OP
- Thread Starter
- #41
The colorations without PFFB will be audible to some. The higher distortion at high frequencies are much less likely to be so.
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Douk A5 Budget Stereo Amplifier Review
- Thread starter amirm
- Start date
I voted fine because the amplifier is not perfect but I agree for $ 100 or less it is a bargain.
With Douk, I feel they are trying to cater to both objectists and subjectists, on one hand they make technical good products and the other hand they implement a possibility to do opamp rolling and there is a thread on ASR about a linear power supply that they are developing. Ofcourse it broadens their market and increases sales numbers so the prices can be low.
With Douk, I feel they are trying to cater to both objectists and subjectists, on one hand they make technical good products and the other hand they implement a possibility to do opamp rolling and there is a thread on ASR about a linear power supply that they are developing. Ofcourse it broadens their market and increases sales numbers so the prices can be low.
OP
- Thread Starter
- #43
We have had extensive discussions around that horribly thought out regulation. And discussed what JA is doing as well.
Which is not what the regulation demands (full range of frequencies). My testing is at 10 frequencies:
I have tested amplifiers recently which will shut down at 1% THD. Using this regulation, the stated power would then have to be zero!
JA is going to have trouble with a lot of high-end amps that are distortion factories. There will be loud cries from companies that send him gear....
DanielT
Master Contributor
Thanks for the test Amir and...
Since I refer to that video, I can fill in a little more info about it. Otherwise, John seems to like the Douk A5 amp. He points out - which we also see thanks to Amir's measurements - the increased distortion higher up in frequency. For the spec sheet type of people, it was not perfect. But then John also points out or asks the question: What is one's ability to hear distortion in the higher or highest frequency registers? Especially if one also takes the age aspect into account in the equation. Thats a dear topic, or question that also pops up often here at ASR.
(in several posts in this thread by the way)
Here filter HP setting to 200 Hz:
...what you said there combined with the low price is what really makes the Douk A5 interesting.
In the video from JohnAudioTech that was published in #35 from 17:00, John also points out what you say about the heat generation/ dissipation if it is fed with 48V.
Since I refer to that video, I can fill in a little more info about it. Otherwise, John seems to like the Douk A5 amp. He points out - which we also see thanks to Amir's measurements - the increased distortion higher up in frequency. For the spec sheet type of people, it was not perfect. But then John also points out or asks the question: What is one's ability to hear distortion in the higher or highest frequency registers? Especially if one also takes the age aspect into account in the equation. Thats a dear topic, or question that also pops up often here at ASR.
(in several posts in this thread by the way)
Here filter HP setting to 200 Hz:
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Old_School_Brad
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Robust little bugger.
Thanks Amir for the review, I had already bought the little A5 because I had never found anything that at such a low price included pffb and Hpf, happy to see the excellent performance now.
The criticisms on this product make me smile. We are talking about a 100 euro amplifier with a reasonably flat frequency response, a filter for sub integration that many of us have repeatedly asked for and a sufficient amount of power for most of the applications for which it is designed.
At 99 euros there is no room for criticism
The criticisms on this product make me smile. We are talking about a 100 euro amplifier with a reasonably flat frequency response, a filter for sub integration that many of us have repeatedly asked for and a sufficient amount of power for most of the applications for which it is designed.
At 99 euros there is no room for criticism
Nice to see a objektiv review of this thing, sad that they did not send the 48v Power supply. For me a little to less Power with this one.
Im curious to see a 3e Audio A7 review. This little class D powerhouses are invade the world so rapid i would Love to see an AVR with this Chip Implementation, would be so many benefits in price, size, weight, Power, Heat, thd and so on...
Im curious to see a 3e Audio A7 review. This little class D powerhouses are invade the world so rapid
i would Love to see an AVR with this Chip Implementation, would be so many benefits in price, size, weight, Power, Heat, thd and so on...
JSmith
Master Contributor
I see they have this on their website... which isn't great;
@Douk Audio... what do you mean by "upgrade sound" and "tailor sound profiles"?
JSmith
I also note that given the peculiar Hpf implementation it is very likely that most buyers will want to use it precisely to integrate a sub, this makes the output power even less of an issue, given that a lot of musical power is absorbed below 100hz.
