I do not understand this kind of reaction. Why would cascoding make a voltage source? And why are we 'Of course' talking about voltage sources? And do voltage sources really have no current limitations? (All 3 questions are rhetorically 🙂).
Have a look at http://www.diyaudio.com/forums/soli...est-symmetrical-amplifier-97.html#post3133228 (post #963) this is cascoded (at the 'vas'). Neither R8 or R33 are voltage sources. If a given design fits the given problem, than it is fine with me, but if I state my opinion then it is just that 'my opinion'. I still think that (Joachims remark) was about CS's vs VS's 🙂
I'm just trying to learn a thing or 2.
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Yes, I presumed the same thing. But I'm surprised that you're agree 100% 😀 Then I'm curious why or how you tackle the issue...
O.k. I did backtrack down to page #80 and could not find any schema posted by Christophe (I just did it again 🙂). I just see (in the previous message by Joachim) a reference to a schema, so if someone will re-post it, or show a link to it, then I will be a happy lurker again 🙂
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So far you didn't show us anything more than just the letters on the screen.
I'm not an expert like you. Very far from that. Because I'm a beginner with very little achievement, I tend to value my works too high, even if it could be just peanuts in your eyes 😀
Christophe's ssa-crescendo was posted in the other thread (The Simple Symetrical Amplifier). I prefer to use google than the search function of this site:
www.esperado.fr - Le crescendo revisité
Give as a link to the schematic/s.
Add that link and your descriptive comment to post1.
O.k. then this is the one? http://www.esperado.fr/images/stories/SSA-Crescendo/ssa-crescendo-def.gif
Yes, in both schema's, and that seems a bit(under statement) low (for the bias adjustment).
The mosfet in use http://pdf1.alldatasheet.com/datasheet-pdf/view/63173/HITACHI/2SK135.html has gate protection build in, so why bother with external protection.
Also, I see (now) that the gate-source cutoff voltage at 100mA and Vds 10V is 0.15 to 1.45 Volt that may just be fine with the 8 Ohm bias regulator.
(I think this is edit 10 🙂)
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L.C, On my computer, both links are broken: they point to a fake post number, then, goes to page 61, depending if you read the thread in reverse or normal order.
A working one ?
http://www.diyaudio.com/forums/solid-state/193923-simple-symetrical-amplifier.html#post3163129
About thus adjustable resistance on my schematic, it is a value for sim.. I will have a look of the value of my adjustable in real world as soon i get some time and courage..
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I wrote already about it. Look here http://www.diyaudio.com/forums/solid-state/193923-simple-symetrical-amplifier-271.html#post3080105
dado
Original schematic of the Crescendo found here:
http://www.solaris.no/electronics/power_amp/elektor_cresc/cresc_1280.gif
Value of the adjustable was 250 Ohms (unchanged -if i remember well- on my modified board.)
In the simul, value of the resistance was tuned for 150Ma of quiescent current in each Power mosfet.
Again, this mod was just for demonstration of CFB versus VFB.
I had tuned my board in real world in a first time, then closed the box with no notes.
Few weeks later, made and publish the simul as i was delighted by the improvement . Not sure the simul reflect the exact value of my real amp.
Unless you have yet a Crescendo at home, i will not recommand to build it, on many aspects, SSA BIGBT HP will be far superior.
As i said in the SSA thread there is no place, in the SSA BIGBT HP where i can feel like the slightest desire to change anything 🙂
Driver is just top of the art.
And the Current Source is a pure perfection.
So, i understand why L.C. was upset reading "best T/SSA in the next few years is none of the circuits available today on this thread" ... after all this masterpiece work.
But L;C. is a cheater, using BIGBT, and we where discussing (in a general way) about using lateral Mosfets for power units, and i suppose Jay had not seen the HP version.
So, please, Jay, don't take the L.C. words too badly. You where not so wrong, after all, because SSA BIGBT HP was not in this TSSA thread 🙂
The problem is those two separated huge threads, and the poor search tool of the forum.
http://www.solaris.no/electronics/power_amp/elektor_cresc/cresc_1280.gif
Value of the adjustable was 250 Ohms (unchanged -if i remember well- on my modified board.)
In the simul, value of the resistance was tuned for 150Ma of quiescent current in each Power mosfet.
Again, this mod was just for demonstration of CFB versus VFB.
I had tuned my board in real world in a first time, then closed the box with no notes.
Few weeks later, made and publish the simul as i was delighted by the improvement . Not sure the simul reflect the exact value of my real amp.
Unless you have yet a Crescendo at home, i will not recommand to build it, on many aspects, SSA BIGBT HP will be far superior.
As i said in the SSA thread there is no place, in the SSA BIGBT HP where i can feel like the slightest desire to change anything 🙂
Driver is just top of the art.
And the Current Source is a pure perfection.
So, i understand why L.C. was upset reading "best T/SSA in the next few years is none of the circuits available today on this thread" ... after all this masterpiece work.
But L;C. is a cheater, using BIGBT, and we where discussing (in a general way) about using lateral Mosfets for power units, and i suppose Jay had not seen the HP version.
So, please, Jay, don't take the L.C. words too badly. You where not so wrong, after all, because SSA BIGBT HP was not in this TSSA thread 🙂
The problem is those two separated huge threads, and the poor search tool of the forum.
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