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Douk Audio U5 mini balanced amplifier

Overview Reviews (1) Gallery

General Information

Features
  • 【Fully balanced headphone amplifier】Adopting fully balanced amplifier circuit and innovative circuit design, the amplifier circuit of U5 always works at a high voltage of 24V even if input DC 5V, with wide frequency response extension, excellent transient response, excellent purity and transparency, and good dynamic range.
  • 【Easily to drive low or high impedance headphones】For a total power output of up to 1400mW under a 32Ω load, U5 can easily power headphones with any low or high impedance (18-600Ω). Volume knob allows you to smoothly adjust volume without any undesirable noise nor any channel imbalances.
  • 【Pure analog design to reproduce music truly】Pure analog amplification circuit and analog control, show you the truest sound, all aspects are in the top-class such as sound field, sound position, details etc.. Adopt original JRC4580 classical op amp, pluggable socket design, convenient to upgrade different op amps to enjoy other sound styles.
  • 【Most cost-effective amp on the market】Mini size and exquisite appearance, and with low distortion, high power and a pure, uncolored sound, you’ll experience subtle details and shocking swings in your music effortlessly. U5, the best helper for all xlr/4.4mm headphones to improve their sound quality.

Warm tips
  • Without DC 5V power adapter, you can use your phone charger, input over 5V will result in damage.

Parameters
  • Audio input: stereo L/R XLR ( 3-core, female)
  • Audio output: XLR ( 4-core, female) / 4.4mm
  • Output power: ≥1400mW (32Ω)
  • Matched headphone impedance: 18-600Ω
  • Frequency response: 20-30KHz
  • Signal to noise ratio: ≥110DB
  • THD: 0.005%
  • Input voltage: DC 5V (recommend above 1A)
  • Dimension(W*D*H): 68*69*28mm / 2.68*2.72*1.50in
  • Net weight: 149g / 0.33lb
  • Package weight: 500g / 1.10lb

Packing List
  • 1*U5 Headphone Amplifier
  • 1*USB to DC Cable

Latest reviews

NymPHONOmaniac

NymPHONOmaniac

Headphoneus Supremus
So cheap yet doesn't sound so cheap
Pros: -Massively open headroom
-Vivid, punchy yet non shouty dynamic
-crazy 1.4W of power output
-decent noise floor and clarity
-good imaging-layering
-not distortion unless ultra sensitive IEM
-precise volume control free of sound imbalance
-USB powered from your laptop
-true balanced output (excellent crosstalk it seem)
-non grainy or unpleasant timbre
-no invasive hiss no muddy dynamic
-more than competent technicaly
-changeable OPamps to improve the sound (if so, it will be insane)
-ultra small
-no brainer price value
Cons: -not the cleanest and more linear sub bass extension
-not crispest treble (perhaps slight roll off around 12khz)
-imaging while good doesnt have cleanest separation space
-will make shine more hard to drive headphones and IEM than average one
-impedance output is surely quite high
-not the most lean or linear amplification (can be a plus for some)
317509493_693470508805621_2918446581716075169_n.jpg

TONALITY: 8.5
TECHNICALITY: 8.2/10
DYNAMIC RENDERING: 9/10
CONSTRUCTION: 8.5/10
PRICE VALUE: 10/10

This is a video review of the ultra budget ultra small Douk Audio U5 balanced headphones amplifier. I was expecting a pretty averag amplifier that would negatively affect clarity and imaging of my headphones and hard to drive IEM, but it wasn't the case at all. You can look comparisons against Xduoo XD05plus for example, using burson V5i dual opamp, but let say result is that U5 sound more open, clean and balanced in dynamic, while XD05plus is warmer with harsher upper mids and treble and more compressed layering as well as high distortion.

CONSTRUCTION
317326637_517455433642860_4774224726634611445_n.jpg

318512823_478032704401155_1889686151775483693_n.jpg

Construction is minimalist and industrial looking, yet not made of plastic and seem sturdy enough. Its very small too. 4.4mm jack is gold plated and of good quality while XLR are basic one. Inner circuitry is clean and well done.
The usb power supply worry me at first, but my laptop dont struggle delivering the power properly and don't get hot or anything even after long use. it most be noted that if you plan using another power supply it need to be DC 5V with minimum of 1a.
The power magig of U5 come from the fact it transform 5V load into 24V, im no electrician and don't know how they achieve this, but it sure boost the gain yet without going disastrous since the o.005% of total harmonic distortion specs seem real, the U5 sound quite clean and just add minimal euphony to definition edge and attack sustain-release.

