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

Guddu

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Dear FMs,

I am intending to post User Impressions & Observations here in this User Impressions | Owner's Thread.
pls note that Amir's measurements & review of this amplifier is in queue and awaited.

I created a thread on O-Noorus D1 which captures details like features, internal pics, quick discussions on several aspects, etc. when I came to know about this amplifier first time:
o-noorus-d1-tpa3255-pffb-stereo-amplifier-front-display-tone-control-with-bypass-and-remote

Here, I mean to summarize:
> what I get as a buyer or user of O-Noorus D1 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 are buying this amplifier

*** I hope other O-Noorus D1 users/owners can also sum up their feedback and some work arounds here to help other potential future O-Noorus D1 owners ***

Here is quick snapshot of this amplifier:
> TPA3255 based PFFB implemented topology
> Front panel large display and volume pot with volume control/on/off/mode operation
> 2 Operational Modes
> BP => ByPass mode
> T&B => Tone mode
> Pre-Out with 3.5mm aux, volume controlled by amplifier's volume
> sub-out, with 80 Hz fixed low pass, volume controlled by amplifier's volume
> RCA input
> Remote
> Case Color: RED for now, manufacturer confirmed that BLUE will be available later
Note: RCA inputs only, no xlr/TRS balanced inputs

Price & Availability
> Price seems to be very reasonable, to me, for this amplifier
> seems like manufacturer is not asking for PFFB premium yet!

*** Amplifier is available on AliExpress at the moment, not on Amazon yet.
*** It's available with or with-out power supply
Note: I did not get this amplifier with power supply, and used a 48v 5a power supply all the time without any issues.

1714405843679.png



Look & Feel:
> Its quite compact profile, more or less similar to size of Topping E50 DAC
> They only have RED color available at the moment, and may make other colors available in future
> Feels decent case, looks very nice with shiny finish
> Looks cute under my TV. Low profile makes things really easy for placement however speaker cable termination requires some considerations
> Metallic heatsink is pasted onto TPA3255 chip which then also couples it to the chassis bottom, then the whole chassis operates as cooling solution
> Chassis also has ventilation on sides and bottom

O-Noorus D1.jpg


Note: RCA input color coding is different than standard, however manufacturer confirmed that next batches would have this corrected.

Power Supply & Remote
> It comes with 36v 5a power supply
> 48 - 50v power supply can be used as well, as filter capacitors used are 63v

Power Supply.JPG


> Remote provided is rather simple, plastic made
> It does work fine, however personally I feel that they should upgrade and find a better remote
> I have already provided feedback to manufacturer, hope they act

Amplifier Mode: BP: ByPass
> It bypasses tone controls
> Remote becomes almost useless, it can only change mode when amplifier is on BP
> Note: Remote Volume Control on Remote does work in BP mode

1. BP Mode.JPG


Amplifier Mode: T&B: Treble&Bass, Tone Control
> Remote becomes fully functional, volume control on remote works
> Bass & Treble adjustments: -10 to +10 db
> Display LED Color: 1 to 8, 8 different colors
> Brightness: 1 to 3 and A4 => low, med, high and A4: Auto Off after about 10 sec
> Note: If you set A4 and then go back to BP mode, Auto Off still works

D1 Mode - T&B.jpg


Volume Control Knob Operation:
> I found it very good, super smooth and responsive with digital control
> Press long for ON/OFF
> Press quick double to change modes: BP vs T&B
> Note: I could not figure out a way to change tones etc. using volume knob, and could only use remote for that.

