GRollins said:
Simulations are great for dialing in a place to start, but nothing beats a manual simulation (building and listening). Half the fun is in building, smoking it and understanding what went wrong.
More emphasis should be placed on getting a stable reference point, ie music you love and a system that doesn't change as you mess with one part of it. This will tell you more, sometimes in a brutally honest way, about your theories than a thousand simulations.
Enjoy, Mike.
Well, as you have just read, there is some disregard for computor simulation in our hobby. I hate to put it down as worthless and wrong, that is not the case. However, truth is, this is the Pass Labs Forum. Anything propagated here has been built, tested, measured with equipment, but most importantly listened to 😀
That is the Pass Philosophy!
As I said, the sim software is a tool. As some have said, it operates with software generally derived from quasi perfect models of components that do not necessarily represent the actuall ones we use. For instance, what is an IRF610? Probably a switching FET for a 10 watt SMP or something. Well, I'm sure the model is optimized for that. Not for a linear amplifier like we are interested in 😕
To point out a few other defects in the sim philosophy, several times I have found that the Fourier plot in my "High Dollar Software" does not even match the data file info 😕 This is $6000 software!!! 😕
I have to admit, I do not generally find it totally wrong when working with existing or new ideas. And I do find it very enlightening quite often.
But, lets be totally honest. It's only one of our tools, it has no ears and no brain and it does not have a clue about anything representing music. It only knows how to deal with pre programed model data, electrical theory and waveforms
Also, being totally honest, I like to sim first too 😀 it's a good place to start 😀
BTW, all of Nelson's stuff sims plenty good enough for me 😎
That is the Pass Philosophy!
As I said, the sim software is a tool. As some have said, it operates with software generally derived from quasi perfect models of components that do not necessarily represent the actuall ones we use. For instance, what is an IRF610? Probably a switching FET for a 10 watt SMP or something. Well, I'm sure the model is optimized for that. Not for a linear amplifier like we are interested in 😕
To point out a few other defects in the sim philosophy, several times I have found that the Fourier plot in my "High Dollar Software" does not even match the data file info 😕 This is $6000 software!!! 😕
I have to admit, I do not generally find it totally wrong when working with existing or new ideas. And I do find it very enlightening quite often.
But, lets be totally honest. It's only one of our tools, it has no ears and no brain and it does not have a clue about anything representing music. It only knows how to deal with pre programed model data, electrical theory and waveforms
Also, being totally honest, I like to sim first too 😀 it's a good place to start 😀
BTW, all of Nelson's stuff sims plenty good enough for me 😎
apassgear, Sorry 
Yea, the gain pot goes from the 10 ohm to the other 10 ohm. If your going to ask why I have 2 10 ohms in there, I don't remember why! You need 20 or 40 or so or it will go bananas at the low end of the pot. I think with only about 25 or 30 ohms you can get pretty rediculous preamp gain if you need it...
The Bias pot goes to the - Supply 😀 😀 😀 I guess that is one of the differences from an N.P. circuit.
I have one with only about 55mA per side and 1K load Rs too. I could not really say which works better but the one with 1K load Rs is much lower temp. and I think a little quieter... BTW I used Caddock 500 and 1K TO-220 Rs for the gain stage load Rs and they are on heatsinks too...
I've never built an Aleph 1.7 but I like mine better than the BOSOZ. I went this far mostly based on the resistance to "current source" loads and the desire to have an S.E. to Balanced Pre. There are those who say a resistive load in the gain stage sounds better 😕 I drive a FET Circlotron amp that I am trying to finish up and put in a final chasisn now, after a year or so. I was going to put the pre in with it since Circlotron is a follower. However, N.P. recently said he might come up with a High Voltage Pre project for his new followers
I'm waiting to see what that stuff is...
BTW, my somewhat extreme diff thing is good for at least 25V or more of clean output for those head room freaks 😀
Yea, the gain pot goes from the 10 ohm to the other 10 ohm. If your going to ask why I have 2 10 ohms in there, I don't remember why! You need 20 or 40 or so or it will go bananas at the low end of the pot. I think with only about 25 or 30 ohms you can get pretty rediculous preamp gain if you need it...The Bias pot goes to the - Supply 😀 😀 😀 I guess that is one of the differences from an N.P. circuit.
