NEW O-NOORUS D4 (TPA3255 PFFB / HDMI ARC / ES9023P)

[harkpabst]

Did I say that? I'm just answering to several posts stating crossover implementation is only possible through an app. btw you have several cheap amps with hpf/ crossover implementation from the likes of rsl, dayton audio or smsl so it shouldn't be that hard/ expensive.

As far as I know only one single post in this thread even mentioned app control. My own post.

Taking this one component (app control) out of its context you suggested "sabaj A30 pro" as a counter proof. I've still not been able to find a device going by this name. But more importantly my intention was not to say a particular smartphone was needed for hpf and lpf. I did state that DSP was needed for really flexible and high quality filtering. The SABAJ A30a does come with a DSP (but I don't know if it's used for filtering).

Now, if a device does digital filtering it just makes sense to offer stuff like freely adjustable crossover frequencies with 1 Hz resolution, level adjustment in 0.5 dB steps (or even finer), delay adjustment in 1 ms steps (or even finer), switchable filter slopes and so on. Adjusting all these parameters through physical knobs or a static menu on the device is pretty much impossible. A dynamic menu structure would certainly require a graphic display on the device (and could well be called an app). A smartphone app or a browser based GUI are certainly to be preferred.

What I'm describing is a different class of devices. I'm aware of that and wouldn't ask that kind of functionality from a roughly $100 device.

 

[zeluxao]

As far as I know only one single post in this thread even mentioned app control. My own post.

Taking this one component (app control) out of its context you suggested "sabaj A30 pro" as a counter proof. I've still not been able to find a device going by this name. But more importantly my intention was not to say a particular smartphone was needed for hpf and lpf. I did state that DSP was needed for really flexible and high quality filtering. The SABAJ A30a does come with a DSP (but I don't know if it's used for filtering).

Now, if a device does digital filtering it just makes sense to offer stuff like freely adjustable crossover frequencies with 1 Hz resolution, level adjustment in 0.5 dB steps (or even finer), delay adjustment in 1 ms steps (or even finer), switchable filter slopes and so on. Adjusting all these parameters through physical knobs or a static menu on the device is pretty much impossible. A dynamic menu structure would certainly require a graphic display on the device (and could well be called an app). A smartphone app or a browser based GUI are certainly to be preferred.

What I'm describing is a different class of devices. I'm aware of that and wouldn't ask that kind of functionality from a roughly $100 device.

You can have the bicycle.
I don't really have the time or the patience.

 

[harkpabst]

You can have the bicycle.
I don't really have the time or the patience..

I'm very grateful.
Investing two sentences, like you did.

 

[ICIETDIYEUR]

LOL

'plus' 1 for harkpabst

 

[Hellboy.]

RSL IA255.1

rogersound-labs-ia255-1-integrated-amplifier

RSL Speakers - A division of Rogersound Labs - is a factory direct loudspeaker manufacturer, since 1970, based in Los Angeles, California. Family owned and operated.

rslspeakers.com

Selectable 90Hz high-pass filter
*No App
*No LCD Screen

 

[harkpabst]

RSL IA255.1

rogersound-labs-ia255-1-integrated-amplifier

RSL Speakers - A division of Rogersound Labs - is a factory direct loudspeaker manufacturer, since 1970, based in Los Angeles, California. Family owned and operated.

rslspeakers.com

Selectable 90Hz high-pass filter
*No App
*No LCD Screen

*No use since it's fixed

 

[ICIETDIYEUR]

People hi !

These two devices can't be compared (and certainly not in terms of performance ).

The iA255.1 doesn't even have an amplification chip from TEXAS INSTRUMENTS but rather from INFINEON in view of its 24 volts of power supply and the (very) low power available...
... but quite important for a headphone however (LOL ).

I will stop there in terms of comparisons because the O-NOORUS D4 exceeds this amplifier in ALL ways.

It's not the fact of adding (clumsily) 4 components (2 per channel, actually capacitors and resistors) and a manual selector that makes it a sufficiently 'acceptable' device to consider that it has a properly designed high-pass filter:

this device is neither more nor less than a simple 'gadget' in my opinion.

