Amplifiers with room correction: worth the cost or just a useless tech?

[SSS]

My opinion is not to rely on conclusion from others. Anyway it is hard to choose between the different class-D modules from far away. When viewing the manufacturers datasheets and desciptions there are differences. But to judge what might be better for own pupose is hard. So one can only select as best and buy it. Myself I don't like class-D at all. I rely on good old stuff with big power supply capacitors and plenty of stored energy. The class-D modules almost all have reduced capability above 10 kHz. OK, it may not count much in hearing. But a harsh sound can be introduced by intermodulation products.

 

[marX]

My opinion is not to rely on conclusion from others. Anyway it is hard to choose between the different class-D modules from far away. When viewing the manufacturers datasheets and desciptions there are differences. But to judge what might be better for own pupose is hard. So one can only select as best and buy it. Myself I don't like class-D at all. I rely on good old stuff with big power supply capacitors and plenty of stored energy. The class-D modules almost all have reduced capability above 10 kHz. OK, it may not count much in hearing. But a harsh sound can be introduced by intermodulation products.

I would gladly trade in the clarity above 10khz for efficiency - hence Class D.

As a side note, I'm waiting a bit more so as to not make any rash decisions like I did (buying the HK Citation amp). Let's see what the 'revised' topping Topping LA90 amp brings to the table and if the faults have been taken care of.

 

[SSS]

I would gladly trade in the clarity above 10khz for efficiency - hence Class D.

As a side note, I'm waiting a bit more so as to not make any rash decisions like I did (buying the HK Citation amp). Let's see what the 'revised' topping Topping LA90 amp brings to the table and if the faults have been taken care of.

Well, good luck. The LA90 was tested pretty OK by Amir. For me this is an amp for speakers not needing much power and amperes. Myself I don't like external power supplies for power amplifiers. Here with 4 A max. and thin long wire I don't trust. If it were a preaplifier only, then OK.

 

[radix]

Well, good luck. The LA90 was tested pretty OK by Amir. For me this is an amp for speakers not needing much power and amperes. Myself I don't like external power supplies for power amplifiers. Here with 4 A max. and thin long wire I don't trust. If it were a preaplifier only, then OK.

Here is the review of the LA90 Discrete. It's a great 70W (4-ohm) amp, or 50W (8-ohm). Not a class D.

 

[marX]

@SSS
I believe you have some valid reasons why you think the cabling is not good enough.

Some offtopic discussion:
I used to believe while designing circuits and stuff, the designers made proper use of applicable best practices to have the best performance in regards to the components they used in the circuit. But sadly it was not the case. For example, when I bought a Chinese no-name DAC, Diyaudio members suggested I add some mains filtering. The differences it made were huge and I was not expecting that.
I added the X and Y caps, a common mode choke, and two ferrite beads on the USB cable. Fairly cheap in terms of the cost of components.

I currently have an earfun speaker but if I connect the USB cable to it from my PC (for charging) while playing music (Topping NX4 DAC - aux cable), there is a huge amount of noise.

So I'm guessing I have to study electrical engineering as well lol
I did Mechanical Engineering (bachelors) some time back and now Computer Science (masters). Electrical Engineering is next

 

[marX]

Amir reviewed the NX4. It looks ok for use as line out -- the noise is great, but there's a little L/R imbalance. Just keep it on low gain.

I'm not an expert on all the different hypex and purifi amps. There's a lot of them. They should all perform about the same if they have the same chipset (e.g. ncx500 or nc252 etc.). There's not a lot for an integrator to muck with, apart from power supply and maybe input buffer and wiring topology. You could search ASR for recommendations on class D amps.

If you're willing to step down from the NCX500, there's a lot of lesser expensive options. The NCX500 is their flagship model, so it will be at a premium. The NC500 is still excellent, and then there's all the NCxMP, like the NC500MP or NC502MP (both are still 500W into 4-ohm). Those are all still very good amplifier modules.

