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Douk Audio A100 [TPA3255 PFFB Mono/Stereo] - User Impressions | Owner's Thread

Guddu

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Dear FMs,

Douk Audio posted a thread about this A100 amplifier HERE sometime back and they shared loads of information with internal pics, measurements like SINAD and power output.

I have recently got Douk Audio A100 amplifier, as I continue with my enthusiasm to explore TPA3255 chip amplifiers, and I have found this amplifier different than others in many ways.
This thread is dedicated to Douk Audio's new TPS3255 amplifier, I intend to share my impressions using this amplifier testing and evaluating features with observating any issues if noticed.
I hope other A100 owners may chime in as well to share their observations, used cases and any issues (if any).

*** I hope other A100 owners can also sum up their feedback and some work arounds here to help other potential owners or interested ones ***

Here, I mean to summarize:
> what I get as a buyer or user of Douk Audio A100 amplifier
> aspects other than measurements that you might be interested in
> testing features & functions to see if there are any issues and how could get around those, if any
> I also hope that this thread could provide some information as to "what to expect" while you look to buy one for yourself

Price (as of 08/08/2024)
* Amazon and Douk's store - 199$ with 48v 5a PSU
* AliExpress - 164.99$ (after 25% off) without PSU, and 202.49$ (after 25% off) with 48v 5a PSU

Package Contents
* Amplifier unit, PSU/power cable and laminated user manual
A100_Packaging_1.JPG

IMG_2453.JPG

- Note that power plug detached cord is 20AWG while DC cable attached to PSU is 18AWG

IMG_2454.JPG


- They have done great job providing Laminated user Manual, which has all the details you might need and even more

IMG_E2459.JPG

IMG_E2456.JPG


- They even included SINAD measurements and frequency response. This is PFFB topology implementation so both the measurements are as good as others with PFFB.

IMG_E2460.JPG


Case Work
- The case is super solid, all aluminium, think and heavy
- Top has thick fins, however sides and bottom had less defined fins
- Front has brushed aluminium touch along with some partly smoother finish
- Honestly, pics don't reallt justify the asthetics but it looks much better in person than pics
- Note the height of the amplifier is twice+ than others we have seen from Aiyima (like A07 pro, max), Fosi (v3 and v3 mono), Topping PA5 II or PA7 etc.
- Front has selection toggle switches and potentiometer knobs for different adjustments, more details later in the post
1723263976440.png


- Back has rather simplified connections - RCA input, aux out, speaker terminals and PSU input
- the speaker terminals are much better than other amplifiers (similar to Topping PA7, Aiyima A07 Max, Aiyima A70 etc.)

1723264336579.png


Summarising input/output on this amplifier:
Note:
I wasn't going to detail this part but it took me some time to read and understand this, so thought someone might use these short cliff notes to get it quickly
- Single ensed or un-balanced RCA inputs only, however no balanced inputs
- RCA input sensitivity: 2v (update)
- Aux out with full band or sub-frequency out, however no sub-out
- Aux out: 2.8v (update)
- Amplifier can function as:
- Stereo/Mono amplifier with full frequency - by selecting first toggle (left) to MONO/STEREO and second toggle (right) to FLAT
- The FLAT mode enabled 2 potentiometer knobs on front, which worked fine with me trying a few times
- 4th knob from left or last one on right - VOLUME - Contols the volume out to speaker output, it had no effect on aux out
- Stereo/Mono Subwoofer Amplifier with low/mid-low frequency - by selecting first toggle (left) to MONO/STEREO and second toggle (right) to SUB
- The SUB mode enabled 2 potentiometer knobs on front, which worked fine with me trying a few times
- 1st knob from left - SUPER-BASS - no markings on the amplifier but it is adjustable -6dB to +6dB BASS
- 2nd knob from left - SW-FREQ - no markings on the amplifier but it is adjustable from 50 - 220 Hz
- Pre-amp with Aux Out
- Aux Out is full band out
- 3rd knob from left (in front) controls and adjusts the volume output to Aux Out

Idle Power Consumption
- A100 used about 9-10 watts when IDLE, connected and powered ON but no sound playing
- measured on 20A smart power plug
A100_Idle+Power.JPG


