BASH and expired patents


FYI, everyone, the BASH patent is basically expired and that is where ’new’ amplification will very very likely...begin to shift into. Don’t know the exact dates but this is what it looks like is happening..

Just a prediction in potentials, is all...

Basically.....BASH is a class AB or C-ish output stage, combined with a pulsed power supply, where the rail voltages dynamically shift in level, in conjunction with the signal.

This is what class D was trying to side step, one might say -- the BASH patent. The BASH/Indigo patent was considered (by me) the better way but it blocked the path forward.

Now that path is again open and it will very probably be the new thing.

The whole idea is to gain efficiency, but have a non switching output. The BASH patent was the best compromise of quality and efficiency.

For the purposes of high end audio, the ending of the BASH patent will probably spell the end of high quality audio oriented class D amplifier development.

That was a 20 year delay....

The trick about Class D, is to remember or cognate the why of it in the first place. The pulse modulated output is not ideal, the filters can only do so much and create huge complications (The pulsed output and filter as a combination).

BASH sidesteps the worst intractable problems of Class D amplifier design and execution... and gives us the best that a high efficiency compact system can do. The problem of development in that area, was that the BASH patent blocked that entire spectrum of design pathways.

Now that path is open.

I speak a little on it (preliminary realization and musing) over here.
teo_audio

Showing 2 responses by kijanki

Basically.....BASH is a class AB or C-ish output stage, combined with a pulsed power supply, where the rail voltages dynamically shift in level, in conjunction with the signal.
Class H appears to be exactly that - class AB output with modulated power supply to minimize power losses.  This scheme is used in my Benchmark AHB2 where modulating of rail voltage is part of AAA (Achromatic Audio Amplifier) patent owned by George Lucas.   The key of AAA amplifier is not only modulation of the rail voltage, but also elimination of looped (recursive) feedback by adding second parallel "error" amplifier that corrects the output by subtracting the "error" form the output value (two sets of output transistors), completely eliminating TIM distortions.   

Perhaps in BASH and class H power supply voltage is modulated with different time constants, but I don't see any sonic benefits of either scheme.  It is used only to minimize power losses.  I believe that BASH was intended for subwoofers. 
@roberjerman:  I found this in "The Poor Audiophile":  

The feed-forward error correction of THX’s AAA™ technology keeps the AHB2 nearly distortion free when driving a heavy load. As noted in our interview with audio legend Laurie Fincham, THX’s Senior Vice President of Audio Research, the AHB2 is the first commercial amplifier in the world to use THX’s patented AAA™ technology to eliminate virtually all forms of distortion.
Perhaps Quad 405 was an early version before AAA was patented.