Krill - The Next Generation

[scott wurcer]

Originally Posted by Steve Dunlap

Thanks for the explanation Scott.

Just for fun, I ran the same circuit at an output of two watts (First Watt was taken) with the same load. I didn't bother with the 8 Ohm sims at this power as there really seems to be no point in it.

It has nothing to do with heat AFAIK there is no commercial SPICE that does a full thermal analysis at every time point.

[Steve Dunlap]

Hi godfry,

I prefer Intusoft. To me, it is easier to use and much faster than LTspice. I will look into the time step (that is what it is called in Intusoft also), but I alredy let the sim run for a few cycles before starting the measurement.

[Steve Dunlap]

Originally Posted by keantoken

Steve, the "capacitor distortion" is a problem with LTSpice's .four command here I think. Even the default capacitor models in LTSpice don't model capacitor distortion.

Also, square wave sources in the schematic not attached to the circuit can cause odd transients in other parts of the circuit, and on an FFT this can look like your amp's distorting especially if the square wave source is the at the test frequency. It helps if the risetime for the source is slower than the timestep.

- keantoken

As I pointed out, I am not using LTspice. Also, what my sims show is shown by D. Self in the link I gave. I will turn off the square wave and look again. I was not aware that could happen, thanks.

[Steve Dunlap]

Originally Posted by scott wurcer

It has nothing to do with heat AFAIK there is no commercial SPICE that does a full thermal analysis at every time point.

I'm not understanding your statement. Where did I mention heat?

[Steve Dunlap]

I reduced the time step and reran the 2W results with the simulated load. I like the results, but I'm not sure I believe they represent real world measurements.

Fourier analysis for v(5):
No. Harmonics: 10, THD: 0.000122025 %, Gridsize: 200, Interpolation Degree: 1

Harmonic Frequency Magnitude Phase Norm. Mag Norm. Phase
-------- --------- --------- ----- --------- -----------
0 0 -0.13848 0 0 0
1 20 3.98495 0.118189 1 0
2 40 4.70141e-006 -66.759 1.17979e-006 -66.877
3 60 7.46678e-007 -59.895 1.87375e-007 -60.013
4 80 2.57768e-007 -12.257 6.46854e-008 -12.375
5 100 2.1945e-007 17.3729 5.50696e-008 17.2547
6 120 3.63374e-007 -2.7229 9.11867e-008 -2.8411
7 140 3.37321e-007 -16.64 8.46489e-008 -16.758
8 160 4.76093e-007 2.79752 1.19473e-007 2.67933
9 180 6.30249e-007 -2.5251 1.58157e-007 -2.6432

Fourier analysis for v(5):
No. Harmonics: 10, THD: 0.00133794 %, Gridsize: 200, Interpolation Degree: 1

Harmonic Frequency Magnitude Phase Norm. Mag Norm. Phase
-------- --------- --------- ----- --------- -----------
0 0 -0.13964 0 0 0
1 200 3.95695 -0.038741 1 0
2 400 4.67692e-005 81.2864 1.18195e-005 81.3251
3 600 2.10765e-005 26.7788 5.32645e-006 26.8176
4 800 7.76899e-006 25.3644 1.96338e-006 25.4031
5 1000 6.06051e-006 16.4463 1.53161e-006 16.485
6 1200 5.21698e-006 14.3948 1.31843e-006 14.4335
7 1400 4.03439e-006 3.54452 1.01957e-006 3.58326
8 1600 3.88129e-006 21.0667 9.80879e-007 21.1054
9 1800 3.9478e-006 27.6629 9.97687e-007 27.7016

Fourier analysis for v(5):
No. Harmonics: 10, THD: 0.000682223 %, Gridsize: 200, Interpolation Degree: 1

Harmonic Frequency Magnitude Phase Norm. Mag Norm. Phase
-------- --------- --------- ----- --------- -----------
0 0 -0.13799 0 0 0
1 2000 3.97386 0.0742918 1 0
2 4000 1.12257e-005 49.0462 2.8249e-006 48.972
3 6000 8.95986e-006 77.5329 2.2547e-006 77.4586
4 8000 9.13103e-006 79.1968 2.29777e-006 79.1225
5 10000 8.54492e-006 93.7172 2.15028e-006 93.6429
6 12000 7.76495e-006 89.168 1.95401e-006 89.0938
7 14000 1.15113e-005 85.4297 2.89674e-006 85.3554
8 16000 9.93978e-006 85.9077 2.50129e-006 85.8334
9 18000 8.98292e-006 80.0946 2.2605e-006 80.0203

Fourier analysis for v(5):
No. Harmonics: 10, THD: 0.00194635 %, Gridsize: 200, Interpolation Degree: 1

Harmonic Frequency Magnitude Phase Norm. Mag Norm. Phase
-------- --------- --------- ----- --------- -----------
0 0 -0.13923 0 0 0
1 20000 3.95574 -0.10303 1 0
2 40000 5.38489e-005 156.587 1.36129e-005 156.69
3 60000 3.68389e-005 -142.74 9.31277e-006 -142.64
4 80000 2.06051e-005 177.059 5.20892e-006 177.162
5 100000 2.40771e-005 -169.89 6.08664e-006 -169.79
6 120000 1.31909e-005 175.77 3.33463e-006 175.873
7 140000 1.49977e-005 -176.68 3.79138e-006 -176.58
8 160000 1.08513e-005 -178.91 2.74318e-006 -178.81
9 180000 1.22494e-005 -174.37 3.09663e-006 -174.27

[scott wurcer]

Originally Posted by Steve Dunlap

I'm not understanding your statement. Where did I mention heat?

The link "Phase Angle vs Transistor Dissipation" maybe useful but has nothing to do with this.

[Steve Dunlap]

Originally Posted by scott wurcer

The link "Phase Angle vs Transistor Dissipation" maybe useful but has nothing to do with this.

You are correct about that. If you scroll down a little, the simulated load I am using is shown. I gave the link instead of posting the schematic to avoid any issues concerning intellectual property or copyright.

[scott wurcer]

Just adds to the confusion without some context. There must be some public domain phasor diagram somewhere.

[Steve Dunlap]

Originally Posted by scott wurcer

Just adds to the confusion without some context. There must be some public domain phasor diagram somewhere.

I should have been more specific. The only thing I was trying to link to on that page was "Figure 1 - Loudspeaker Equivalent Circuit". That was so everyone could see what I was using as a simulated speaker load.

[godfrey]

Originally Posted by Steve Dunlap

I prefer Intusoft. To me, it is easier to use and much faster than LTspice.

My sympathies.
Simming with LTspice is about as much fun as trimming the lawn with a nail scissors.