Douk A5 Budget Stereo Amplifier Review

[effj]

View attachment 438140
A note of caution regarding the implementation in the high pass filter.
I took this measurement from a video review that tested the response at different positions of the knob.
Green response flat with the filter off.
Red response with the filter at minimum, blue response with the knob at 12 o'clock, so half the adjustment has almost no effect on the filtering, then at three o'clock we notice a slightly inclined roll off starting from about 200hz, and finally at the end of the travel the roll off starts slowly but already from 1khz.
The best way to integrate it will be to try it, measure, try again, measure again etc etc

I noticed this subjectively when trying to integrate it with my sub’s LPF. Thanks for confirming!

 

[Foxxy]

That seems odd (to me). Does this make sense, given the operating parameter for pulse-width modulation amplifiers? Is there something else going on (e.g., upstream of the power amplifier) to explain the heat - or am I just too naive?

Well, that small DIM package has only a limited heat dissipation capability.

I noticed this subjectively when trying to integrate it with my sub’s LPF. Thanks for confirming!

Oof. The main reason I got this was because of the filter. And now it turns out it's actually kinda bad? I feel next time around such a feature needs a more thorough test in the official review.

 

[Jmudrick]

Well, that small DIM package has only a limited heat dissipation capability.

Oof. The main reason I got this was because of the filter. And now it turns out it's actually kinda bad? I feel next time around such a feature needs a more thorough test in the official review.

Kinda bad only if the high pass is set at a rather high level ( 120-220hz). It would be unusual to want to do that in anything but a tiny desktop speaker system where nobody would need the power on tap with the Douk.

 

[Jon L]

I would MUCH rather have a low pass filter to use for my multiple subwoofers whose plate amps have died (they all die eventually).

Oh, Douk A5 sounds much better to MY ears with decent discrete opamps. I don't care if it's psychoacoustics, but placebo demonstrably works in medicine

0330251320_HDR by drjlo2, on Flickr

 

[Roland68]

Well, that small DIM package has only a limited heat dissipation capability.

Oof. The main reason I got this was because of the filter. And now it turns out it's actually kinda bad? I feel next time around such a feature needs a more thorough test in the official review.

I almost ordered it because of the filter, but luckily I read about it beforehand.
The filter is actually unusable.

I would MUCH rather have a low pass filter to use for my multiple subwoofers whose plate amps have died (they all die eventually).

If you need an amplifier with a low-pass filter for your subwoofer, then the AIYIMA A70 MONO is a good option.

 

[Jon L]

If you need an amplifier with a low-pass filter for your subwoofer, then the AIYIMA A70 MONO is a good option.

Nah, even from Ali, Aiyima A70 mono costs about 50% more for half the channel (mono vs two of Douk A5).

 

[Roland68]

Nah, even from Ali, Aiyima A70 mono costs about 50% more for half the channel (mono vs two of Douk A5).

You're right.
But...
- With the A5, you only get slightly more than 1/3 of the power; 59 watts per channel isn't very much for a subwoofer.
- even with a larger power supply, the A5 will barely reach more than 80-90 watts per channel at 4 ohms.
- even at low power levels, the A5 seems to get quite warm, and things aren't any better with the subwoofer.
- and you still need to buy a low-pass filter for your subwoofer.

It was just a nicely meant note.

 

[Jmudrick]

I almost ordered it because of the filter, but luckily I read about it beforehand.
The filter is actually unusable.


If you need an amplifier with a low-pass filter for your subwoofer, then the AIYIMA A70 MONO is a good option.

How is the filter "actually unusable"? It's doing exactly what most would want to do with it.

 

[Roland68]

How is the filter "actually unusable"? It's doing exactly what most would want to do with it.

At least, that's what it is for me.
Ideally, a steep or very steep filter would be one that can also be shifted within a certain frequency range, e.g., from 20 to 80, 100, or 120 Hz.
But from everything I've seen so far, the starting point can only be shifted by 10 Hz, from about 20 to 30 (more like 28) Hz, but the steepness of the filter decreases drastically.
For me, that's the opposite of ideal, but that's my personal opinion based on the information available. I could be wrong.

 

[Jmudrick]

At least, that's what it is for me.
Ideally, a steep or very steep filter would be one that can also be shifted within a certain frequency range, e.g., from 20 to 80, 100, or 120 Hz.
But from everything I've seen so far, the starting point can only be shifted by 10 Hz, from about 20 to 30 (more like 28) Hz, but the steepness of the filter decreases drastically.
For me, that's the opposite of ideal, but that's my personal opinion based on the information available. I could be wrong.

High pass set at 80hz or so works perfectly well especially when using EQ to smooth over crossover via Wiim or with ARC as I'm using. For $89 (or 2x that) I find it hard to criticize.

