Topping LA90 Discrete Amplifier Review

[Doodski]

Why not simply use a large washer/plate under the device mounting screw instead of a scrap of pcb material?

I dunno. It's tacky for sure. I've seen this method used to restrain wires but not power transistors. Saving grace is there are those screws through the power transistors to hold them to the heatsink.

 

[Deleted member 48726]

I never had a desktop setup, just headphones, but what do you have against desktop, isn't it better that people can get quality sound when working or doing stuff in their pc/workspace?

Full size amps are tested regularly, today we had another review. And better not to go the way you are implying in the last sentence (if I understand correctly what you are saying), the companies send stuff to be tested and they are tested, just because you don't find these products interesting doesn't mean other people feel the same.

I may be old school this way. A setup like you're describing isn't HiFi in my mind. And that is perfectly acceptable to debate but this is my opinion.

I admit I have missed the review you linked. Thanks. EDIT: I read that it's a re-review due to issues with the first sample so nothing new. But none the less I missed it.
What I meant IR to the last sentence was that if sponsors are the means to more (objective!) reviews of full size amps I am okay with it.

 

[BeeKay]

Does not look like a clamp. The transistors are screwed on to the heat sinks. Looks like a spacer. Why so angry?

 

[shpong]

Beside all criticm , it sounds silky smooth and very clean. The down side is it's low power output. So the company positioning for this product is clearly for high sensitivity speakers.

 

[Triliza]

I may be old school this way. A setup like you're describing isn't HiFi in my mind. And that is perfectly acceptable to debate but this is my opinion.

I admit I have missed the review you linked. Thanks. EDIT: I read that it's a re-review due to issues with the first sample so nothing new. But none the less I missed it.
What I meant IR to the last sentence was that if sponsors are the means to more (objective!) reviews of full size amps I am okay with it.

I am old school like that myself, headphones are more immersive in such a case for me, but after joining ASR I have seen many people using desktop setups, so more power to them with decent equipment.

It's not for me to decide anyway, but sponsors will bring aboard new challenges, complains, and put in question the credibility of the reviews, we have them now without sponsors, imagine what will happen then.

 

[Deleted member 48726]

I am old school like that myself, headphones are more immersive in such a case for me, but after joining ASR I have seen many people using desktop setups, so more power to them with decent equipment.

It's not for me to decide anyway, but sponsors will bring aboard new challenges, complains, and put in question the credibility of the reviews, we have them now without sponsors, imagine what will happen then.

I agree. Equipment like the one in question is great news for those guys and it's awesome. It just isn't fitting into my world of HiFi..

Sponsored equipment or not. If reviews of said equipment continues of same quality and procedure as usual the numbers don't lie and comparisons are objective no matter if the equipment is sent by afiliate/sponsor or not. It's not exactly like those youtuber reviews that claim to be objective disregarding afiliate links but put no objective data behind their blessings. -Here we have numbers!!

 

[PuX]

1/4" jack is also a standard.

yep, common in pro audio.

 

[sarumbear]

yep, common in pro audio.

So is XLR

 

[Trudius]

Quite easily, actually. Some products can be built like a tank and have great quality components but have poorly-measuring circuit designs.

Except that it would be suicidal for the companies making them. I mean the average customer is not going open the components to check which brand of transformers, transistors, capacitors, etc. their unit has.

 

[Mrgoogle]

This is a review and detailed measurements of the Topping LA90 Discrete balanced stereo amplifier. It was sent to me by the company and costs US $799.
View attachment 278528
The case is the same as the IC-based Topping LA90 which is fine with me given its high quality look and feel. The power switch doubles as input selector once the unit is on. Volume control can be bypassed using switch in the back:
View attachment 278530

As before, power is provided by a hefty, 64 volt switching power supply rated at 4 amps (likely provides higher current in short bursts). The amplifier as you see is all balanced with three inputs. You have a selection of low and high gains (although the latter should really be called medium gain). It can be bridged and nicely tolerates even 4 ohm loads in that mode. Trigger is provided to enable one power switch to turn on a series of devices.

Note that this is a traditional amplifier and not class D. There is no remote so if you need that, you have to use a DAC/pre-amp with that capability.

