On the DiyAudio, you have to listen to the dumb people who don't know anything, but have built lots of amps. Most of the time when i don'r understand something, the breakthrough only comes when i have built it and worked through the concept. My mind doesn't work well in theory
, not that others cannot do so. I am just not programmed that way. BTW, I lke to draw little squiggly AC signal symbols all over schematic to help me understand sometimes. If you want to have fun with mental exercise, look at Amazing Fet Circltorton
, not that others cannot do so. I am just not programmed that way. BTW, I lke to draw little squiggly AC signal symbols all over schematic to help me understand sometimes. If you want to have fun with mental exercise, look at Amazing Fet Circltorton
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I have a short response to your claim, Thorsten: "Read Zen Variations 7"
That article, from Nelson Pass himself, shows a SuSy amplifier with nothing but a current source at the tail. There are no degeneration resistors at all.
The way I understand it is that the error current is in excess of the current source, and thus the error current has to flow from one arm/leg to the other. Look at this part of the circuit as a single node with three branches. According to Kirchoff's first law, if the current source remains constant, then any error current on one arm/leg will have to appear as a negative current on the opposing arm/leg, and that's the whole magic of Super Symmetry.
By the way, this is helpful discussion. When I read Papa's SuSy articles, it is sometimes difficult to understand how big the effect of minor changes can be. For example, the Donut seems to have more in common with a bridged Son of Zen, because of the degeneration resistors, whereas ZV7 removes those resistors to make SuSy. Granted, ZV7 also adds feedback, but I don't think that feedback alone makes it SuSy.
That's a great question!
As evidence, I present Exhibit One: ZV6, where Papa removed the resistors from Son of Zen in order to Xploit it. I would not claim that to be proof, but it's an important starting point to study.
I just looked at Patent # 5,376,899 ... and I notice that every example circuit given there has separate current sources for each input transistor, as well as a single resistor linking the two sources. Make me think, at least.
Well, part of the SUSY description is that each stage feeds back negatively to the other stage. What I find interesting is that the articles depict an inverting stage, such that local feedback is technically negative. But besides the obvious feedback connections, there must also be a path for error signals to pass from one side to the other.
Another thing that I have been pondering is the distinction between the typical voltage output amplifier and the rare current output amplifier. I assume that there could be some huge changes in the SUSY circuit depending upon whether it should be a current source for the speaker (ideal) or a voltage source (possibly easier to design).
That was -and is- mainly to improve efficiency of the circuit , and to give him a chance to be working ok with just one single ended input .
Susy does work with degeneration resistors just the same , but typically well when both ( balanced) signals are applied at the inputs .
Of course a current source design ends to be itself " a current source " when feedback is applied . So that to say that SuSy will be a voltage amplifier for sure .
The elegance of this circuit is that the variable resistor that controls AC voltage from MOSFET A's source pin to MOSFET B's source pin also passes any distortion created by MOSFET A to MOSFET B. where it is canceled out by identical inverse-polarity distortion at MOSFET B's drain. This same mechanism occurs with distortion from MOSFET B that is transferred through the resistor to MOSFET A. This is the patented differential error correction. A further bit of cleverness is that differential distortion-cancellation occurs whether you use a balanced or a single-ended input or output.
Aleph P, is that description corresponding to susy?
Aleph P, is that description corresponding to susy?
Generg , my friend - you remember two iterations of P ?
1.0 - without overall feedback , so - not SUSY
1.7 - with two independent overall feedback nets , but what's common for both halves is horizontal ( also adjustable ) resistive bridge ;
neat and funny ...... and that's the one you are describing
let's just say it this way - greater impedance of that horizontal bridge - lesser SUSY amount ; lesser impedance of that horizontal bridge - greater SUSY amount .
in case of any typical source resistor , situated between mosfet/Jfet source and common CCS (common for two halves of gain stage ) , we can take those source resistors as negligible .
not knowing that is OK .
but - insisting on fact of these source resistors and their function in SUSY mechanismus is not just lack of knowledge .
point is - for any ( serious) newbie around , possibly reading this thread - do not take for granted any tech question written 'till this moment , simply because of fact that there is no (at least not yet ) dialog between OP and other participants .
