I am planning to measure the amount of feedback. However, since I am a COMPLETE NOVICE at this kind of measurement, I think I need somewhat detailed guides. Of course, the target is the XSOZV2 (on page 30). Could you give me a bit more specific instruction—particularly about the load and about the source having very low impedance? What are these to be?
Thanks.
JH!
This is how I see it, if this can be of any help.
NFB applied in dB = (log((XHighGain/XLowGain)*10))*20
XGain means Vout/Vin.
An other more simple way, quote from Nelsons from his article "DIY OpAmps".
A simple rule of thumb about open loop gain and feedback is that the difference between the open loop gain and the actual output gain is how much feedback has been applied. If the open loop gain is 60 dB (X1000) and the actual output gain is 20 dB (X10), then 40 dB (X100) of feedback has been applied.
Gain in dB = (log(Vout/Vin)*20
Open loop gain is gain without the NFB-loop.
🙂
This is how I see it, if this can be of any help.
NFB applied in dB = (log((XHighGain/XLowGain)*10))*20
XGain means Vout/Vin.
An other more simple way, quote from Nelsons from his article "DIY OpAmps".
A simple rule of thumb about open loop gain and feedback is that the difference between the open loop gain and the actual output gain is how much feedback has been applied. If the open loop gain is 60 dB (X1000) and the actual output gain is 20 dB (X10), then 40 dB (X100) of feedback has been applied.
Gain in dB = (log(Vout/Vin)*20
Open loop gain is gain without the NFB-loop.
🙂
How to approximate the open loop gain? 
How to approximate the closed loop gain?
How to calculate the open loop gain?
How to calculate the closed loop gain?
How to measure the open loop gain?
How to measure the closed loop gain?
How to approximate the closed loop gain?
How to calculate the open loop gain?
How to calculate the closed loop gain?
How to measure the open loop gain?
How to measure the closed loop gain?
Output capacitors
For an experiment, I added output caps to my X-amp as drawn in red. The caps are of 4700uF/35V/85degC ordinary electrolytic. First of all, these caps block me not to see DC at the speaker cable connectors. Most of all, however, my interest was in the sound effect.
I expected that the caps would degrade the sound. Yeah, it was so however surprisingly as much as I could draw a conclusion that I would keep them there. 🙂
Drinking a cup of coffee and listening to music...
For an experiment, I added output caps to my X-amp as drawn in red. The caps are of 4700uF/35V/85degC ordinary electrolytic. First of all, these caps block me not to see DC at the speaker cable connectors. Most of all, however, my interest was in the sound effect.
I expected that the caps would degrade the sound. Yeah, it was so however surprisingly as much as I could draw a conclusion that I would keep them there. 🙂
Drinking a cup of coffee and listening to music...
Attachments
There seems to be a subtle difference in sound. I however can not feel it clearly. Could I feel any subtle difference in taste between two different excellent wines? I do not think so.
I will keep the caps.
JH
I will keep the caps.
JH
sure you can!jh6you said:
Excellent don't mean the same!
Both can be excellent, in different ways
it's the same for amps
jh6you
This xsoz of yours...
I could understand the initial experimentation, having the SOZ and -X-ing it up by adding a couple of feedback resistors. I completely fail to see the reason for this circuit to even exist. Why not just build the AX? It gives you -X- with a more firendly input impedance and saves you the money and the space of 4 output caps. I think this circuit is a waste of time, space and entropy.
This xsoz of yours...
I could understand the initial experimentation, having the SOZ and -X-ing it up by adding a couple of feedback resistors. I completely fail to see the reason for this circuit to even exist. Why not just build the AX? It gives you -X- with a more firendly input impedance and saves you the money and the space of 4 output caps. I think this circuit is a waste of time, space and entropy.
grataku
As I recall, no one hasn´t described the difference between the Aleph-X and an (specified) XSOZ, may be Nelson has, I don´t know. But I should be very surpriced if they had the same sound, since the Aleph-X consists of 2 gainstages and not just one, and also it does have 3 active currentsources in contrast to my version of the XSOZ wich only consists of passive cs´s.
