A power sweep in 2 Ohm is quite stressful for the amp. Some very well regarded amps shutdown before the 4 Ohm sweep is complete.Where is the documentation or review of this unit being pushed to its limits before shutoff. That is the only reason anyone buys this over the 1ET400a. Unless you just want bragging rights. The 1ET400a handles 2 ohm loads.
But you are right, this is not a power stress test by itself. Our amplifiers need to withstand the CTA-2034 noise (i.e. crests at 700W, average at -12 dB) in 2 Ohm during 30 minutes. If it shuts down before, it will not got on sale in this form. Looking at you stereo Hypex NC500 OEM...
I never heard about a 1ET400A shutting down due to thermals. I rarely heard about the 1ET400A clipping into very difficult loads. The 1ET7040SA avoids this.
On a side note, I find quite interesting that boXem has been criticized several times in this thread for basic engineering stuff (choice of power supply, thermals, ...) while being the only small company led by an actual engineer, moreover with 24 years of practice (who admittedly is not very patient, is not always polite and [email protected] at marketing ).
So, now that I have 5 minutes, some engineering basics as a starter.
1. To reach and use the 950 W in 2 ohm from the datasheet, you need
- a power supply with +/- 72 V rails, to avoid amplifier clipping
- a power supply able to output 1035 W (950 W at the output + 85 W of losses) to avoid the power supply to collapse
Although almost all of them advertise such a power, I am not aware of a single amplifier sold with such a power supply.
2. Once the power supply rails can reach values above or equal to 70V, you can't use binding posts with metal parts within reach if you want to sell in EU. I am again not aware of an amplifier meeting these two criteria.
3. For good cooling, you need
- high thermal conductivity
- low thermal mass
- as much surface as you can
A big block of aluminum doesn't tick one of these.