Amplifier Internal or PCB Pictures: HERE
> Note: It uses Chemi-con Nippon KY 63v 2200uF capacitors, and dual power supply +-12v for opamps

Size comparison (size is same as O-Noorus D3): HERE

Idle Power Consumption:
Powered ON but no audio playing
> Around 10watts
> Even, It keeps around 10watts if played arrox. up to 70-72 db SPL
IMG_E1873.JPG


Amplifier Case Temperature
> I played it a bit loud for my likings, around 80-85 db and the case remained just warm and I didn't think it could be an issue
> note: I used 48v 5a power supply all the time

My Setup, Connectivity and Pairing devices:
PC & nVidia Shield Pro (source) >>>> Topping E50 >>>>RCA out>>>> O-Noorus D1 >>>> Speaker Selector >>>> ELAC DBR62 Speakers
PC & nVidia Shield Pro (source) >>>> Topping E50 >>>>balanced out>>>> Fosi v3 Mono Amplifiers >>>> Speaker Selector >>>> ELAC DBR62 Speakers

Setup.JPG


Setup 2.JPG


Sub-Out
> I tested with my ELAC powered sub, it worked fine without any issues
> Amplifier volume control also controls the sub-out (and pre-out as well)

Illusional and Delusional Stuff - How I feel about O-Noorus D1 after listening for few hours

Note:
you might want to ignore this part as its purely based on my setup, in-room response and my likings.

There was no huss or noise on full volume on my Elac DBR62 speakers, amplifier was dead silent and clean.
Sound wise, there isn't much to say really, it worked as good as any other amplifier in my setup. it felt detailed and quite balanced to my likings.

Take a look at the following quick freq. sweep captured with mic placed near to speaker, and tell me what can you make out of it:

O-Noorus D1 vs Fosi v3 mono.jpg

Your assessment of the above graph is welcome!

Some considerations and notes:
> Speaker binding post is small, just like other similar amplifiers, and so its more suitable & safe for banana plugs than bare wire or spades
> Remote provided works, but I would personally try to see if a can find a universal remote that works with it
> Sub-Out RCA plug is of RED color coded in my unit, so I mistakenly connected normal RCA input a few times. Not really an issue, but just requires careful connection once
> A faint pop noise is there when switching/changing mode: BP & T&B, and when powering off the amplifier. Its nor sharp noise like many others but it is there.
> I had Topping E50 next to it, and when I used E50's remote to change anything it also showed option moving on O-Noorus D1. It did not change any settings or anything, did not cause any issues but I observed this. To verify, I tried using E50's remote directly on the amplifier and it did not do anything other than browsing menu.

Overall, it is compact good looking amplifier with many features which aren't there with other PFFB based amplifiers yet.
It is RCA input only, no balanced inputs but I personally didn't find it an issue specially on this price.
It performed really good in my setup, can not say anything for long term reliability to be honest but it feels well built except the remote which works but I wish if they could do better.
 

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dr_mick51

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I ordered one yesterday. I was looking at the D3 months ago but not having RCA and instead having 3.5mm jack was something I was not happy about. Also, I'm using an external DAC so, all those extra inputs are just wasted.

Having a remote control and digital volume control is something very desirable. We don't have to worry about channel imbalance as with the A07 Max. Then yesterday when I was looking on Aliexpress I saw the D1. I though it was a typo at first, then I realized this was a different amp which keeps all the things I like about the D3 and removing those extra features I was not planning to use, and fixing what I needed to be fixed and gave back those RCA inputs.

Finally they "fixed" the sub out and pre-out. Those are now controlled by the main volume control as well, and they were able to add Post Filter FeedBack (PFFB) which decreases THD+N , increases SINAD and provides better control on speaker frequency response and achieving better Load independency. I could not avoid ordering it right away.

@Guddu , that frequency response plot shows the D1 being flatter. I don't see those peaks at 150Hz and 200Hx, and the overall high end (>4kHz) is flatter compared the the V3 mono. Good deal.
 

dr_mick51

Active Member
Joined
Mar 12, 2022
Messages
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217
Dear FMs,

I am intending to post User Impressions & Observations here in this User Impressions | Owner's Thread.
pls note that Amir's measurements & review of this amplifier is in queue and awaited.

