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Topping LA90 Review (Integrated Amplifier)

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 27 4.0%
  • 2. Not terrible (postman panther)

    Votes: 44 6.5%
  • 3. Fine (happy panther)

    Votes: 167 24.5%
  • 4. Great (golfing panther)

    Votes: 443 65.1%

  • Total voters
    681

Toku

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How a 92db SNR chip can deliver 120db SINAD ?
It is due to Topping's boasting magical skills.
The details are all black boxes, but it seems that it is realized by applying NFB in multiple stages. PA5 adopts the same method.
The magic of NFB can provide excellent numerical data, but it also has a negative side when it comes to sound quality.
A non-NFB amplifier is a completely opposite idea.
 

DualTriode

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It is due to Topping's boasting magical skills.
The details are all black boxes, but it seems that it is realized by applying NFB in multiple stages. PA5 adopts the same method.
The magic of NFB can provide excellent numerical data, but it also has a negative side when it comes to sound quality.
A non-NFB amplifier is a completely opposite idea.

Is it a composite amplifier.

I am impressed with the power supply. Is it regulated?

If you look at many Class AB amplifiers, they are dominated by power supply harmonics.

What is up with the LA90 power supply is it high frequency switching?

Thanks DT
 

Toku

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Is it a composite amplifier.

I am impressed with the power supply. Is it regulated?

If you look at many Class AB amplifiers, they are dominated by power supply harmonics.

What is up with the LA90 power supply is it high frequency switching?

Thanks DT
LA90 is an amplifier using TI's LM3886 Class AB IC chip. This IC is used one each for left and right cH.
This chip is used in various Chinese amplifiers.

The LA90's power adapter is the high frequency switching power supply you are talking about.
 

tonycollinet

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...The magic of NFB can provide excellent numerical data, but it also has a negative side when it comes to sound quality....

I have a lot of respect for your knowledge and experience of a number of class D amplifiers - but that is an "audiophile folklore" type of statement. NFB improves the numbers because it reduces distortion, and output impedance. Both of these improve fidelity, and hence sound quality.

From the point of view of fidelity, improved numbers are improved sound quality.
 

solderdude

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How a 92db SNR chip can deliver 120db SINAD ?

By adding more open loop gain and thus more NFB and thus better numbers and signal fidelity as small errors due to limited NFB in a standard chip are now also correctable due to the added gain (and thus feedback) in the total amplifier/feedback path.
 

soundofmusic

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Hello. I've got the Polk R200 speakers. Absolutely fantastic. I've got a Denon PMA-800NE integrated amp which I like but I think it could be improve so I'm debating whether to get the LA90. I use only an RME 9632 soundcard as a DAC with RCA outputs which sounds fantastic but I'm interested to hear the Topping D90LE.

Of course, the D90LE and LA90 can use balanced connections. Has anyone compared the D90LE/SE to the RME 9632 or similar? I bought the RME ADI-2-DAC in both it's AKM and ESS versions and I didn't like them as much as my PC soundcard but I was using a worse amp and speakers.

Finally, do you think the LA90 has enough power for the R200 speakers, or not? I listen to music at a good volume - I just did a 10 minute dB test with my phone and the max is 83.5 dB. I'm currently listening to them at a distance of 2.8 meters but I might want to listen to them at a distance of 4.5m.
 
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Piere

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It must be indeed a composite amplifier. That uses simply a nested feedback loop. Baxandall described that already in the 60-ties. I wonder why that comes to market commercially nowadays and not decades earlier! The basics are rather simple. Engineering a bit trickier, but doable by a skilled engineer. I am enjoying a LM3886 composite amp for around 8 years now! Can't measure distortion, it's below the capabilities of my sound card ;) (M-Audio Audioplile192). Besides vanishing distortion a CA has other advantages too! The amp is much less sensitive for speaker impedance influences, this sometimes means better control of bass units. But also PSRR increases dramatically. Something class-D doesn't do.
 

Markelian

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LA90 is an amplifier using TI's LM3886 Class AB IC chip. This IC is used one each for left and right cH.
This chip is used in various Chinese amplifiers.

The LA90's power adapter is the high frequency switching power supply you are talking about.
Let me guess, LM3886 with a small signal opamp for error correction in its feedback loop a-la what @tomchr made with modulus-286
Here is the thread on DiyAudio
Or same thing but with Howland current pump topology a-la My_ref, late Mr.Penasa already published in early 2000s
Diyers had this level of performance for 2 decades now, was wondering when someone would actually notice you can top charts at ASR for almost "free"..
Actually totally agree with poster above and his sentiment, pure wonder nobody thought to copy this before, it was litterally on the table the entire time..

I wouldnt be surprised if this LA90 had more power with a higher voltage brick, i built a My_ref and you can arbitrarily limit when it poops out if i just lower or raise the voltage (to a degree).
LM3886 is actually a bit harder to find these days so the only reason i can see a manufacturer mass producing with this part at this day is if they stumbled upon these designs.