Case Heating & Tempreture - Better than others (updated)
- The amplifier case remain cool on idle, this is unlike any other TPA3255 amplifier I have (and believe you me that I have many of those)
- I have Ascend Sierra-lx hooked up to A100, which do play lower base frequencies and eats up some good power, and amplifier case did get just warm to touch in playing quite loud to longer period
- Whatever Douk Audio did, working on this amplifier with better thermal performance. This amplifier is running cool or just warm in my setup while other amps are running towards hotter side in same setup
- This also makes me believe that this amplifier can easily be used for passive subwoofer, thermal performance of this amplifier is best so far (to me)

Hiss/Noise and Pop Sound on Power ON/OFF

- NO HISS or any noise at all on FULL Volume position to my speakers, nothing on putting ear to tweeter
- NO POP sound on power ON/OFF toggle switch
- So this amplifier is handling these common issues much better than other TPA3255 amplifiers I have owned

My Setup
A100_Display_4.png

nVidia Shield & Laptop >>>> Emotiva xmc-1 Gen2 >>>>>RCA>>>>> Douk A100 amplifier >>>>> Ascend Sierra-lx speakers

Subjective Impressions
- Very clean and balanced sound with very clear stereo separation
- Sound is really strong, lower volume had similar attributes as higher volume
- No complains at all... only praises
- Here is quick REW sweep for Douk A100 vs Topping PA7:

index.php


Some Notes and considerations:
- The RED LED in front is thankfully quite mild, does not cause any disturbance.
- I am listening A100 in stereo mode most of the time as I have got only 1 unit, however 2 x mono setup would be amazing as well!
- The case edges are a bit sharp, and so requires a bit careful handling. Slighly softer and smooth edges would have been nice.
- The bottom could use 2-3 cm high feets to provide some clearence on bottom, I would surely use some feets myself and would sugget to others as well (4 small silicon spacers are included in the package but i think slighly bigger would make more sense).
- SUPER-BASS and SW-FREQ knobs in front has no number marking, this had made it difficult to get to any approx. specific value. I wish if they could have put a dot for every 10dB variance or something to make it easier to adjust and avoid kind of confusion.
- I feel that the stock AC power cord (20AWG) is thin to use with 48v 5a psu and this amplifier, I am using a different 18AWG AC cord and it matches with DC cord part of stock PSU. Douk should upgrade the AC cord for safer operation. (some corrections made)
- Power input port has marking 24 - 48v, however @Douk Audio provided 51v psu measurements running the amplifier to its peak. Probably Douk Audio are not suggesting to use anyting above 48v?
- The amplifier case is completely closed, no airflow possibility through it. TPA3255 Chip is screwed to bottom and using case as radiator but wouldn't some ventilation help for heat build up inside for other components!

A few suggestions @Douk Audio
What did I miss most!
<having these makes it easy to integrate the amplifier within a setup, kind of must to have these days>
- Volume bypass
- Triggered input or auto ON/OFF

Something for a different amplifier: @Douk Audio
- A simpler mono/stereo power amplifier version of this A100 would suit many scenarios very well.
- I really think the same case with no no buttons/knobs in front, or just power toggle would look very good. The knobs on A100 aren't totally matching with brushed aluminium look behing it.
- Same thermal performance, and same filters avoiding hiss or any pop sound on power ON/OFF.
- No volume control, no SUB mode, aux out or sub out - may be, no tone controls.
- A 3 or 4 channel power amplifier version of this A100 is something everyone is asking other vendors, probably you should look at that.
 

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Thank you for that review. I got tired of waiting so I'm enjoying a Fosi ZA3.
 
My impressio: It looks quite "cheap" in its current appearance and the measurements shown are "not so good"... Who "designed" that as is ???
It might have a better temperature management as the Fosi Audio V3 mono but still lacks some escape possibilities for enclosed (hot ?) air at the top.
Due to its lower temperatures this might not be as problematic as on the Fosi Audio V3 mono...
 
Many youtube reviews now for this Douk A100, a few with some comparision with other similar products.
Subjectivists are appreciating A100.
Looks like a few used the idea of using fins block on top of their (other brand) amplifiers to help with temp. control!
 
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