Apollon is a European hypex/purifi/icepower amp manufacturer. I've heard very good things about their build quality, but they are not a budget brand.

There's also boXem, outlaw audio, buckeye, ati, and many more. You could look at the recommended amps at https://www.audiosciencereview.com/forum/index.php?pages/Reviews/.

I'm sure there's other threads with recommended class D amps.

I checked out the various manufacturers you listed. Love their designs, especially boXem and Apollon. Looks more like a work of art than a capable power amplifier.
The cost is slightly more than Audiophonics but I guess its worth it.

I'm still leaning towards the Audiophonics NCx 500 amp and continuing to use the Topping NX4 DSD DAC for the foreseeable future.

 

[SSS]

@SSS
I believe you have some valid reasons why you think the cabling is not good enough.

Some offtopic discussion:
I used to believe while designing circuits and stuff, the designers made proper use of applicable best practices to have the best performance in regards to the components they used in the circuit. But sadly it was not the case. For example, when I bought a Chinese no-name DAC, Diyaudio members suggested I add some mains filtering. The differences it made were huge and I was not expecting that.
I added the X and Y caps, a common mode choke, and two ferrite beads on the USB cable. Fairly cheap in terms of the cost of components.

I currently have an earfun speaker but if I connect the USB cable to it from my PC (for charging) while playing music (Topping NX4 DAC - aux cable), there is a huge amount of noise.

So I'm guessing I have to study electrical engineering as well lol
I did Mechanical Engineering (bachelors) some time back and now Computer Science (masters). Electrical Engineering is next

To study EE is a good idea. But just reading some good EE books will enlight you. On the other hand, practical experience is what you cannot buy. Must be done by doing which I did during my life. @cabling, I use short and thick cables and wires as far as possible. This depends on what I want to reach when building/restoring audio gear.

 

[SSS]

Here is the review of the LA90 Discrete. It's a great 70W (4-ohm) amp, or 50W (8-ohm). Not a class D.

Seems to be a great amp according to the measurement data.

 

[marX]

To study EE is a good idea. But just reading some good EE books will enlight you. On the other hand, practical experience is what you cannot buy. Must be done by doing which I did during my life. @cabling, I use short and thick cables and wires as far as possible. This depends on what I want to reach when building/restoring audio gear.

And maybe some shielding as well?

I read here that some of the Audiophonics amps have mains hum due to long AC cabling and no shielding.

 

[SSS]

And maybe some shielding as well?

I read here that some of the Audiophonics amps have mains hum due to long AC cabling and no shielding.

Of course also shielding. Forgot to mention this, and further ground loops, inhibit of magnetic coupling, and so on. Thats a question of practice and experience which is not always taught when studying EE at the university.

 

[radix]

Of course also shielding. Forgot to mention this, and further ground loops, inhibit of magnetic coupling, and so on. Thats a question of practice and experience which is not always taught when studying EE at the university.

There are literally books written only on grounding and shielding. EE is a fascinating topic, especially analog and RF. It's fairly easy to have the basic push-pull topology or filter circuits, but when one really looks at the practical implementation there are lots of other factors like temperature stability, oscillations, bias stability, inductive coupling, board layout, wiring, testability, low failure rate, etc. If it were simple, everyone could make SOTA performing products.

 

[SSS]

There are literally books written only on grounding and shielding. EE is a fascinating topic, especially analog and RF. It's fairly easy to have the basic push-pull topology or filter circuits, but when one really looks at the practical implementation there are lots of other factors like temperature stability, oscillations, bias stability, inductive coupling, board layout, wiring, testability, low failure rate, etc. If it were simple, everyone could make SOTA performing products.

Right, this is why I love it.

 

[marX]

Sorry to bring this thread back. There has been a development!
I bought the Revel M16 for < £590 from the Nottingham HiFi store.

BTW, loved the behaviour of the staff. An honest, working class-like demeanour. Not claiming to know everything and trying to push stuff down my throat.