Topping LA90 Discrete Measurements
There is a lot to measure here given the fact that we have dual gains and bridge mode. Let's work our way through it starting with low gain in stereo mode:
View attachment 278532

Incredibly, the LA90 Discrete matches the performance of its IC based unit, landing on its perch on top of all other amplifiers ever tested:
View attachment 278533

Switching to high gain costs you a few dBs but you are still ahead the competition:
View attachment 278534

So feel free to use this mode. Noise performance continues to be superb:
View attachment 278535
View attachment 278536

Frequency response is flat of course and load independent:
View attachment 278537

Crosstalk is better than average amplifier but is a step down from the regular LA90:
View attachment 278538

Multitone showcases the superbly low distortion levels:
View attachment 278539

Let's see how we are doing in power department starting with 4 ohms:

View attachment 278540

We wind up good bit more power at 70 watts (vs 56 watts for normal LA90) while giving up nothing in spectacular noise and distortion department. Allowing for more distortion gets us more power:
View attachment 278542

8 Ohm performance follows the same path:
View attachment 278543

Tests so far have been at 1 kHz (other than multitone) so let's vary that and see what happens:
View attachment 278544
In a word, wow! The amplifier simply doesn't care what frequency you throw out it! This is a quite a step ahead of normal LA90 which itself was state of the art.

Power on is silent but off may create a faint noise depending on your speaker sensitivity:
View attachment 278548

Warm up showed one channel struggling a bit but later I found the power connector not fully tight so maybe that was the cause:
View attachment 278549

Regardless, it behaved correctly after a minute.

Topping LA90 Discrete Bridged Measurements
As with normal LA90, bridge mode still provides superb performance:
View attachment 278550
View attachment 278551

The name of the game is power though so let's see what we get into 4 ohm:
View attachment 278552

Notice how we get more power but distortion is nowhere to be found until we clip.

View attachment 278553

Wow! This makes a great case for using a pair of these amps. You get so much power out of each one, rivalling much larger amplifiers.

Reactive Load Testing
The LA90 has a very sharp clipping point. This means that it goes from vanishingly low distortion to full clipping. Combine this with aggressive protection circuit which shuts the unit off and you have the make up of a system that can't be measured in batch mode as my Powercube setup uses. If I set the voltage for 8 ohm load, then it causes the amp to shut down when driven at 4 ohm. Good news is that the amplifier doesn't care about reactive loads. Here are the results for 8 ohm for example:

Maximum Output
4/11/2023
12:13 AM
Maximum Output Level Results
Selected Load    Ch1 (Vrms)    Ch2 (Vrms)   
8 Ohm; 60 deg Capacitive    21.2    21.3   
8 Ohm; 30 deg Capacitive    21.1    21.2   
8 Ohm; 0 deg Resistive    21.0    21.0   
8 Ohm; 30 deg Inductive    20.2    20.3   
8 Ohm; 60 deg Inductive    20.9    21.0

I could not get a similar output at 4 ohm due to limitation of the instrumentation as stated above. But if I drove the parameters manually, I could get it to tolerate reactive loads just as well.

Selecting 2 ohm caused the protection circuit to kick in. I didn't have time to mess with that.

I spent nearly 2 hours trying to get this test done with the amplifier being pushed to clipping and shut down probably 50 to 100 times. Even though the case got pretty warm, the amp continued to function without complaining.

Conclusions
Traditionally in high-end audio when a company says they are using discrete designs, I get prepared for bad performance. Topping once again proves that this is no barrier for their designers. The discreate LA90 not only matches the exemplary performance of the IC based LA90, but betters it in power handling, producing more power (a needed feature). Pushing noise and distortion down in our top tier performance is very hard but Topping has no problem maintaining its significant lead over even best of the best amplifiers. Their skills and execution in this regard leaves me speechless.

Needless to say, it is my absolute pleasure to add Topping LA90 Discrete to my recommended list. Today is a happy day!

P.S. Power amplifiers are least reliable audio products (due to high currents and voltages involved). New designs sometimes need to prove themselves in this regard. So if you are risk averse, please don't be the first to purchase this amplifier.

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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

Just wonder if had Power Cube ( from audio graph) under BW measurement and THD vs freq. you could even see how these value would change with reactive load, such as Stereophile

 

[wwenze]

Except that it would be suicidal for the companies making them. I mean the average customer is not going open the components to check which brand of transformers, transistors, capacitors, etc. their unit has.

The company seems to be doing very well

睿志音响

The R7HE MK2 made publication in the 2023 Stereophile Recommended Components listing.
https://www.stereophile.com/content/recommended-components-2023-edition-digital-processors

 

[wwenze]

Just wonder if had Power Cube ( from audio graph) under BW measurement and THD vs freq. you could even see how these value would change with reactive load, such as Stereophile

View attachment 279318

View attachment 279317

Please understand that the Ayre V-3 is a... "design using different philosophy"... which has a very high output impedance for a speaker amp

As expected from a design with no loop negative feedback, the output impedance was moderately high at a measured 0.33-0.38 ohms up to 1kHz, increasing to 1.14 ohms at 20kHz.]

