Hi, Pavel
Well, those sims are worth what they worth...
They provide some infos about the THD ratio,
but of course, the fourier analysis dont show
the phase values for each harmonics, although
the computed values match well the graph displayed..
Of course, there s other criterions that must be took
in a design ,stability being as important if not more
than THD ratios, provided those latter are kept
at values on the order of the the amp noise ...
Anyway, i will complete those graphs with other
significant parameters as stability, slew rate, noise
and so on..
Wahab,
for me your work is worth much,
the simulations showed estimation of amps behavior,
even if they are only 50% true - look what a clear indication of right harmonics spectrum.
After this you "convinced" me to build JLH 10W which I thought was not interesting because of gnfb.
Thank you for this.
I am curious to see more from you!
Hi, Pawel
Thank you for the kind words.
Here some clues about the JLH10W.
First, the quiescent current is dependant of the power
devices beta (Hfe) , so you ll have to adapt two resistors
to set the current.
I did the test with 1.7A and 40V PS, so the amp is pure
class A beyond the simmed ouput level , but this
amount to 70W thermal dissiption.
With less current, the figures are not as appealing
although globally better than a SET.
I join a graph that show the dependence oh THD/Iq,
and the schematic used to simulate it.
Quiescent current is set by proportionately adjusting
R12/R13 to :
180R/470R for 1.7A
270R/620R for 1.27A
360R/1K for 0.85A
Of course this depend of the power devices gain, so these
values are just indicative..
best regards
w
Looks like the AX is truly "blameless" ! 
You have to do the GX (below) I have it beating the AX where it counts (high order components). I see the symasym beats the AX in 7/9th... those are baddies .
If you need current GX1.2 its in its .asc/ schema (It is both below and on my WS).
OS
You have to do the GX (below) I have it beating the AX where it counts (high order components). I see the symasym beats the AX in 7/9th... those are baddies .If you need current GX1.2 its in its .asc/ schema (It is both below and on my WS).
OS
Attachments
Looks like the AX is truly "blameless" !
If you need current GX1.2 its in its .asc/ schema (It is both below and on my WS).
OS
Hi , Ostripper
Hmm..That s right on the THD front, i still didn t simulate
some other equally important parameters.
Thank you for the definitive schematic of your mongrel/gx ,
i will test it soon with a(nother) die hard variation of the blameless..
OT posts removed. Please stay on topic.
Thank you panomaniac, I was about to lose my temper and get sinbinned for sure this time, had I answered the member and his friends that came trolling here.
Wahab, can you please compare your amp to these as well, Im more interested in the harmonic profiles obtained and I know your design is symmetric. Many believe that symmetric designs leads to profiles that has mainly odd order distortion but Ive found that this is not always the case.
Its quite interesting to see members that have strong objections against measured performance actually providing some proof that some measurements do count themselves, ableit some are oblivious to the fact, isnt this ironic
The most striking example is the dx blame amp, everyone knows that its creator strongly objects to any measurements and claims this amp to sound very good and this is what counts, if this is to be true, (I havent built it nor will I) the irony is that this design of his is also the design that shows better measured performance compaired to his other designs, go figure.
Wahab, can you please compare your amp to these as well, Im more interested in the harmonic profiles obtained and I know your design is symmetric. Many believe that symmetric designs leads to profiles that has mainly odd order distortion but Ive found that this is not always the case.
Its quite interesting to see members that have strong objections against measured performance actually providing some proof that some measurements do count themselves, ableit some are oblivious to the fact, isnt this ironic
The most striking example is the dx blame amp, everyone knows that its creator strongly objects to any measurements and claims this amp to sound very good and this is what counts, if this is to be true, (I havent built it nor will I) the irony is that this design of his is also the design that shows better measured performance compaired to his other designs, go figure
.
I would like to contribute with a real-life measurement, as I have many times found that simulations did not fit. This is a symmetric design. Loopback measurement (thus some 50Hz multiples).
