The HiFime UDP80 is a true Digital PWM amplifier with no A/D conversion, no preamp or any analog signal path anywhere before the output stage. This makes a very direct link between the digital source and the outputs going to the speakers, creating a very clear audiophile sound.
The UDP80 amp uses similar technology as our DDX320 amp that’s only sold as DIY (and currently sold out) and the popular UD80 USB amplifier. It has an USB input that accepts all sample rates and files up to 96kHz/24bit and there is now also an optical input that accepts up to 192kHz/24bit. The amp will automatically detect the input source.
USB and SPDIF inputs
The UDP80 amplifier uses the Savitech SA9023 USB receiver to connect to a USB host, and it accepts all samples rates from 32kHz to 96kHz and 16/24bits. It uses USB Audio Class 1 native drivers for Windows, Mac and Linux, no extra drivers need to be installed. It will work with the same devices as our Sabre DAC support (SA9023 version) - which includes iPhone/iPads and many Android devices. More Android devices might work when using the USB Audio player pro software.
The digital i2S signal is sent to the St Microelectronics' STA328 chip where PCM is converted to Pulse width modulation (PWM) signal and then amplified using DDX® power output stage, enabling it to drive speakers directly. This high quality conversion from PCM audio to DDXs patented tri-state PWM switching waveform provides over 100 dB SNR and dynamic range.
This is quite different from how a regular class D or T amplifier with digital inputs works - which include a DAC which first convert the digital signal to analog which is then passed on to the amplifier section where it is converted back to PWM. This true digital technology avoids these extra steps of D/A and A/D conversion.
The UDP80 can be powered from 11V to 36V. Max 34V is recommended to have some safety margin.
The recommended supply voltage depends on speaker impedance:
8 ohm speakers:
We recommend our 34V power supply for the UPD80, but you can use any DC power supply of max 34V and 6A. (updated from 36V)
4 ohm speakers:
21V is sufficient for 4 ohm. A high (36V) supply voltage used with 4 ohm speakers might damage the amplifier.
6 ohm speakers:
28V is recommended.
The output power will vary depending on the speaker impedance.
The amp is very minimalistic in is functions. There is a digital volume knob (logarithmical 20kohm), which will also power down the amp to standby when it's set to minimum.
The speaker connectors are AWG14-26 connectors and the connector is detachable from the amplifier. Connect the speaker cables to the plug while disconnected from the amp to make sure there are no accidental shorts. Note: The negative outputs are not common and cannot be connected together.