 

[Audionaut]

But from everything I've seen so far, the starting point can only be shifted by 10 Hz, from about 20 to 30 (more like 28) Hz, but the steepness of the filter decreases drastically.

It looks to me as if the filter slope is the same and the frequency is variable

 

[Roland68]

View attachment 440923

It looks to me as if the filter slope is the same and the frequency is variable

The measurements I've seen so far say something different.
But I didn't want to start a discussion about it, and maybe the measurements are inaccurate.
On top of that, my expectations are too high.

High pass set at 80hz or so works perfectly well especially when using EQ to smooth over crossover via Wiim or with ARC as I'm using. For $89 (or 2x that) I find it hard to criticize.

For the price, you probably can't complain.
Perhaps my expectations are too high, and at that price, it's not worth discussing.

 

[Jmudrick]

The measurements I've seen so far say something different.
But I didn't want to start a discussion about it, and maybe the measurements are inaccurate.
On top of that, my expectations are too high.


For the price, you probably can't complain.
Perhaps my expectations are too high, and at that price, it's not worth discussing.

What measurements are you talking about??

 

[Talisman]

...

The reviewer is Italian but the on-screen measurements are valid, the responses with the filter set at 12 o'clock, 3 o'clock, and at the end of the stroke were also measured

 

[thewas]

The reviewer is Italian but the on-screen measurements are valid, the responses with the filter set at 12 o'clock, 3 o'clock, and at the end of the stroke were also measured

Thank you for posting this, the high pass filter measurements are painfully missing from the ASR review (its just a couple of sweeps and minutes more and can be more relevant and audible then anything else) and show its poorly implemented and thus rather useless feature:

Hope some people didn't buy it because of it and possibly the rating of several might be different if such was shown in the review.

 

[Talisman]

Thank you for posting these, the high pass filter measurements are painfully missing from the ASR review (its just a couple of sweeps and minutes more) and show its rather a poorly implemented and thus useless feature:
View attachment 440995 Hope some people didn't buy it because of it and possibly the rating of several might be different if such was shown in the review.

I also posted exactly the graph you show, but it seems that few people cared about it.
But two considerations
the active filter but set to minimum is still useful to remove the sub bass frequencies in small bookshelf speakers, those frequencies are often not reproducible by those speakers and do nothing but create distortion and drain the amplifier's power for nothing

The cutoff frequency that starts at about 200hz could be used if calibrated well with the sub filter to have a decent implementation of the subwoofer

 

[thewas]

the active filter but set to minimum is still useful to remove the sub bass frequencies in small bookshelf speakers, those frequencies are often not reproducible by those speakers and do nothing but create distortion and drain the amplifier's power for nothing

Yes, but rather like subsonic/rumble filter, not one for adding a subwoofer.

The cutoff frequency that starts at about 200hz could be used if calibrated well with the sub filter to have a decent implementation of the subwoofer

With that weird and early slope someone would need to equalise significantly to compensate the roll off below 1 kHz which can be done of though but is not what someone expects from a decent high pass.

 

[Talisman]

Yes, but rather like subsonic/rumble filter, not one for adding a subwoofer.



With that weird and early slope someone would need to equalise significantly to compensate the roll off below 1 kHz which can be done of though but is not what someone expects from a decent high pass.

I don't disagree with what you write, I just wanted to point out that it's not totally useless and that probably for the price paid it's currently the best possible compromise that allows at least a vaguely decent integration between bookshelf speakers. The filter could certainly have been implemented better, that's for sure.

 

[MAB]

I don't disagree with what you write, I just wanted to point out that it's not totally useless and that probably for the price paid it's currently the best possible compromise that allows at least a vaguely decent integration between bookshelf speakers. The filter could certainly have been implemented better, that's for sure.

Yeah, I think the point is it would be nice to see these features tested, so we know what the actual response is. I have been hesitant to buy these so-called integrated amps for use with subs, the one I did buy had useless high-pass filter for sub integration. This Douk isn't useful for any purpose I would think of, maybe someone could use this filter response. To implement a filter I would consider useful shouldn't cost much, and testing this feature which some people would consider important isn't costly either.

Also, I like to know when an audio manufacturer produces a filter like this, which I consider a poor attempt to execute a very simple filter. It's not just a slap in the face of people who genuinely bought this device to integrate a sub with, but also speaks to the manufacturer's competence since a high-pass filter is a basic foundational circuit, trivial to implement, and not really an area where compromises are necessary or acceptable.

 

[Jmudrick]

I don't disagree with what you write, I just wanted to point out that it's not totally useless and that probably for the price paid it's currently the best possible compromise that allows at least a vaguely decent integration between bookshelf speakers. The filter could certainly have been implemented better, that's for sure.

Definitely not useless. Reduces the <40hz load to my bookshelves (Infinity IL10) letting the two subs carry that load. Would I like a more flexible HPF yes. But I see it as basically a freebie with a very decent amp. No regrets.