[voltwide]

(13.02.2019, 01:51 PM)christianw. schrieb:

Zitat:about 75dB at 20kHz, which is 20dB better than my previous designs

Muss man auch erstmal "leise" abbilden..

Zitat:One thing is that I've developed a sampled domain model for self-oscillating loops that remains valid for all duty cycles, so it can predict closed loop response exactly under all conditions. This then allows finding a loop design that has very high loop gain (about 75dB at 20kHz, which is 20dB better than my previous designs) without running into stability problems near clip. A design procedure like this can't be patented because you can't prove that someone has been using it, so in a break from past style I'm not going to publish any details of this mathematical model. It's a trade secret, plain and simple.

Then there is the loop structure that allows better control of the closed loop frequency response. My previous amp* has approximately a 1st order roll-off. Now, since the output filter naturally has a second order roll-off it means that this amp could be overdriven with out of band noise from e.g. DSD recordings (in fairness, only when you cranked a quiet recording high). Also a first order response already droops noticeably by 20kHz which was sometimes remarked upon by numbers people. Eigentakt has a well-defined 2nd order response which stays dead flat in the audio band and rolls off in a fully controlled manner with a sensible -3dB point of 60kHz. The loop structure used to get this behaviour is subject of a patent application. A few other items are not really germane at the moment but were worthwhile enough to put in a separate patent application.

Alter Wein in neuen Schläuchen? Was sagen die anwesenden Fachkräfte? Warum ist da bisher noch keiner drauf gekommen und warum ist "dead flat" noch nicht in den ICs angekommen? Brauchts da Ausgangsdrosseln mit Feedbackwindungen?

Also ich hatte eigentlich angenommen, dass schon die vorigen designs ein feedback-Netzwerk höherer Ordnung beinhalten, um bei 20kz noch hohe Gegenkopplungsfaktoren zu ermöglichen. Dieses Spiel hat Bruno Putzey nun wohl noch ein Stück weiter getrieben.