Topping LA90 vs Topping PA5 II - Objectivist considerations

[Yorkshire Mouth]

As I often note, whilst I've learned a lot over the past few years, I'm still learning in all areas; some more than others. So my question may reveal the limitations of my knowledge, misunderstandings, etc. Please be kind, and correct me gently. I have one purpose for the post, but several discussion points.

I'm wanting to compare the Topping LA90 and PA5 II, using Amir's own excellent video on understanding amp measurements , along with this thread on the thresholds of audibility for amps and DACs.

From what I can seem the LA90 is effectively transparent to the source, within the threshold of human audibility (that's discussion point 1, I suppose), whilst the PA5 II passes that test too in many areas, though not by as much (discussion point 2, I think), apart from (i) frequencies above 10khz or so in multitone, and SINAD, and maybe signal to noise ratio. For the former, at 58 my hearing is dropping enough for that small amount of distortion over 10khz or so to be inaudible to me (my hearing has been measured, BTW - maybe discussion point 3).

As I understand it, the LA90's SINAD of 120 means that, even playing music at 120db, you'll hear no noise from the amp. For the Topping, you might start to hear noise at 105db. So (discussion point 4), is that right, if I never use the Topping PA5 II at above 105db, does this difference become meaningless? And presumably close to meaningless if I only stray above 105db very occasionally?

Nearly there, (discission point 4), Amir measures signal to noise ratio for the LA90 at 21 bits at 5W, 23 bits at full power. For the PA5 II it's 17.6 bits at 5W and 20 bits at full power. My understanding is that the limits of analogue tapes used in recording studios pre-digital, and the limits of human hearing, 20 bits is pretty much the limit. Now, I intend to use the amp as a power amp, controlling volume from a pre amp. For the LA90 there's a switch, for the PA5 II I presume it's case of turning it to full volume (happy to corrected). If I use it as a power amp (switched to this, or on full) do I automatically use the 'full power' signal to noise ratio measurement?

So finally, in short, given that I use my speakers in near field, and never really crank them up anyway, is there any real-world audible advantage of the LA90 over the PA5 II?

Many thanks, sorry for the long-winded post with multiple link.

Merry Christmas, over to you.

 

[Yorkshire Mouth]

Any takers?

 

[wavetrade]

I don't think that it will sound any different in the situation you describe. I have the PA5 II myself and think it sounds fantastic and was a great purchase. Thinking I wanted more power I later purchased a Audiophonics NCX500 amp. It also sounds fantastic. But I do not notice it sounding any better than the PA5 II, even with LS50 Meta speakers that are supposed to be somewhat challenging to drive. If I could do it all over I would have skipped buying the second amp.

 

[F1308]

Standing by for a yes to click on the LA90 Discrete buying link now placed under my huge, inverted Windows mouse pointer.

 

[Julf]

Nearly there, (discission point 4), Amir measures signal to noise ratio for the LA90 at 21 bits at 5W, 23 bits at full power. For the PA5 II it's 17.6 bits at 5W and 20 bits at full power. My understanding is that the limits of analogue tapes used in recording studios pre-digital, and the limits of human hearing, 20 bits is pretty much the limit.

So far I have not come across any mainstream commercial recordings that would get even close to a SNR of more than the equivalent of 16 bits. Same goes for studios and home listening environments.

 

[Yorkshire Mouth]

So far I have not come across any mainstream commercial recordings that would get even close to a SNR of more than the equivalent of 16 bits. Same goes for studios and home listening environments.

Given the above, can you see any measurable difference between the two which would make an impact in real-world listening, given the limits of human hearing (and my caveat about volume levels and listening distance?

 

[Julf]

Given the above, can you see any measurable difference between the two which would make an impact in real-world listening, given the limits of human hearing (and my caveat about volume levels and listening distance?

No.

 

[maty]

15 kHz

 

[HarmonicTHD]

Given the above, can you see any measurable difference between the two which would make an impact in real-world listening, given the limits of human hearing (and my caveat about volume levels and listening distance?

No.

And if your are still unsure. Take one of the online ABX distortion tests and see if you can hear 65dB SINAD for a 15kHz test tone just to cover the worst case.

