Charles Hansen said:
Charles,
Could you elaborate on that? I'd be very interested to clean this up in my own AP1 as well.
When you said:
"But there are several options with regard to how to connect the DUT. Single-ended versus balanced, floating versus grounded. And the grounding connection has an internal fuse that is all-too-easily blown that has no external indicator. So sometimes you *think* the DUT is grounded to the System One when it actually isn't..."
it sounds like an operator error. And sure, I've done my share of that; the AP doesn't really shine in the User Friendliness dept.
Jan Didden
Jan, Bob was impugning my design and my design reputation. It is consistent with his other remarks concerning the JC-1 and potential instability.
He did not ask me if the design was stable with capacitive loads, he just implied that is probably was NOT stable, because it did not have an output coil. Yet, IF he had done a little background research, he would have found that we used the JC-1 with electrostatic speakers at several CES conventions, and that the same major electrostatic speaker manufacturer, both owned and demoed the loudspeakers with the JC-1 power amps all over the USA. IF there had been a stability problem, it would have been detected, but then I don't simulate, I MEASURE, with a complete variation of cap load up to 10 uF or more, when the amp is driven with as square wave, just like I did 40 years ago. Who needs simulation when you have an amp to measure directly?
He did not ask me if the design was stable with capacitive loads, he just implied that is probably was NOT stable, because it did not have an output coil. Yet, IF he had done a little background research, he would have found that we used the JC-1 with electrostatic speakers at several CES conventions, and that the same major electrostatic speaker manufacturer, both owned and demoed the loudspeakers with the JC-1 power amps all over the USA. IF there had been a stability problem, it would have been detected, but then I don't simulate, I MEASURE, with a complete variation of cap load up to 10 uF or more, when the amp is driven with as square wave, just like I did 40 years ago. Who needs simulation when you have an amp to measure directly?
john curl said:
Then why didn't you say so
? That would have ended it then and there. Jan Didden
john curl said:
Regardless your JC-1 case with Bob, it is good to use reliable simulation even in case you have a real amp to measure directly. Simulation is valuable for optimisation and it can show a broad set of parameter-dependent plots in a reasonable time (for example derivative of transfer function with respect to whole range of input voltages, derivative of output impedance and many others). It would take months to get it from real measurements. I vote for both simulation and real measurements, especially nowadays when simulation tools are powerful, when properly exploited. Combination of both worlds is, IMHO, the best way to get the best results.
I would agree with you, PMA. IF you are well set up to do good simulations as you are, then that can be valuable in conjunction with real measurement, but please understand: I just build them the best that I can, and then get the results. There is little that I can really do to greatly improve performance, once the initial parameters are established. Often, it is just what the devices can do, and tradeoffs in design. For example, one output device might have more nonlinear capacitance, but a more linear beta curve than another. Going through the incredible effort to PROPERLY model these devices, might take man-months to do right. Is it really worth it, IF you select an output device for a number of reasons, including availability and price, and not for any specific quality?
Jan, my answer to you is that he didn't ask what I did to insure amp stability. He just went on about it without me in the loop.
PMA said:
Don't despair. It only took me a few months to learn how to do it
😉
Pavel's hints in this and other threads helped! Thanks, Pavel.
I can add that I find that MicoCap 9 simulates distortion fairly accurately. I am impressed.
Sigurd
Well, I agree with you, in general. I do hope to get more effective simulations soon. So far, no success. Some progress, able to import schematic, but not to run TA.
Sigurd Ruschkow said:
Yes it does, but distortion analysis in MC9 may have restrictions in some cases. Especially if you need more than one signal source (there is only one to be chosen). Anyway, you can do almost arbitrary access to harmonic analysis through transient analysis, where you can do whatever you need.
john curl said:
Do you have windows PC, or Mac platform? In case of windows PC, the MC9 file must work.
Few minutes ago I sent cir file created in MC9 eval version, together with translations to PSpice and Microcap Spice. I hope this would help.
I have found out that it is even more difficult to make comparisons between components. To make a fair comparison is hard, I agree, but to to search for the optimal combination of components is even harder.
