O-Noorus D1 [TPA3255 PFFB] Stereo Amplifier - User Impressions | Owner's Thread

[Zek]

Mon ami m'a refiler son amplificateur non fonctionnel j'ai débourser $$ pour le faire réparer et maintenant il fonctionne.
cependant mon technicien affirme que l'implantation des pièces est très mal faite certaines sont soudées croche sur le circuit imprimé aucune protection sur la connexion souder etc...
les coils chauffés...
UNucune pâte thermique pour le dissipateur relié à la puce ti 3255...
Donc, il ne m'offre aucune garantie que d'autres soucis ne surviendront pas à court terme.
les fils s'écrasent sur le tableau et sont à risque.
Donc, faite inspecter votre ampli à sont arriver.

Google Translate:
My friend gave me his non-functional amplifier. I paid $$ to have it repaired and now it works.However, my technician claims that the installation of the parts is very poorly done, some are soldered crookedly on the printed circuit, no protection on the solder connection, etc.the heated coils...No thermal paste for the heatsink connected to the ti 3255 chip...So, it doesn't offer me any guarantee that other problems won't arise in the short term.the wires crash into the board and are at risk.So, have your amp inspected when it arrives.

 

[Audiovue]

@Audiovue Please write in english.

Just translate

 

[Tell]

Just translate

It's an english forum, so write in english.

 

[Jimbob54]

This is an English language forum so we request members do post in English.

 

[Audiovue]

It's an english forum, so write in english.

Stop insulting me. Grrrrrr

 

[Jimbob54]

Stop insulting me. Grrrrrr

That is not an insult. It's a statement of fact along with a reiteration of advice previously given.

 

[UAN]

I replaced the NE5532 op amp with an LM4562 and now the amplifier sounds much better. I compared it with PA5 II and didn’t notice a difference.
Very good.

 

[dr_mick51]

I replaced the NE5532 op amp with an LM4562 and now the amplifier sounds much better. I compared it with PA5 II and didn’t notice a difference.
Very good.

I use 2x OPA1612 opamps I soldered to DIP8 adapters. Of course the amplifier sounds amazing.
I also replaced the thermal paste(between chip and heatsink) with a better one just for peace of mind. The amp gets slighly warm at 97-98°F after a while.
I really like the digital volume control and the remote controller. I have a couple of vintage DACs with no volume control, so it is super useful for me.

 

[FanatNsk]

I replaced the NE5532 op amp with an LM4562 and now the amplifier sounds much better. I compared it with PA5 II and didn’t notice a difference.
Very good.

I have a question about the input sensitivity of the rca input. What is the voltage threshold before overload begins? What will happen to the output signal if I apply a 2Vrms sine wave to the amplifier input, will there be distortion on the multi-tone signal?

 

[audionub]

@UAN, @dr_mick51, I would like to replace op amps too. I just have a basic soldering iron, can I do it with that? Putting in a DIP8 adapter sounds like a good idea too.

@UAN how does the improvement sound?

 

[UAN]

.

@UAN how does the improvement sound?

To my ears the sound became better.

 

[dr_mick51]

@UAN, @dr_mick51, I would like to replace op amps too. I just have a basic soldering iron, can I do it with that? Putting in a DIP8 adapter sounds like a good idea too.

@UAN how does the improvement sound?

Well, if you have a thin soldering tip, thin (0.6mm) autectic solder and flux you can do it yourself. Pay attention to pin orientation and watch videos before doing it.
Practice first if you have not done it before.
You solder the adapter pins first because they take more time and heat(and probably a bigger solder tip) to solder those big pins(compared to the opamp small pins). You dont want to overheat the opamps while trying to solder the adapter pins.
Please let me know if you need some assistance.

 

[redjr]

that seems really strange

like i cant see how sending a board and asking the end user to replace the board himself is better than just asking the customer to send the faulty unit back and then offering a refund??

all this over $100 and some post???


if you are smashing out 1,000s of units on a line than you are going to get a set number of defects, that's just life

why would you escalate things over $100 lol

Or, just buy from Amazon for easy returns. Sure you might pay a little more, but you know you'll never be out the total cost of the product. Make it Amazon's problem, not yours.