I am shure, that the Aleph-X can drive difficult loads and has a lot more power, so if this is what you are after then the Aleph-X must be your choice. But for my little listening room, 30 m2, I can hear some very loud music from my 7W XSOZ, and far from the point of clipping, and I am very happy about the sound it produces at this level. I have heard a lot of other amps, still no one as good as mine after the X-ing, at least ito my ears.
The Aleph-X does not qualifi as a Zen amp, that is an other reason why SOZ an XSOZ is still here. The low inputimpedance is no problem, when you turn your BOSOZ into a XBOSOZ everything will turn out just nice. An other reason is, if you already have a SOZ and BOSOZ, it is very easy to X them. For me it has ben fun to make the X design from SOZ and BOSOZ, I wouldn´t have ben able to make the Aleph-X, but with the expierience I have got to day, then may be.
I understand that you are happy with your Aleph-X, but what a boring world it woud be, if we only had the Aleph-X.
So the let us keep the audiofanatism outside dogmatisme an welcome all the differences.
By the way, when I get the time, I will try the Aleph-X, it is a terrific work done by Grey and others.
As I recall, no one hasn´t described the difference between the Aleph-X and an (specified) XSOZ, may be Nelson has, I don´t know. But I should be very surpriced if they had the same sound, since the Aleph-X consists of 2 gainstages and not just one, and also it does have 3 active currentsources in contrast to my version of the XSOZ wich only consists of passive cs´s.
I am shure, that the Aleph-X can drive difficult loads and has a lot more power, so if this is what you are after then the Aleph-X must be your choice. But for my little listening room, 30 m2, I can hear some very loud music from my 7W XSOZ, and far from the point of clipping, and I am very happy about the sound it produces at this level. I have heard a lot of other amps, still no one as good as mine after the X-ing, at least ito my ears.
The Aleph-X does not qualifi as a Zen amp, that is an other reason why SOZ an XSOZ is still here. The low inputimpedance is no problem, when you turn your BOSOZ into a XBOSOZ everything will turn out just nice. An other reason is, if you already have a SOZ and BOSOZ, it is very easy to X them. For me it has ben fun to make the X design from SOZ and BOSOZ, I wouldn´t have ben able to make the Aleph-X, but with the expierience I have got to day, then may be.
I understand that you are happy with your Aleph-X, but what a boring world it woud be, if we only had the Aleph-X.
So the let us keep the audiofanatism outside dogmatisme an welcome all the differences.
By the way, when I get the time, I will try the Aleph-X, it is a terrific work done by Grey and others.
henrik,
I am far from thinking that we should all have alephX's. Actually quite the opposite. I don't know if I like that there are 1000 boards just like mine floating around!
Your minimalistic X I can understand, as it is true to to the Zen spirit with the passive CS and I bet it performs very differently from the AX.
The jh6you version with full blown active CS, without the benefit of the Zen4 input stage and now with output caps... I just don't know.
I am far from thinking that we should all have alephX's. Actually quite the opposite. I don't know if I like that there are 1000 boards just like mine floating around!
Your minimalistic X I can understand, as it is true to to the Zen spirit with the passive CS and I bet it performs very differently from the AX.
The jh6you version with full blown active CS, without the benefit of the Zen4 input stage and now with output caps... I just don't know.
grataku said:
Do you want to buy my impolite, rude, offensive response? 😉I presume that X-SOZ of Henrik¡¯s will give us very good sound. I also presume that Aleph-X of Grey¡¯s will do the same. I get to have the impression based on the presumption, not based on the fact, because I have never experienced with my ears the sounds coming out of the two amps. Yeah, the Aleph-X might be the king.
The Aleph-X has two stages: the input diff amp stage, which is x-fied, and the balanced output gain stage with negative feedback to the front end. Meanwhile, mine has no input stage, but the single output diff amp gain stage, which is x-fied with somewhat negative feedback. Mine is considered simpler along the signal path. This is the key point I have thought about.
