guidocorona
I remember no more than one year ago you advocating that the day of class D would come once designers adopted Gallium Nitrite transistors switching at 1.5Mhz....
1graber2
E.g., “even”George has said he finds Class D acceptable at the 1.5 MHz switching speed. How much are those SE-1s?
What I said was G, they can’t yet because the mainstream manufacturers (Motorola, Hitachi, Fairchild STMicroelectronics Texas Instruments ect ect) haven’t started manufacturing them yet for maybe $2 each, because GAN is invented and made by a small (relative to the above) development company (EPC-Co) , they on sell the licence to major manufacturers to make them.
(EPC-Co) also invented the power Mosfet in the 60’s which the major manufacturers use under licence from them to make. Yes Technics has the GAN probably direct from EPC in limited supply, and you can bet they’re not $2 each, hence the $30k price tag on the SE-R1, anlong with limited tooling costs.
I’ve always stated that the 1.5gHz switching frequency used in $30k Technics SE-R1 was a massive stepping stone in the right direction, instead of the 400-600mHz used today by others. Because at 1.5gHz the low order output filter can remove "almost" all the switching noise without any effects down to around 5khz into the audio band which happens with all other Class-D’s now.
As Cyril Hammer of Soulution amps also says, we need to get even higher, he’s at 5gHz I’ve always thought 3gHz is fine, and when I see that on the way with future technology, it’s time for me to start advertising my boat anchors.
Cheer George