Now I have to decide on the amplifier.

 

[marX]

So, I'm running low on cash after some purchases. So, for like ~£100, what are my options reg. integrated amplifiers for the Revels?
Any suggestions?

PS: I would be upgrading to a 'proper' amp after like a year. Just have to make do with this setup for some time.

 

[Rednaxela]

A second hand Sony STR-DB940. No frills, powerful, indestructible, with digital inputs, and (digital) bass, mid, and treble control with variable frequency. And of course sub out with adjustable crossover.

Otherwise maybe an old Denon AVR with digital GEQ.

 

[marX]

A second hand Sony STR-DB940. No frills, powerful, indestructible, with digital inputs, and (digital) bass, mid, and treble control with variable frequency. And of course sub out with adjustable crossover.

Otherwise maybe an old Denon AVR with digital GEQ.

That thing is a bit big for my liking. But yeah, it looks like its well built.

 

[marX]

BTW, I came across this Yamaha AS 501. I have the older version, AS 500 in my country which I like. Is this 'new' one better than that?
I remember going to purchase a Q Acoustics speaker and the dealer dissing me in public for having an 'agricultural' amp like the Yamaha AS 500 instead of an 'audiofool' amp!

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£160

 

[RDoc]

The latencies are equal to the number of taps in samples. There is always a trade off between delay and frequency resolution. 1024 samples at 44.1 is 23ms, 65536 is more than one second of delay. So, the disadvantage of FIR filtering is that it eventually becomes incompatible with video playback, if you want to use your system for that.

The threshold for bad lip-sync is usually considered to be around 120-200ms, so you wouldn't want to use more than (say) 8192 taps at the very most, for any gaming or video applications.

I beg to differ.

The acceptable delay is very individual. For example, I do amateur dance and theater videos in venues where I'm about 60' back from the stage. I record sound in both my cameras and on stage mics. When editing, I use the audio from my camera to sync the video with the on-stage mic recordings which is what I use in the video so I can eliminate room echo, audience noise, etc. For myself, the ~50 msec lip sync error is invisible. For my wife and a female producer I worked with, it's intolerable. I'm not sure where their limits are, but it's below 50 msec. Once I moved the sound by 50 msec relative to what the camera recorded everyone was happy.

This has happened more than once with different people, all female incidentally. I wonder if women are generally more sensitive to lip sync than men. Or maybe I'm just particularly insensitive. In any case, 100 msec or more is not going to work for a lot of people.

 

[kemmler3D]

I beg to differ.

The acceptable delay is very individual. For example, I do amateur dance and theater videos in venues where I'm about 60' back from the stage. I record sound in both my cameras and on stage mics. When editing, I use the audio from my camera to sync the video with the on-stage mic recordings which is what I use in the video so I can eliminate room echo, audience noise, etc. For myself, the ~50 msec lip sync error is invisible. For my wife and a female producer I worked with, it's intolerable. I'm not sure where their limits are, but it's below 50 msec. Once I moved the sound by 50 msec relative to what the camera recorded everyone was happy.

This has happened more than once with different people, all female incidentally. I wonder if women are generally more sensitive to lip sync than men. Or maybe I'm just particularly insensitive. In any case, 100 msec or more is not going to work for a lot of people.

Sure, that is totally fair. 100-200ms is where it becomes really obvious to most people, even those who aren't sensitive to it. I think the just-detectable threshold is probably a lot lower. If you're really paying attention, something being one frame out of sync at 24fps (41ms) can be obvious.

 

[marX]

Just a small update. I got the Fosi Audio V3 amp during the sale. I'm not convinced about the sound quality though so I went to all the hifi shops around here for any deals. The lowest one is this...https://www.richersounds.com/denon-dm41-dab-blk.html - the price is 199 quid.

Then there is the Marantz PM 6007 for 349.

An alternative option is to keep the Fosi amp and wait for the Black Friday sales.
What do you guys say?