 

[WHQL]

I just received my O-NOORUS D1 from Amazon and I have to say, for $99 I am very impressed so far. I am using it with a WiiM Ultra DAC and it is driving B&W DM604 S3 Tower Speakers, which are not the easiest to power. I am using the included 36V 5A power supply and I am surprised at the power output. The amplifier is dead quiet and to my ears the performance is excellent. My main system contains Arcam/Anthem/Revel components and at lower listening levels, this combo comes closer to it in sonics than I would have thought possible. Amazing, really. Regarding heat, I have the D1 in BP Mode with the volume set at 60 and after several hours of listening with the bass turned up, the amplifier became warm, but not hot. The included remote functions perfectly and is actually pretty useful.

I have a 48V 5A GaN Power Supply coming that I plan to swap in and compare. I noticed that the provided output level chart shows 36V and 42V at 5A, but not 48V at 5A. I am not sure why there is no 48V 5A option shown. At 48V 5A, the output should be over 100W per channel at 8 ohms. Hopefully, it will not increase heat significantly.

 

[WHQL]

I did some listening tests with two alternate power supplies. Using a 48V5A GaN power supply, I was not able to detect any difference at any volume I tried. Next I tried a Fosi 48V10A power supply. With this power supply, I did notice a very slight increase in bass at the lowest octaves. I was also able to lower the amplifier volume from 60 to 50 and achieve about the same output volume as with the stock 36V supply. Note, the Fosi 48v10A supply cost me more than the D1 amplifier itself. Not worth it in my setup. I ultimately went back to the 36V5A power supply that O-Noorus supplied with the unit.

 

[maxchau]

The D1 amp is uber transparent. Give it a cleanest power supply (solid state super cap bank) and feed R2R decoder into it, you will have a very satisfying system. I found 36V 5A supply plenty.

 

[dr_mick51]

The D1 amp is uber transparent. Give it a cleanest power supply (solid state super cap bank) and feed R2R decoder into it, you will have a very satisfying system. I found 36V 5A supply plenty.

You are absolutely right. Clean power is more important than raw power. Why do you need a noisy SMPS with 48V at 10A if most (if not all) my music is heard at 0.1 to 1W, lets give it some headroom, let's say 10W/ch max.
Also people seem to forget how output power works on audio amplifier. The output power depends on the input signal (attenuated by the pot) x the whole amplifier gain(opamp gain plus chip amp gain).
If you provide a 2V at 0dBFS (test tones) with the pot at maximum (minimal attenuation) this means 2V will be multiplied by the amplifier gain. (TPA3255 based amps with PFFB usually have around 20dB gain, PFFB usually reduces 6 to 7dB if gain) so, 20db means 10x times higher. Therefore we "should" get 20VRMS at the output. These 20vrms require a peak voltage of 20/0.707=28.28VDC carrier signal to allow that output swing.
20VACrms means 20x20/8=50w or 20x20/4=100w which perfectly matches the datasheet:

The voltage required to reach 50w at 8ohms, or 100w at 4ohms is just 28.28v, with the enough amperage to sustain that power.
200w at 4ohm requires 200/28.28=7A
100x at 8ohm requires 100/28.28=3.5A
If you have 4ohm speakers you may be out of luck because there are not many 30-32V power supplies with 7A or more.
In that case you have to find a bigger power supply (usually the 48V/10A, but because of the 48V, its because of the higher amperage).
The issue is the people wrongly believe that they get more power because of the higher voltage while they are still feeding the amp with the same 2VACrms input signal at 0dBFS. Remember the calculation for output power?. It only depends on input signal and amplifier gain, and power supply with enough voltage and amperate to sustain that output signal.
If you want more than 100w at 4ohms, then you need to provide a hogher input signal(by using a preamp). If you provide 3VACrms then you will output 30VaC rms swings, which now requires 30/0.707=42.42VDC power supply to produce
30x30/4=900÷4=225W theoretical watts(which also matches the datasheet power curve).
These total 450W requires now 450/48=9.37A which the 48V/10A power supply can provide, but only if your input signal is 3VACrms 0dBFS, and here is where everything falls apart because we dont lusten to music at 0dBFS. Music plays at at least 4 to 6 times lower volume. Which means that the theoretical 3V now become 0.5V to 0.75V of music and now all the calculations become
0.75v x 10=7.5V output swing which need 10.6VDC power supply and can only produce 7.5x7.5/4=14.06W per channel.
Why do you need the 48V/10A power supply then?
Power supply capacitors and amplifier bulk capacitors can provide a way higher instant power for those "intensive transients" on the music, this is the same PMPO concept of decade ago when manufacturers advertised their amps with 1000PMPO watts when in reality they were only 100W rms.
Again, clean power is more important than raw power.
Even a 24V Linear Regulated power supply or a "good" SMPS like Meanwell followed by a Linear Regulator board with 2A capacity is much better and more than enough.
Feeding clean power does not need to be expensive. Again, I accept there is a lot of expensive "snake oil"out there(more than $500 for a power supply?, no way) just add a 1.5A to 2A regulator board to your 32V (or even lower) SMPS and you are golden.
You can also do this for DACs and streamers, just remember those regulator boards require a voltage drop to work, if you want to produce 12V then you need a 15 to 18V power supply, or get one of those adjustable power supplies), for the Wiim Pro for example you need a 9V power supply for a 5V regulator board with the "1.5A LT3042 + PNP trasistor" design. This board comes in 3.3v, 5v, 9v and 12v.. LM317 boards come with variable output up to 37V.
I wish I could afford expensive stuff, that's why I always find cheaper alternatives.
You can even build a nice and cheap Linear power supply from scratch with a transformer ($30) and a rectifier/regulator board($20), and your own case, or buy it already built for $80-$100). Or simply add a Linear regulator board to your existing power supply.

