I put this together but it seems I haven't learned how to set it up to run. Maybe someone can check it for me.
Thanks, Terry
Thanks, Terry
Terry,
Try this into your spice directive:
;ac oct 10 10 20000000
.options plotwinsize=0
.options numdgt=8
.param freq 1k
.param num_fft_pts 4096
.param timestep {1/{{freq} * {num_fft_pts}}}
.four {freq} 19 8 V(Vout)
.tran 0 {15/freq} {2/freq} {timestep}
This seems to work well, delivers a distortion profile, and adjusts the graph for different frequencies. The 10/10/20000000 is a frequency train that the forum assumes is a Skype number; ignore that. The expert on this is Keantoken.
Cheers,
Hugh
Try this into your spice directive:
;ac oct 10 10 20000000
.options plotwinsize=0
.options numdgt=8
.param freq 1k
.param num_fft_pts 4096
.param timestep {1/{{freq} * {num_fft_pts}}}
.four {freq} 19 8 V(Vout)
.tran 0 {15/freq} {2/freq} {timestep}
This seems to work well, delivers a distortion profile, and adjusts the graph for different frequencies. The 10/10/20000000 is a frequency train that the forum assumes is a Skype number; ignore that. The expert on this is Keantoken.
Cheers,
Hugh
indeed Uncle Charlie.....they do become annoying at times and when challenged to post pictures of what they have done comes up with lame excuses....
how i wished they would stop.....but this is a public forum....and even if half of them go, this forum will be lifeless....
continue having fun.....😉
Terry,
Delete C2. It's shorting away most of the input!
Now, reduce the input amplitude from 1V to 600m, then the output will be around 14.14Vp, which is +20dBU. Label the output Vout, so you can pick up the distortion analysis, and you will have this:
Fourier components of V(vout)
DC component:-0.0781562
Harmonic Frequency Fourier Normalized Phase Normalized
Number [Hz] Component Component [degree] Phase [deg]
1 1.000e+03 1.298e+01 1.000e+00 0.52° 0.00°
2 2.000e+03 5.546e-03 4.271e-04 98.55° 98.03°
3 3.000e+03 1.054e-03 8.118e-05 3.80° 3.27°
4 4.000e+03 3.724e-04 2.868e-05 -139.64° -140.16°
5 5.000e+03 3.074e-04 2.368e-05 -179.11° -179.63°
6 6.000e+03 1.991e-04 1.534e-05 174.60° 174.07°
7 7.000e+03 1.631e-04 1.256e-05 179.91° 179.38°
8 8.000e+03 1.477e-04 1.137e-05 -179.25° -179.77°
9 9.000e+03 1.319e-04 1.016e-05 -179.94° -180.46°
10 1.000e+04 1.183e-04 9.107e-06 179.95° 179.43°
11 1.100e+04 1.074e-04 8.273e-06 -179.97° -180.49°
12 1.200e+04 9.853e-05 7.588e-06 -179.95° -180.48°
13 1.300e+04 9.096e-05 7.005e-06 -179.97° -180.49°
14 1.400e+04 8.445e-05 6.504e-06 -179.97° -180.50°
15 1.500e+04 7.882e-05 6.070e-06 -179.97° -180.50°
Total Harmonic Distortion: 0.043743%
This is a very good profile, a monotonic decrease of harmonics, which is very natural.
Cheers,
Hugh
Delete C2. It's shorting away most of the input!
Now, reduce the input amplitude from 1V to 600m, then the output will be around 14.14Vp, which is +20dBU. Label the output Vout, so you can pick up the distortion analysis, and you will have this:
Fourier components of V(vout)
DC component:-0.0781562
Harmonic Frequency Fourier Normalized Phase Normalized
Number [Hz] Component Component [degree] Phase [deg]
1 1.000e+03 1.298e+01 1.000e+00 0.52° 0.00°
2 2.000e+03 5.546e-03 4.271e-04 98.55° 98.03°
3 3.000e+03 1.054e-03 8.118e-05 3.80° 3.27°
4 4.000e+03 3.724e-04 2.868e-05 -139.64° -140.16°
5 5.000e+03 3.074e-04 2.368e-05 -179.11° -179.63°
6 6.000e+03 1.991e-04 1.534e-05 174.60° 174.07°
7 7.000e+03 1.631e-04 1.256e-05 179.91° 179.38°
8 8.000e+03 1.477e-04 1.137e-05 -179.25° -179.77°
9 9.000e+03 1.319e-04 1.016e-05 -179.94° -180.46°
10 1.000e+04 1.183e-04 9.107e-06 179.95° 179.43°
11 1.100e+04 1.074e-04 8.273e-06 -179.97° -180.49°
12 1.200e+04 9.853e-05 7.588e-06 -179.95° -180.48°
13 1.300e+04 9.096e-05 7.005e-06 -179.97° -180.49°
14 1.400e+04 8.445e-05 6.504e-06 -179.97° -180.50°
15 1.500e+04 7.882e-05 6.070e-06 -179.97° -180.50°
Total Harmonic Distortion: 0.043743%
This is a very good profile, a monotonic decrease of harmonics, which is very natural.