Attachments
Thank you panomaniac, I was about to lose my temper and get sinbinned for sure this time, had I answered the member and his friends that came trolling here.
Wahab, can you please compare your amp to these as well, Im more interested in the harmonic profiles obtained and I know your design is symmetric. Many believe that symmetric designs leads to profiles that has mainly odd order distortion but Ive found that this is not always the case.
Its quite interesting to see members that have strong objections against measured performance actually providing some proof that some measurements do count themselves, ableit some are oblivious to the fact, isnt this ironic
The most striking example is the dx blame amp, everyone knows that its creator strongly objects to any measurements and claims this amp to sound very good and this is what counts, if this is to be true, (I havent built it nor will I) the irony is that this design of his is also the design that shows better measured performance compaired to his other designs, go figure
Hi, Homemoder
I will set a bnuch of sims for symetric differentials , including a few
of my designs , in a try to compare them to single differentials siblings.
As i already stated, those latter are generally easier to get to low THD
than the symetrical differential topologies.
About Carlos designs, i was careful to choose the devices
that did gave the best results for both DX and Blame ES.
So far, the tests i did made with both topologies show that
there s some room for improvement while retaining stability
for all the the class AB amp that i did simulate in this thread.
cheers,
w
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Hundreds of Dx Blame ES units have been built, many builders compared and they were all impressed. It sounds like many members are missing two things:
1. There are different ear tastes among members, many of them met at Dx Blame, others met at SYMASYM, others at APEX, and others at Ostripper, etc, etc, etc...
2. From what I have seen here, the correlation between a good sounding amplifier and its distortion levels and profile can not be defined in accordance to a specific group of people because they have what technically appears to perfect distortion levels and profile, what sounds good, sounds good, regardless of how bad some people try to make it appear here when criticizing the distortion dose or profile an amplifier has.
Can you Wahab, explain to me why there are people preferring SYMASYM on Dx Blame, others preferring Dx Blame on SYMASYM, some others prefer APEX and others did not like some amplifier over another, some others after they saw AX measurements started to like it for the sake of being technically approved by some members here? You know that many of these guys have built two or three amps of these, it is always up to their taste. Dx Blame, SYMASYM, APEX, OSTRIPPER are just names, think about the real process going behind scenes, you will see that your technical data here for many amplifiers did not reflect why people liked that amplifier's sound over another, at the same time could not explain why they liked it, you can't say people are stupid or they don't know their ears, Wahab.. So as you could do the measurements, I need you to explain to me why, answer my questions about people's behavior rather than just showing me measurements using a software and models that no one else has..
1. There are different ear tastes among members, many of them met at Dx Blame, others met at SYMASYM, others at APEX, and others at Ostripper, etc, etc, etc...
2. From what I have seen here, the correlation between a good sounding amplifier and its distortion levels and profile can not be defined in accordance to a specific group of people because they have what technically appears to perfect distortion levels and profile, what sounds good, sounds good, regardless of how bad some people try to make it appear here when criticizing the distortion dose or profile an amplifier has.
Can you Wahab, explain to me why there are people preferring SYMASYM on Dx Blame, others preferring Dx Blame on SYMASYM, some others prefer APEX and others did not like some amplifier over another, some others after they saw AX measurements started to like it for the sake of being technically approved by some members here? You know that many of these guys have built two or three amps of these, it is always up to their taste. Dx Blame, SYMASYM, APEX, OSTRIPPER are just names, think about the real process going behind scenes, you will see that your technical data here for many amplifiers did not reflect why people liked that amplifier's sound over another, at the same time could not explain why they liked it, you can't say people are stupid or they don't know their ears, Wahab.. So as you could do the measurements, I need you to explain to me why, answer my questions about people's behavior rather than just showing me measurements using a software and models that no one else has..
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That s too much questions in a single shot , most of which
are psychologicaly oriented, and thus impossible to answer
shortly.
About the models i use, please do not spread things that
you didn t even bother to ask about , as this is pure deffamation.