 

[maxchau]

You are absolutely right. Clean power is more important than raw power. Why do you need a noisy SMPS with 48V at 10A if most (if not all) my music is heard at 0.1 to 1W, lets give it some headroom, let's say 10W/ch max.
Also people seem to forget how output power works on audio amplifier. The output power depends on the input signal (attenuated by the pot) x the whole amplifier gain(opamp gain plus chip amp gain).
If you provide a 2V at 0dBFS (test tones) with the pot at maximum (minimal attenuation) this means 2V will be multiplied by the amplifier gain. (TPA3255 based amps with PFFB usually have around 20dB gain, PFFB usually reduces 6 to 7dB if gain) so, 20db means 10x times higher. Therefore we "should" get 20VRMS at the output. These 20vrms require a peak voltage of 20/0.707=28.28VDC carrier signal to allow that output swing.
20VACrms means 20x20/8=50w or 20x20/4=100w which perfectly matches the datasheet:
View attachment 423694
The voltage required to reach 50w at 8ohms, or 100w at 4ohms is just 28.28v, with the enough amperage to sustain that power.
200w at 4ohm requires 200/28.28=7A
100x at 8ohm requires 100/28.28=3.5A
If you have 4ohm speakers you may be out of luck because there are not many 30-32V power supplies with 7A or more.
In that case you have to find a bigger power supply (usually the 48V/10A, but because of the 48V, its because of the higher amperage).
The issue is the people wrongly believe that they get more power because of the higher voltage while they are still feeding the amp with the same 2VACrms input signal at 0dBFS. Remember the calculation for output power?. It only depends on input signal and amplifier gain, and power supply with enough voltage and amperate to sustain that output signal.
If you want more than 100w at 4ohms, then you need to provide a hogher input signal(by using a preamp). If you provide 3VACrms then you will output 30VaC rms swings, which now requires 30/0.707=42.42VDC power supply to produce
30x30/4=900÷4=225W theoretical watts(which also matches the datasheet power curve).
These total 450W requires now 450/48=9.37A which the 48V/10A power supply can provide, but only if your input signal is 3VACrms 0dBFS, and here is where everything falls apart because we dont lusten to music at 0dBFS. Music plays at at least 4 to 6 times lower volume. Which means that the theoretical 3V now become 0.5V to 0.75V of music and now all the calculations become
0.75v x 10=7.5V output swing which need 10.6VDC power supply and can only produce 7.5x7.5/4=14.06W per channel.
Why do you need the 48V/10A power supply then?
Power supply capacitors and amplifier bulk capacitors can provide a way higher instant power for those "intensive transients" on the music, this is the same PMPO concept of decade ago when manufacturers advertised their amps with 1000PMPO watts when in reality they were only 100W rms.
Again, clean power is more important than raw power.
Even a 24V Linear Regulated power supply or a "good" SMPS like Meanwell followed by a Linear Regulator board with 2A capacity is much better and more than enough.
Feeding clean power does not need to be expensive. Again, I accept there is a lot of expensive "snake oil"out there(more than $500 for a power supply?, no way) just add a 1.5A to 2A regulator board to your 32V (or even lower) SMPS and you are golden.
You can also do this for DACs and streamers, just remember those regulator boards require a voltage drop to work, if you want to produce 12V then you need a 15 to 18V power supply, or get one of those adjustable power supplies), for the Wiim Pro for example you need a 9V power supply for a 5V regulator board with the "1.5A LT3042 + PNP trasistor" design. This board comes in 3.3v, 5v, 9v and 12v.. LM317 boards come with variable output up to 37V.
I wish I could afford expensive stuff, that's why I always find cheaper alternatives.
You can even build a nice and cheap Linear power supply from scratch with a transformer ($30) and a rectifier/regulator board($20), and your own case, or buy it already built for $80-$100). Or simply add a Linear regulator board to your existing power supply.