I am reasonably sure that this A5 with bookshelf speakers cut at 100 hz and integrated with a sub can work at much higher volume and with less distortion than a fosi V3 connected to the full range to the same speakers.
I am reasonably sure that this A5 with bookshelf speakers cut at 100 hz and integrated with a sub can work at much higher volume and with less distortion than a fosi V3 connected to the full range to the same speakers.
Just a few more side by sides (all PFFB, albeit the Fosi is 3255 BBTL in addition to PFFB and runs at 48 V, and the PA5II and 3e A5 are 3251 and both run at 36 V, and yes, they are a lot more expensive while the Fosi is not considering its power):
The Topping and 3e are in a class of their own. The Fosi is actually quite good at 1 kHz for HHD (highest harmonic distortion). The Douk sticks out with it high HD3. Its HD2 is excellent (but that is easy to achieve), and its higher orders, i.e. HD5 and up, are actually a tad worse than the Fosi).
When you look at the multitone IMD, you can see that the two champions have about - 120 dB "grass" at 1 kHz, slowly rising to -115 resp. -110 dB at 10 kHz. The Fosi is at maybe - 118 dB at 1 kHz, rising to -100 dB at 10 kHz. The Douk's rise begins at well below 1 kHz, hits - 100 dB at 1 kHz and - 80 dB at 10 kHz.
Two-tone shows the same picture, the champions achieve - 80 dB lowest order products, the Fosi -70 dB and the Douk -60 dB.
The Douk clearly has the lowest PFFB loop gain and the lowest loop bandwidth. That is achieves low THD at 1 kHz (with the exception of HD3) is amazing, and that it almost perfectly load invariant is close to a miracle given that the loop cannot be of much help at beyond 20 kHz. The HD3 probaby originates in the preamp or is down to one component in the power amp acting up.
Finally, the HF THD+N, fully in line with the previous results:
The Topping and 3e are in a class of their own. The Fosi is actually quite good at 1 kHz for HHD (highest harmonic distortion). The Douk sticks out with it high HD3. Its HD2 is excellent (but that is easy to achieve), and its higher orders, i.e. HD5 and up, are actually a tad worse than the Fosi).
When you look at the multitone IMD, you can see that the two champions have about - 120 dB "grass" at 1 kHz, slowly rising to -115 resp. -110 dB at 10 kHz. The Fosi is at maybe - 118 dB at 1 kHz, rising to -100 dB at 10 kHz. The Douk's rise begins at well below 1 kHz, hits - 100 dB at 1 kHz and - 80 dB at 10 kHz.
Two-tone shows the same picture, the champions achieve - 80 dB lowest order products, the Fosi -70 dB and the Douk -60 dB.
The Douk clearly has the lowest PFFB loop gain and the lowest loop bandwidth. That is achieves low THD at 1 kHz (with the exception of HD3) is amazing, and that it almost perfectly load invariant is close to a miracle given that the loop cannot be of much help at beyond 20 kHz. The HD3 probaby originates in the preamp or is down to one component in the power amp acting up.
Finally, the HF THD+N, fully in line with the previous results:
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It means that they are a company that aims for profit and not just technological glorification. They know that many customers have this vision and certainly do not intend to cut off a slice of the market in the name of an "incorruptible faith in science"
Such drastic positions are a luxury that buyers can have, not companies. Let's just analyze what they do, which is much more science-based than what those two sentences say.
Sokel
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You can certainly have "sound profiles" .
When I have some time I'll post some charts about what some really good but sensitive op-amps like LME49720 can do to a circuit that are not made for it.
(both noise AND FR)
It certainly changes "the sound"
Other than that as much as I hate taking price as a criterion it's unavoidable here.
For under 100 is more than ok.
Thanks Amir!
DanielT
Master Contributor
Well, hm. With the power supply Amir tested it with, 59 watts into 4 Ohm, 33 watts into 8 Ohm. With fairly high sensitive 4 Ohm speakers maybe. But that's not a lot of power in this Douk A5 amp.
