This is a review and detailed measurements of the Douk Audio A5 stereo class D amplifier. It was sent to me by the company and costs US $99.99 as of this writing on Amazon including free shipping.
I really like the look of the unit. The control on the right turns the amp on and adjusts the volume. The knob on the left adjusts a high-pass filter which is nice to have to tailor the bass response for typical bookshelf speakers this amp will be driving. And allowing subwoofer integration (although you have to bring your own splitter). Back panel is what you expect:
While the unit is rated up to 48 volts, the supplied power supply as you see is rated at 32 volts @ 5 amps. The terminals are rather small but I still managed to attach my chunky locking banana plugs into them.
As an interesting touch, a plexiglass cover is easily removed to change op-amps but also change switches which change the RGB lighting inside!
Give the market segment they are going after, the lighting is a low cost differentiation.
If you are not familiar with amplifier measurements, please watch my tutorial on it:
[And subscribe to the channel
]
Douk Audio A5 Amplifier Measurements
As usual, we start with our 1 kHz tone into 4 ohm load at 5 watts to bring out both noise and distortion:
That's above average performance and better than I expected:
I had not realized the A5 at this price had PFFB (post filter feedback) which reduces output impedance and load dependency until I measured frequency response:
I was also surprised by the good performance of the high-pass filter at the setting I used. There is no ringing despite high attenuation. Very nice!
Another pleasant surprise was again, above average channel separation:
The implementation is not perfect though as there is more high frequency distortion as seen in our intermodulation distortion tests:
Noise performance is excellent especially for the class:
Power is fitting with price but more modest than the more expensive competitors (from memory):
These chip based implementations are quite robust, not even turning on protection as I beat it in my "FTC like" full bandwidth and longer term test (45 seconds or so):
EDIT: forgot power vs frequency:
Reactive loads don't matter to it either, going all the way down to 2 ohm (NOTE: both channels driven but only one channel loaded):
The amplifier was stable almost at power up:
I didn't realize the volume control was also the power switch so I just disconnected the AC cable for on/off noise test:
Conclusions
Our journey into these pocket/desktop amps started around this $100 price range but without PFFB feature. This caused high frequency variations which we accepted as a trade off to get such a low cost. Companies then stepped up and implemented PFFB but the cost was increased. Douk A5 disrupts this market by providing PFFB at the $100 price mark. There is a bit of high frequency distortion penalty there but otherwise, the rest of tests show excellent engineering, put a big smile on my face!
I am happy to recommend the Douk Audio A5 stereo amplifier.
EDIT: video review of Douk A5 posted as well:
------------
As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
I really like the look of the unit. The control on the right turns the amp on and adjusts the volume. The knob on the left adjusts a high-pass filter which is nice to have to tailor the bass response for typical bookshelf speakers this amp will be driving. And allowing subwoofer integration (although you have to bring your own splitter). Back panel is what you expect:
While the unit is rated up to 48 volts, the supplied power supply as you see is rated at 32 volts @ 5 amps. The terminals are rather small but I still managed to attach my chunky locking banana plugs into them.
As an interesting touch, a plexiglass cover is easily removed to change op-amps but also change switches which change the RGB lighting inside!
Give the market segment they are going after, the lighting is a low cost differentiation.
If you are not familiar with amplifier measurements, please watch my tutorial on it:
[And subscribe to the channel
]Douk Audio A5 Amplifier Measurements
As usual, we start with our 1 kHz tone into 4 ohm load at 5 watts to bring out both noise and distortion:
That's above average performance and better than I expected:
I had not realized the A5 at this price had PFFB (post filter feedback) which reduces output impedance and load dependency until I measured frequency response:
I was also surprised by the good performance of the high-pass filter at the setting I used. There is no ringing despite high attenuation. Very nice!
Another pleasant surprise was again, above average channel separation:
The implementation is not perfect though as there is more high frequency distortion as seen in our intermodulation distortion tests:
Noise performance is excellent especially for the class:
Power is fitting with price but more modest than the more expensive competitors (from memory):
These chip based implementations are quite robust, not even turning on protection as I beat it in my "FTC like" full bandwidth and longer term test (45 seconds or so):
EDIT: forgot power vs frequency:
Reactive loads don't matter to it either, going all the way down to 2 ohm (NOTE: both channels driven but only one channel loaded):
The amplifier was stable almost at power up:
I didn't realize the volume control was also the power switch so I just disconnected the AC cable for on/off noise test:
Conclusions
Our journey into these pocket/desktop amps started around this $100 price range but without PFFB feature. This caused high frequency variations which we accepted as a trade off to get such a low cost. Companies then stepped up and implemented PFFB but the cost was increased. Douk A5 disrupts this market by providing PFFB at the $100 price mark. There is a bit of high frequency distortion penalty there but otherwise, the rest of tests show excellent engineering, put a big smile on my face!
I am happy to recommend the Douk Audio A5 stereo amplifier.
EDIT: video review of Douk A5 posted as well:
As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
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