Also not sure i get all these 50W is nothing people, thousands are building for example Nelson Pass's amps which rarely go above 10W (and the crowd who likes to waste 300W of power for 10W out doesn't exactly listen to bookshelves), and i dont think i've ever listened to music louder than about 3W (granted its nearfield and SPL drops off by inverse square law).
But come on, 20W already should be illegal to have if you live in an apartment, and 50W surely enough for all but the largest of rooms.
There are genuinely people who might need the power but im willing to bet 90% of these people never put a voltmeter in AC mode to the binding posts of their speakers while playing as loud as they ever listen, and calculating the actual (roughly) power with their speaker's nominal impedance.
This is like when you get used to seeing 1000HP supras on youtube and now scoff at everything in the three digit range
 
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Piere

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Sure! 50 Watts is enough for most satellite speakers! Ad a sub and enjoy! But this Topping is IMO half way with their approach with a SMPS power-brick and capacitive splitted power rails (as far as I understand from previous posts). The LM3886 is on the market for over 25 years now and well established. I've build many, many active speakers with it over the years and 10 years ago experimented with a CA version with great success. Its sound quality is top and the chip is nearly indestructible when used within its design specs and not treated too terribly bad. But....... to get the chip really shining it asks for a beefy dual power supply. Measuring sinad at 1 kHz and multitone responses with a resistive load, are limited to just that. But that doesn't show its muscles needed for some impact with "oomph and punch" with real speakers (yes very subjective, I know ;)). It is often in the 50 watts class, amps are blamed for. Here a review from a more listeners perspective. It mentioned just that as a con: "Lacks oomph and punch, not that impactful"
 
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pvehling

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This lower noisefloor compared to Purifi is impressive, but is that even audible at all on the Purifi? Considering 2x LA90 or dual mono Audiophonics Purifi.

My speakers are 8ohm 92dB sensitive, so 5 watts is actually pretty loud in my listening position

index.php
 

pvehling

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The noise floor of the amplifiers, both this and purifi is so low as to be academic. The noise floor only becomes a problem with gain up front or a noisy source.
Thanks for the reply! I'd have both options in low gain, with a very quiet pre (SMSL SP400). Although I do run analog as well (vinyl and tape), but I already know nothing can fix the noise from those. I'll consider both now..
 

Markelian

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Thanks for the reply! I'd have both options in low gain, with a very quiet pre (SMSL SP400). Although I do run analog as well (vinyl and tape), but I already know nothing can fix the noise from those. I'll consider both now..
Both noise floor, distortion, and anything else about both of these amps are so good to be completely transparent, and at least according to popular ASR thought audio is a "solved problem" at this tier of performance. It's purely up to your personal choice of size, aethetics, price, how you feel on a certain day, whatever...
IMO LM3886 in this configuration (that we speculate is the case at least) sounded pretty good when i had something similar..
 

mike70

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But that's the whole point - to get it so low that you know you're never going to be able to hear any distortion, in any listening scenario.

It's ok, but I think the point is ... once you reach the inaudible point ... you don't need something "even more inaudible"

Since 90 - 100 dB SINAD, everything must be more or less the same.
 

Alexium

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It's ok, but I think the point is ... once you reach the inaudible point ... you don't need something "even more inaudible"

Since 90 - 100 dB SINAD, everything must be more or less the same.
Right, but it has to be 90 dB (or at least 80) during the quiet parts of the music, not at 5 Watts.
 

Steven Holt

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20W already should be illegal to have if you live in an apartment, and 50W surely enough for all but the largest of rooms.
Thank you for your comment. My (imperfect) understanding of this is that people like high powered amps -- 100, 200, 300W -- is because of what is called 'dynamic headroom', or what I think of as 'power'. A smaller power amp has to work harder to produce a given amount of power than a larger powered amp. Think of a car -- a car with a 4 cyl. engine has to work harder to produce a given amount of horsepower than a 8 cyl. engine. Hence, amps with more power don't have to work as hard at a given volume as amps with less power. This should make them run cooler and last longer than low wattage amps. Of course, it's a bad idea to crank any amp. I had a friend who owned a Carver amp. When he turned that thing up to near max, it had quite a heat signature. I hope this helps.
 

James Romeyn

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Lower most is my email Q to Topping, directly below is Topping's reply. Interesting to confirm that "power" chips are divided into groups such as Bipolar and MOSFET. I deleted his name to save his email inbox.

I met an interesting guy in Spokane who designed and sells a well-received chip amp PCB at DIYaudio. I presume he uses this same LM3886 chip. My system employs satellite speakers exclusively with natural cutoff in the range of 70 Hz or 100+ Hz w/the port plugged. Sub system is a state-of-the art distributed array. Seems like an ideal application for a chip amp like the LA90.



It is Bipolar.

Best Regards!

----------------------------------

26th Jiaomen Road, Huangge Town, Nansha, Guangzhou, China

Zip code: 511455

---- Replied Message ----

FromJames Romeyn
Date10/18/2022 11:07
To
Subject

I realize that LA90’s output circuit is a chip. Are such chips split into groups like Bipolar and MOSFET, same as regular discrete power transistors? If yes, what type is the LA90 chip?

Kind regards,

James
 
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