What I mean here is that if I for ex want to test what resistors are the best ones in a design, I can do that by making exact copies of the design sans the resistors that are different, and start making listening tests. I then choose say resistor Q to be the best ones.
Then I build another batch of amps with these resitors Q, and change capacitor type for each board, and do listening tests. I then choose cap type Z to be the best.
I will then never find out if any other combo resistor+capacitor exists that might sound even better together.
What I am trying to say, is the there are combinations of componens that make 1 + 1 = 3,
and these combinations willl then be missed.
Sigurd
What I mean here is that if I for ex want to test what resistors are the best ones in a design, I can do that by making exact copies of the design sans the resistors that are different, and start making listening tests. I then choose say resistor Q to be the best ones.
Then I build another batch of amps with these resitors Q, and change capacitor type for each board, and do listening tests. I then choose cap type Z to be the best.
I will then never find out if any other combo resistor+capacitor exists that might sound even better together.
What I am trying to say, is the there are combinations of componens that make 1 + 1 = 3,
and these combinations willl then be missed.
Sigurd
Charles Hansen said:
hi john,
You got to have admin access, know the administrator pw.
Grab us a screenshot, more than willing to help.
/Roland
You got to have admin access, know the administrator pw.
Grab us a screenshot, more than willing to help.
/Roland
I do some balanced designs, and then I use the inverter to create the inverted signal needed, and thus get two signal sources (controlled by the sine wave generator naturally).
If you have any idea to improve MC9, send Spectrum Software an email. Bill, the support person, is a very nice person to deal with,
and they enjoy to hear from us users!
MC10 is in the works, and maybe they can add what you want to do. They have already added stuff that I wanted to have, and will add some other ideas I have for MC10
🙂
Sigurd
If you have any idea to improve MC9, send Spectrum Software an email. Bill, the support person, is a very nice person to deal with,
and they enjoy to hear from us users!
MC10 is in the works, and maybe they can add what you want to do. They have already added stuff that I wanted to have, and will add some other ideas I have for MC10
🙂
Sigurd
PMA said:
PMA, congratulations to your very interesting analysis!
Mr. Wurcer, I repeatedly read your statements about spice. Especially the one that some of todays ICs go into production based purely on simulation. Knowing where you come from, I'm deeply impressed and start into the Spice-adventure.
What happens? I just have to find out how hard it is to get reasonable results.
I have the impression that most folks think they just need to hammer the schematic into spice and hit 'run' to get deep insight into a circuit - including distortion spectra and noise. But in fact I had to know how the circuit works right from the beginning, including dc-working points.
Up to now simulations of only the simplest amps gave me reasonable results. More complex topologies as a Supersymmetry-amp, or the infamous Cello amp just give complete banana, as my collegue here would say.
Wrong gain, funny frequency response, for sure wrong bandwidth - at least dc-working points seem to be always correct.
Working myself in numerical fields I'm sure of the mathematical foundations of spice, but nevertheless I have no idea how it is possible that I get repeatedly funny results (without any warning or hint that the numerics have a problem).
Amazing how other people simulate sometimes much bigger amps and get reasonable results.
And especially how strongly some people believe in spice-results in general.
All the best, Hannes
Mr. Wurcer, I repeatedly read your statements about spice. Especially the one that some of todays ICs go into production based purely on simulation. Knowing where you come from, I'm deeply impressed and start into the Spice-adventure.
What happens? I just have to find out how hard it is to get reasonable results.
I have the impression that most folks think they just need to hammer the schematic into spice and hit 'run' to get deep insight into a circuit - including distortion spectra and noise. But in fact I had to know how the circuit works right from the beginning, including dc-working points.
Up to now simulations of only the simplest amps gave me reasonable results. More complex topologies as a Supersymmetry-amp, or the infamous Cello amp just give complete banana, as my collegue here would say.
Wrong gain, funny frequency response, for sure wrong bandwidth - at least dc-working points seem to be always correct.
Working myself in numerical fields I'm sure of the mathematical foundations of spice, but nevertheless I have no idea how it is possible that I get repeatedly funny results (without any warning or hint that the numerics have a problem).
Amazing how other people simulate sometimes much bigger amps and get reasonable results.
And especially how strongly some people believe in spice-results in general.
All the best, Hannes
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