Audiobyte Hydra Stack: Hydra.Vox + Hydra.Hub + Hydra Zap

[RS13]

Hi Gents,

I have been following this thread with interest. Recently purchased a SuperHub and agree that PCM 705/768 Linear Phase might be the better option. The DSD implementation is more intimate but suffers from lower volume and loss of detail which pushes me back to PCM. I mainly use it as a USB>I2S DDC to a Denafrips DAC. Occasionally use uPNP/mconnect/asset but lack of volume is too bad. I think Tidal Connect is on their roadmap.. Unsure if Camilla DSP which is also on their roadmap might fix the DSD issue. Hopeware?

I wanted to ask if other SuperHub owners have encountered what appears to be an FPGA buffer issue - the player will stop outputting audio until either the sample rate is toggled or the track/stream is reset. From what I can find, this seems to be a known issue. Unfortunately, Audiobyte appears focused on FPGA development for their new VOX rather than addressing this. Seems concerning that such a serious bug affecting core functionality remains unfixed while development focuses elsewhere - perhaps a case of ADHD development? Would really like to see this resolved so I can use higher PCM bitrates without worrying about playback stopping. Currently, the higher the bitrate, the quicker these interruptions occur.

1. Feature Implementation: DSD volume/detail issues, incomplete OpenHome support, buffer problems limit upsampling, streaming instability.
2. Buffer Management: PCM streaming randomly goes silent, worse at higher bitrates, worse with upsampling enabled, temporary fix requires stream reset.
3. Software Development: Using 2017-era USB drivers, known issues unfixed, no communication from support I can see, no clear development timeline.

 

[m-i-c-k-e-y]

agree that PCM 705/768 Linear Phase might be the better option. The DSD implementation is more intimate but suffers from lower volume and loss of detail which pushes me back to PCM

Volume can be increased thru your preamp/amp. On my ears (volume matched), DSD is somewhat °intimate° and clean (somewhat clinical) with regards to PCM w/c has more soundstage, "raw"/natural, dynamic and more definition.

what appears to be an FPGA buffer issue - the player will stop outputting audio until either the sample rate is toggled or the track/stream is reset.

I have a Hydra.HUB and don't have those issues on my Win11 PC. Try increasing buffers from your player app.
What I have encountered (if i remember it correctly, was it Hub or Vox?) that it skips 1 or 2 seconds of the song (esp DSD). My stop gap solution was increasing the prebuffer stage on my player. Subsequent FW updates has resolved those issues

 

[RS13]

Hey thanks, I appreciate your suggestion, I saw searching around on the little information out there a post on AB's facebook page about the issue from another user where it's a known issue, they acknowledge it and even go so far to suggest they're working on other things in priority.

Last June 2024 they released an update for the SH, unclear if in that update they introduced this issue or if it was always there. Surprised not more people are talking about it, the buffer is on the SH side, not so much the player/source.

I have to give DSD a more full run, volume match my preamps. Interesting your 'clinical' observation - I need more time with it.

This is a known software issue that will be fixed, however we are currently in the final stages of SuperVOX PFGA design. This fix is high priority for us, but we also need to launch the dac, for which the hardware is finished. Please have a little bit more patience. Thank you for understanding!

 

[m-i-c-k-e-y]

What i mean clinical is that its sound was clean and became "somewhat" unnatural.

 

[RS13]

It sure is an interesting change in sound character, as we're typing I just switched over to DSD512 and volume matched my preamps. Definitely the stage is more narrow, does sound processed maybe. I need more time with it.

Also unsure if this buffer issue affects DSD upsampling too, short bit of time will tell! I was thinking further about their facebook posts, this last exchange was July 2024 and nothing from them since - I sure hope this company is going to be around to send out an update/fix or even their new DAC!

 

[RS13]

Hey, you know what else, I should probably call out some of the SuperHUB's strengths too. The issue I'm referencing, while huge considering it affects to a large extent the functional value proposition of the device itself, is the only real draw back. Tidal Connect, CamillaDSP, are on their roadmap apparently and would be nice to see, but basic streamer capability with upnp is definitely there. The strong points I'd say are totally in the hardware. The chassis is just beautiful, weighty aluminum with a great feel, the internal components are what I would pick - Kemet polymer caps throughout the processing board for example, great mains filter, 60000uF of combined filtering on secondary, and their little touch screen and display experience is one of the best I've seen/interacted with - it's very very slick. Also their iOS app, while outsourced, also has a great UI for the basic function changes of the SH. And their update interface is really great too - Just wish they'd load it up with the update I'm looking for .