Regards.

PS: again 'plus' 1 for harkpabst

 

[Hellboy.]

*No use since it's fixed

I know. But it's better than nothing.

 

[harkpabst]

I know. But it's better than nothing.

True, I won't argue against this. In particular for the typical use cases it's certainly a bonus.

I wouldn't even consider this amp (and most similarly priced items) as a component of my main system. But fact is that some of these miniature amps are so good technically, they are perfectly fit for highest quality home systems. For this I prefer the power amps with the least set of features (like e.g. V3 Mono and in particular the 3e Audio A5/A7 series) combined with a preprocessor/DAC (like e.g. the WiiM Ultra) implementing stuff like sub out and room correction

 

[Guddu]

@Alexander Lin
Are measurements available for different inputs?
Does RCA input go through ADC and then DAC to amplification or directly to amplification?

 

[Alexander Lin]

View attachment 418329

@Alexander Lin
Are measurements available for different inputs?
Does RCA input go through ADC and then DAC to amplification or directly to amplification?

The RCA signal is amplified directly without going through the ADC/DAC.
We will test different inputs later.

 

[Robertosimus]

Thank you for your suggestion. You mentioned that D3 PRO cannot be added, but we will add it to future models.
However
----Adjustable high pass filter for mains with usable range (40Hz to 120Hz for example)
This will add some components, and we are worried that some noise will be introduced or the sound quality will be affected.
We will try to develop it and see the final effect.

i'm a bit confused by everyone in this discussion.
Aren't these the most common scenarios:
Scenario 1: A person uses full range speakers an no subwoofer.
For this scenario the ampifier needs a full range for the main speakers.
For this scenario the ampifier does not need a low pass for the subwoofer output.

Scenario 2: A person uses small speakers and an active subwoofer with internal low pass.
For this scenario the ampifier needs a high pass for the main speakers ~ around 120hz.
For this scenario the ampifier does not need a low pass for the subwoofer output.

Scenario 3: A person uses full range speakers and an active subwoofer with internal low pass.
For this scenario the ampifier needs a full range for the main speakers.
For this scenario the ampifier does not need a low pass for the subwoofer output.

So a low pass for the subwoofer is never needed but high pass ~120hz for the main speakers is very very usefull.

So would'nt a full range/high pass toggle (cheap and efficient) or variable range (adds more costs and risks) for the main speakers and no low pass for the subwoofer be a better option for the amplifier?

Maybe this can still be implemented in the D3 PRO?

Also i dont like the fixed low pass for the sub at 80Hz. That could result in a gap between 80Hz for the subwoofer and ~120Hz for the main speakers.

Like what many have asked in the D1, D3 and D4 threads:

Adjustable high pass filter for mains with usable range (40Hz to 120Hz for example)

Adjustable low pass filter for sub with usable range (40Hz to 120Hz for example)

If we can't have both then high pass filter for mains is preferred for the majority since we assume people buying the "PRO" already have an active sub or dedicated sub amp with crossover control.

We (the consumers) do appreciate when the designer/manufacturers are trying to listen to feedback by the way!

I fully support the request for a high pass filter for the mains, not necessarily adjustable but why do you want a low pass filter for the (unpowered) subwoofer output?

 

[harkpabst]

i'm a bit confused by everyone in this discussion.
Aren't these the most common scenarios:
Scenario 1: A person uses full range speakers an no subwoofer.
For this scenario the ampifier needs a full range for the main speakers.
For this scenario the ampifier does not need a low pass for the subwoofer output.

Scenario 2: A person uses small speakers and an active subwoofer with internal low pass.
For this scenario the ampifier needs a high pass for the main speakers ~ around 120hz.
For this scenario the ampifier does not need a low pass for the subwoofer output.

Scenario 3: A person uses full range speakers and an active subwoofer with internal low pass.
For this scenario the ampifier needs a full range for the main speakers.
For this scenario the ampifier does not need a low pass for the subwoofer output.

