DirectStream DAC MKII Beta Tester Reviews

Exactly what I’m thinking.


Hope yours dosnt have issues.

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All part of the beta process…

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I am going to start out with i2S which is what I am currently using with the MKI. I don’t typically have any other inputs connected to my DS. I haven’t hooked up our Oppo to it. I prefer to rip discs and play them via Roon. I simply don’t have room to store them where they would be conveniently accessed.

But, I will test USB as well.

I also have a Fluke Infrared thermometer, so I will be monitoring external temp of the MKII.



If there’s something in particular you want tested please let us know. This topic is getting a bit long to glean what may/may not be an issue.

Perhaps a sticky at the top with the latest items you are interested in.

Known issues so far, please let me know what I missed:

USB doesn’t do quadrate.

Turning the power off on unused Ethernet/remote debugging, USB or I2S inputs isn’t in the UI

The green/red light on I2S inputs can be a bit confusing. I don’t think the Mk II uses quite the same algo as the DS yet, but we’ll check into it.

Bitperfect testing is disabled pending testing the dual AES features.

Dual AES is disabled pending more testing.

Optional setting of polarities of the I2S bits is disabled pending more testing.

Probably fixed in next FPGA software:

Auto input select can cause “blurbles” for a short while after a track change, this sound can also be a hiss that fades away.

Switching to coax or having the auto input select switch to coax might mute the box or cause the input selection status on the top of the screen “chatter”. Similarly for TOSLink when the source is 176.4 or 192k.

Apparently at least one of you got a version of the FPGA software that inverts the bits in I2S inputs. This will change the polarity of I2S and the display will say 44.1/24 instead of 44.1/16 for Redbook, but is otherwise benign. This was fixed in the next FPGA software release.

Display related issues:

Size of fonts

Default displays that depend on whether a fixed output level is set.

Documenting things like the connection status green/red


Unknown issue wherein the unit “mutes” in the middle of a track and stays muted with other inputs selected, but keeps displaying input, sample rate and sample width correctly if input selection is changed.

Potential problem where the unit gets warmer/hot. May or may not be related to spontaneous muting.

Experiments that would help us:

I might have missed it, but so far I don’t know of a box that isn’t hot but with a single input connected (of AES3, I2S or TOSLink) that has gone silent in the middle of playing a track.

Also there’s a potential difference between units going silent in the middle of a track, vs those who have an input that doesn’t seem to work when other inputs are working.


My streamer is not from PSA, and I have green light. I am using an AQ 48 HDMI.

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I’ve got the MK2 set at 100, and my BHK Pre set between 25 and 35, depending on source and music selected. Sounds great in my room/setup


The green/red light on I2S inputs can be a bit confusing. The software checks to see if the “connector present” line is set on the HDMI socket. It also can check if there is a valid sample rate on the input and it can check if there is a non-static valid signal. I don’t think the Mk II uses quite the same algo as the DS yet, but we’ll check into it.

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Just wanted to try something else. Had MK2 completely off for about an hour. Unplugged I2S cable and plugged in my Kimber Illuminations coax. Rebooted. Optical came up so listened to the football game that was on for 45 minutes with no issues and then as soon as I switch to coax to stream some music all sound went out. Mk2 not running hot. About the same as when I’m using JR. Coax has red light on.

Switching to coax causing an issue is something that I think I’ve fixed in the next FPGA code. I’ll add it to the known issues list above.


@ted - do you have a beta MKII that is from the same build run as the one we are testing? If not, and you want one, I can send you mine before I unpack it. I am down in Portland, I can send it up to you first thing Monday if need be.

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I appreciate the offer, but I have a unit from the current build, a unit from the last board run and a few boards from runs previous to that. I’m all set on that account. FWIW I have a lot of miles on all of them.


I ran all different digital types through both PST and the streamer, and I could not duplicate the music stopping issue of yesterday. The system was on for four hours which was about the same time it stopped yesterday. I will have music all day to see if the problem will occur later. MK2 has run cooler than yesterday for sure.

Here is my early sonic review. DS MK II, after a day, is starting to show its charm! There is no need to bring back the DS to compare because it is too obvious MK II does EVERYTHING better. I experienced a deep and tight bass that I knew my big speakers are capable of but had never produced until now. Also, the pace, rhythm, and dynamics are better presented no matter what the source was. Even at this early burn-in stage, it is remarkable how quiet it sounds. I could not hear “noise” from the DS before, but hearing MK2 I felt I heard all those digital noises in the past. MK2 delivers glorious music that is quite additive, and it is coming from my oldest CDs too.


@dchang05 - remind me, was your MKI modded? If so, what mods?

It only has 3M absorbers on chips and an M1 fuse, nothing else. MK2 is running by stock fuse now.

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Ok, I give up on my experiments. Shut everything down again and swapped back in my I2S cable. Restarted and streamed music for 35 minutes before losing sound again. Longest so far but nothing seems to be working right. Not running hot so that’s one good thing.


That’s exactly the settings I use on the main system and my best sounding setup.

Paul McGowan | CEO800-PSAUDIO
Boulder, Colorado

Thanks, Ken. I am on my phone at a recording session so can’t answer fully. The red light has two states green and red indicating lock to a source (if we are talking the same light).

Paul McGowan | CEO800-PSAUDIO
Boulder, Colorado

How about that as soon as I thought my MK2 is doing better it stopped working. This time I was switching from I2S 2 streamer to I2S 1 PST. I tried to play a SACD, and nothing came out. Then no matter which sources I tried it did not work anymore. I had the system on for a bit over 5 hours, I think.

I shut down MK2 and will wait. :frowning_face: