TOPIC:

I've just received my new miniDSP SHD and first impressions are very good.

However, I did notice that it produce a pretty loud buzzing/hum when in standby.

Any ideas

sounds like a classic ground-loop. can you describe all the connections in your set-up? signal and power. and is it connected to a safety earth wall socket?

The SHD is connected to:

• 230v mains in UK
• ethernet for streaming connection to router
• Analogue out 1 and 2 via RCA to analogue CD input of Arcam SA30.

The Arcam SA30 is also connected to 230v mains UK and the stereo speaker outs are connected to some passive speakers.

Note: It is worth knowing that I cannot hear any buzz or hum from the SHD when the unit is powered on from being in standby.

Standby mode???

Just leave it on all the time.
It's always a good practice to switch off power amplifiers first and switch them on last.

Dave.

dreite wrote:

Standby mode???

Just leave it on all the time.
It's always a good practice to switch off power amplifiers first and switch them on last.

Dave.

I use the miniDSP to put it into standby when not in use to save electricity.

I follow your method for the Arcam which is in effect being used for its power amplification.

This doesn't fix the issue though as the buzzing/hum loudness of the miniDSPSHD in standby is pretty alarming.

Do others have the same issue or is mine just faulty?

dbwinter wrote:

I use the miniDSP to put it into standby when not in use to save electricity.

Any saving in the case of the SHD is trivial or even non-existent from what I can tell (based on a real-time electricity use monitor). I'm talking less than 1 W here. It's not clear what if anything is actually powered off when placing the unit in standby. Voumio is still running for example. However, I do put my SHD in standby overnight but always after switching my power amp off.

I've never put my SHD in standby before switching my power amp off so I can't comment on this but I did find that muting the output could cause an audible hum when I was using an RCA connection to my power amp (and no inline attenuators). My guess was that muting changed the grounding, and possibly the same happens putting the unit in standby.

I'm a bit unclear whether you're talking about buzzing/hum from your speakers, or from the SHD itself though?

Out of curiosity, why are you using an SHD with an Arcam SA30? I'm just asking as it looks like the Arcam has Dirac live functionality so it seems an unlikely pairing.

My SHD only draws about 9 watts when powered up.

Regardless, when you power down some audio equipment connected cabling can become unterminated and thus can start acting as antennas.
I suspect that's what you're experiencing here. Your SHD is probably working normally.
Although we could conclude that if the "standby" mode is not maintaining a proper termination on cabling, then it's not working very well.

Ultrasonic, for reference, please check your SHD power consumption when in the standby mode.

Dave.

Ultrasonic wrote:

dbwinter wrote:

I use the miniDSP to put it into standby when not in use to save electricity.

I'm a bit unclear whether you're talking about buzzing/hum from your speakers, or from the SHD itself though?

From the SHD

Ultrasonic wrote:

dbwinter wrote:

I use the miniDSP to put it into standby when not in use to save electricity.

Out of curiosity, why are you using an SHD with an Arcam SA30? I'm just asking as it looks like the Arcam has Dirac live functionality so it seems an unlikely pairing.

You are so right, it really is the most unlikely pairing!

Unfortunately (and as a long term Arcam fan), the Arcam SA30 will be returned back to the supplier (once we are out of lockdown in the UK) as it suffers from terrible distortion on its current firmware - when it is good, it really is fantastic, when its bad, it's at the other end of the pile.

Life is too short and hence, I'm now on the miniDSP forums. Apart from the SHD not working with my MacBook on OS 11 (Big Sur) and this strange buzzing issue on standby, the miniDSP SHD seems to work rather well and will soon be seeking an active speaker/power amplifier to accompany it.

dbwinter wrote:

From the SHD

OK, I've just tested mine and it does make slightly more noise when in standby but I have to be really close to the unit to hear it. I do genuinely think putting it into standby does so little that I wouldn't overly stress about just choosing not to.

As you've ended up with an SHD somewhat not out of first choice I'll mention that one thing you've gained is the functionality to properly integrate a subwoofer, which is the key reason I own one and something I'd encourage you to explore long term if it's not already in your plans.

I'm in the UK too by the way.

Ultrasonic wrote:

dbwinter wrote:

From the SHD

As you've ended up with an SHD somewhat not out of first choice I'll mention that one thing you've gained is the functionality to properly integrate a subwoofer, which is the key reason I own one and something I'd encourage you to explore long term if it's not already in your plans.

I'm in the UK too by the way.

I got the SA30 for my birthday, so disappointment is an understatement.

I had heard of miniDSP but what sparked my interest was the objective measurement of the SHD on audiosciencereview.

I am currently exploring options for the power amp stage but ruled out the power amp version of the SHD based on the above measurement website.

Potentially, I may use a subwoofer (use a Rel Stentor 2 in my main set up) in the future, so this is useful to know.

Ultrasonic wrote:

dbwinter wrote:

From the SHD

OK, I've just tested mine and it does make slightly more noise when in standby but I have to be really close to the unit to hear it. I do genuinely think putting it into standby does so little that I wouldn't overly stress about just choosing not to.

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.

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.

dbwinter wrote:

Potentially, I may use a subwoofer (use a Rel Stentor 2 in my main set up) in the future, so this is useful to know.

Do at least give it a try sometime. Here's something from another forum on reasons to do so:

www.hifiwigwam.com/forum/topic/145973-subwoofers-for-music/

Absolutely....give it a try....
Mine is at 70Hz crossovered and inject a solid base to mains.....

Power amps should be turned off before preamps are so you won't hear anything then.
SHD is a preamp.