So a low pass for the subwoofer is never needed but high pass ~120hz for the main speakers is very very usefull.

So would'nt a full range/high pass toggle (cheap and efficient) or variable range (adds more costs and risks) for the main speakers and no low pass for the subwoofer be a better option for the amplifier?

Maybe this can still be implemented in the D3 PRO?

Also i dont like the fixed low pass for the sub at 80Hz. That could result in a gap between 80Hz for the subwoofer and ~120Hz for the main speakers.



I fully support the request for a high pass filter for the mains, not necessarily adjustable but why do you want a low pass filter for the (unpowered) subwoofer output?

You're making some good observations but I come to different conclusions.

I agree that it's too much to ask for all this functionality from a little desktop amp. But consequently, please just don't implement any of this half-heartedly. A fixed frequency (and slope) high pass or sub out with low pass filter on such a device can be seen as "better than nothing", true. But I'd rather like to not see this at all. Save the money, make it a pure amp and leave competent subwoofer integration to a dedicated device upstream for those who want it.

Scenario 2 and 3 are too complex to be handled like this for good results. Stuff like a miniDSP HD or a perceiver like the WiiM Ultra are much better suited to this task. Those who fall into scenario 1 won't be missing anything.

 

[bolo_nz]

Also i dont like the fixed low pass for the sub at 80Hz. That could result in a gap between 80Hz for the subwoofer and ~120Hz for the main speakers.

Even if we did get fixed high pass why do you want it to be 120Hz? If you're on this forum you probably at least have decent bookshelf speakers that can go down to 80-50Hz.

Isn't the goal for a sub to be crossed as low as possible?

But yes, if they can't implement variable high pass then its better to not do it at all

 

[Robertosimus]

Even if we did get fixed high pass why do you want it to be 120Hz? If you're on this forum you probably at least have decent bookshelf speakers that can go down to 80-50Hz.

Isn't the goal for a sub to be crossed as low as possible?

But yes, if they can't implement variable high pass then its better to not do it at all

Yeah im a bit biased in this one. I intend to use the amp to drive 2 satellites as a computer desktop setup which should be crossed at 120hz.

This could work for many bookshelves but might not be ideal. Maybe a 3 setting toggle for 80-100-120hz or 80-100-150hz would be better. Im not sure what the cost difference between a fixed, 3 position fixed or variable high pass would be.

Shouldn't the subwoofer low pass set at at least the lower limit of the high pass for the main speakers? So that tue whole range is covered?

 

[bolo_nz]

Shouldn't the subwoofer low pass set at at least the lower limit of the high pass for the main speakers? So that tue whole range is covered?

Yeah sorry I should've worded it better, crossing the sub close to the limit of the main speakers

 

[capslock]

View attachment 418329

@Alexander Lin
Are measurements available for different inputs?
Does RCA input go through ADC and then DAC to amplification or directly to amplification?

I was puzzled by that since PFFB TPA3255 tend to have a SINAD in the high 90s or low 100s.

 

[capslock]

Has anyone ordered from O-Noorus directly? Do they prepay EU-VAT like Aliexpress, hifigo, Linsoul do?

They have an Aliexpress store (and prices seem to be the same as on their homepage), but the D4 is not listed on Ali.

 

[TonyJZX]

I was puzzled by that since PFFB TPA3255 tend to have a SINAD in the high 90s or low 100s.

isnt that a best case example with XLR and only if its a pure power amp like a Fosi V3 mono?

if you insist on putting in hdmi and digital conversion then you will lose sinad

BUT I feel like anything good enough for redbook is close enough?

 

[capslock]

isnt that a best case example with XLR and only if its a pure power amp like a Fosi V3 mono?

if you insist on putting in hdmi and digital conversion then you will lose sinad

BUT I feel like anything good enough for redbook is close enough?

The 3e Audio A5 was just reviewed here and maintains 102 to 103 dB SINAD via RCA for low gain / high gain. Same thing for the Topping PA5 II, about 2 dB lower with RCA but still way north of 100 dB.