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

[Audionaut]

The traffic on this page is very limited, but perhaps someone who shortlisted the O-Noorus D1 will be interested.

A few of the things I noticed:
- The display and remote control are very practical and I wouldn't want to be without them
- The volume scale runs up to 80 - but can be moved even further manually
- The amplifier is quiet in every respect, both mechanically and electrically, even at full volume, which I really appreciate

I like the design more and more, because the red, very flat aluminum housing and display are quite unique in the Ti TPA3255 world.

I haven't done any cross-comparisons yet, but so far I'm very satisfied with the amplifier connected to the Elac BS 203 A with 86 dB/2.83V/1m.

It really is like a new toy for me at the moment and I'm currently more pleased with this little red thing than I was with components costing a few thousand euros.

 

[Audionaut]

I fitted the O-Noorus D1 with the Aiyima 48V 10A GaN power supply just for the sake of interest.

It sounds better to my ears, although the standard power supply with 36V and 5A is also perfectly OK for listening to music at a high level.

But: The small amplifier gets considerably warmer under load and reaches surface temperatures of 46 degrees Celsius.

Although this is within the specifications, lower temperatures are always better for electronic components.

So I didn't order a cheap heat sink, but a 0.51 K/W heat sink, which is a little oversized and also a little too big, because I didn't take into account in the dimensions that they are of course given "over all", i.e. with connections, and not just for the housing itself.

So I briefly considered exchanging it, but then simply fixed it in place with thermal tape.

The small and stylish amplifier now has Morgoth's crown on its back and plenty of current and voltage available.
It is barely warm to the touch, even at high levels over long periods of time.

Is this all sensible and economical?
Probably not, but I enjoy it.

 

[ICIETDIYEUR]

Hello Audionaut

I have a suggestion for you:

- replace the small rubber 'feet' with 1cm high ones

- 'glue' a COPPER heatsink with 0.5cm fins from below and you can even add screws at each corner by making small holes tapped from the bottom of the case
(this will allow you to use thermal paste that is much more effective than the 'adhesive thermal strips' like on your heatsink)

With this solution you actually come into direct contact with the heatsink of the TPA3255 itself in contact with the bottom of the case so the calories will start to evacuate as soon as they come from their source by limiting the heating of the case as much as possible, which is not very thick, it is true

Without the slightest 'pretension', I think that the suggestion could be more visually acceptable but it is a matter of personal taste and I have absolutely nothing against your solution that others may prefer

However, I would like to point out that without this 'assembly' the TPA3255 is VERY FAR from its Tj Max as indicated by its datasheet, which you can check by consulting them on the TEXAS INSTRUMENTS website.

See you soon

 

[Krampi]

Hello Audionaut

I have a suggestion for you:

- replace the small rubber 'feet' with 1cm high ones

- 'glue' a COPPER heatsink with 0.5cm fins from below and you can even add screws at each corner by making small holes tapped from the bottom of the case
(this will allow you to use thermal paste that is much more effective than the 'adhesive thermal strips' like on your heatsink)

With this solution you actually come into direct contact with the heatsink of the TPA3255 itself in contact with the bottom of the case so the calories will start to evacuate as soon as they come from their source by limiting the heating of the case as much as possible, which is not very thick, it is true

Without the slightest 'pretension', I think that the suggestion could be more visually acceptable but it is a matter of personal taste and I have absolutely nothing against your solution that others may prefer

However, I would like to point out that without this 'assembly' the TPA3255 is VERY FAR from its Tj Max as indicated by its datasheet, which you can check by consulting them on the TEXAS INSTRUMENTS website.

See you soon

Heat escapes from the bottom of the case by heating the area above it. I do not think this solution is practical.

 

[ICIETDIYEUR]

@ Krampi:

Audionaut is a person who likes to understand and experiment it seems so I don't doubt for a moment that he has tested what I suggested and that I mentioned above: he will be able to bring us the observations he will have made about its effectiveness

 

[Audionaut]

Heat escapes from the bottom of the case by heating the area above it. I do not think this solution is practical.

The main reason why I won't be doing this is that I think the solution I have chosen is the technologically better implementation, because the housing itself is the heat sink and the heat exchange to the attached heat sink with 0.51 K/W works perfectly and exactly as I had imagined. In addition, the attached heat sink is completely free-standing and the fins lift the desired and intended orientation.

I would also have to change something again. What for?

With a heat sink implementation under the housing, firstly the already limited ventilation openings would be blocked and secondly the convection would be very poor.

 

[Krampi]

@ Krampi:

Audionaut is a person who likes to understand and experiment it seems so I don't doubt for a moment that he has tested what I suggested and that I mentioned above: he will be able to bring us the observations he will have made about its effectiveness

I look forward to hearing Audionaut's observations and experiences.

