Pronounced hiss on certain hi-rez albums with new DAC (MHDT Labs Orchid)

Core Machine
Mac Mini

Network Details

Audio Devices
MHDT Labs Orchid DAC

Library Size
20,000 Plus

Description of Issue

New DAC MHDT Labs Orchid (Previous DAC’s Bryston BDA-3 and DAC section of Oppo 105), using USB connection, the sound is excellent, with the exception of a pronounced “hiss” on a few albums. Not all most (about 30) that I tried were perfect, but 2 Hi Rez files, Brubek-Time Out and Shelby Lynne-Just a Little Lovin’, have a pronounced hiss.

Looking for suggestions on what I might have done in the set up to cause this? I’m sure it’s operator error. Thanks

Have you tried using USB?

Not sure why this should be an issue on hi rez only but I would look at those tubes first…

To eliminate the possibility it has anything to do with the resolution per se you can try a hi Rez piece where you hear the hiss and then play the same track from the “CD quality” version on your streaming service.

Check the sample rates of the albums that produce hiss, then try other albums of the same sample rate

yeah, did that and all good, no hiss. It’s really weird just those 2 files and they play fine on other DAC’s

good idea, I tried that and other files of the same res work fine. The Brubek is 176/24 and the Shelby Lynne is 192/24

sorry I should have said, it is hooked up via USB

Try downsampling to 96kHz using Roon DSP Engine and see if the hiss is still there.

Yes that could be it. The Orchid can process HiRez, but only our 44/24.

The Orchid is fully capable of 192/24.
I owned one for about 6 months but connected by spdif.
Can you try spdif connection just in case something funky with the USB?

So I bought the Mac mini so I could use the SPDIF if I wanted, but… this one, bought used does not support it, even though there looks to be a spot for the mini SPDIF that I bought for it. the system does not have the driver for it. So I hooked my computer back into the USB DAC section on the Oppo 105, and absolutely no noise on those 2 albums (via USB) dead quiet. It’s just so weird, doesn’t make any sense to me…

Sounds like some very odd issue with the usb input of the Orchid.
But why just those two albums is beyond me.

yeah, it’s so weird, and I love the sound of the DAC beyond that. I try about once a year to get into digital, then find myself just listening to vinyl, sell the current DAC the regret it about 6 months later and start the cycle again. But the DAC’s have gotten so good, and it’s so simple, I thought I’d try an MHDT again (loved the Havana back in the day), and I couldn’t find a used Bryston BDA-3 (what I sold back at the beginning of the pandemic since I wasn’t using it, but it was truly sublime in my system). I’ll get in touch with the guy in Tawain who builds these, he’s a great guy. Thanks for the help guys, I thought it was just my ignorance of Roon, and it was a setting I could change.

Some playback chain can be sensitive to ultrasonic content. That’s why I suggest trying downsampling to 96kHz and see if that makes any difference.