TOPIC:

Ultrasonic wrote:

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.

Yes, definitely used the UMIK1 standard 0 deg calibration file.

I did mess about with the frequency scale.

I think there's some issue with your REW settings but irrespective of this your comment that something sounds like it's going to blow up means you should contact support as something isn't right at all.

Getting down close to my SHD I realised there was no way I was going to pick up the difference I could hear close up at 50 cm away so I ended up laying my UMIK-1 directly on top of my SHD. In this position I measured the following two spectra in standby (blue) ad ON (red), where the curves are the Peak curves saved after it had been measuring long enough to have stabilised.

Ultrasonic wrote:

I think there's some issue with your REW settings but irrespective of this your comment that something sounds like it's going to blow up means you should contact support as something isn't right at all.

Getting down close to me SHD I realised there was no way I was going to pick up the difference I could hear close up at 50 cm away so I ended up laying my UMIK-1 directly on top of my SHD. In this position I measured the following two spectra in standby (blue) ad ON (red), where the curves are the Peak curves saved after it had been measuring long enough to have stabilised.

Thank you so much - I will now contact support as yours shows very little difference and it looks like mine is faulty.

I concur with @Ultrasonic that you should contact support, there appears to be a hardware fault. Meanwhile please avoid going into standby mode.

entripy wrote:

I concur with @Ultrasonic that you should contact support, there appears to be a hardware fault. Meanwhile please avoid going into standby mode.

Thank you for everybody's help - I will switch the SHD off at the the mains socket to be safe.

entripy wrote:

I concur with @Ultrasonic that you should contact support, there appears to be a hardware fault. Meanwhile please avoid going into standby mode.

I contacted support as suggested and they have now released a new firmware for the SHD:

I have installed the new firmware (Rev 1.15 / FW 1.25 / 26 Jan 2021) and the buzzing is now negligible in standby mode and is similar to when powered.

Great!!!

However........

I also checked the power consumption before and after:

Old firmware: standby = 1.3w, on = 13w when streaming
New firmware: standby = 10.8w, on = 13w when streaming

So we've removed the problem at the expense of creating over 8 x the power consumption in standby. This doesn't look like a great solution, as the whole point of standby is that it uses a small amount of power. In fact, it now uses more standby power than my power amplifiers, AVR, plasma TV, Sky, TV stick, Xbox x2, LCD TV x 2 all put together.

There is an issue as some people have no problems with buzzing and being on the previous firmware.

I think the power supply board is still faulty as it shouldn't buzz with a low load, it's either the transformer itself or the capacitors (I'd go with the transformer being the root cause).

I've read that v1.073 in the web based Volumio indicates that I have the new version of hardware streamer.

Perhaps the reason why others haven't experienced the buzzing issue in standby is that the latest SHD hasn't been released for a long period (I only received mine in the last 2 weeks).

I wonder what the hardware changes are exactly?

My replacement Power Supply arrived yesterday and was fitted successfully.

The new FW was launched today:

New FW = 1.27.

Power 'standby' = 1.6w, Power 'on' = 15w [Test passed]

Buzzing = no buzzing apparent from SHD unit [Test passed]

Power on, then standby, back on. Ethernet connects - tried this a couple of times [Test passed]

Well done MiniDSP

I am a new SHD user and one of the first things I noticed was system hum when the SHD goes to standby OR when I go into mute.
In both cases I hear a relay switch so I suspect that the analog output is disconnected, which means the inputs to my power amps are effectively floating and picking up hum. A workaround is to leave the SHD on and lower the volume.
If it is a relay disconnecting the outputs a much better solution would be for the relay to isolate from the SHD analog output internally and short the output socket pins to ground.

Regards
13DoW

13DoW wrote:

I am a new SHD user and one of the first things I noticed was system hum when the SHD goes to standby OR when I go into mute.
In both cases I hear a relay switch so I suspect that the analog output is disconnected, which means the inputs to my power amps are effectively floating and picking up hum. A workaround is to leave the SHD on and lower the volume.
If it is a relay disconnecting the outputs a much better solution would be for the relay to isolate from the SHD analog output internally and short the output socket pins to ground.

Regards
13DoW

Are you on the latest firmware?

I had this issue. The buzz was very loud when in standby connected to my Naim Nait amplifier.
I could never use the standby feature.
For the longest time I thought it was just the Naims grounding.
Eventually I decided to look closer into it and turned out to be that the mains cable Ground Pin was not connected on the wall socket side.
I swapped the cable out for one that was and it solved the issue.
Dead silent when it in stanby (and changing presets etc).

Worth a check.

+1 with previous post on properly shielded RCA cable.
Had this same issue with my SHD Power + SVS SB 100 PRO, and the humming scales with the subwoofer gain.
It is just because SHD floats the output when in standby/mute, if you try to just have the RCA cable disconnected from the SHD, it will still make the same hum.
For me the BJC LC-1 cable worked, completely no hum even when the sub gain is at maximum.