Germany's best known hat wearer!! And how about (Professor) Tony Cragg - probably the best known Minimalist sculptor working in Germany - if not in Wuppertal Park!!!!
I thought that was Gunter von Hagens.
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Germany's best known hat wearer!! And how about (Professor) Tony Cragg - probably the best known Minimalist sculptor working in Germany - if not in Wuppertal Park!!!!
Looks a little like Arman, these artists give the term "derivative" a new twist. I'd hate to have to counsel some rich guy on what "assemblage" of debris to buy. Hmm, not to far off of the audio salon.
Or a Dimitri cascode.
Dimitri Danyuk, “On the Optimization of Enhanced Cascode,” Preprint #7571, Presented at the 125th AES Convention, October 2–5, 2008 San Francisco, CA, USA.
Edmond,
At figure 1/d, upper part combo, Q6/Q11/R12/LEDs+diodes/R15...if I'm not mistaking, this is an Baxandall Super Pair CCS right? High gain, ultra low Cob, high speed, ultra high output impedance...just perfect CCS...if it doesn't oscillates like hell (I managed to use one as LTP CCS...pure luck I guess
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I know exactly what you mean!
Evidently Tony Cragg has nominated sub-contractors walking the banks of major rivers in search of suitable materials found at the waterline. If he had me on his payroll I could have given him several well washed large trees just after the November floods! Also a few dead sheep and even two salmon - without eyes.I only know of him as I worked with his brother for a while - he also had some strange ideas, but generally quite gifted.
Edmond,
At figure 1/d, upper part combo, Q6/Q11/R12/LEDs+diodes/R15...if I'm not mistaking, this is an Baxandall Super Pair CCS right? High gain, ultra low Cob, high speed, ultra high output impedance...just perfect CCS...if it doesn't oscillates like hell (I managed to use one as LTP CCS...pure luck I guess
Hi Ivo,
No, it's not exactly a Baxandall super pair. The current gain is simply determined by beta of Q5. Q6 is the 'main' cascode tranny and Q11 'recycles' almost all Ib of Q6 back to the input of Q6. This way the output impedance will indeed be very high and no Cob Miller effect.
You're right, much chance of instability as with so many circuits that use positive feedback.
If you like you may consider Q6 & Q11 as a Baxandall super pair (is it this what you meant?)
C. E.
Yes, I know they form a Baxandall super-pair, but my point is that Q5 is cascoded by Baxandall super pair CCS if I'm not mistaking.
OK aparatusonitus, Edmond I have to stick with my story for now, No LED's no caps . After some checking a few points. That input cascode arrangement requires a network complimentary to the gain network, this gets far from general purpose. Secondly (though I did not do an exhaustive look) it also messes with the transient response. A quick check with a simple FET on FET cascode and the improvement was equally good (now a silly -126dB).
So for now 22-33pF Ccomp at gain of 20db, nice symmetrical slew at 500-600V/us. For gain of one you could increase input degeneration to 125 Ohms or so and use 100pF Ccomp for 200-300V/us. Even at full 20p-p G = 1 into 100 Ohms the seconds are -106 to -110 dB.
Yes, a conceptual exercise on the single stage amplifier.
. After some checking a few points. That input cascode arrangement requires a network complimentary to the gain network, this gets far from general purpose. Secondly (though I did not do an exhaustive look) it also messes with the transient response. A quick check with a simple FET on FET cascode and the improvement was equally good (now a silly -126dB). So for now 22-33pF Ccomp at gain of 20db, nice symmetrical slew at 500-600V/us. For gain of one you could increase input degeneration to 125 Ohms or so and use 100pF Ccomp for 200-300V/us. Even at full 20p-p G = 1 into 100 Ohms the seconds are -106 to -110 dB.
Yes, a conceptual exercise on the single stage amplifier.
Attachments
a common source fet followed by a common gate fet is a single stage?..
perhaps, like the word cascode for this arrangement, we can find
a word to name a combination of common source + common source fets
so we can say that it s also a single stage..
regards,
wahab
I don't consider a cascode as a stage, by single stage I mean a single gm and high impedance node as opposed to a CM loaded diff pair and a VAS (2) or a multistage nested feedback circuit (>2).
If you are talking Zen concepts and a stage is one FET those are different semantics.
OK aparatusonitus, Edmond I have to stick with my story for now, No LED's no caps
You are right on target Scott, I was just pushing some ideas from jcx that I implemented in single stage lineamp/headamp. For transient response problems maybe you should try lag compensation from VAS to input.
To tell you the truth, that's my favorite...I was hoping you will use it at some point...simple, elegant and effective solution for input capacitance. Thank you Scott ;-)
Pretty fast don't you think
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