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O-Noorus D1 - TPA3255 PFFB Stereo Amplifier - Front Display, Tone Control (with bypass) and Remote

Exact and also with the possibility of additional orange display to better 'match' some DAC TOPPING. Normally, this should be the case since I already have photos ;)

BOX.jpg


ORANGE.jpg


But I won't show you the PCB...

:p
 
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It would be better if it had openings on the top for better ventilation of the interior space.
top cover.jpg
 
Hello.

The holes on the top of the case can be a solution but indeed the fact that 'things' can get into it leads to reflection.
Other solutions such as a larger size of the heatsink in contact with the TPA3255 chip and the case are adopted as on O-NOORUS D4 model for example.

The only 'problem', which is not a problem in fact, is that the heat transfer by dissipation naturally follows the case and is concentrated in the upper part, normal since the heat rises ('pushed' by the cooler and less dilated air in the lower part), which means that the user may believe in an abnormal heating of the device when it is not the case.

As a reminder, the TEXAS INSTRUMENTS DATASHEETS indicate a temperature range of the operating junction up to a maximum of 150°C.

A TPA3255 chip powered without any modulated signal dissipates up to 75°C, so it is quite normal and far from the maximum temperature to observe up to around 45°C on the top of the case current models of O-NOORUS amplifiers related to the 'nature' of the box used for them.

I have carried out all the tests and measurements possible after careful control of the diagrams and everything is working normally.

I obtained a maximum of 45°C on the top of the case in its center with a 'laser' thermometer placed exactly 20cm from it.

This measurement was carried out in a room with an 'atmosphere' at 30°C for 52% relative humidity -> It cost me a lot in heating, LOL :D

There is therefore absolutely no risk of reliability of its amplifiers which could be heat-related under normal conditions of use ;)

Regards.
 
Hello @Alexander Lin . Thanks for the new year greetings mail from the onoorus company! Best wishes to you too. Is there any news on the D3 PRO release date to share?
 
Hello @Alexander Lin . Thanks for the new year greetings mail from the onoorus company! Best wishes to you too. Is there any news on the D3 PRO release date to share?
Hello, we will try to release it in January. January 29 is the Spring Festival, so we will release it before the long holiday. If it is too late, we will release it in mid-February.
 
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.
 
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This little amplifier continues to impress me. Question for the O-Noorus folks. I swapped out the included 32V5A power supply for a 48V5A GaN Power Supply. Overall, there is slightly more power available but I also noticed a subtle change in tonality as well. The mid-range and high frequencies are stronger, however there seems to be a decrease in bass. Is this a characteristic of the D1 amplifier or a characteristic of the TPA3255 chip in general? Higher voltage = more mid-range, less bass, more overall volume ?
 
This little amplifier continues to impress me. Question for the O-Noorus folks. I swapped out the included 32V5A power supply for a 48V5A GaN Power Supply. Overall, there is slightly more power available but I also noticed a subtle change in tonality as well. The mid-range and high frequencies are stronger, however there seems to be a decrease in bass. Is this a characteristic of the D1 amplifier or a characteristic of the TPA3255 chip in general? Higher voltage = more mid-range, less bass, more overall volume ?
Do you have a 48V 10A power supply? Try different currents. The voltage is increased, and the bass needs more current.
 
People hi !

I tried a lot of different power supplies (voltages, currents) for amplifiers equipped with the TPA3255 chip and the best 'compromise' I got in terms of available power, heat dissipation, distortion and 'musicality' was with a 42V - 8.3A power supply.

There are many models on ALIEXPRESS and these are much better suited than the 'Gan' type power supplies (48V-5A or 48V-10A) usually offered.

Do not try to use higher voltages/currents because they can only be really 'useful' (at least properly 'exploited' if the DIY realization is coherent) on 'high-level' DIY models such as those made from the PCBs of SYLPH AUDIO or 3eAudio for example.

Brands that offer 'high-end' equipment usually sell a PSU adapted to their amplifier and there is no need to replace it at the risk of 'deteriorating' the performance of the equipment as it is offered.
 
People hi !

I tried a lot of different power supplies (voltages, currents) for amplifiers equipped with the TPA3255 chip and the best 'compromise' I got in terms of available power, heat dissipation, distortion and 'musicality' was with a 42V - 8.3A power supply.

There are many models on ALIEXPRESS and these are much better suited than the 'Gan' type power supplies (48V-5A or 48V-10A) usually offered.

Do not try to use higher voltages/currents because they can only be really 'useful' (at least properly 'exploited' if the DIY realization is coherent) on 'high-level' DIY models such as those made from the PCBs of SYLPH AUDIO or 3eAudio for example.

Brands that offer 'high-end' equipment usually sell a PSU adapted to their amplifier and there is no need to replace it at the risk of 'deteriorating' the performance of the equipment as it is offered.

@Alexander Lin Is it an option to add a 42V - 8.3A power supply to the D3 PRO as order option instead of the 36V 5A ? This might prevent people from switching to the 48V psu's and improve the lifespan of the onoorus products and increase customer satisfaction.
I am aware that this will raise the price which is acceptable for a PRO version.
 
People hi !

I tried a lot of different power supplies (voltages, currents) for amplifiers equipped with the TPA3255 chip and the best 'compromise' I got in terms of available power, heat dissipation, distortion and 'musicality' was with a 42V - 8.3A power supply.

There are many models on ALIEXPRESS and these are much better suited than the 'Gan' type power supplies (48V-5A or 48V-10A) usually offered.

Do not try to use higher voltages/currents because they can only be really 'useful' (at least properly 'exploited' if the DIY realization is coherent) on 'high-level' DIY models such as those made from the PCBs of SYLPH AUDIO or 3eAudio for example.

Brands that offer 'high-end' equipment usually sell a PSU adapted to their amplifier and there is no need to replace it at the risk of 'deteriorating' the performance of the equipment as it is offered.
Thanks for the input! This is interesting as I have not seen any of the TPA3255 amplifier manufacturers offering that as an option. However, the O-Noorus website does show a 42V option in their D1 watt power table. I will check out ALI for 42V power supplies. For now, I will probably go back to the O-Noorus supplied 32V5A supply.
 
How is this PFFB circuit of the o-nuurus D1 marked on the picture supposed to work?
It looks like a few resistors to me.
1000022961.jpg
 
Hello Audionaut :)

Thank you for your question ;)

The implementation of the PFFB circuit in the O-NOORUS D1 amplifier is strictly in accordance with the recommendations mentioned in the TEXAS INSTRUMENTS datasheet ->

TI PFFB DATASHEET.jpg


There are 4 passive components per channel for PFFB (here the channel A on the diagramm).

The 'BTL mode' used for the O-NOORUS D1 amplifier uses two amplification channels of the TPA3255 chip for the left channel and two channels for the right channel.
So there are 8 passive components per channel: what you can observe on the PCB on the right side.

Some of these components are 'hidden' on the left side by the large 2200μF/63V NIPPON CHEMI-CON KY capacitor which is part of the PVDD circuit.

We don't reinvent hot water...

Kind regards.
 
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