Like, most recommended headphone amps nowadays have an Z-out of <1 even at 20kHz

So this is an issue that doesn't appear on... designs that focuses on measured performance. Which the Ayre V-3 is not. The resulting speaker load THD pattern can hence be explained: At higher frequency such a design suffers from poor GBW hence lower linear working range at HF hence THD increases with frequency. The reason for poor GBW is due to output voltage not being able to keep up, which already happens without load due to reactive components in circuit/transistor modelling. And by adding more reactive loading, you're making it even worse, on top of a graph that already has higher THD at HF on its own.

I can suggest a middle ground - Measure output impedance, which might be kind of useful, and will tell you what kind of graph you will get on your speaker simply by doing some math. And output impedances below 0.1ohm won't even matter - The connector becomes a bottleneck instead.

Add: What frequency response variation to realistically expect:

Amplifier Output Impedance (Damping Factor) and Speakers

This is a reprint of an article written ca. 2011-2012. I've been meaning to rewrite and update it, but Life and Work keeps getting in the way, so I am reposting the original as-is. Take it for what it's worth, an introductory take on one of the potential causes for differences in sound among...

www.audiosciencereview.com

 

[Billy Budapest]

Except that it would be suicidal for the companies making them. I mean the average customer is not going open the components to check which brand of transformers, transistors, capacitors, etc. their unit has.

It happens all the time. Many so-called “audiophile” components are very heavily built and utilize very expensive parts, and perform horrendously on the test bench. Very common.

 

[Billy Budapest]

Why not simply use a large washer/plate under the device mounting screw instead of a scrap of pcb material?

Agreed. This choice is quite odd.

 

[nagster]

Agree 100%. Life spam in amplifiers is real. I'm currently experiencing this phenomenon. I have a stereo array of Meyer Sound M2Ds speakers in the main worship center at the church I work for since 2011. Each array has 5 x M2Ds speakers. Each speaker used to cost around $20K back in 2006, so total we are talking about $200K worth of speakers. Those Meyer Sound arrays were purchased back in 2007 and manufacture date was 09/2006. At the end of last year 1 UX amp module failed. I got a replacement module directly from Meyer Sound for $1500. Then in January 2023 another UX amp module failed, so ordered a second one. Last month 2 x UX amp modules failed as well. Called Meyer Sound and ordered 5 x UX amp modules. Long story short, these amps reached their life cycle after 18 years of use so most likely during this year all UX amp modules are going to be replaced with new ones. Now look at this, Meyer Sound still provides support for a speaker that was discontinued about 12 years ago and purchased 18 years ago. That is what I call Customer Support for life.

2006 UX Amp Module:

View attachment 278927

2023 UX Amp Module:

View attachment 278928

I like the sound of Meyersound, so I often use it.
The image is the amplifier unit of 1100-LFC. I got it back the other day after it was repaired.
My favorite of the subs. A 900 or 750 sounds even cleaner, but I like the punch of the 1100. I haven't heard the 2100 yet.
Good support for older models. Maybe they will accept it even if it is HD-1. As long as Mr. John Meyer is enrolled, it seems to be safe.
By the way, JM-1P is recommended for point sauce. If you haven't heard it yet, please listen to it.

 

[JSmith]

spam in amplifiers is real. I'm currently experiencing this phenomenon

I certainly hope not...

... sorry, couldn't resist.


JSmith

 

[B.A.T.]

THE SPEAKER GAUNTLET // Topping LA90 Discrete (Part 3)

 

[Snr_Rvrs_Eng]

Quite frankly, stunning performance. It makes One wonder what the establishment has been doing all these years....other than sitting on their laurels of course.

Creating a very low distortion amplifier - although not trivial - is not that difficult nowadays.
All the distortion mechanisms in transistor-based gain blocks are well known and documented.

It is a frustrating fact that the auditory system is not at all sensitive to THD related artifacts.

Mr Amir's measurements are valid nevertheless. Why?

* Good objective performance means engineers have done their job right.
* Unfortunately, ultra low THD does not necessarily translate into great audible performance.

The establishment is doing their best to decipher the relationship between electronics circuit design & subjective audible preference.

 

[JktHifi]

THE SPEAKER GAUNTLET // Topping LA90 Discrete (Part 3)

He heard distortion then made an oreo, then he throwed the remote second time to the floor.

 

[okok]

topping famous for fail rates now? 10%?