For whatever reason you refuse to see the reality of the situation. Topping 'seem' to create some really good designs but then fail to implement them into properly engineered products. Even basic engineering knowledge tells you dissipating heat needs to be be dealt with at the design stage. The stupidity of horizontal finning is a classic example; cramming everything into the smallest space possible is another and because no one has had the common sense to try to identify if component choice is another reason for failed units the forum is none the wiser as to why or how exactly the product is defective.
Surely it must be obvious that Apos know they have a turkey on their hands and that Topping is refusing to deal with the problem. The word that comes to mind with Topping is hubris, a very bad state of mind for a commercial company to have. A successful company will turn a negative into a positive by confronting the problem head on, admitting that the product/s have issues and deal with them, even if that means redesigning and using a different enclosure. All the reviews state what an exceptional performance is achieved by the LA90D. To me it's a no brainer but then I'm a rational person.
What will you do if the retailer does nothing - right off your investment, make the huge mistake of getting involved with lawyers or find someone with real engineering experience to take a look and very probably identify and solve the problems.
To be fair, the "performance" (which is mostly impressive THD shown in static test) is not so exceptional as it cold be.
If you have curiosity, soldering station and a bunch of not exceptional or expensive components, you can assembly Wolverine, for example, with 0.000095% THD at 80 watts on 8 ohm load and extremely clear distortion spectrum:
This thread is for people to discuss their builds, build issues, and parts for the DIY Class A/B "Wolverine" Power Amplifier. The boards are currently available through group buy's when they are held. @jjs is servicing the USA and Canada regions. @stuartmp is servicing the other regions. Main...
www.diyaudio.com
In general, all this is not even interesting, because by the depth of feedback or by the multiple feedbacks architecture in combination with their depths, someone can "squeeze out" very low THD.
It's been very boring for a long time.
Not only the sizes are suspicious and strange in this amplifier.
Unipolar power supply is absolutely strange.
Power supply is obviously underpowered and has unknown dynamic characteristics (this is obviously a switching power supply and it should be with absolutely wonderful and special properties that meet the needs of an amplifier with a top frequency of 20 kHz and a high slew rate), anyway it's as strange as possible.
All this is very strange, because in a good amplifier, powering is a very tangible part of its cost, and such a trick in a class AB amplifier is either a design error or a deliberate significant reduce of the cost of production.
There is no special "science" in all this, this is pure engineering, and this is quite obvious, and potential buyers simply must be warned about this because they are not engineers for the most part.
