yes true, this was simply a VAS differential desing.
I have a couple of questions if any of you guys can answer would be great:
1) is this design (referring to kaneda) what so called double differential configuration?
2) i was also interested on exploring the folded cascoded topology:
is there any good thread and/or link that extensi vely covers this subject?
I am also looking at the AD797 simplified schematic on the datasheet as a good example of folded cascode design.
I can't completely understand it though.
I like the Cn compensation cap that cancels the interaction the distortion contribuite of the output stage.
Is Cc the compensation cap for stability of the circuit?
i don't know if my analysis is correct or not...but...if a discrete implementation of this circuit was attempted....wouldn't it need special attention to the current source's value by selecting the devices for specific parameters so that the current at the tail of thefolded cascode matches the sum of the other currents (I7=I1+2*I4)?
I can't undestand how the output stage is driven actually.
Anyways...if there would be any good 3d on folded cascode i might be exploiting a bit further this interesting topology.
By all means...i know there isn't a best of....but accordingly to your experience guys which topology (double differential or folded cascode) do you think sounds better?
I have a couple of questions if any of you guys can answer would be great:
1) is this design (referring to kaneda) what so called double differential configuration?
2) i was also interested on exploring the folded cascoded topology:
is there any good thread and/or link that extensi vely covers this subject?
I am also looking at the AD797 simplified schematic on the datasheet as a good example of folded cascode design.
I can't completely understand it though.
I like the Cn compensation cap that cancels the interaction the distortion contribuite of the output stage.
Is Cc the compensation cap for stability of the circuit?
i don't know if my analysis is correct or not...but...if a discrete implementation of this circuit was attempted....wouldn't it need special attention to the current source's value by selecting the devices for specific parameters so that the current at the tail of thefolded cascode matches the sum of the other currents (I7=I1+2*I4)?
I can't undestand how the output stage is driven actually.
Anyways...if there would be any good 3d on folded cascode i might be exploiting a bit further this interesting topology.
By all means...i know there isn't a best of....but accordingly to your experience guys which topology (double differential or folded cascode) do you think sounds better?
For Paul Joyce
I see way back in this thread that you built the Paul L. Rossiter Head amp of AudioXpress sep. 2006.
So did I, but did not realize until too late that my MC cart. is 30 ohms, and the PLR head amp input is 10 ohms :-/. Noise is very low indeed (lower than my phono stage), but the sound has a "spacious echo". My friends say its typical to impedance mismatch.
Would you think it possible to raise the input impedance above e.g. 100 ohm by increasing R5/R6 (R1/R2 in your schematic) and also increase supply voltage to compensate for lower R5/R6 collector current ?
I see way back in this thread that you built the Paul L. Rossiter Head amp of AudioXpress sep. 2006.
So did I, but did not realize until too late that my MC cart. is 30 ohms, and the PLR head amp input is 10 ohms :-/. Noise is very low indeed (lower than my phono stage), but the sound has a "spacious echo". My friends say its typical to impedance mismatch.
Would you think it possible to raise the input impedance above e.g. 100 ohm by increasing R5/R6 (R1/R2 in your schematic) and also increase supply voltage to compensate for lower R5/R6 collector current ?
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