I have one with only about 55mA per side and 1K load Rs too. I could not really say which works better but the one with 1K load Rs is much lower temp. and I think a little quieter... BTW I used Caddock 500 and 1K TO-220 Rs for the gain stage load Rs and they are on heatsinks too...
I've never built an Aleph 1.7 but I like mine better than the BOSOZ. I went this far mostly based on the resistance to "current source" loads and the desire to have an S.E. to Balanced Pre. There are those who say a resistive load in the gain stage sounds better 😕 I drive a FET Circlotron amp that I am trying to finish up and put in a final chasisn now, after a year or so. I was going to put the pre in with it since Circlotron is a follower. However, N.P. recently said he might come up with a High Voltage Pre project for his new followers
I'm waiting to see what that stuff is...BTW, my somewhat extreme diff thing is good for at least 25V or more of clean output for those head room freaks 😀
flg said:
As I don't understand how the program is written, I don't use it.
I feel better in trying to understand the circuits with collection of
the small things written down in the books.
Have quit smoking cigarettes; instead smoke few numbers of
cigarillos . . . I think I'm terrible.
I was born lazy and had a relapse. I tossed a few calculations I was tired of doing by hand into a spreadsheet. The rest I do on an ordinary calculator. Not even a graphing one.
You don't need anything more than some pretty basic algebra to do this stuff. I took calculus in school. I've never needed it--which is good, because at this point all those memories have pretty much turned to dust, anyway.
I was really excited back when I first heard about simulation programs. Ohm's Law writ large! Cool! Man, all the capacitors, resistors, inductors...and active devices analyzed within an inch of their lives. Then reality set in. Sure the calculations are within reach, but the models are poor and frequently difficult to find (note the number of posts asking what model someone is using and where they got it), and the results are not exactly what you'd call dependable predictions of what you'll actually see when you build the circuit.
There's a thread here wherein someone got really, really excited because his circuit had 0% distortion. Somehow, the fellow's BS detector didn't trip. Clearly, there's no such thing in the real world. That is (or should be) a Duh! Yet his simulation, with its perfect components, claimed near perfection and he got his tail feathers all a-fluff. If someone can show me where to buy perfect transistors, I will be very grateful, indeed. So will Nelson, John Curl, Charles Hansen, et. al.
Time is my most precious commodity. If I've only got an hour to spend on electronics, it's a no-brainer. I'll hit the bench and try a real circuit rather than diddle an unpredictable, undependable computer model. Once you've done the simulation, you still don't know if the circuit will work or not (witness the number of people who insisted that the Aleph-X couldn't work--if I'd wasted my time on simulations, I'd never have built the circuit...because the simulations said it couldn't be done!), so you really don't know any more than you did when you started. You only think you do.
If only I had back all the hours I wasted in front of a tube simulating...
Grey
P.S.: I don't know what to do about the people who put Nelson's circuits into a simulator "to see if they work." Strangle 'em, I guess. Put 'em out of their misery.
You don't need anything more than some pretty basic algebra to do this stuff. I took calculus in school. I've never needed it--which is good, because at this point all those memories have pretty much turned to dust, anyway.
I was really excited back when I first heard about simulation programs. Ohm's Law writ large! Cool! Man, all the capacitors, resistors, inductors...and active devices analyzed within an inch of their lives. Then reality set in. Sure the calculations are within reach, but the models are poor and frequently difficult to find (note the number of posts asking what model someone is using and where they got it), and the results are not exactly what you'd call dependable predictions of what you'll actually see when you build the circuit.
There's a thread here wherein someone got really, really excited because his circuit had 0% distortion. Somehow, the fellow's BS detector didn't trip. Clearly, there's no such thing in the real world. That is (or should be) a Duh! Yet his simulation, with its perfect components, claimed near perfection and he got his tail feathers all a-fluff. If someone can show me where to buy perfect transistors, I will be very grateful, indeed. So will Nelson, John Curl, Charles Hansen, et. al.
Time is my most precious commodity. If I've only got an hour to spend on electronics, it's a no-brainer. I'll hit the bench and try a real circuit rather than diddle an unpredictable, undependable computer model. Once you've done the simulation, you still don't know if the circuit will work or not (witness the number of people who insisted that the Aleph-X couldn't work--if I'd wasted my time on simulations, I'd never have built the circuit...because the simulations said it couldn't be done!), so you really don't know any more than you did when you started. You only think you do.
