Elso Kwak said:
Oh come on, he is just affraid that everyone would be laughing to his "professional" amplifiers 😉
Yeap.darkfenriz said:
And if you change both base connections to left side its gonna be cascoded...
Edit: need some coffeine in this time of day...
Hi all.
Being a simple ma...person, I gravitate towards implicitly simple topologies that confer distinct theoretical and definitive practical
advantages over conventional simple ( conga line, follow me) topologies....
Since the Vas stage is such a poor interface and brings with it so many conundra.. I say dispense with it. Away with it. It can take it's early effect and miller effect and p... off!
Now there's a simple amplifier I can understand.
Cheers,
greg
Being a simple ma...person, I gravitate towards implicitly simple topologies that confer distinct theoretical and definitive practical
advantages over conventional simple ( conga line, follow me) topologies....
Since the Vas stage is such a poor interface and brings with it so many conundra.. I say dispense with it. Away with it. It can take it's early effect and miller effect and p... off!
Now there's a simple amplifier I can understand.
Cheers,
greg
http://www.analog-innovations.com/SED/EnhancedCurrentMirrors.pdf
And some more current mirrors 😀
Then we would also need results of degenerated wilson and degenerated "swappped cascode" 😉
And some more current mirrors 😀
Then we would also need results of degenerated wilson and degenerated "swappped cascode" 😉
Hi darkfenriz,
Because!
Well because they introduce more poles and zeros.. complexities in the forward path, lose bias definition and waste volts! But mostly they raise impedance against collector impedance and suck PS on the potential divide!
That's my take.
Cherrs,
Greg
Because!
Well because they introduce more poles and zeros.. complexities in the forward path, lose bias definition and waste volts! But mostly they raise impedance against collector impedance and suck PS on the potential divide!
That's my take.
Cherrs,
Greg
bocka said:
Hi boca,
Any comments on the JFET/Bipolar symmetrical folded cascode schematic in post #40? Goal: low noise, low distortion, high output current drive with EF bipolar output stage.
darkfenriz said:
Wow, looks linteresting.
Two sets of current mirrors. Also I like how the emitter follower driving the VAS is set up. The VAS should still get full swing, even with all those mirrors and stuff taking some of the supply volts.
NICE!
Hi LineSource,
Yes I like the folded cascode very much. But as a trade-off to my experience they are sensitive to local oscillations. Low distortion is not one of the merits of the folded cascode but they have less high order distortion which is most important to me. This is because the voltage between the input LTP is usually higher than a typical LTP and VAS amp caused by the lower overall gain.
Hi circlomanen ! Really ? you are so lucky . I 'm often trouble in CFP input . Can I view your schematic ? 🙂
Hi Amplifierguru ! Yes , Current mirror sound awful . That was the past . I didn't match any transistor when I built a amp with current mirror before . Mr Evils and Sam9 also use current mirror . Even Mr Evils use current mirror in a sym amp .
Hi mr l ! I viewed your picture . I tried to buid " cascode input " . Amp is too easy to oscilate and I have just removed it
Stochino's amp is a sym amp with current mirror but his VAS is so complex that I can't understand it ,and I dont' like a Class A output stage
some one says that sym amp with current mirror can only work in simulate software . I also failed for 4 times but I didn't match any tst
Shinichi-Kamijo succeed in building a lot of sym amp with current mirror http://www.ne.jp/asahi/evo/amp/guide.htm
Sefl 's amp ,Slone's amp ,etc .. use Darlington VAS . So i think that Its noise will higher than dual-differential amp . Hoping high gain of current mirror can decrease noise
some one says that sym amp with current mirror can only work in simulate software . I also failed for 4 times but I didn't match any tst
Shinichi-Kamijo succeed in building a lot of sym amp with current mirror http://www.ne.jp/asahi/evo/amp/guide.htm
Sefl 's amp ,Slone's amp ,etc .. use Darlington VAS . So i think that Its noise will higher than dual-differential amp . Hoping high gain of current mirror can decrease noise
Thank you ! I have some though about thompson current mirror .
If PNP tst in thompson current mirror is 2n5401 , Swap is better than thompson . In the real world , there is no a pnp tst which has 5 beta
The current through Q15 will depend R2 . I can't understand why it is call a current mirror
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