mhdt Orchid - hum noise

Hi all

I have been having issues with my Orchid (again) but this time is more frustrating. I hear a very strong hum noise when the dac is turned on and it doesn't go away, even when playing music, even if the music masks it a little. The noise is very evident and I'm wondering if not working properly and I'm afraid the dac will stop working all together any time. I have changed power cables, connection cables, tried 3 different tubes and the issue is there with zero improvement. The hum gets louder as I turn up the volume.

Did any of you ever experience this issue? 

any suggestion on how to solve it is welcome.

thank you in advance.




There are products you can buy which claim to eliminate ground loops; that cause hum to occur; such as the Ebtech Hum X. More likely than not, if this is sporadic or new behavior altogether from the Orchid DAC, it could mean a bad power transformer in the DAC. So maybe that would have to be replaced.

Are you using a power conditioner? Although it is true that all audio gear has power filtering modules and power transformers that clean up the AC and feed the parts/mainboard regulated DC, a good power conditioner can take the strain off internal power transformers for good...feeding each one clean electricity. This means audio components can run at optimal temperatures and may last longer.

Check out my profile. What I’m using works wonders. While some may disagree considering the low cost, I believe the practical application of technology and proper engineering/design are far more important than a high asking price, which doesn’t necessarily guarantee top quality or performance.


Hi This started this week, I have the dac for around 1 year and never noticed it before. Let me be clear that this is not negligible, it is loud and it only get worst as I increase the volume, as if a constant hum sound was being plaid. It doesn't matter if there is any sign/music being sent to the dac through any of the digital inputs (USB or toslink or RCA). As soon as I turn on the dac I hear the noise thought the speakers, if I turn down the volume the noise goes away. looking inside doesn't show any issues. I was wondering if it could be something in the tube connectors/solder or indeed in the power supply. :(

I think you should send it to the manufacturer for service. He is a straight shooter and will take care of it. even if you have to send it to China. And maybe just buy a used DAC to tide you over in the meanwhile.

Linear Tube Audio here in the US can fix it.  Unplug the USB cable and see if it goes away. 

I'm waiting for feedback from the manufacturer. Unfortunately I'm in Europe so LTA may not be the best option but thanks for the suggestion, always good to have options.

I made this little clip:


it was playing well for an 1h and after I started noticing this hum once again. I turned off the music when I recorded the clip, actually even without any signal the hum is there. I even test it without any tube and the hum is there. As soon as I turn off the dac, it goes away, turning up and down to volume nob also increases / decreases the audible noise. 


Did you disconnect the usb cable? I had the same sort of issue when my usb cable was connected. Let me know.  

thx for bringing more suggestions that may help me troubleshooting this issue. I'm not using USB, I mostly use RCA. Actually the USB cable wasn't even connected when I first noticed the issue. I have tried with USB and no difference. Actually, even without any sign sent to the dac or cable connected (appart from the audio out) I get the same issue. When I first turn it on, no issues at all, but after an hour, give or take, this hum starts.

By the way, one of the reasons I got this dac was also after reading some of your reviews and mods :) I actually waited for a few months to see if you were selling any moded orchid :) ... just a side note. Thx once again, I appreciate your message. I'm starting to think I can't escape to send the dac in for repair.

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