This unit was loaned to me by Kitsune HiFi for testing
The Holo RED is a fairly interesting device in that it can act as both a streamer and a DDC. You can’t hotswap between these two modes as to run it as a USB DDC you need to connect a USB source then turn it on, otherwise it’ll start up in streamer mode, but the flexibility of having these two functionalities in one box is pretty fantastic.
It features just about all the IO you could possibly ask for. I2S output with pinout configurable using the DIP switches on the bottom of the unit, AES, SPDIF over BNC, Coax and TOSLINK optical, as well as USB in and out. And of course Ethernet for the streamer.
When using it as a streamer, the ‘brain’ of the operation is a pi CM4 module.
“Why didn’t they develop their own solution?” you might ask. Well the simple answer is there’s no need to reinvent the wheel if a good solution exists. A CM4 is a great choice for running the streamer software without drastically increasing the cost of the device. The pi itself doesn’t affect sound quality, that’s dependent on the actual output hardware. And additionally, using a CM4 means that whilst the RED ships with its own operating system that allows for using it as a Roon endpoint, HQPlayer, Tidal connect and others, you can swap to a different software choice if you’d like.
When using the RED as a USB DDC, the pi is not in use and everything is handled by the RED hardware itself.
The USB output is also not connected directly to the pi, and instead is ‘reclocked’ (retransmitted) using the RED’s clock and a clean 5V supply.
The USB output supports up to 1.536Mhz PCM and DSD1024. The I2S output supports upto 768khz PCM and DSD512.
SPDIF is limited to 192khz as on the vast majority of devices.
– Audio Precision APx555 B-Series Analyzer
– AudioQuest Carbon digital cables (1.5m)
– RED OS used during testing
– Device and test setup are running on regulated 230V power from a Furman SPR-16-Ei
– 44.1khz and 48khz real music played through device during measurement
– Jitter analysis is configured to use an AES3 standard 700hz high-pass filter, and a 100khz butterworth low-pass filter
– Coax output used unless otherwise specified
To measure jitter, the device is connected to the digital input of the APx555, and the analyzer is set to analyze jitter, not audio content.
These measurements do not show audio/analog info, but instead show the spectrum of jitter, ie: time-domain inconsistencies.
This is the primary factor that a good streamer or DDC will seek to improve.
Jitter at 44.1khz is amazing, in fact, it’s the best of any device I’ve tested. Slightly beating the previous champ the Rockna Wavedream NET though still within margin of error so I’d realistically say the two are tied.
Jitter performance at 48khz is again the best I’ve tested. Absolutely phenomenal performance!
Additionally worth noting that performance did not change regardless of whether USB input or streaming input was used.
How about noise?
Noise is again incredibly low. Additionally even though the device uses a linear power supply, there are no mains leakage components going above 1uV (0.000001 V)
With regards to the I2S output I’m currently having some trouble with my clock divider so I’ll need to add my I2S measurements once I get that sorted, but until then, L7 Audiolab has done a test of the I2S output using a clock divider and jitter is as low as you’d expect. In fact there’s literally nothing visible on the result beyond noise from the device he’s using as a clock divider itself!
The Holo RED is the lowest jitter and one of the lowest noise digital sources I’ve tested. Absolutely incredible performance that sets the current benchmark for a streamer or DDC. The fact that this level of performance is achieved at under $1000 is honestly incredible.
Well done Jeff!