Most of it depends on the listening volume of course. It's hardly an amp that you have for nightclub high volume techno music. But on the other hand I don't think anyone would even think of using it like that.
HP that relieves Douk A5 from working with the lowest frequencies is an advantage in that regard. With this solution, you can better manage to power up the speakers to the desired (slightly higher than without HP) volume.
(I know you know this, I'll mention it to others reading this thread)
Let a powerful sub work with techno bass and you'll be at least a little bit closer to having a dance party at home.
Edit:
That said, I have to weigh in a very important factor. The price of the Douk A5 amp. That combined with the PFFB implementation plus HP filter makes it,in my eyes,a attractive amp.
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JSmith
Master Contributor
They are also alienating part of their original market though due to this type of thing, without providing proper evidence of their claims. Either show a measurable and audible improvement, or don't mention it. Sure, physically leave the option there... but don't make such unsubstantiated claims. Let the good products stand on their own merit.
Making such claims may well fall foul of some countries consumer laws as well, in regards to deceptive advertising and encouraging customers to modify a new device.
It also may make customers think Douk have not used the appropriate or "best" opamps and that they need to "upgrade" the opamps to get the most out of their purchase... i.e. FOMO. One positive is the comments on their site are rather minor, nothing like Fosi Audio claiming customers need different opamps based on music genre.
If they were really keen, they would educate their customer base as to why opamp rolling is an exercise in folly and a waste of money, then use that as a marketing point/difference. I don't think it's too much of a stretch for a company to be honest and moral about such things. 2c
JSmith
Yes, please post!You can certainly have "sound profiles" .
When I have some time I'll post some charts about what some really good but sensitive op-amps like LME49720 can do to a circuit that are not made for it.
(both noise AND FR)
It certainly changes "the sound"
Other than that as much as I hate taking price as a criterion it's unavoidable here.
For under 100 is more than ok.
Thanks Amir!
Regarding cost optimization, they could have saved that half-baked glass lid and invested the money in better components.
JeremyFife
Major Contributor
Thank you for (another!) interesting review, there's been a lot of Douk talk recently.
Cracking little amp, for hardly any money. Issues at higher frequencies are totally forgivable, and probably inaudible.
Nice to see a high-pass filter that seems to be implemented well. The sort of speakers that will be paired with this amp won't produce lower frequencies anyway, and then the limited power can be used much more effectively. Very sensible.
Cracking little amp, for hardly any money. Issues at higher frequencies are totally forgivable, and probably inaudible.
Nice to see a high-pass filter that seems to be implemented well. The sort of speakers that will be paired with this amp won't produce lower frequencies anyway, and then the limited power can be used much more effectively. Very sensible.
One tough little ship, might have to nickname it The Defiant.
They are selling into a crowded marketplace, seem to have used a little creative license to encourage sales through OP amp rolling ( my idea of hell but people enjoy it ) , along with the light display and implementation of PFFB , they've done well to distinguish themselves at this price range . It's best to appeal to the widest audience possible so I don't hold the ' creativity ' against them .
Thanks for the review Amirm , it's great to see such efforts down at the lower end of the price spectrum. It didn't used to be this way as I remember it !
I think Douk should be thanking you for the exposure too, possibly sending some fine tea over to the Seattle area or maybe send a representative over to valet your camper van.
They are selling into a crowded marketplace, seem to have used a little creative license to encourage sales through OP amp rolling ( my idea of hell but people enjoy it ) , along with the light display and implementation of PFFB , they've done well to distinguish themselves at this price range . It's best to appeal to the widest audience possible so I don't hold the ' creativity ' against them .
Thanks for the review Amirm , it's great to see such efforts down at the lower end of the price spectrum. It didn't used to be this way as I remember it !
I think Douk should be thanking you for the exposure too, possibly sending some fine tea over to the Seattle area or maybe send a representative over to valet your camper van.
This is excellent I have been wondering when Aiyima and Fosi Audio might introduce a proper HPF so congratulations to @Douk Audio - only thing I think it might be missing is a trigger input.
welwynnick
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Thanks Amir, that's the test I particularly like to see.Oops. just added to the review:
Cheers, Nick
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