Thank you so much for the reply. I really appreciate the math which I will spend time to fully digest !

 

[Audionaut]

Here's the little darling.
It replaces the small and, in my opinion, very good Nobsound Bluetooth amplifier with TPA3116 in my study.

First impressions of the O-Noorus D1 >>> Clean finish, not much bigger than the TPA3116 amplifier, so quite small.

Remote control and display are a real feature for me, which I appreciate.
The display color can be customized, which is also a nice feature.

The connections are functional and of standard quality.

It is nice that the FiiO and the O-Noorus are both 120mm wide and also similar in height.
I think that fits very well visually.

The D1 is paired with the WiiM mini, which feeds into the FiiO BTA30 via an optical connection, which acts as a DAC. From there it continues into small Elac Anniversary.

I don't want to say much about the sound yet, I'll let it play for a few hours first. With this one, for example.

 

[Audionaut]

Impressions: O-Noorus D1 amplifier

First of all, the following impressions of the sound are of course completely subjective and do not claim to be universally valid.

The O-Noorus D1 is a compact Class D amplifier with the powerful TPA3255 chip, which impresses me with its technical features and sonic performance in its price class. The device was tested together with the WiiM mini, FiiO BTA30 and Elac loudspeakers with various music styles, including jazz, fusion, rock, metal, world music and classical symphonies. The playlist included tracks by Nenad Vasilic, Bela Fleck, Dominique Fils-Aimé, Boris Blank, Gojira, Tool, Ballaké Sissoko and Beethoven.

Sound >>>
Treble
The O-Noorus D1 delivers clear and precise highs without harshness or excessive sharpness. High frequencies are reproduced with good resolution, so that cymbals, strings and acoustic instruments appear detailed in recordings. The fine detail in pieces with a lot of overtones is very good.

Mids
The mids sound open and natural, giving voices and instruments a pleasant presence. Vocal recordings by Dominique Fils-Aimé or Adelle and the percussive sounds of Bela Fleck in particular are reproduced realistically and authentically. The amplifier ensures a clear reproduction of complex arrangements and separates individual instruments cleanly from one another.

Bass foundation
The bass range of the O-Noorus D1 is powerful but controlled. Low basses are reproduced with authority without drifting into boominess. The amplifier demonstrates its capabilities particularly in powerful tracks by Bela Feck, Boris Blank, Gojira and Tool and ensures clean and dynamic bass reproduction. Acoustic basses, such as in the tracks by Nenad Vasilic, also benefit from the amplifier's precision.

Transparency & stage
A positive characteristic of the O-Noorus D1 is its transparency and spatiality. Fine details are retained and the sound stage is wide and deep. Instruments can be located precisely and do not appear to be overlaid. Ballaké Sissoko's kora recordings, for example, benefit from the natural staging and clarity of the amplifier.

Heat development >>>
The heat development remains moderate and has not presented any problems to date.

Power supply unit >>>
The power supply unit has so far remained cool even under high loads or at high volumes and does not emit any background noise. I doubt whether a more powerful power supply will necessarily lead to a better sound, as I have already experienced the opposite.

Conclusion
The O-Noorus D1 impresses as a powerful TPA3255 amplifier with a transparent sound image. Clear highs, natural mids and a tight bass foundation ensure a satisfying listening experience. Transparency and spatiality make it an excellent choice even for demanding listeners. Anyone looking for a compact but powerful amplifier will make a good choice with the O-Noorus D1, I think.

PS
I ordered directly from O-Noorus.
The price for the complete package including power supply was 99 USD, which was about 95 Euro after conversion. There was no customs duty.