Holo audio May User manual

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梅v1.1
Note: Please connect DC power cable before AC power cable. Disconnect the AC power before disconnecting the DC power. Failure to do so could potentially cause damage.

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Product Overview
梅
“The Possibility Of”
by Holo Audio
A new generation DAC of fully discrete resistor network (commonly known as R2R).
The new generation of linear compensation technology solves the accuracy errors caused by resistor
tolerance, after compensation, reaching a variance of 0.00005% tolerance accuracy.
Proprietary anti-jitter technology that provides a full amplitude of anti-jitter without increasing noise floor
and other undesirable effects.
Based on this new generation of technology May “梅”can provide a SINAD of >115dB and a dynamic range
of >130dB, which represents the performance limit reached by today's most advanced R2R architecture
DAC.
Using the ultimate performance of PLL+FIFO technology, provides 0.1Hz Third-Order low-pass ability to
inhibit jitter. It also uses a high-performance femtosecond VCXO as the PLL clock source. Under the premise
of being almost immune to the front-end jitter, it can also lock up to 1.5us-2us @ 1KHz signal with high
jitter. (It can lock up to 1.5us-2us @ 1kHz signal with high jitter on the premise of almost being immune
front-end jitter).
Dual Mono DAC L/R channels are independently powered by their own dedicated transformer in the PSU
chassis. This provides better channel separation and more accurate sound stage.
Supports USB and I2S up to DSD1024 and PCM1.536MHz sample rates.
The USB interface uses proprietary firmware with ultra-low latency, a highly reliable data transmission, ideal
USB eye pattern measurements that contributes to 2-4 times higher performance than official firmware.
Two sets of independent HDMI-I2S input interfaces are provided, and each set of I2S has a four-way
independent circuit, as opposed to standard LVDS chip, making I2S clock signals subject to lower
interference and lower jitter. In addition, each group of I2S inputs can be configured with specific pinout
configuration, making it compatible with most of the HDMI-I2S digital devices on the market.

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COAXIAL1, COAXIAL2, OPTICAL, AES
PCM 44.1-192K (24bit)
DSD 64X （DOP）
USB
PCM 44.1K-1.536M (32bit)
DSD 64-512X （DOP）
DSD 64-1024X （Native）
I2S1，I2S2
PCM 44.1K-1.536M (32bit)
DSD 64-1024X
PCM 48K NOS
THD+N 0.00017% @1K(-115dB)
DNR 130dB
Voltage Output 2.9Vrms (RCA), 5.8Vrms (XLR)
DSD 128X
THD+N 0.00025% @1K(-112dB)
DNR 115dB
Voltage Output 1.45Vrms (RCA), 2.9Vrms (XLR)
Size (Main Box)
430x300x55mm (W x L x H, Dimensions do not include protruding parts）
Size (Power Chassis）
430x300x55mm (W x L x H, Dimensions do not include protruding parts）
Weight
18kg/39.68lbs
Power Input (configurable, see label on
bottom of unit for specified input）
220-230V 50/60Hz –Fuse Type 2A SB 5x20mm
110-115V 50/60Hz –Fuse Type 4A SB 5x20mm
Power consumption
60W

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Included Accessories
AC Power Cable x1
DC Power Cablex1
USB Cable x1
Remote Control x1

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POWER, DISPLAY MODE / MENU, OVER SAMPLING / ←, SOURCE/→
Left of display:
(Indication light is RED when powered in Off-State, and GREEN when ON)Press and hold this button for 1 second to switch the
power on and off. In the off state, all is power is off except for the standby circuit and red indication light, other
circuits of the May "梅" will stop working and stop outputting.
Right of display, 4 buttons from left to right:
In the silent mode, some of the May "梅" output stage circuit turns off. However, the power
consumption is essentially unchanged, and will maintain its hot machine state.
In normal operation (display) mode, press this button to select whether to turn off
the display automatically; in configuration (menu) mode, press this button to select the configuration item.
←In Normal (over-sampling) mode, press this button to select oversampling mode. In
configuration mode, press this button to change the configuration mode (left).
→In Normal mode, press this button to select the digital source. In configuration mode, press
this button to change the configuration mode. Select the digital input source, including USB (ground isolated), RCA,
BNC, AES, fiber optic, I2S-1 and I2S-2.

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directly converts the original data. Since digital oversampling caN cause time domain
distortion such as ringing effects, NOS can avoid these problems. Generally speaking, NOS has a significant impact
on other performance indicators, but the May “梅”is designed to maintain good performance in NOS mode.
Super-sampling the PCM to a higher frequency PCM
oversampling the DSD to a higher frequency DSD
performing a digital to analog conversion.
whether it is PCM input or DSD input, always oversample to PCM for digital
analog conversion.
Whether in PCM input or DSD input, super-sampling to DSD
mode for digital analog conversion.
How to enter Configuration mode:
In shutdown mode (powered off state, red light indicated) press and hold the menu button and power button to
enter menu mode. Then press the menu button to select the configuration mode, press the left button or right
button to change the configuration mode.
Select from HOLO, ALT1, ALT2, ALT3. Reference I2S Port Pinout for an explanation and the I2S line sequence. (See page 10)
Select from HOLO, ALT1, ALT2, ALT3. Reference I2S Port Pinout for an explanation and the I2S line sequence. (See page 10)
STANDARD, the analog RCA output is normal polarity, balanced XLR output 1-Ground, 2-Hot, 3-cold.
REVERSED, the analog RCA output is reverse polarity, balanced XLR output 1-Ground, 2-Cold, 3-Hot.
Select ON to turn on the PLL function and work with all digital input signals to eliminate Jitter.
Select OFF to turn off the PLL function.

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Note: please connect DC power before AC power. Similarly, disconnect the AC power before disconnecting the DC
power supply. Failure to do so could potentially cause damage.
1.
2. DAC (main) –Rear Panel

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Mute
Display Mode Settings
Display Input Settings
Volume+ * (N/A for May DAC)
Volume -* (N/A for May DAC)
Analog Output
Settings
Sampling
Modes Settings
Remote Control
*This is a universal HOLO AUDIO remote. Volume (+/-) is not applicable to the “梅”May DAC as there is no pre-amp built
in, will work simultaneously with other HOLO Audio branded products i.e. pre-amps and head-amps.

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I2S Port Pinout
Using LVDS differential transmission. Physical interface and HDMI consistent, you can use the HDMI cable. But note that
the electrical signal transmission is I2S, not conventional HDMI audio and video signals.