 

[Audionaut]

so I don't doubt for a moment that he has tested what I suggested and that I mentioned above: he will be able to bring us the observations he will have made about its effectiveness

No, look above

 

[ICIETDIYEUR]

Hi.

This cannot be written on the basis of mere presumptions: the only way to find out is to experiment methodically, otherwise it is pure speculation.

But you are satisfied with your solution: this is what is most important

 

[Krampi]

Hi.

This cannot be written on the basis of mere presumptions: the only way to find out is to experiment methodically, otherwise it is pure speculation.

But you are satisfied with your solution: this is what is most important

Simple thermodynamics, not just an assumption

 

[ICIETDIYEUR]

Simple words, just a hypothesis

 

[tomriddle]

Hi, I have to share this with you, cause this D1 is really better than most of TPA3255 amp I tried. Its sound quality is really better.

Look at my cheap 5.1 set with 2 D1 amps. One for L R main speakers, one for center channel and a 12 inch 2nd hand passive subwoofer.
Surround is using a pair of powered 5 inch speakers which were replaced by these new 8 inch cheap main speakers.

Before D1 I was using the Berrybak BRU5 amp, it would power these 8 inch speakers OK, but after I got these D1 amps, they sound really really different, with the same DC 48V 9.4A fish tank / LED PSU.

D1 is really much better, originally I think I could use the BRU5 for subwoofer with one D1, since BRU5 has DSP and it could adjust LR channel with different gain, and has EQ for subwoofer.
But D1 makes me want to throw BRU5 away, I thought TPA3255 should be more or less all the same, but I was wrong, and I don't know it's the PFFB feature or there might be something wrong with the BRU5, it's like my wife could hear the difference.

The key for using a single D1 as the center and subwoofer amp is you have to find a proper way to shift the gain between 2 channels, since normally subwoofer should be 3-6db higher than center or even 12-15db higher if your subwoofer is not as good, since some cheap woofer can't sound loud below 50-60Hz.

Maybe you can mod the D1 with some resistors to shift the gain, but I made 2 preamps in a single box as below instead.

One passive preamp for center channel from 5.1 DAC, one powered subwoofer preamp for the sub out from D1.

The passive preamp board has about 6-10db attenuation even at max, its really really cheap if you can find on AliExpress, and the powered preamp is ZK-PRO1, is has 7 JRC 2608 op amp and with low frequency cut feature.

So all I did was just drill some holes on a plastic box, and some cabling. I didn't want to touch main L R channels with these cheap preamp board.

The final result is amazing, this set works well on both 2.0, 2.1 and 5.1 cases.

The AV switcher is passive, so ideally it wouldn't affect sound at all, I use it to switch subwoofer signal between no signal, DAC and D1.

These are my 2 cents, hope it helps, now my home 5.1 set gives me different feeling than my 5 E5XT studio set.

The con part, the knob on the D1 is not so accurate, my center speaker could sound loud and it vibrates the knob, it may rotate around a bit and the percentage number on D1 could jitter. The remote is not always working, some time one click on the power button on the remote could turn on/off both, sometimes it works for only one, sometimes it doesn't work at all. Heat issue, it's hot, but a bit cooler than BRU5, I use a 12cm usb fan to solve, just ordered a speed adjustable cable for this.

 

[Tell]

Is the D1 overheating?

 

[tomriddle]

Is the D1 overheating?

Both D1 and BRU5 are around 50 Celsius aka. 122 Fahrenheit without active cooling after heavy usage.

BRU5 would sound stuttering after whole day about 12 hours of use without turning off or fan cooling, I think TPA3255 has protective mode, maybe it's the cause.
The passive cooling design of BRU5 and D1 is simillar, both have chip underneath, heat to the metal case.

But I use a usb silent 12cm fan on D1, this fan could make both D1 about equal to room temperature, as I put them stacking like in picture. I haven't test D1 more than 4 hours so far, no stuttering, no heating issue at all.

Reason of using a fan, I contacted with a TPA3255 board designer (ZK product designer, they have a nice product ZK-ASP21 naked board, but without PFFB), their naked 600W dual TPA3255 amp board product always have active 8-9cm fan, he suggested me using a fan.

Also I have seen naked board amp burning video, maybe 3116 or 3118 chip or other brand.

I just ordered another USB 5V - 12V fan cable, with speed adjustment, that could make the fan really silence.

 

[Tell]

Both D1 and BRU5 are around 50 Celsius aka. 122 Fahrenheit without active cooling after heavy usage.