I created a thread on O-Noorus D1 which captures details like features, internal pics, quick discussions on several aspects, etc. when I came to know about this amplifier first time:
o-noorus-d1-tpa3255-pffb-stereo-amplifier-front-display-tone-control-with-bypass-and-remote

Here, I mean to summarize:
> what I get as a buyer or user of O-Noorus D1 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 are buying this amplifier

*** I hope other O-Noorus D1 users/owners can also sum up their feedback and some work arounds here to help other potential future O-Noorus D1 owners ***

Here is quick snapshot of this amplifier:
> TPA3255 based PFFB implemented topology
> Front panel large display and volume pot with volume control/on/off/mode operation
> 2 Operational Modes
> BP => ByPass mode
> T&B => Tone mode
> Pre-Out with 3.5mm aux, volume controlled by amplifier's volume
> sub-out, with 80 Hz fixed low pass, volume controlled by amplifier's volume
> RCA input
> Remote
> Case Color: RED for now, manufacturer confirmed that BLUE will be available later
Note: RCA inputs only, no xlr/TRS balanced inputs

Price & Availability
> Price seems to be very reasonable, to me, for this amplifier
> seems like manufacturer is not asking for PFFB premium yet!

*** Amplifier is available on AliExpress at the moment, not on Amazon yet.
*** It's available with or with-out power supply
Note: I did not get this amplifier with power supply, and used a 48v 5a power supply all the time without any issues.

View attachment 366678


Look & Feel:
> Its quite compact profile, more or less similar to size of Topping E50 DAC
> They only have RED color available at the moment, and may make other colors available in future
> Feels decent case, looks very nice with shiny finish
> Looks cute under my TV. Low profile makes things really easy for placement however speaker cable termination requires some considerations
> Metallic heatsink is pasted onto TPA3255 chip which then also couples it to the chassis bottom, then the whole chassis operates as cooling solution
> Chassis also has ventilation on sides and bottom

View attachment 366673

Note: RCA input color coding is different than standard, however manufacturer confirmed that next batches would have this corrected.

Power Supply & Remote
> It comes with 36v 5a power supply
> 48 - 50v power supply can be used as well, as filter capacitors used are 63v

View attachment 366674

> Remote provided is rather simple, plastic made
> It does work fine, however personally I feel that they should upgrade and find a better remote
> I have already provided feedback to manufacturer, hope they act

Amplifier Mode: BP: ByPass
> It bypasses tone controls
> Remote becomes almost useless, it can only change mode when amplifier is on BP
> Note: Remote Volume Control on Remote does work in BP mode

View attachment 366685

Amplifier Mode: T&B: Treble&Bass, Tone Control
> Remote becomes fully functional, volume control on remote works
> Bass & Treble adjustments: -10 to +10 db
> Display LED Color: 1 to 8, 8 different colors
> Brightness: 1 to 3 and A4 => low, med, high and A4: Auto Off after about 10 sec
> Note: If you set A4 and then go back to BP mode, Auto Off still works

View attachment 366686

Volume Control Knob Operation:
> I found it very good, super smooth and responsive with digital control
> Press long for ON/OFF
> Press quick double to change modes: BP vs T&B
> Note: I could not figure out a way to change tones etc. using volume knob, and could only use remote for that.

Amplifier Internal or PCB Pictures: HERE
> Note: It uses Chemi-con Nippon KY 63v 2200uF capacitors, and dual power supply +-12v for opamps

Size comparison (size is same as O-Noorus D3): HERE

Idle Power Consumption:
Powered ON but no audio playing
> Around 10watts
> Even, It keeps around 10watts if played arrox. up to 70-72 db SPL
View attachment 366687

Amplifier Case Temperature
> I played it a bit loud for my likings, around 80-85 db and the case remained just warm and I didn't think it could be an issue
> note: I used 48v 5a power supply all the time

My Setup, Connectivity and Pairing devices:
PC & nVidia Shield Pro (source) >>>> Topping E50 >>>>RCA out>>>> O-Noorus D1 >>>> Speaker Selector >>>> ELAC DBR62 Speakers
PC & nVidia Shield Pro (source) >>>> Topping E50 >>>>balanced out>>>> Fosi v3 Mono Amplifiers >>>> Speaker Selector >>>> ELAC DBR62 Speakers

View attachment 366681

View attachment 366682

Sub-Out
> I tested with my ELAC powered sub, it worked fine without any issues
> Amplifier volume control also controls the sub-out (and pre-out as well)

Illusional and Delusional Stuff - How I feel about O-Noorus D1 after listening for few hours

Note:
you might want to ignore this part as its purely based on my setup, in-room response and my likings.