I'm still here just because of some possible innocent newbie reading these lines , one day ........
1.0 - without overall feedback , so - not SUSY
1.7 - with two independent overall feedback nets , but what's common for both halves is horizontal ( also adjustable ) resistive bridge ;
neat and funny ...... and that's the one you are describing
let's just say it this way - greater impedance of that horizontal bridge - lesser SUSY amount ; lesser impedance of that horizontal bridge - greater SUSY amount .
in case of any typical source resistor , situated between mosfet/Jfet source and common CCS (common for two halves of gain stage ) , we can take those source resistors as negligible .
not knowing that is OK .
but - insisting on fact of these source resistors and their function in SUSY mechanismus is not just lack of knowledge .
point is - for any ( serious) newbie around , possibly reading this thread - do not take for granted any tech question written 'till this moment , simply because of fact that there is no (at least not yet ) dialog between OP and other participants .
I'm still here just because of some possible innocent newbie reading these lines , one day ........
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I remember reading a thread by GRollins where this was discussed. By having horizontal resistor bridge, you have a mechanism that is already trying to balance the circuit like in SOZ. I believe thta is why it was deleted for ZV6. IT would work depending on resistance chosen, but would diminish the effects of SUSY.
I would assume that the current continues through said resistor and is not completely arrested at this point. Does conventional vs electron flow come into play in this particular topic?
I wish they had a greenhorn emoticon so I could put it in my avatar thingie.point is - for any ( serious) newbie around , possibly reading this thread - do not take for granted any tech question written 'till this moment , simply because of fact that there is no (at least not yet ) dialog between OP and other participants .
I'm still here just because of some possible innocent newbie reading these lines , one day ........
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exactly - as in any differential gain stage ; usual LTP with sources/emiters/cathodes tied also have that horizontal bridge , but with R=0
irrelevant , with that resistor value determined just with linearisation purpose
......
I wish they had a greenhorn emoticon so I could put it in my avatar thingie.
you can use my avatar then ...... I'm all greenhorn
Thanks Zen Mod, indeed I hear a small difference between the sounds resulting from the two extremes of the pot (between the two sources......mostly with lower impedance the sound seems to be a bit more vivid to me......)
Correct, I was speaking generally of P and forgot for the moment the existence of the older model.
Main reason for making a contribution was the remark that susy is only possible with voltage amps ....... ( if I understood the comment in a right way)
Correct, I was speaking generally of P and forgot for the moment the existence of the older model.
Main reason for making a contribution was the remark that susy is only possible with voltage amps ....... ( if I understood the comment in a right way)
@buzzforb:
I think you can still link your edited parts with my replies
SUSY is simple ;
but I can't even imagine few things :
- brainstorming which eventually led to inventing it (even if it was partially boiled water in moment of patenting )
- hard work needed for achieving sweet spot for any particular gain stage , varying ratios between OLG and CLG - just to name two of several factors
so - kudos to Papa ; it's easy to be clever post hoc
I think you can still link your edited parts with my replies
SUSY is simple ;
but I can't even imagine few things :
- brainstorming which eventually led to inventing it (even if it was partially boiled water in moment of patenting )
- hard work needed for achieving sweet spot for any particular gain stage , varying ratios between OLG and CLG - just to name two of several factors
so - kudos to Papa ; it's easy to be clever post hoc
Thanks Zen Mod, indeed I hear a small difference between the sounds resulting from the two extremes of the pot (between the two sources......mostly with lower impedance the sound seems to be a bit more vivid to me......)
Correct, I was speaking generally of P and forgot for the moment the existence of the older model.
Main reason for making a contribution was the remark that susy is only possible with voltage amps ....... ( if I understood the comment in a right way)
take UGS as example ; pure SUSY
it can be pure voltage stage , or it can be xconductance stage - depending of rest of the circuit
is -sort of - xconductance gain stage
No doubt all credit goes to Mr Pass. I can't even completely understand it, much less invent it.
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