Cheers,
Hugh
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It is as useful as the models.
It gives an indication of the profile of the distortion.
This is helpful, focusses research into topologies. Text recognition was poor when it started, now it's very useful and used in all sorts of dictating situations, such as Hansard in the Australia Parliament. Gotta start somewhere!
BTW, your file does not have supporting directives to get a good harmonic profile. Try the edits I used earlier, they give a very definitive profile.
Hugh
It gives an indication of the profile of the distortion.
This is helpful, focusses research into topologies. Text recognition was poor when it started, now it's very useful and used in all sorts of dictating situations, such as Hansard in the Australia Parliament. Gotta start somewhere!
BTW, your file does not have supporting directives to get a good harmonic profile. Try the edits I used earlier, they give a very definitive profile.
Hugh
You can "play" with this schematic. It can be biased in class A, but "nothing" real will be gained, but only heat..
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Ah, but you are assuming that lower THD is a better sound........
This is controversial. What is the THD of a tube amp? 0.2%, 0.5%, 2%? Do tube amps offer all sound 'bad'?
The argument has been wasting time for 60 years. I'm outa here!
This is controversial. What is the THD of a tube amp? 0.2%, 0.5%, 2%? Do tube amps offer all sound 'bad'?
The argument has been wasting time for 60 years. I'm outa here!
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For sure it is better for sound, the less distortions (all kinds), the better. Maybe not "nicer, emotional " for someone, this is really controversial, but as close to input signal as possible ,is always better. Not only THD, it is only one number, but CCIF, IMD, multitone, S/N ratio.. At various levels and frequencies and with complex load.
Amplifier should only, according name, to amplify ( or as close as we can reach), this is what I am striving for. Not to create new sound and to serve as "glamourizer", according someones taste. For this purpose it is better to use some sort of effect DSP procesor and change sound as you like. It has one very important advantge, you can press bypass button...
Try tube amp with THD 1% with dynamic , complex music signal..Result is quite different from reality, you get completly "new" orchestra, but a bit disharmonic. And this is very easy to measure e.g with multitone.
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Hi Terry, I think that 470uF should be 1nF. That's how it is on the original schematic.
Maybe here. But i labeled a "toy" playing with simulation only, it is a tool before to try something real. But real performance depends on realization details, have to be verified with measurments, and i see no sense to make an class A amplifier which distorted so much , if the only advantage of class A should be low distortion.
I believe the instructions in the first post was this.
So far the only person who has offered one up is Bigun and even he doesn't suggest running his amp in Class A so is it really Class A?
The one you posted says clearly Class B so it doesn't really fit the criteria.
As for harmonically absent reproduction, I don't know any recording engineers who mix and master music expecting it to be played back on completely sterile sound systems.
Hopefully some of the folks will follow the simple criteria of the thread and come up with some interesting designs.
Blessings, Terry
I wrote also " It can be biased in class A, but "nothing" real will be gained, but only heat.."
It means only to change one resistor value (R16 to 1k4), result is THD 10kHz/50W 0.000366%..
It means only to change one resistor value (R16 to 1k4), result is THD 10kHz/50W 0.000366%..
They mastered it so, as they expects (wants)to be reproduced. Adding any "harmonical" content (read distortion) is only your modification of original, as if you are "improving" the meal by master cook by adding ketchup, salt, etc. Maybe it will be "better" for (only) you, but it is then different meal, you have not to buy it. So simple it is. Any "improvemet" is only distortion. Would you drink clear water from dirty bottle?
Would I add salt to my food? Cream to my coffee? Speakers to suit my taste? Do most of the top amps sound similar? Do I select amp speaker combinations to suit the music I want to listen to? Do the amps/speakers that my son uses to mix on at the recording studio he works at color the sound? Does he use his ears and not measurements to mix and master? Can the sound be colored by harmonic balance and not distortion?
Yes to all.
Yes to all.
But you have only salt (distortion profile of used amplifier), and it will be added to each meal, independent of actual taste, to meat , to coffe, to juice, to cakes. Here is no way to distinguish "meal" and to change "improvement" according momentary needs ( do not look on amplifier so "anthropomorphical").
If you like it, i wish you "bon appetit". But I will rather rely on original taste.
Try to think about fact , that if amplifiers sound different (in the same chain, with the same recording), so some of them must change (distort) signal. Changing harmonic balance of given signal means to distort original harmonic content. No way to avoid this.
To make an amplifier is strictly technical challenge, no art nor black magic. And at last, try to distinguish "make a music" and "reproduce music" . Quite different discipline.
If you like it, i wish you "bon appetit". But I will rather rely on original taste.
Try to think about fact , that if amplifiers sound different (in the same chain, with the same recording), so some of them must change (distort) signal. Changing harmonic balance of given signal means to distort original harmonic content. No way to avoid this.
To make an amplifier is strictly technical challenge, no art nor black magic. And at last, try to distinguish "make a music" and "reproduce music" . Quite different discipline.
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