BRU5 would sound stuttering after whole day about 12 hours of use without turning off or fan cooling, I think TPA3255 has protective mode, maybe it's the cause.
The passive cooling design of BRU5 and D1 is simillar, both have chip underneath, heat to the metal case.

But I use a usb silent 12cm fan on D1, this fan could make both D1 about equal to room temperature, as I put them stacking like in picture. I haven't test D1 more than 4 hours so far, no stuttering, no heating issue at all.

Reason of using a fan, I contacted with a TPA3255 board designer (ZK product designer, they have a nice product ZK-ASP21 naked board, but without PFFB), their naked 600W dual TPA3255 amp board product always have active 8-9cm fan, he suggested me using a fan.

Also I have seen naked board amp burning video, maybe 3116 or 3118 chip or other brand.

I just ordered another USB 5V - 12V fan cable, with speed adjustment, that could make the fan really silence.

They should be able to handle quite a bit higher temps than 50 degrees, but if that's not the case then they really are a no go!

 

[Audionaut]

They should be able to handle quite a bit higher temps than 50 degrees, but if that's not the case then they really are a no go!

These are the outside temperatures.
Even if the housing is connected to the heating TPA3255 via heat exchangers, the temperatures inside the device and especially near and above the amplifier IC are likely to be much higher.
The large capacitors are located in the immediate vicinity and in a horizontal position.

For this reason and because I use a 48V 10A power supply with the D1, I have attached a 0.51 K/W heat sink to the housing of the device, which reliably keeps the temperature below 40 degrees Celsius even under high load for hours on end.

 

[Tell]

These are the outside temperatures.
Even if the housing is connected to the heating TPA3255 via heat exchangers, the temperatures inside the device and especially near and above the amplifier IC are likely to be much higher.
The large capacitors are located in the immediate vicinity and in a horizontal position.

For this reason and because I use a 48V 10A power supply with the D1, I have attached a 0.51 K/W heat sink to the housing of the device, which reliably keeps the temperature below 40 degrees Celsius even under high load for hours on end.

Yeah of course it's higher inside, but it from a short google the chip itself should be able to stand quite a bit higher heat, and again if it's not built for it and you need a fan then the whole thing is just badly constructed.

 

[Audionaut]

Yeah of course it's higher inside, but it from a short google the chip itself should be able to stand quite a bit higher heat, and again if it's not built for it and you need a fan then the whole thing is just badly constructed.

Of course, the TPA3255 can withstand these temperatures, even for long periods of time.
For me personally, the main concern is the long-term operational reliability and service life of the components, especially the capacitors, for which a lower temperature is simply better.

It's not a design flaw in that sense, especially not with the standard 36V 5 power supply, where the temperatures are also much cooler, but with the 48V 10A I prefer the additional passive heat sink I installed, which is normally also installed in Class A power amplifiers, to dissipate a large part of the heat.

The flat enclosures, which are also heat sinks, from O-Noorus and Fosi Audio (V3 mono, for example) are very stylish and small, but they could be improved in terms of their thermal capabilities.

 

[tomriddle]

I replaced the 12cm with a 9cm smaller fan teared down from an old cpu cooler, with speed control USB cable, this is really silent, and cool down the D1 well. I'm using a 48V psu.

If you want to use passive heat sink, you have to take care of insulation, putting metal directly on top will shut down both of my D1's LED light.

D1 remote actually works, it was the batteries dead , after replaced, it controls both D1 fine.

 

[AdrianusG]

Both D1 and BRU5 are around 50 Celsius aka. 122 Fahrenheit without active cooling after heavy usage.

BRU5 would sound stuttering after whole day about 12 hours of use without turning off or fan cooling, I think TPA3255 has protective mode, maybe it's the cause.
The passive cooling design of BRU5 and D1 is simillar, both have chip underneath, heat to the metal case.

But I use a usb silent 12cm fan on D1, this fan could make both D1 about equal to room temperature, as I put them stacking like in picture. I haven't test D1 more than 4 hours so far, no stuttering, no heating issue at all.

Reason of using a fan, I contacted with a TPA3255 board designer (ZK product designer, they have a nice product ZK-ASP21 naked board, but without PFFB), their naked 600W dual TPA3255 amp board product always have active 8-9cm fan, he suggested me using a fan.

Also I have seen naked board amp burning video, maybe 3116 or 3118 chip or other brand.

I just ordered another USB 5V - 12V fan cable, with speed adjustment, that could make the fan really silence.

"Both D1 and BRU5 are around 50 Celsius aka. 122 Fahrenheit without active cooling after heavy usage."

That is weird, my 30+ years old Quad 306, after hours and hours of playing barely exceeds 40 Celsius, and that's a class AB design.

I thought class D was supposed be be efficient?