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Douk Audio H7 Amplifier Review

Rate this stereo amplifier

  • 1. Poor (headless panther)

    Votes: 16 6.8%
  • 2. Not terrible (postman panther)

    Votes: 80 33.8%
  • 3. Fine (happy panther)

    Votes: 123 51.9%
  • 4. Great (golfing panther)

    Votes: 18 7.6%

  • Total voters
    237

amirm

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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.
Douk Audio H7 stereo class D amplifier balanced amp review.jpg


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:
Douk Audio H7 stereo class D amplifier balanced amp power supply back panel review.jpg


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:
Douk Audio H7 stereo class D amplifier TI TPA3255 specifications.png


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:
Douk Audio H7 stereo class D amplifier balanced XLR measurement.png


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:
Best desktop budget amplifier review.png


Zooming in:

Best desktop budget amplifier 2023 review.png


Noise performance is quite good for class although short of the TI specs:
Douk Audio H7 stereo class D amplifier balanced XLR SNR measurement.png


As is typical of budget class D amplifiers, the frequency response varies with what load (speaker) you connect to it in treble region:
Douk Audio H7 stereo class D amplifier balanced XLR Frequency Response measurement.png


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:
Douk Audio H7 stereo class D amplifier balanced XLR Multitone measurement.png


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:
Douk Audio H7 stereo class D amplifier balanced XLR crosstalk measurement.png


Let's see how it does in power department starting with 4 ohm load:
Douk Audio H7 stereo class D amplifier balanced XLR power into 4 ohm measurement.png


This is good bit of power and only gets better if we allow 1% THD:
Douk Audio H7 stereo class D amplifier balanced XLR max and peak power into 4 ohm measurement.png


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:
Douk Audio H7 stereo class D amplifier balanced XLR power into 8 ohm measurement.png


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:
Douk Audio H7 stereo class D amplifier balanced XLR power into 4 ohm vs frequency measurement.png


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:
Douk Audio H7 stereo class D amplifier warm up measurement.png


Finally, there is likely to be some audible pop on both turn on and off:
Douk Audio H7 stereo class D amplifier balanced XLR Power On off Pop Sound Tick measurement.png


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.
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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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This is quite competent performance for such a low price, were it not for the response that varies with load we would have a clear winner.
but even so, considering the feature set, power and aesthetics it's a great piece.
Thanks for the review!
 
Thank you @amirm,
Some years ago, I had purchased a ClassD amp which arrived with a 32Vdc adapter, but the webpage had stated that it was a 48Vdc adapter.
When inquired about the discrepancy I was told that the TI's TPA3255 life-expectancy significantly reduces with DC@48V.
Is this true?
I also don't know whether the use of a higher input voltage results in any significant changes to your measurement results (re: @32Vdc).
 
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).
Thank you for the review.

If you see this as a power amplifier then dual level controls has been the norm all along. I don’t recall any power amplifier with a single volume control and a balance control. Do you see this as an integrated amplifier, which would normally have a single volume and balance control?
 
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Do the separate volume controls have any detents to aid in matching channels? Even without that they could have been marked in a way to be more of an aid to matching channels. Unless as said it is a pure power amp and those controls are for trimming. They are marked volume however.
 
Do the separate volume controls have any detents to aid in matching channels?
They do but they don't match. At the same detent, one was outputting 5 watts and then other 5.2 watts or so. I had to nudge it between the two detents to get them to match.
 
If you see this as a power amplifier then dual level controls has been the norm all along. I don’t recall any power amplifier with a single volume control and a balance control. Do you see this as an integrated amplifier, which would normally have a single volume and balance control?
I do see it as an integrated amp with dual selectable inputs and volume controls.
 
well done DOUK. WELCOME TO THE REAL WORLD. Amirm., thank you.

As I read many reviews here, I am concerned about how many new items have issues (some small, some less so.) right out of the gate.... quality control may be going the way of customer service in the "just deal with it" world.
Hmmm...uh-oh! .... Yikes makes me wonder how much shoddy work i have done in my life.
 
They do but they don't match. At the same detent, one was outputting 5 watts and then other 5.2 watts or so. I had to nudge it between the two detents to get them to match.
That actually would be about a .17 db mismatch. Not great, but not terrible. Plenty of stereo volume controls show that level of mismatch.
 
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As I read many reviews here, I am concerned about how many new items have issues (some small, some less so.) right out of the gate.... quality control may be going the way of customer service in the "just deal with it" world.
As a rule, amplifiers will be less reliable than other audio gear. Components are being stressed under heat and abuse of connection/disconnection of the load.
 
When inquired about the discrepancy I was told that the TI's TPA3255 life-expectancy significantly reduces with DC@48V.
Is this true?
All else being equal, probably so. The idle power consumption will go up so the amp runs at more elevated temperatures resulting in reduce lifetime. The better the cooling though, the less the concern is here. At these prices though, I would just push it to run where I want it and if it dies, it dies. :)
 
Nice to see a VU meter on a decent TPA3255 based amp, looks ok too and test results are fine @amirm.

There are two other brands using the same design as Douk/Nobosound, the Aoshida A7 and the Suca Audio U7 all having the VU meter and separate volume controls etc.;


@shpong posted these images in another thread of the Suca U7;

index.php
index.php
index.php
index.php


I note these can take up to a 48V/10A power supply, but still will never get close to 300W x 2 as suggested in all marketing specs.


JSmith
 
Nice to see a VU meter on a decent TPA3255 based amp, looks ok too and test results are fine @amirm.

There are two other brands using the same design as Douk/Nobosound, the Aoshida A7 and the Suca Audio U7 all having the VU meter and separate volume controls etc.;


@shpong posted these images in another thread of the Suca U7;

index.php
index.php
index.php
index.php


I note these can take up to a 48V/10A power supply, but still will never get close to 300W x 2 as suggested in all marketing specs.


JSmith
OOOOOoooo and there are OP amps to roll au plenty. :p (j/k.)
 
This is a awesome little unit for US $144. I would buy it. It's cool. The Ti TPA3255 is really boosting the current for US $144! It's cute too. I would have never thought we would see a quality compact amp IC powerhouse like this. I'm used to STK ICs and they suck. Thanks for the review @amirm. Great stuff.

EDIT: I misidentified this amp not as the TPA3255 and thought that this unit is new and exiting... :D OOOPs.
 
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What does the VU meter measure?

Input or Output?

If it is adjustable, how to calibrate it?

Or is it eye candy?
 
Dual volume? I feel like this is some joke from a Rick and Morty episode... but it was dual-bag bro!! This is a terrible design design, one that made me vote headless panther. Very poor design decision.
 
If one doesn't need XLR inputs, this Douk seems no better than the less expensive Aiyima 08 Pro.

Or is the sensitivity knob on this Douk a real differentiator?
 
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