This is a review and detailed measurements of the Douk Audio H7 stereo class D desktop amplifier. It was kindly drop shipped to me by a member and costs US $144.
Right away we see differentiation in the form of the nice looking VU meter. Not only that there is a control to set it sensitivity which is a must in my view. The backlight is nice and bright and goes well with that yellow/orange ring. The case is machined aluminum so feels nice and heavy for its size. The switches and controls are surprisingly robust and impart a feeling of quality. In other words, this is in entirely different class compared to typical budget desktop amplifiers. Surprised continue to the back side:
Yes, we have real, full size XLR inputs! Of course there is also RCA input but they also added a set of RCA outs. I am assuming that is to connect subs and out but there is no internal filtering.
The heart of the unit is TI's TPA3255 single chip stereo class D amplifier with very lofty specs:
Wide input range is provided. Included power supply is manageable with 32 volts output with 5 amps of current. If you are going to drive higher impedance speakers and you want to go louder, you may want to up that to 48 volts.
One negative which actually follows some "high-end" gear is dual volume controls. Yes, to increase or lower the volume, you have to crank both of them. I would have wanted to see a single volume control with a balance knob. As is, you can set them once and use an upstream DAC with its volume control (and remote). That is how I tested it by setting the gain to 29 dB and treating it as a power amplifier. You can see the position of the volume controls in the picture for that gain setting.
Douk Audio H7 Measurements
Let's start with our usual 1 kHz dashboard into 4 ohm load using XLR input:
The SINAD of the good channel at 82 dB is above average for all amplifiers tested. But for some reason the other channel (in blue) is distorting more which drags the average down some:
Zooming in:
Noise performance is quite good for class although short of the TI specs:
As is typical of budget class D amplifiers, the frequency response varies with what load (speaker) you connect to it in treble region:
This means you may hear brighter or softer sound depending on exact impedance of the speaker. Best to use EQ and tailor that to taste.
Distortion is kept very low at 5 watts:
The less good channel lost 1 bit here (not shown). So still quite good and more than enough for the application.
Crosstalk is very good for any amplifier let alone a budget one:
Let's see how it does in power department starting with 4 ohm load:
This is good bit of power and only gets better if we allow 1% THD:
I ran this three times as I could not believe it breaking into 3 digit department! 200 watts out of this little box? Granted, the test is short term but still, that is quite healthy.
Switching to 8 ohm we naturally get less power:
Note that most speakers are around 4 ohm in bass frequencies where most of the volume is so don't go optimizing for this unless you know you have an 8 ohm speaker in that region.
EDIT: forgot originally to post the power vs frequency:
There is only a dB or so impact due to warm up (one channel getting better and the other, worse) so I would just turn it on and use:
Finally, there is likely to be some audible pop on both turn on and off:
Kind of strange to see the blue channel die out that way. This may have something to do with that channel also underperforming in the dashboard.
I had no luck trying to test the H7 with my powercube reactive loadbox. It caused some kind of interference that would keep it from switching loads. Will need to spend more time investigating what is going on.
Conclusions
The Douk H7 breaks new ground in multiple areas from nicely done VU meter, nice looking case, and very good measured performance. The only issue is if you can live with dual volume controls. I am happy to see such differentiation in this highly price sensitive and crowded market.
I am going to recommend the Douk Audio H7 amplifier.
-----------
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/
Right away we see differentiation in the form of the nice looking VU meter. Not only that there is a control to set it sensitivity which is a must in my view. The backlight is nice and bright and goes well with that yellow/orange ring. The case is machined aluminum so feels nice and heavy for its size. The switches and controls are surprisingly robust and impart a feeling of quality. In other words, this is in entirely different class compared to typical budget desktop amplifiers. Surprised continue to the back side:
Yes, we have real, full size XLR inputs! Of course there is also RCA input but they also added a set of RCA outs. I am assuming that is to connect subs and out but there is no internal filtering.
The heart of the unit is TI's TPA3255 single chip stereo class D amplifier with very lofty specs:
Wide input range is provided. Included power supply is manageable with 32 volts output with 5 amps of current. If you are going to drive higher impedance speakers and you want to go louder, you may want to up that to 48 volts.
One negative which actually follows some "high-end" gear is dual volume controls. Yes, to increase or lower the volume, you have to crank both of them. I would have wanted to see a single volume control with a balance knob. As is, you can set them once and use an upstream DAC with its volume control (and remote). That is how I tested it by setting the gain to 29 dB and treating it as a power amplifier. You can see the position of the volume controls in the picture for that gain setting.
Douk Audio H7 Measurements
Let's start with our usual 1 kHz dashboard into 4 ohm load using XLR input:
The SINAD of the good channel at 82 dB is above average for all amplifiers tested. But for some reason the other channel (in blue) is distorting more which drags the average down some:
Zooming in:
Noise performance is quite good for class although short of the TI specs:
As is typical of budget class D amplifiers, the frequency response varies with what load (speaker) you connect to it in treble region:
This means you may hear brighter or softer sound depending on exact impedance of the speaker. Best to use EQ and tailor that to taste.
Distortion is kept very low at 5 watts:
The less good channel lost 1 bit here (not shown). So still quite good and more than enough for the application.
Crosstalk is very good for any amplifier let alone a budget one:
Let's see how it does in power department starting with 4 ohm load:
This is good bit of power and only gets better if we allow 1% THD:
I ran this three times as I could not believe it breaking into 3 digit department! 200 watts out of this little box? Granted, the test is short term but still, that is quite healthy.
Switching to 8 ohm we naturally get less power:
Note that most speakers are around 4 ohm in bass frequencies where most of the volume is so don't go optimizing for this unless you know you have an 8 ohm speaker in that region.
EDIT: forgot originally to post the power vs frequency:
There is only a dB or so impact due to warm up (one channel getting better and the other, worse) so I would just turn it on and use:
Finally, there is likely to be some audible pop on both turn on and off:
Kind of strange to see the blue channel die out that way. This may have something to do with that channel also underperforming in the dashboard.
I had no luck trying to test the H7 with my powercube reactive loadbox. It caused some kind of interference that would keep it from switching loads. Will need to spend more time investigating what is going on.
Conclusions
The Douk H7 breaks new ground in multiple areas from nicely done VU meter, nice looking case, and very good measured performance. The only issue is if you can live with dual volume controls. I am happy to see such differentiation in this highly price sensitive and crowded market.
I am going to recommend the Douk Audio H7 amplifier.
-----------
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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