How do I solve this high pitch whining sound?

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jtaytay

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I'm flummoxed by a noise when connecting a different dac to my system. Set up is: Tisbury Preamp to Winsome Labs T amp (vol at max so it's used like power amp) to some Leema Xero speakers. I was using a Khadas toneboard as a dac and sounded great with no issues. Then swapped it out for SMSL Sanskrit 10th Anniv dac. Once introduced, a high pitched whine appeared through the speakers. I've tried various things to identify the cause so far:

1. Removed pre amp and used Winsome Labs with its own volume control - still whine
2. Changed phono cables and USB cable - still whine
3. Changed SMSL dac for another I have which works perfectly in another system - still whine with different dac.
4. Put Khadas back in and whine disappears
5. If I reduce the maxed out volume on the Winsome Labs Mouse, the whine reduces, but reducing the Tisbury pre volume does not reduce whine
6. Strangely, if i put downward pressure on the Winsome Labs mouse top (quite flimsy top), the whine reduces (but doesn't go away) and if I play with the phonos going into the back of it, the whine changes and reduces in volume.

Can someone help with an explanation and solution? I can't get my head round why both SMSL dacs cause a whine through my speakers which is influenced by putting pressure on the top of my case, yet I've never had a problem like this with any other set up (been quite a few) that I've used the Winsome Labs mouse amp in. Why would both SMSL dacs cause a similar issue through this set up? Hmmmm?
 
Are the DAC's galvanically isolated? If not, then that could be the issue. My son had that issue with a DAC and the PS Audio M700's. He borrowed an Intona that provides Galvanic Isolation and the high pitched whine went away. He did not have that issue with his Parasound A21 amp.

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are you sure it's not your mother in-law locked in the closet ...........
 
I don't know whether the DACs are galvanically isolated - had a quick search and couldn't see that. I've not had problems with them in various other set ups, just this one.
 
Alkyogre said:
Did you attach the line and neutral side of your power cable on the right side in your equipment?
Click to expand...

I'm not sure what this means. The dac draws power from a USB connection. In fact, there are two usb sockets. I use it as a usb dac connected to my pc so the second usb connection is redundant and not used. Does this affect what you think might be the problem? As mentioned, the whining sound doesn't happen with this dac in other setups.
 
jtaytay said:
I don't know whether the DACs are galvanically isolated - had a quick search and couldn't see that. I've not had problems with them in various other set ups, just this one.
Click to expand...

Many inexpensive DAC's are not galvanically isolated. If I was a betting man I would put all my money that that is the problem. It sounds just like my son's issue with an Emotiva Big Ego that he was using until he upgraded to a Cary integrated with built in DAC.
 
Just an update - I've realised that the Winsome Labs Mouse amp does produce a little noise when at maximum volume. I've never been aware till I used it with a preamp since the volume has never gone over midway. And, for some reason, when I connect the SMSL dac the noise increases. The increase disappears when I turn the dac off or change the selected input on the dac to one not receiving a signal. I've no idea why this happens (galvanic isolation as suggested????) and why shifting the phono cables or pushing down on the top of the amp changes the loudness and pitch of the sound, given this doesn't happen with a different dac and different phonos, nor with the SMSL dac in other set ups etc as explained. I've dropped the amp manufacturer a line to see if they have ideas. The manufacturers website does say to max out the volume to bypass the preamp if you want to use it as a power amp. I presumed from that they are suggesting there should be no audible noise introduced even at maximum volume. I am wondering if the phono sockets at the back of the amp are getting a bit ropey - moving the phono in the socket can introduce some crackle and noise and change the whining sound. Again, in other set ups, the amp sounds absolutely fine as does the dac. Maybe just one of those matches not made in heaven then. Pity, as, ignoring the noise issue, the actual sound quality is very good. Thanks for the help and suggestions. I appreciate that this is one of those areas where there may be no easy answer but some persistence and trouble shooting might drill down to where the problem is and its solution. Or I'll give up, use a different dac and listen to some music!
 
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Some of the better power conditioners/distributors (e.g., Shunyata) have features to eliminate noise emanating from components in your system and traveling to other components via their power cords. Maybe something to look into if you haven't already.
 
Same question, your dac was feeded by the USB, but your amp has a normal power cable. Did you place the cable the right way in your amp with the line and neutral on the right side?

Second what you can try, hook your power cable on another group with a long cable, is it still there?

Third, disconnect everthing one by one, with high amp volume. Is there another piece of equipment disturbing?
 
Hi Alkyogre, I'm still not sure what you mean regarding the live and neutral on the right side. The power cable can only go in to the amp one way so there is no way to swap live and neutral. I tried various things to isolate the problem in my system - changed amp, dac, cables etc. As mentioned, the problem relates to the amp, and seems to be worsened by the SMSL dac when connected to a live output. I may have misunderstood your suggestions though.
 
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