317508314_669050468028986_125631008448947465_n.jpg

The stock OPamp are basic 4xJRC4580, yet doesn't justify urgen upgrade since their no invasive hiss or distortion with this amp ,again, its not a THX AAA endgame clean clarity, but sens of transparency, articulation of layering of most of all spatial openess headroom is incredible.
But you can easily swap it for an upgrade that can scale up performance of U5, i will need to order 4 OPamps of same model and sure share impressions of what you get. Let say, its more than welcome.
As well, while input is balanced XLR, you can use 3.5se to XLR cable, but i can't say how it will on performance like dynamic and noise floor.

317904460_803187690744694_1129053554108436174_n.jpg


This amps deliver 1400mw@32ohm, surely have high impedance but will be ok with 32ohm and higher IEM. The U5 drive my Final E5000 like no other of my amps, i couldn't beleive it, was expecting distortion or warmer tonality but got the opposite, E5000 become clean W shape with ultra punchy chunky bass, fowards open vocal and extra treble air, imaging and layering was notably improved as well as soundstage.
Hifiman Sundara result was similar, again, great bass punch, lively dynamic and great sens of openess that doesnt make instrument feel distant.

I can't recommend you enough this mini amp, it might be budget audiophile end game solution for hard to drive planar and IEMs.

You can order the U5 for 40$ for Douk Audio Ali express store here (non-affiliated link):https://www.aliexpress.com/item/1005003782094643.html
My full detailed review including comparisons against Haafee HA9, Xduoo XD05plus and VE Megatron can be find hre:




--------
Join CHIFI LOVE audio community here if you wanna discover more hidden gems like this:
https://www.facebook.com/groups/517665269706033

You can follow my instragram here, very active since i'm back on it, it include reels too:
https://www.instagram.com/nobordersaudiophile/?hl=fr

And for diversify audio products review, my No Borders Audiophile still exist, and will focus on mid tier audio products for detailed written review from now on (it might go bilingual too, so if your french plz subscribe!): https://nobordersaudiophile.wordpress.com

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6Channel
6Channel
Well, I can shed a bit more light:
After a tremendous experience with the U3, I elected to see if the U5 could light up my HE6se's. Stock 4580's with a 1A wall wart (5V! - a secret is keeping these Douks fed with no more than 5V!) resulted in "sleepy" audio, at best. So, I swapped in some premium 5532s and a 4A (5V !) power supply. VOILA ! All of your "CONS" vanish, though I can't comment on suspected output impedance or IEM impact (I don't do IEMs). The result may not compete with an integrated amp for the headbangers among us, but for me SQ outta this U5 is stunning right now. Oh ya: I'm a firm 5532 junkie.

Others' comments have me wondering if a battery pack could improve upon the power source.
ATimoff
ATimoff
@6Channel I ordered a U5. With the prospect of trying to replace 4 chips with the original NE5532P. They're not bad. The output signal rise rate is > 9 V/µs vs 5 V/µs in the 4580D! Otherwise, the parameters are close. Did you directly insert these chips into the connectors or did you change something in the circuit?
sofastreamer
sofastreamer
would it be possible to replace the opas for the Sparkos ss3602 dual discretes? would be quite expensive as it takes four of them, but would they fit including closing the amp?
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Comments

6Channel

6Channel

100+ Head-Fier
ATimoff, sorry I didn't see you'd commented and asked about my swap: I researched the 4580 vs 5532, and figured I could swap them directly. Nary a blip - dead quiet, and the speed & HF extension shines. I've ordered 4562's, but still trying to find out whether those 4580's are paralleled in each channel or if they're series, building on each other. Owing to the total power out, I'm guessing they're paralleled (means chips need to be the same). Some say the 5532 or 4562 might require .1uF poly-film caps across power pins, but I'm not convinced that effort will yield much at this level.
 
ATimoff

ATimoff

Head-Fier
I regularly viewed the forum. But I also didn't see a reply message. Magic...

I got a U5. For experiments. I took out my old, dusty DAC (Audiolab M-DAC) from the pantry.
Connected and .... stunned. I will not resort epithets. The sound meets the high criteria.
It does not make noise or distort the sound at normal volume.
It is well balanced! I used good full-size headphones of 32 and 150 ohms.

Where does so much power come from in several operational amplifiers?
I thought there was an output transistor stage in the circuit.
But I don't see it in the pictures.

There are disadvantages too. You still need LPS (>3A).
A passive attenuator is needed at the input (-20 ... -40 dB).
Without an attenuator, the signal is in the area of the potentiometer
with a noticeable channels imbalance. I avoid digital methods of controlling source volume!
I did not disassemble the U5. I left it as a sample.
For risky experiments, I ordered a second U5.

