VFA Topology Amplifiers for Audio

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Lets start this thread with the post of a high performance VFA so we can discuss - maybe dadod you want to put your design up. I can't put my e-Amp up because I am in Bali on a break (beautiful by the way) and only have iPad and no PC!

We discused VFA type in quite detail already, but if there are enough interest I will present my TT amp schematic again here.
Now what interest me more is CFA design and how to get best of it as there is no literature about, exept CFA op amps and some schematic presented here on this forum. I personally don't know any book written how to design good CFA audio amp.
BR Damir
 
We discused VFA type in quite detail already, but if there are enough interest I will present my TT amp schematic again here.
Now what interest me more is CFA design and how to get best of it as there is no literature about, exept CFA op amps and some schematic presented here on this forum. I personally don't know any book written how to design good CFA audio amp.
BR Damir
A good way to educate yourself is to take Lazy Cat's VSSA and put it in the sim. Put measurement probes in about every lead / node and do some DC stepping. That way I figured out how the DC operating point configuration can be performed and how the gain can be set/calculated. Takes a little to wrap your head around but it's really not that hard :)
 
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I think your TT amp is a good reference for further discussion dadod, so I would propose you put it up. I think basic MC has been with us for many years, but over the last few years, alternative comp schemes have entered the mainstream. Examples are TMC and older ideas like TPC and MIC (note TMC has also been around for quite a while but I think we have to credit Edmond Stuart for popularizing it in the last few years).

So, for me personally, the big challenges with VFA are:-

1. Establish if there are any fundamental and new comp schemes
2. Routinely hit <1 ppm at 20 kHz ( you can do it now, but such amps are complex and IMV very 'tweaked' designs that would be difficult to reproduce)
3. Further explore the use of mosfet output stages as a way to extend the ULGF and establish quantitative limits on the ULGF
4. Further explore VAS/TIS structures to establish which offers the best performance
5. Conduct a fundamental study on the topological benefits of Blameless vs folded cascode vs fully balanced symmetrical designs covering distortion (incl. spectra analysis), SR, bandwidth and PSRR
 
A good way to educate yourself is to take Lazy Cat's VSSA and put it in the sim. Put measurement probes in about every lead / node and do some DC stepping. That way I figured out how the DC operating point configuration can be performed and how the gain can be set/calculated. Takes a little to wrap your head around but it's really not that hard :)

I have done that already, if you followed that thread you could noticed my simulations. I tried even TMC on VSSA. And I don't like big elcos used in the feedback path.
 
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