• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Hum and hiss after connecting miniDSP SHD

Smidge

Member
Joined
Mar 8, 2021
Messages
53
Likes
21
Location
Netherlands
Hi all,

After adding the SHD to my audio chain there is audible hum and hiss coming through the speakers. I added an audio file (no pun intended) so you can hear for yourself: Link to audio


Previously I had another DAC without grounding that didn’t seem to add noticeable noise through my speakers. I’m aware of the possibility of ground loops and read many threads on ASR and did the following to analyze and verify:

I unplugged everything and started connecting devices one by one to locate where the noise is introduced. The outcome is that by connecting the SHD via RCA to my amp the noise is introduced. Even without any cables connected to the inputs of the SHD. The noice is only audible when the SHD input is selected on my amp. I also connected the SHD directly to the power amp - bypassing the pre-amp of my integrated amp - and again the same hum and hiss.

To try to mitigate possible ground loop issues I tried:
- connecting the SHD and amp to the same wall power outlet
- connecting all audio devices to one single power strip

This didn’t seem to make any difference.

Unfortunately my amp doesn’t have balanced inputs. I’m now at the point where I’m considering to sell my integrated amp and buy a power amp with balanced inputs, but that isn’t a guarantee the issues will disappear. So before going this path, I want to verify if the issues are indeed introduced via the grounding of the SHD. All my wall outlets are grounded, but I was thinking to connect the SHD to a non-grounded power strip. But I’m not sure this is a responsible thing to do from a safety point of view.

Everything above is what I thought of and did so far but I’m a newbie on these things and I might be overlooking other things.

Any thoughts?
 

abdo123

Master Contributor
Forum Donor
Joined
Nov 15, 2020
Messages
7,424
Likes
7,940
Location
Brussels, Belgium
Btw, having a cable connected is enough to complete a circuit and cause ground loops (Like a USB cable). There doesn’t have to be data going through it.
 

Hayabusa

Addicted to Fun and Learning
Joined
Oct 12, 2019
Messages
787
Likes
519
Location
Abu Dhabi
" connecting the SHD and amp to the same wall power outlet "

Also try to swap the polarity of power plug for the SHD...
 
OP
S

Smidge

Member
Joined
Mar 8, 2021
Messages
53
Likes
21
Location
Netherlands
" connecting the SHD and amp to the same wall power outlet "

Also try to swap the polarity of power plug for the SHD...
I just tried all different polarity options with the amp and SHD but the outcome is all the same unfortunately .
 
OP
S

Smidge

Member
Joined
Mar 8, 2021
Messages
53
Likes
21
Location
Netherlands
Hi all,

After adding the SHD to my audio chain there is audible hum and hiss coming through the speakers. I added an audio file (no pun intended) so you can hear for yourself: Link to audio


Previously I had another DAC without grounding that didn’t seem to add noticeable noise through my speakers. I’m aware of the possibility of ground loops and read many threads on ASR and did the following to analyze and verify:

I unplugged everything and started connecting devices one by one to locate where the noise is introduced. The outcome is that by connecting the SHD via RCA to my amp the noise is introduced. Even without any cables connected to the inputs of the SHD. The noice is only audible when the SHD input is selected on my amp. I also connected the SHD directly to the power amp - bypassing the pre-amp of my integrated amp - and again the same hum and hiss.

To try to mitigate possible ground loop issues I tried:
- connecting the SHD and amp to the same wall power outlet
- connecting all audio devices to one single power strip

This didn’t seem to make any difference.

Unfortunately my amp doesn’t have balanced inputs. I’m now at the point where I’m considering to sell my integrated amp and buy a power amp with balanced inputs, but that isn’t a guarantee the issues will disappear. So before going this path, I want to verify if the issues are indeed introduced via the grounding of the SHD. All my wall outlets are grounded, but I was thinking to connect the SHD to a non-grounded power strip. But I’m not sure this is a responsible thing to do from a safety point of view.

Everything above is what I thought of and did so far but I’m a newbie on these things and I might be overlooking other things.

Any thoughts?
The noise gets louder when I turn up the volume knob on the amp.
 

suttondesign

Addicted to Fun and Learning
Forum Donor
Joined
Feb 4, 2019
Messages
732
Likes
1,310
Location
Bellingham, WA
Hi all,

After adding the SHD to my audio chain there is audible hum and hiss coming through the speakers. I added an audio file (no pun intended) so you can hear for yourself: Link to audio
Everything above is what I thought of and did so far but I’m a newbie on these things and I might be overlooking other things.

Any thoughts?

Yup. I had to switch to balanced connections on a MiniDSP 4x10HD. That completely solved the problem. Another forum member said better unbalanced cables -- shielded ones -- would solve the problem, but I didn't try that.
 