There was no huss or noise on full volume on my Elac DBR62 speakers, amplifier was dead silent and clean.
Sound wise, there isn't much to say really, it worked as good as any other amplifier in my setup. it felt detailed and quite balanced to my likings.

Take a look at the following quick freq. sweep captured with mic placed near to speaker, and tell me what can you make out of it:

View attachment 366688
Your assessment of the above graph is welcome!

Some considerations and notes:
> Speaker binding post is small, just like other similar amplifiers, and so its more suitable & safe for banana plugs than bare wire or spades
> Remote provided works, but I would personally try to see if a can find a universal remote that works with it
> Sub-Out RCA plug is of RED color coded in my unit, so I mistakenly connected normal RCA input a few times. Not really an issue, but just requires careful connection once
> A faint pop noise is there when switching/changing mode: BP & T&B, and when powering off the amplifier. Its nor sharp noise like many others but it is there.
> I had Topping E50 next to it, and when I used E50's remote to change anything it also showed option moving on O-Noorus D1. It did not change any settings or anything, did not cause any issues but I observed this. To verify, I tried using E50's remote directly on the amplifier and it did not do anything other than browsing menu.

Overall, it is compact good looking amplifier with many features which aren't there with other PFFB based amplifiers yet.
It is RCA input only, no balanced inputs but I personally didn't find it an issue specially on this price.
It performed really good in my setup, can not say anything for long term reliability to be honest but it feels well built except the remote which works but I wish if they could do better.
Have you tried to open it and replace the opamps? That dual rail power supply for opamps is always nice.
 
OP
Guddu

Guddu

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Have you tried to open it and replace the opamps? That dual rail power supply for opamps is always nice.
I haven’t opened the case yet, I actually has no reason as we already got internal pcb view and all and I don’t have any others opamps to try.
 
OP
Guddu

Guddu

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I ordered one yesterday. I was looking at the D3 months ago but not having RCA and instead having 3.5mm jack was something I was not happy about. Also, I'm using an external DAC so, all those extra inputs are just wasted.
I have got D3 as well, which I will run against this D1 this week.

@Guddu , that frequency response plot shows the D1 being flatter. I don't see those peaks at 150Hz and 200Hx, and the overall high end (>4kHz) is flatter compared the the V3 mono. Good deal.
It is flatter, wasn’t expecting but it’s cool.
These measurements were taken just to see what I get from both amplifiers in terms of differences, I placed the mic less than a feet away to avoid room effect.
 

MCH

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Thanks again @Guddu , this sort of "features and use" reviews are very useful for this kind of products. And at 83 eur shipped, this one could be a game changer!
If you want to run a measurement of the frequency response of the amp itself, it is super easy, you only need a few resistors and an audio interface, see here:


My vote goes also for inside pics, as the ones available are not high quality (my interest is seeing how feasible would be to add differential inputs. Shouldn't be difficult if bypassing the DSP.)
IMO that no control works when bypassing the tone controls might even be good news, as it probably indicates that it is working as a regular analog power amp. What scares me of this amp is the quality of the ADC - I am assuming that the input gets digitalized, and ADC at this price point.... won't be stellar I am afraid, but if you can't hear noise, I guess it doesn't matter. edit: comparing the pictures with its brother D3, seems that it is using the same NJW1194 tone/volume control IC (longer IC in the picture)
 
Last edited:
OP
Guddu

Guddu

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Thanks again @Guddu , this sort of "features and use" reviews are very useful for this kind of products. And at 83 eur shipped, this one could be a game changer!
If you want to run a measurement of the frequency response of the amp itself, it is super easy, you only need a few resistors and an audio interface, see here:

Thanks, I will try to understand this and get this stuff for fun.