The models i use are the ones everyone got by there, including
your amp s designer..
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Nope, it means that what comes closest to reality is not necessarily appreciated.
Hi wahab,
I don't know how to run simulations, so the amount of work involved for each run is not known to me. You have done a great deal of work here by anyone's standards and I thank you for that.
Knowing that simulations are not 100% accurate does not diminish their value. They do show tendencies that various designs may have, so there is the value. The fact that you picked a good assortment of popular amplifiers certainly makes this relevant to any person who wants to compare the physical build they have access to vs. the simulation. I have to say that I'm also anxious to see some newer designs that aren't yet mature too. That may help with their development. The SYMASYM benefited from simulation and measured performance, resulting in what I would consider a worthy design for general use. It's also a really good starting point for other ideas, a test bed. It was also a popular amplifier with most people (apparently everyone's ears voted positively for this one.). If it's not too much trouble, I'd like to see ostripper's newest design simulated when you have time. The PaX amplifier that Jan made would be very interesting to look at if it's possible to do. I know that amplifier uses an IC in a different way than the manufacturer intended, so the model that device may be a problem.
You've included amplifiers that most people can use as a yardstick. So they can follow the design choices that create the kind of sonics they prefer. Very useful no matter what type of amplifier "you" like the sound of.
Hi jacco,
Still, some designs may work to hide bad behavior of other equipment in the system. Change the room / speakers or source and preferences may change.
-Chris
I don't know how to run simulations, so the amount of work involved for each run is not known to me. You have done a great deal of work here by anyone's standards and I thank you for that.
Knowing that simulations are not 100% accurate does not diminish their value. They do show tendencies that various designs may have, so there is the value. The fact that you picked a good assortment of popular amplifiers certainly makes this relevant to any person who wants to compare the physical build they have access to vs. the simulation. I have to say that I'm also anxious to see some newer designs that aren't yet mature too. That may help with their development. The SYMASYM benefited from simulation and measured performance, resulting in what I would consider a worthy design for general use. It's also a really good starting point for other ideas, a test bed. It was also a popular amplifier with most people (apparently everyone's ears voted positively for this one.). If it's not too much trouble, I'd like to see ostripper's newest design simulated when you have time. The PaX amplifier that Jan made would be very interesting to look at if it's possible to do. I know that amplifier uses an IC in a different way than the manufacturer intended, so the model that device may be a problem.
You've included amplifiers that most people can use as a yardstick. So they can follow the design choices that create the kind of sonics they prefer. Very useful no matter what type of amplifier "you" like the sound of.
Hi jacco,
So true.
Still, some designs may work to hide bad behavior of other equipment in the system. Change the room / speakers or source and preferences may change.
-Chris
Hi, Wahab,
Long awaited comparisons.
As the model I built was DX Blame ST (not ES), I ask you to kindly try to simulate this amplifier against AX, Ultimate Fidelity, Symasym and/or any other one you think would be useful.
The reasons are:
1) I intend to built another different amplifier;
2) More than 50 guys are building DX Blame ST right now, and this would be an useful tool, also for learning purposes.
Thank you.
All the best,
Max.
Long awaited comparisons.
As the model I built was DX Blame ST (not ES), I ask you to kindly try to simulate this amplifier against AX, Ultimate Fidelity, Symasym and/or any other one you think would be useful.
The reasons are:
1) I intend to built another different amplifier;
2) More than 50 guys are building DX Blame ST right now, and this would be an useful tool, also for learning purposes.
Thank you.
All the best,
Max.
Hi, Anatech
Thank you for the words.
Simulations for circuits such as classic amps are
way enough accurate, as we are using only a meager
number of components, while a soft like LT spice can emulate
circuits with ten of thousands of bjts, provided you have
the computing power...
Processors using hundreds of millions transistors are first
simulated not only in term of logical functions, but also as
electrical circuits ,and they work, which is the prove that
simulators work well in EE engineering area...
cheers
w
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