I'm sure that I'm either missing Peter's point or a bit to tired right now.
Peter: Is it the input impedans that you feel is the problem, or is it the Zen construction at all? Don't get me wrong. I welcome all input on the matter. Especially since I'm not an expert on the subject.
How much power, in watt's can one suspect to get from a single Zen v5 stage? I got interested in the Zen by the fact that it was a very simple construction, and Mr. Pass makes a strong point about just this. This is also why I love tube equipment, because you can make them function and very well sounding with very few components. This and the fact that when the Alpha series was in production (pardon) they kicked ***. So how bad can a construction that Mr. Pass has put his name on be? But, this is a bit besides the point.
Is anyone getting Raka's post, or is it just me?
By the way. Is there any real differens between X-ing and bridgeing?
/Johan Ch
Peter: Is it the input impedans that you feel is the problem, or is it the Zen construction at all? Don't get me wrong. I welcome all input on the matter. Especially since I'm not an expert on the subject.
How much power, in watt's can one suspect to get from a single Zen v5 stage? I got interested in the Zen by the fact that it was a very simple construction, and Mr. Pass makes a strong point about just this. This is also why I love tube equipment, because you can make them function and very well sounding with very few components. This and the fact that when the Alpha series was in production (pardon) they kicked ***. So how bad can a construction that Mr. Pass has put his name on be? But, this is a bit besides the point.
Is anyone getting Raka's post, or is it just me?
By the way. Is there any real differens between X-ing and bridgeing?
/Johan Ch
Johan Ch
Re why I don't "like" the Zen:
I was hoping I would not have to go there - please send any flames to Johan Ch and not to me. My general gripes with the original Zen is the resistive load. That is where I lost interest, and have not found great love of the topology since. It gets better (for me) with the current sourced variants. I am also not a fan of capacitively coupled units, and I prefer balanced operation (at least if they are not separate normal units operated as "balanced"). Ask me why I like steak or why I find certain femal body-types more beautiful to look at instead ...
The X scheme is somewhat complicated in that it requires a balance of currents. That is essentially a construction issue. In my view there has been far too much emphasis placed on the "X" resistor - I consider it almost the same as source degeneration with a single current source, and I suspect it has to go if you want really high gain anyway so it performs a similar function. Other than that it is relatively straightforward and has the following advantages:
1. DC levels kept at or near the same potential
2. Just about as much gain as you might care for
3. Single stage
4. The various types of feedback employed are essentially local. We have all been taught to "hate" global feedback (meaning in my simplified view of the world feedback which spans more than one gain stage).
5. Feedback SHOULD provide tighter control than original Zen.
Whether it sounds better is another matter.
Petter
Re why I don't "like" the Zen:
I was hoping I would not have to go there - please send any flames to Johan Ch and not to me
. My general gripes with the original Zen is the resistive load. That is where I lost interest, and have not found great love of the topology since. It gets better (for me) with the current sourced variants. I am also not a fan of capacitively coupled units, and I prefer balanced operation (at least if they are not separate normal units operated as "balanced"). Ask me why I like steak or why I find certain femal body-types more beautiful to look at instead ...The X scheme is somewhat complicated in that it requires a balance of currents. That is essentially a construction issue. In my view there has been far too much emphasis placed on the "X" resistor - I consider it almost the same as source degeneration with a single current source, and I suspect it has to go if you want really high gain anyway so it performs a similar function. Other than that it is relatively straightforward and has the following advantages:
1. DC levels kept at or near the same potential
2. Just about as much gain as you might care for
3. Single stage
4. The various types of feedback employed are essentially local. We have all been taught to "hate" global feedback (meaning in my simplified view of the world feedback which spans more than one gain stage).
5. Feedback SHOULD provide tighter control than original Zen.
Whether it sounds better is another matter.
Petter
Petter
What you suggests for an XZen is just the the first example Nelson uses in his patent to describe the X or supersymmetry.
You don´t like Zen, OK?
Johan Ch
There is a big difference between bridged amps and X.
Quoting Nelson:
The essence is still using a symmetric feedback arrangement
around a differential pair which isolates error from signal
and uses it to make distortion on two halves identically
in phase and thus cancelled.
Earlier, someone commented on simply using the front
end in the patent with the folded cascode and all, which
if scaled up for current would make an interesting Xzen
I have X´d the SOZ with some great sonical advanteges.
What you suggests for an XZen is just the the first example Nelson uses in his patent to describe the X or supersymmetry.
You don´t like Zen, OK?
Johan Ch
There is a big difference between bridged amps and X.
Quoting Nelson:
The essence is still using a symmetric feedback arrangement
around a differential pair which isolates error from signal
and uses it to make distortion on two halves identically
in phase and thus cancelled.
Earlier, someone commented on simply using the front
end in the patent with the folded cascode and all, which
if scaled up for current would make an interesting Xzen
I have X´d the SOZ with some great sonical advanteges.
Henrik said:
Yes, that is exactly it, and I don't understand that there would be any problems with that. I went through the thread and saw no mention of it.
Henrik said:
Sure, this is the same thing. I have not tried it at more than 30mA per leg where it works perfectly. The "difficulty" I guess is getting unnecessary power loss to a minimum (such as current sources).
What I see most people "Xing" the Zen do is to essentially build mostly separate gain stages and not taking care of a differntial pair in the middle. What I also see a lot (and it might not be a big deal) is a lot of coupling caps etc. I don't personally like that approach.
Petter
jh6you said:
You like the beautiful female body only, not beautiful heart...?
This is getting out of hand
. For me the heart is something that you have to experience, but I can still enjoy visually aestetically pleasing designs based on foundations that I consider "sound" I am not sure if it is worth making more parallells to audio schematics. Also, I do like steak. Please don't ask me why.Petter
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