My vote goes also for inside pics, as the ones available are not high quality (my interest is seeing how feasible would be to add differential inputs. Shouldn't be difficult if bypassing the DSP.)

IMO that no control works when bypassing the tone controls might even be good news, as it probably indicates that it is working as a regular analog power amp. What scares me of this amp is the quality of the ADC - I am assuming that the input gets digitalized, and ADC at this price point.... won't be stellar I am afraid, but if you can't hear noise, I guess it doesn't matter.
Okay, I will try to take internal pictures if I can open it up easily.
 
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Bleib

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A few very early impressions, just received the unit
Pop-noise suppression should be included
Remote should be more responsive, sensitive
Volume 1 starts at a too high volume, some will use this on desktop with quite sensitive speakers
 

TonyJZX

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i think this is the same remote topping uses

its not bad but its not great, also not sure where the actual IR eye on the device is
 

gasolin75

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48 - 50v power supply can be used as well, as filter capacitors used are 63v


HEAT at high volume above 36 volt ???
 
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Guddu

Guddu

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HEAT at high volume above 36 volt ???
Not an issue at all, yet!
I am running it with 48v 5a psu from day 1 and it’s always cooler than other amps I have on desk at the moment.
 

gasolin75

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O-NOORUS often has has 2 inputs, one analog and one usb, can usb handle highest non mqa quality from tidal (i think highest normal quality is 24 bit and 96khz)

Im interested in a PA-316 and a PA70 (pa70 has no heatsink, will that be a problem ?)

They both have 2 inputs + sub out, one for my pc and one for my source selector, for my cdplayer, tt and tape deck,bass is left treble is right,bluetooth and a 24 volt not 4.5 a psu but 24 volt and 6.5 a psu, it costs under 100 euros with shipping

2024-05-06 17_30_38-Audiophonics – Google Chrome.jpg
 
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Guddu

Guddu

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Im interested in a PA-316 and a PA70 (pa70 has no heatsink, will that be a problem ?)
MA12070 or other Infineon chips have been implemented without heatsink by almost every manufacturer. I think I read somewhere that Infineon have mentioned that it doesn't need one.
 
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gasolin75

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I would be scared to use one at high levels (even when i did have one)
 
OP
Guddu

Guddu

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I would be scared to use one at high levels (even when i did have one)
It’s not difficult to just put a small heat sink on the chip directly if dismantling case isn’t an issue.
 

gasolin75

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Official 16bit 48K is max from the usb of a O-NOORUS PA-316 and guess also the PA-70
 

gasolin75

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It’s not difficult to just put a small heat sink on the chip directly if dismantling case isn’t an issue.

The 12070 will make more heat at any load above 2.5W than the 3116D2 with both running on a 24V supply due to lower efficiency. Power in = (Power out / Efficiency %)

#1220

Ordered the O-NOORUS PA-316 to get usb in (direct from my pc 16 bit 48khz, not first to source selector) line in for the rest (source selector, then line in), (sub out is there in case i need it), bass left , treble right, 24 volt 6.5 a psu not 24volt and 4.75 a, less heat above 2.5 watt compared to a ma 12070 based amp + im pretty shure it has a heatsink.price with 2-5 day standard delivery 84 euros total using paypal (said 80.72 but total a little extra,taxes,vat what ever)

 
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A pffb design with plenty of power, a sub crossover, power-amp function and a remote at that price.. sounds like a bargain to me. The price is so low it makes me think have some corners been cut, but having seen a few photos of the innards it seems ok I think.

Wonder if there's a signal sensing auto-on/off function when used as a power amp (BP mode).
 
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