using REW, with one of the plots showing background noise. I'm going with the switched mode power supply. I must admit it sounds a lot more than 15dB above the background noise!!

^Where was the microphone positioned for the above measurement and what settings did you use? Are the curves an average or a peak? I'm asking so I can measure the same to compare. I suspect I'm going to find mine is a lot quieter...

50 cm away, pointing slightly above the top of the SHD, 1/48 smoothing.

I didn't average the responses.

It sounds like the SHD power supply or whatever is making the noise is going to blow up!

dbwinter wrote:

50 cm away, 1/48 smoothing.

I didn't average the responses.

It sounds like the SHD power supply or whatever is making the noise is going to blow up!

I'll have a quick measure but your graph looks odd compared to what I know my own background measurements look like with a UMIK-1. Did you have the calibration file applied? I'm not just talking about because you've used a linear frequency scale for some reason.