I am proud to present you the new class ABimproved. 😀
It works this way -> 0 volts class A standby current, some voltage -> less standby current.
This is a very good hybrid between class A and AB, actually this is real class AB. Normal class AB is just class B with more standby current.
Conclusion => hybrid between A and B (new classes: class A, class AB, class Bi, class B)
😱
FFT is @ 20khz.
It works this way -> 0 volts class A standby current, some voltage -> less standby current.
This is a very good hybrid between class A and AB, actually this is real class AB. Normal class AB is just class B with more standby current.
Conclusion => hybrid between A and B (new classes: class A, class AB, class Bi, class B)
😱
FFT is @ 20khz.
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propogation delay ....
Consider a slow opto (like the 4n35).
100's of uS propagation delay will be there.
I know the model shows good performance , but it lies.
This method has been tried , OEM's and forum god's 😀 .... have gone the
non-optical way for class AB2 (what is is typically referred to as).
For reference - Auto Bias part II
Even this arrangement slows down a fast EF3. I altered mine for
comparison.
OS
Consider a slow opto (like the 4n35).
100's of uS propagation delay will be there.
I know the model shows good performance , but it lies.
This method has been tried , OEM's and forum god's 😀 .... have gone the
non-optical way for class AB2 (what is is typically referred to as).
For reference - Auto Bias part II
Even this arrangement slows down a fast EF3. I altered mine for
comparison.
OS
Do opto couplers have to have that much propagation delay? In optical telecom world they are very fast. An LED ( actually laser diode ) and a phototransistor or photodiode can be made to handle 50GB/s trunk lines. Light propagation is 11ns per foot and couplers are separated by mm.
ok 😀
i found out its the same result like normal AB with 250mA bias current (+-23V supply voltage)
another idea was to boost the bias only in HF range 😀
i found out its the same result like normal AB with 250mA bias current (+-23V supply voltage)
another idea was to boost the bias only in HF range 😀
Shame about the class ABi dream. There are plenty more biasing schemes to experiment with and prove to yourself that there is nothing new to find - just better or cheaper ways to apply the existing bias control systems - and there are many and various ones to play with.
The link given by ostripper works fine for me. Here it is again, copied from the same site: Auto Bias part II It is to member Edmond Stuart's site which covers some serious professional work on class AB audio design - not for beginners.
The link given by ostripper works fine for me. Here it is again, copied from the same site: Auto Bias part II It is to member Edmond Stuart's site which covers some serious professional work on class AB audio design - not for beginners.
its not working for me, i tried again.
when i think now i realize that there is no need of autobias.
the bias current is high only at crossover region.
its good only if you boost it for high frequencies. 😛 😉
The Circlophone has a sliding bias so it's virtually a class A but doesn't run as hot - or is it class AB2? The transistors never switch off in the Circlophone.
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