Edit: yes the issue affects DSD too, it just flipped off. The only mode it doesn't seem to have the issue with is 44.1 - 44.1 everything for me until they fix..

 

[m-i-c-k-e-y]

For me is its converter/upsampler function.

 

[RS13]

On SuperHUB it is as well, related to bitrate which includes upsampling.

Either
1- I feed it something higher than 44.1, it will overrun buffer and stop

-OR-

2- Engage transcoding to anything higher than 'native' (windows audio set to 44.1) and it will eventually stop since it's higher than 44.1 - windows bitrate setting in my case.

So are you saying the HydraHUB suffers the same bug? If yes, they must have reused the same FPGA.

I wish they were reading the thread.

 

[m-i-c-k-e-y]

No my Hydra.Hub does not have those.

 

[DrDen]

My Shanling ET3 I2S output is fully compatible with Holo Cyan 2 as many users reported. My Vox has “PS Audio” configuration in its menu, works fine with the Cayin iDAP6 via any HDMI cable. But ET3 doesn’t work with any settings.
Meanwhile some people report their ET3 work with PS Audio DACs via standard HDMI cable. Since PSA and Holo I2S configurations are different, I’m confused. Could it be that “PS Audio” of the Vox is not the same as real PS Audio?

 

[nikolaindigo]

My Shanling ET3 I2S output is fully compatible with Holo Cyan 2 as many users reported. My Vox has “PS Audio” configuration in its menu, works fine with the Cayin iDAP6 via any HDMI cable. But ET3 doesn’t work with any settings.
Meanwhile some people report their ET3 work with PS Audio DACs via standard HDMI cable. Since PSA and Holo I2S configurations are different, I’m confused. Could it be that “PS Audio” of the Vox is not the same as real PS Audio?

Can you maybe test does any other device work over I2S with VoX?

 

[DrDen]

Can you maybe test does any other device work over I2S with VoX?

I did, Cayin iDAP6 was my digital source via I2S. Standard HDMI cable works well.

 

[nikolaindigo]

I did, Cayin iDAP6 was my digital source via I2S. Standard HDMI cable works well.

Sorry...I did not get that in your previous post. Some people that had issues...VOX did not want to work with their source. There is a dip switch inside VOX (on grey colour heat sink models) and it needs to be turned ON (I think) (to disconnect I2S isolation) and then after that VOX I2S PS audio setting should actually work. But you said it works with Cayin. There can be other thing depending of the source/streamer...VOX needs to have from the source 3.3-5v voltage on pin 18 of the HDMI input in order to "unlock" the port. Otherwise it won't work even if all other HDMI pins are ok for PS audio standard. Unfortunately there is all this mess with I2S connections and different HIFI producers using their own configuration for HDMI. It is not standardized. That is why I think USB on VOX is the best way to go...and less headache.

 

[DrDen]

Very interesting!
My Vox has three menu options for I2S configuration: PS Audio, Rockna and “Other”(whatever this mean).
I read earlier about these switches inside, maybe my item was made later.

 

[DrDen]

Sorry...I did not get that in your previous post. Some people that had issues...VOX did not want to work with their source. There is a dip switch inside VOX (on grey colour heat sink models) and it needs to be turned ON (I think) (to disconnect I2S isolation) and then after that VOX I2S PS audio setting should actually work. But you said it works with Cayin. There can be other thing depending of the source/streamer...VOX needs to have from the source 3.3-5v voltage on pin 18 of the HDMI input in order to "unlock" the port. Otherwise it won't work even if all other HDMI pins are ok for PS audio standard. Unfortunately there is all this mess with I2S connections and different HIFI producers using their own configuration for HDMI. It is not standardized. That is why I think USB on VOX is the best way to go...and less headache.

Thank you, it seems to be the reason why it doesn’t work.