The HiFimeDIY UD80 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 and the outputs going to the speakers, creating a very clear audiophile sound.
UD80 is UD20's bigger brother and is quite powerful with up to 2x80W @ 8 ohm. And while UD20's bass is on the lighter side, the UD80 has a deep powerful bass. It still has that ultra clear audiophile sound quality made possible by this digital technology.
The UD80 amplifier uses the Savitech SA9023 USB receiver to connect to a USB host (computer, iPad etc). Datatransfer is asynchronous, and it accepts all samples rates from 32kHz to 96kHz and 16/24bits. 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 avoid these extra steps of D/A and A/D conversion.
The UD80 can be powered from 10V to 35V and the power supply requirements and the output power will vary depending on the speaker impedance. The absolute max is 36V, however a 36V might output slightly above 36V which can damage the UD80.
8 ohm loads: Up to 2 x 80W. 35V required for minimum distortion and 6.3A current for 2x 80W. We have also used it with lower voltage supplies with great results. Output is around 2x60W from 30V supply and 2x36W from 24V supply.
4 ohm loads: Up to 2 x 50W. 21V required for minimum distortion, and 7A current for 2 x 50W. You can use any power supply from 21V to 35V with same results, but a 21V 7A power supply will be smaller and cheaper than a 35V 7A power supply.
Power supply options
We have several options for power supplies for the UD80. As a general option we recommend the 35V 6A supply (soon available). If you know you'll use only 4 ohm speakers, then you can chose the 24V 8A supply instead (soon available). We have also used the 32V adjustable power supply with good result. This 32V5A supply has very low ripple, and will be able to make the amp output 2 x 50W at 8 ohm and 2 x 25W @ 4ohm.
The Connexelectronic SMPS300R can be used if you don't mind a little bit of DIY. Use 38V turned down to 35 for 8 ohm speakers, and 28V power supply can be adjusted down to minimum for 4ohm speakers. The 200W SMPS power supply we're selling will also work good and requries only minimal tweaking.
The amp is very minimalistic in is functions. There is a volume knob which will also power down the amp to standby when the volume control is set to minimum.
Banana types speaker plugs is used to reduce risk of shorts between positive and negative outputs. The negative outputs are not common and can not be connected together.
The UD80 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 some iPads and some Android devices. More Android devices might work when using the USB Audio record pro software.
- Fully digital amplification
- DDX® power output stage
- Up to 2 x 80W at 8 ohm, 2x50W at 4 ohm
- 100dB SNR and dynamic range
- Asynchronous USB mode
- Accept sample rates 32kHz, 44.1kHz, 48kHz, 88.2kHz, 96kHz and 16 and 24 bits
- USB input (no analog inputs!!)
- No drivers for Windows, Mac and Linux. Some iPad's and Android devices also works.
- Low power consumption 23mA when standby and 150mA when active
- Accepts DC power from 10 to 36V
Dimensions: 12.5cm x 9cm x 3.8cm including volume knob
Questions: (moved from reviews)
I'm waiting for your 36V 6A power supply to by the UD80. any delay ?
What is the UD80's DDX® power output stage, STA508, STA510A Like T1 amp and DDX 320 ?
Power output stage is sta328. The 36V 6A supply should be ready in 2-4 weeks. The 32V supply can be used.
This amp probably has a DSP-based volume control ?
If it's digital what is the resolution?
A detailed picture of the inside would be also helpful in making a choice.
Hi, the power is DPS based and resolution is 8 bit. We will add a inside photo soon.