Some other Source Follower COnfigurations - Page 43 - diyAudio
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Old 13th December 2012, 04:42 AM   #421
EUVL is offline EUVL  Europe
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I started a new thread on the DAO SE here :

The DAO SE all-FET Class-A ZGF Headphone Amplifier


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Old 7th March 2013, 02:02 PM   #422
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Lightbulb again

inverted source follower:
I would like only remain that it
has good linearity,
high input impedance,
~270mA bias,
negative thermal coefficient for fets
and is so simply...
do you know other followers running @swing 30V with distortion ~-150dB?
Attached Images
File Type: png sch.png (16.3 KB, 463 views)
File Type: png sine30v.png (12.6 KB, 387 views)
File Type: png fourier.png (12.9 KB, 355 views)
Attached Files
File Type: asc b2 simple inv follower.asc (5.3 KB, 17 views)
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Last edited by padamiecki; 7th March 2013 at 02:13 PM.
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Old 8th March 2013, 04:06 AM   #423
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Not sure if im doing sthg wrong but i tried to sim using your asc file and get strange results .... see attached pic ...
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Old 8th March 2013, 06:53 AM   #424
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Quote:
Originally Posted by kasey197 View Post
Not sure if im doing sthg wrong but i tried to sim using your asc file and get strange results .... see attached pic ...

did you have and use cordell-models.txt like attached?
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File Type: txt Cordell-Models.txt (19.7 KB, 13 views)
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Old 8th March 2013, 07:39 AM   #425
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yeap...i got mine off his webpage I'll try using the one you uploaded instead..
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Old 8th March 2013, 08:10 AM   #426
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Quote:
Originally Posted by kasey197 View Post
yeap...i got mine off his webpage I'll try using the one you uploaded instead..
wait,
today I got this without the changes in asc...
I do not understand...
will keep you informed about the mistakes
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File Type: png sine.png (6.3 KB, 314 views)
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Old 8th March 2013, 08:32 AM   #427
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Guys
it looks like the circuit has got the gain during the night
(250mV at the input)
sorry for inconvenience, I have no idea why the circuit's behavior has changed, I will try to find and correct the mistake
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File Type: png sine.png (11.7 KB, 50 views)
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Old 8th March 2013, 09:40 AM   #428
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Default The explanation:

in post 422 I clicked directly V1 voltage source...
and that was the reason of amazing low thd result...

in real life this circuit has positive feedback and act like voltage amp, not clear follower

do not send me to for this
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Old 8th March 2013, 10:07 AM   #429
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> in real life this circuit has positive feedback and act like voltage amp, not clear follower

Glad you found out for yourself.


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Old 19th June 2013, 12:14 PM   #430
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Thumbs up this time I have checked

this is clear inverted follower with voltage sources instead of big caps at the input to let ltspice make good calculations/simulation.

thd:
N-Period=1
Fourier components of V(vout)
DC component:0.0260207

Harmonic Frequency Fourier Normalized Phase Normalized
Number [Hz] Component Component [degree] Phase [deg]
1 1.000e+03 1.447e+01 1.000e+00 -0.01 0.00
2 2.000e+03 1.492e-02 1.031e-03 -92.14 -92.12
3 3.000e+03 5.350e-03 3.697e-04 9.32 9.33
4 4.000e+03 8.804e-04 6.084e-05 80.75 80.76
5 5.000e+03 4.018e-04 2.777e-05 -149.71 -149.69
6 6.000e+03 8.482e-05 5.862e-06 -113.99 -113.98
7 7.000e+03 5.179e-05 3.579e-06 52.64 52.66
8 8.000e+03 1.114e-05 7.698e-07 46.49 46.50
9 9.000e+03 7.858e-06 5.431e-07 -115.42 -115.40
Total Harmonic Distortion: 0.109745%
Attached Images
File Type: png sch.png (24.6 KB, 121 views)
File Type: png sine.png (13.9 KB, 117 views)
File Type: png fft.png (6.7 KB, 37 views)
File Type: png ac.png (9.0 KB, 33 views)
Attached Files
File Type: asc inv foll 2409240voltsource.asc (3.4 KB, 3 views)
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