 

[Julf]

15 kHz

And your point is?

 

[Bleib]

I used to have a LA90, which worked and looked fine. But I sold it and went with PA5 II plus because it's impossible to hear the difference.
Granted, there might be super high efficient speakers where LA90(D) sounds cleaner, but for most speakers this isn't a problem.

Edit: I also liked that I have RCA inputs now, although in general these amps have too few inputs and should come with a remote

 

[maty]

If you listen to very good recordings with physical instruments and voices, it is better that the distortion at 15 kHz be > 80 dB. If not, it will not matter.

 

[maty]

@Bleib

Main: Topping E70, Topping pa5 II plus, Guru Audio Q10

Measurements

One moment, please...

 

[Julf]

If you listen to very good recordings with physical instruments and voices, it is better that the distortion at 15 kHz be > 80 dB. If not, it will not matter.

Any harmonic distortion at 15k will be at 30k or higher, so you won't hear it. IM is a different issue, but fortunately most music doesn't have much energy that high up, so no problem.

 

[Yorkshire Mouth]

Any harmonic distortion at 15k will be at 30k or higher, so you won't hear it. IM is a different issue, but fortunately most music doesn't have much energy that high up, so no problem.

I think my hearing struggles with 15khz, and if I can hear anything at that frequency it’s deep into roll off territory, let alone 30hz.

 

[Bleib]

@Bleib


Measurements

One moment, please...

Off topic, and doesn't paint an honest picture either as they are for instance meant to very close to a acoustically treated wall (early reflections taken care of). For right bas response they also have to be at a correct height, it's all meant to sound normal in average Swedish apartment. There are plenty of other measurements out for Ino Audio piPs which this is a commercial variant of. It's the most neutral speaker I have heard so far which does not cost an arm and a leg. It's fast, detailed and does the pulse tests brilliantly, making many speakers sound muddy and unfocused in comparison. Obviously not meant to play as loud as some floorstanders (the maximum SPL is around 104dB @ 100hz with the smaller Junior+)
Elac DBR62 for instance has some extra energy in the 100hz region, this isn't the case with Q10. I have compared these two and 62 sounds tired in comparison.
I also have other speakers at home which are not listed in the signature.

Here they are compared to a bigger Dali:

And are not placed close to a wall, according to a comment it resulted into less perfect sound but I have never experienced this at home:
"I think they are too warm against the wall. And they lose the large image."
Using headphones the Dali instantly loses detail but obviously has more energy in the bas region. To gain extra bas with the brand it will cost more, buy bigger Guru or Ino audio such as Guru Audio 28. I don't notice anything particular with the vocals, I have yet to experience loudspeakers with no noticeable distorsion. If I notice it with Q10 then it's usually some dialogue in movies, but it's not much.

My goal is either Guru Audio QM60 or Ino Audio pi60(s), they go significantly lower, play louder and lower the distorsion. Those with deep pockets buy additional subwoofers. One of Ino's play up to 155dB @ 1 meter distance, obviously a lot cleaner at a much more reasonable sound level.

Here are Ino loudspeakers that cost even more than pi60 playing superbly clean

 

[grogi.giant]

15 kHz

While less distortion is always an indication of engineering excellence, second harmonic distortion of 15 kHz shows at 30 kHz. It will bother only your dog...

The distortion of 5kHz (measured in @amirm reviews), and frequently quoted in spec sheet 6.3kHz are the ones to look at.

 

[Yorkshire Mouth]

While less distortion is always an indication of engineering excellence, second harmonic distortion of 15 kHz shows at 30 kHz. It will bother only your dog...

Just to be clear, my dog Ralph is a big fan of Dark Side of the Moon, and I need to take his feelings into consideration.

 

[Billy Budapest]

Which retailer is selling the standard (discontinued) LA90 on closeout?

 

[Yorkshire Mouth]

A quick follow up if that’s okay.

I’m going to throw into the mix the PA7, and…

…the amp may be driving a pair of Revel M106s, which I understand aren’t the easiest to drive.

Comments? Any difference?