About OpAmp:
JRC4580D is pleasant, but sleepy.
All x5532x is worthy of attention. It's a classic!
We should try the popular ones OPA2604,1612,1622,1656.
When choosing, I look at the maximum output current of the OpAmp.
The higher the better (If there are no transistors).
For comprehension: https://vpayaem.ru/inf_ou_audio.html
But it all depends on the specific circuit on the board.

I wonder what is the current nominal resistance of the input potentiometer U5?
It seems that Douk Audio sometimes unexpectedly changes the nominal value of such regulators.
In the process of releasing the model. The input impedance is important for the selection of a passive
attenuator and an XLR-cable model.
 
6Channel

6Channel

100+ Head-Fier
ATimoff said:
I regularly viewed the forum. But I also didn't see a reply message. Magic...

I got a U5. For experiments. I took out my old, dusty DAC (Audiolab M-DAC) from the pantry.
Connected and .... stunned. I will not resort epithets. The sound meets the high criteria.
It does not make noise or distort the sound at normal volume.
It is well balanced! I used good full-size headphones of 32 and 150 ohms.

Where does so much power come from in several operational amplifiers?
I thought there was an output transistor stage in the circuit.
But I don't see it in the pictures.

There are disadvantages too. You still need LPS (>3A).
A passive attenuator is needed at the input (-20 ... -40 dB).
Without an attenuator, the signal is in the area of the potentiometer
with a noticeable channels imbalance. I avoid digital methods of controlling source volume!
I did not disassemble the U5. I left it as a sample.
For risky experiments, I ordered a second U5.

About OpAmp:
JRC4580D is pleasant, but sleepy.
All x5532x is worthy of attention. It's a classic!
We should try the popular ones OPA2604,1612,1622,1656.
When choosing, I look at the maximum output current of the OpAmp.
The higher the better (If there are no transistors).
For comprehension: https://vpayaem.ru/inf_ou_audio.html
But it all depends on the specific circuit on the board.

I wonder what is the current nominal resistance of the input potentiometer U5?
It seems that Douk Audio sometimes unexpectedly changes the nominal value of such regulators.
In the process of releasing the model. The input impedance is important for the selection of a passive
attenuator and an XLR-cable model.
Click to expand...
My first U5 had intolerable imbalance, but they're so cheap I ordered up another and it seems to track very evenly. Pleasant but sleepy sums up the 4580. I've generally lucked out, as everything I've owned with 5532's sounds just about right at the end of the processing chain. And, as you apparently discovered, it responds better the more amperage as you can cough up at ~5V. Many of these Chinese mfgrs hinge their power solution on 5V, above which their circuitry can run you into distortion & other artifacts. I've experimented with other bipolar chips, but always wind up back with 5532s. Might be a difficult case for throwing 4 X Sparkos/Burson/Muses circuits at this bargain piece. We should enjoy it for what it is !

I will never discourage cleaner & higher-amperage power supplies, however !!

I took a run last year to figure out the pot characteristics, but it's board-mounted & too tricky to figure out whether readings are influenced by other already-mounted board components. So, I'm happy enough to run with what they are.
 
ATimoff

ATimoff

Head-Fier

@6Channel ​

I agree. I came to the same conclusions. The power supply is important! I will try the listed series of operational amplifiers on the second U5. It is not advisable to use extremely expensive and exclusive chips in it. If there is an interesting result, I will share the information. I wonder what is the input resistance of your U5 (pins 1-2 and 1-3)? A low-quality potentiometer can be a bottleneck.
 
6Channel

6Channel

100+ Head-Fier
ATimoff said:

@6Channel ​

I agree. I came to the same conclusions. The power supply is important! I will try the listed series of operational amplifiers on the second U5. It is not advisable to use extremely expensive and exclusive chips in it. If there is an interesting result, I will share the information. I wonder what is the input resistance of your U5 (pins 1-2 and 1-3)? A low-quality potentiometer can be a bottleneck.
Click to expand...
Many, many audiophools (like me) swear by character & strength of the fancy plug-in circuits, and I've popped for Burson & Muses - they're very interesting, but for my listening pleasure they "pay a price" somewhere in the audio spectrum. It's been pointed out that about 80% of produced audio we've enjoyed for over 30 years was run through boards loaded with 5532s, from recording to final mix-down. Even today you will find hand-picked 5532s (variability is a serious thing) in 5-figure audio components. Low-quality potentiometer ??? I paid $39US for my replacement U5, and I've seen 'em new from China for $26. We're talking -cheap- . I shelled out $90 for an esoteric Stateside pot for a project in the Late Seventies. Now, I'm even embarrassed to admit that pot purchase, but it's dwarfed by what I popped for caps & tube sockets.

Why do I mess with U5 ?? Because it sounds really, really good now compared to some fancy amps I've heard. The curveball I'll toss in here is that my U3 sounds even better - the third 5532 is the charm.
 
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