Do I need the input diff amp stage as in the Aleph-X? If so, my BOSOZ is the equivalent diff amp of the input line stage. Do I need the ¡°generalized¡± high input impedance of XSOZV2? I do not really think so.
Do you imagine that the XSOZV2 gives us bad sound? If so, I should say that the balanced Zen V2 must give us very bad sound. The original Zen V2? Very very bad sound. The original Zen? Hopeless sound. Should I say so? No, I should not. All are untrue.
Have you ever heard of XSOZV2 sound actually?
I have not wasted any of time, money, space, and DIY-fun. The XSOZV2 is created 100% based on Nelson Pass design plus his in-house technology about simple circuit and its sound. I dare to propose Nelson Pass to consider XSOZV2 (or similar one) as a future Zen-X DIY-project, in respect of the sound...
JH
PS
Are you talking about the output caps? Please read this: http://www.diyaudio.com/forums/showthread.php?s=&threadid=10258
The output caps are used even to well known commercial products.
I have several single-stage "Zen" balanced designs which
employ the "Supersymmetric" technique. Just about any
amplifier with an input diff pair can be turned into an X,
but it only seems to work well with simple circuits and low
open loop gain. (too bad, huh?)
No doubt some of these will become projects, but we are
still fleshing out our commercial offerings, and tend to
structure our DIY efforts for minimal conflict in this regard.
On the other hand, you guys seem to be doing a decent job
duplicating a lot of this stuff, and I don't see why you should
have to be particularly dependent on official copies from me.
... because only the official copy under your name could win total trustworthiness,Nelson Pass said:
and could clean up the misleading if any.
JH
If I thought you guys were wandering far from the
path, I surely would jump in.
pass/ - likes to be the high concept guy like halo.
path, I surely would jump in.
pass/ - likes to be the high concept guy like halo.
Hi Guys, now, I would like to make a conclusion on the XSOZV2 shown at the top of this page.
Power rating:
(a) With the circuit shown above
- Total Mosfet power dissipation: 85W/Ch
- Output power: 15W/Ch, 8 Ohms and 8W/Ch, 4 Ohms
(b) With R16 reduced from 1.5k to 700 and others remain the same
- Total Mosfet power dissipation: 85W/Ch
- Output power: 30W/Ch, 8 Ohms and 15W/Ch, 4 Ohms
(c) With R0 reduced from 0.5 to 0.33 and R16 increased from 1.5k to 2k and others remain the same
- Total Mosfet power dissipation: 130W/Ch
- Output power: 30W/Ch, 8 Ohms and 30W/Ch, 4 Ohms
(d) With R0 reduced from 0.5 to 0.33 and others remain the same
- Total Mosfet power dissipation: 130W/Ch
- Output power: 30W/Ch, 8 Ohms and 50W/Ch, 4 Ohms
I have no other data.
For your info, my current version is (b).
Thanks for your having shown your interests in the XSOZV2.
JH
Power rating:
(a) With the circuit shown above
- Total Mosfet power dissipation: 85W/Ch
- Output power: 15W/Ch, 8 Ohms and 8W/Ch, 4 Ohms
(b) With R16 reduced from 1.5k to 700 and others remain the same
- Total Mosfet power dissipation: 85W/Ch
- Output power: 30W/Ch, 8 Ohms and 15W/Ch, 4 Ohms
(c) With R0 reduced from 0.5 to 0.33 and R16 increased from 1.5k to 2k and others remain the same
- Total Mosfet power dissipation: 130W/Ch
- Output power: 30W/Ch, 8 Ohms and 30W/Ch, 4 Ohms
(d) With R0 reduced from 0.5 to 0.33 and others remain the same
- Total Mosfet power dissipation: 130W/Ch
- Output power: 30W/Ch, 8 Ohms and 50W/Ch, 4 Ohms
I have no other data.
For your info, my current version is (b).
Thanks for your having shown your interests in the XSOZV2.