OP
S

Smidge

Member
Joined
Mar 8, 2021
Messages
53
Likes
21
Location
Netherlands
Yup. I had to switch to balanced connections on a MiniDSP 4x10HD. That completely solved the problem. Another forum member said better unbalanced cables -- shielded ones -- would solve the problem, but I didn't try that.
Yeah, since I already have shielded RCA cables going balanced seems the way forward
 
OP
S

Smidge

Member
Joined
Mar 8, 2021
Messages
53
Likes
21
Location
Netherlands
Are there any miniDSP SHD owners here that could check the following:

I noticed the SHD itself produces a soft hissing noice when you put your ear very close to the device. And maybe my ears are playing tricks with me, but the hissing noise from my speakers sounds very similar. This makes me think the miniDSP itself might be the culprit.

Do you notice this too? Or could I have a faulty device? I’m about to contact miniDSP about this but it would help to know if this is a common issue or not.

Although balanced connections might take away the symptom from my speakers, I would expect the SHD to not introduce any audible artifacts.
 
OP
S

Smidge

Member
Joined
Mar 8, 2021
Messages
53
Likes
21
Location
Netherlands
Are there any miniDSP SHD owners here that could check the following:

I noticed the SHD itself produces a soft hissing noice when you put your ear very close to the device. And maybe my ears are playing tricks with me, but the hissing noise from my speakers sounds very similar. This makes me think the miniDSP itself might be the culprit.

Do you notice this too? Or could I have a faulty device? I’m about to contact miniDSP about this but it would help to know if this is a common issue or not.

Although balanced connections might take away the symptom from my speakers, I would expect the SHD to not introduce any audible artifacts.
I have put a wire between the ground connecter of my amp and a case screw of my SHD and the noise remains. Maybe it isn’t a ground loop afterall?
 

Glasvegas

Active Member
Forum Donor
Joined
Apr 13, 2020
Messages
293
Likes
203
Are there any miniDSP SHD owners here that could check the following:

I noticed the SHD itself produces a soft hissing noice when you put your ear very close to the device. And maybe my ears are playing tricks with me, but the hissing noise from my speakers sounds very similar. This makes me think the miniDSP itself might be the culprit.

Do you notice this too? Or could I have a faulty device? I’m about to contact miniDSP about this but it would help to know if this is a common issue or not.

Although balanced connections might take away the symptom from my speakers, I would expect the SHD to not introduce any audible artifacts.

Just tried it. No sound whatsoever from the SHD or speakers.

You should raise a support ticket. They usually respond very quickly allowing for time difference.
 
OP
S

Smidge

Member
Joined
Mar 8, 2021
Messages
53
Likes
21
Location
Netherlands
Just tried it. No sound whatsoever from the SHD or speakers.

You should raise a support ticket. They usually respond very quickly allowing for time difference.
Thanks for letting me know. I just submitted a support ticket.
 

Glasvegas

Active Member
Forum Donor
Joined
Apr 13, 2020
Messages
293
Likes
203
Thanks for letting me know. I just submitted a support ticket.

Let us know how is goes. They have a reputation for good customer support.
 

q149

New Member
Joined
Apr 13, 2021
Messages
3
Likes
0
I had exactly the same issue as you had with the hiss. I recently purchased an SHD that seemed to be originating from a december 2020 production batch that had this problem. I've got it replaced with a brand new one from the same batch with the exact same problem.

Reseller said they were in contact with minidsp to solve the problem but there didn't seem to be any progress recently, so I cancelled the purchase and got my money back. Seem to be some serious quality control issues at minidsp though.
 
OP
S

Smidge

Member
Joined
Mar 8, 2021
Messages
53
Likes
21
Location
Netherlands
I had exactly the same issue as you had with the hiss. I recently purchased an SHD that seemed to be originating from a december 2020 production batch that had this problem. I've got it replaced with a brand new one from the same batch with the exact same problem.

Reseller said they were in contact with minidsp to solve the problem but there didn't seem to be any progress recently, so I cancelled the purchase and got my money back. Seem to be some serious quality control issues at minidsp though.
That sounds alarming. I’m still waiting for a reply from miniDSP support.
 

Glasvegas

Active Member
Forum Donor
Joined
Apr 13, 2020
Messages
293
Likes
203
That sounds alarming. I’m still waiting for a reply from miniDSP support.

Is the hum/hiss only audible when the unit is in Standby? If so, this is a known problem. Seems to be an issue with the power supply.

https://www.minidsp.com/forum/shd-series/18460-buzzing-hum-from-the-shd-when-in-standby?limitstart=0

Surprised you haven’t heard back from miniDSP support. I bought my unit in January 2021. I didn’t have this problem, but they sent me a new power supply “just in case”.
 
Top Bottom