If only I had back all the hours I wasted in front of a tube simulating...
Grey
P.S.: I don't know what to do about the people who put Nelson's circuits into a simulator "to see if they work." Strangle 'em, I guess. Put 'em out of their misery.
sorry, but i don't agree with you.
I don't have much experience with simulators but in this case, for example, was enough a propertly change on the setting, to get it goin'!
Who knows if a propertly set up for the Aleph X model would have helped it to work (on the simulation)...who knows! (i will probabilily try next)
I personally think that the simulator it's just a start and no more of that!
Don't get wrong: i'm a real audiophile and so ...for me.... the listening is VERY important and can't be replaced by anything.
Last thing: i don't put Nelson Pass circuit into simulation because i have doubts that they work.
It's, in the case, the opposite concept.
Since i'm convinced that they work perfectly..i use them to get a better handle of all the simulators (Capture, VHDL, PSpice -Advanced SIM) and to get more expierence on building projects.
As i outlined above, this is for me just a way of improving my knowledge.
The fun will come then when i will build the preamp and then find out that it sounds really refined!
But then i will have the "paranoia" to be able to build something as nelson does...and it's when i will hit the reality and have to work very hard....but this is another story 🙄
Anyway.....now i'm going to take the cicuit on PCB Editor and PCB Router and try to buid the board.
I will certainly need your help......
i would like to understand how a ground plan works....and if there are rules for the layout (i know there are!).
I will search on the forum.
as far as i know the hum is correlated with the layout...so.....mmm let's see..... 😎 !
Thanks for the comments.
Stefano.
I don't have much experience with simulators but in this case, for example, was enough a propertly change on the setting, to get it goin'!
Who knows if a propertly set up for the Aleph X model would have helped it to work (on the simulation)...who knows! (i will probabilily try next)
I personally think that the simulator it's just a start and no more of that!
Don't get wrong: i'm a real audiophile and so ...for me.... the listening is VERY important and can't be replaced by anything.
Last thing: i don't put Nelson Pass circuit into simulation because i have doubts that they work.
It's, in the case, the opposite concept.
Since i'm convinced that they work perfectly..i use them to get a better handle of all the simulators (Capture, VHDL, PSpice -Advanced SIM) and to get more expierence on building projects.
As i outlined above, this is for me just a way of improving my knowledge.
The fun will come then when i will build the preamp and then find out that it sounds really refined!
But then i will have the "paranoia" to be able to build something as nelson does...and it's when i will hit the reality and have to work very hard....but this is another story 🙄
Anyway.....now i'm going to take the cicuit on PCB Editor and PCB Router and try to buid the board.
I will certainly need your help......
i would like to understand how a ground plan works....and if there are rules for the layout (i know there are!).
I will search on the forum.
as far as i know the hum is correlated with the layout...so.....mmm let's see..... 😎 !
Thanks for the comments.
Stefano.
Stefanoo said:
Something's wrong here...you're using circuits to learn a software program? From my (admittedly) music-centric viewpoint, that's kinda-sorta...well...backwards. But if playing with software is more important to you than building circuits and listening to them, then have at it.
I confess that I'm not clear as to how you feel that simulation programs give you experience building circuits. They don't. All they do is give you experience at simulating things--experience which doesn't translate very well (if at all) into the real world. Only building circuits can give you experience building circuits.
Grey
don't get wrong!
I really like to get more practice on BUILDING projects!!!
My viewpoint is that the simulator, if properly used, can help you-- but not replace the actual practice.
That's all i meant!
I really like to get more practice on BUILDING projects!!!
My viewpoint is that the simulator, if properly used, can help you-- but not replace the actual practice.
That's all i meant!
Stefanoo said:
Is the "PCB Router" an auto-router? If so, please don't waste too much time playing with that. Place the components wisely connect them and if you get trapped, swap some of the components. The auto-router doesn't have the slightest idea of what kind of circuit you are making, so it will most likely do a lousy job. Furthermore you'll not learn much about routing.
Stefanoo said:
I doubt you'll gain much from making a ground-plane, but if you are determined to do so, I don't think it'll hurt...
Hum on the layout is mostly related to how you lay your gnd traces, but I think a general rule is to keep noisy traces away from delicate signal traces. It is however easier to get hum from bad wiring schemes...
The supply voltage is quite high, so you should make sure to place those traces sensible too!
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