JH
Sound of Henriks X Soz
for all who are in doubt of the quality of the Sound of X soz , combined with X Bosoz: BUILD THEM, THEN YOU CAN FIND OUT !
meanwhile i tested my ones against 9000 Euro Octave tube amp pre/amp combination and Luxman c03/m03`s:
the x soz is one of the best i ever heared and im` in search to find something better, but did not find until today!!!
the only thing is that the speakers must fit to theX Soz,.
i have less time in moment, but the parts of aleph x still lie in my box. i`m shure, that aleph x ` dont sound that much better. ...soooon i`ll know
regards,
Ralf
for all who are in doubt of the quality of the Sound of X soz , combined with X Bosoz: BUILD THEM, THEN YOU CAN FIND OUT !
meanwhile i tested my ones against 9000 Euro Octave tube amp pre/amp combination and Luxman c03/m03`s:
the x soz is one of the best i ever heared and im` in search to find something better, but did not find until today!!!
the only thing is that the speakers must fit to theX Soz,.
i have less time in moment, but the parts of aleph x still lie in my box. i`m shure, that aleph x ` dont sound that much better. ...soooon i`ll know
regards,
Ralf
I agree SOZ(have not xed yet) is hard to beat when matched to the correct speaker. Indeed, when I look at a circuit for an Aleph or AlephX I see SOZ attached to various electronic ornaments(brilliant Pass patents) to make it more efficent, speaker friendly and I would guess to retain the SOZ's overall character.
BUILD THEM, THEN YOU CAN FIND OUT
No title can be more apropriate.
Well , I'm now with the x-bsoz .
It is somehow unforgettable the sweet and non agressive musical narration that this circuit is capable to .
Every listening session become an event I find .
A short list of my set up:
CD/SACD Sony scd xb 940 The I/V converter is the PassLabs D1
This converter is the best I ever listen to from a digital source.
My old Headphones Sennheiser HD 520.
As you can read at the bottom of the .pdf file Henrik x-bsoz and x-soz this circuit is " capable of driving hp at 60ohm se or bal " True!
I feel my HP happy with it !
The thing that more than others impress me is the bass region :
articulated , dinamic , delicate ; it passes trough my ears and reach the bottom zones of my body without fatigue, a sweet flow of sensations.
The equilibrium between the stages is "another planet " the instruments are reproduced in all their armonics contents , round tonalities and intriguing textures.
A big value for this kind of performance is to take back at the D1 I/V stage , no doubt.
The Henrik X-bsoz is just what you need after for an exceptional - new - good listening experience .
GREAT SHOT PASS DIY !
A would refear of just one record that I liked recently and is from
Telarc , a direct stream digital recording (on cd) by Michel Camilo named TRIANGULO a trio of piano bass and drums .
The piano takes up the scene with a unexpected coherence and dinamic contrast.
Finally: highly recomandable , good sounding circuit .😉
No title can be more apropriate.
Well , I'm now with the x-bsoz .
It is somehow unforgettable the sweet and non agressive musical narration that this circuit is capable to .
Every listening session become an event I find .
A short list of my set up:
CD/SACD Sony scd xb 940 The I/V converter is the PassLabs D1
This converter is the best I ever listen to from a digital source.
My old Headphones Sennheiser HD 520.
As you can read at the bottom of the .pdf file Henrik x-bsoz and x-soz this circuit is " capable of driving hp at 60ohm se or bal " True!
I feel my HP happy with it !
The thing that more than others impress me is the bass region :
articulated , dinamic , delicate ; it passes trough my ears and reach the bottom zones of my body without fatigue, a sweet flow of sensations.
The equilibrium between the stages is "another planet " the instruments are reproduced in all their armonics contents , round tonalities and intriguing textures.
A big value for this kind of performance is to take back at the D1 I/V stage , no doubt.
The Henrik X-bsoz is just what you need after for an exceptional - new - good listening experience .
GREAT SHOT PASS DIY !
A would refear of just one record that I liked recently and is from
Telarc , a direct stream digital recording (on cd) by Michel Camilo named TRIANGULO a trio of piano bass and drums .
The piano takes up the scene with a unexpected coherence and dinamic contrast.
Finally: highly recomandable , good sounding circuit .😉