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First cycle distortion - Graham, what is that?
First cycle distortion - Graham, what is that?
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Old 16th December 2020, 12:37 AM   #501
bimo is offline bimo  Indonesia
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Quote:
Originally Posted by nattawa View Post
……Yes, but not with straight Miller compensation, which is what petr_2009's amp being on topic is.
You can have relative high slew rate with only Miller compensation if use high current in LTP.
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Old 16th December 2020, 03:22 AM   #502
petr_2009 is offline petr_2009  South Korea
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A colleague approached me and thanked me for bringing up the topic of vector distortion measurements using the Baksandall and Hafler methods.
Since Hafler's method is the simplest and does not require anything other than an oscilloscope, he decided to test his amplifier using a 1 kHz square wave signal.
By changing the correction, he managed to reduce the signal transit time by 4 times, which had a positive effect on the sound quality. But since he did not manage to lower it below 100 ns, he decided to make a new amplifier.
I also checked both models with this method, here are the test results
Attached Images
File Type: png Hafler.png (77.4 KB, 166 views)
File Type: png Self-1_Hafler.png (80.0 KB, 162 views)
File Type: png Self-2_Hafler.png (78.5 KB, 162 views)
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Old 16th December 2020, 04:55 AM   #503
petr_2009 is offline petr_2009  South Korea
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slew rate can be measured in two ways
Attached Images
File Type: png Self-1_FPBW.png (80.3 KB, 162 views)
File Type: png Self-1_SR.png (20.8 KB, 155 views)
File Type: png Self-2_FPBW.png (82.9 KB, 37 views)
File Type: png Self-2_SR.png (20.9 KB, 37 views)
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Old 16th December 2020, 07:00 AM   #504
jan.didden is online now jan.didden  Europe
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Of course it can be done. Pretty much anything can be done - it's just engineering.

By the way can we agree to use 'compensation' for compensation rather than 'correction', and 'square wave' rather than 'meander' for a square wave?
I understand that we are not all native English speakers (I'm not) but a common vocabulary helps understanding. Thanks all.

Jan

Last edited by jan.didden; 16th December 2020 at 07:03 AM.
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Old 16th December 2020, 07:04 AM   #505
jan.didden is online now jan.didden  Europe
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Quote:
Originally Posted by petr_2009 View Post
slew rate can be measured in two ways
That 2nd and 4th graph doesn't look like slew rate but rather like rise time. Slew rate would look like a straight line.

Jan
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Old 16th December 2020, 07:46 AM   #506
chip_mk is offline chip_mk  Macedonia
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Quote:
Originally Posted by petr_2009 View Post

Since Hafler's method is the simplest and does not require anything other than an oscilloscope, he decided to test his amplifier using a 1 kHz square wave signal.
The upper trace, what amp generated that trace? What amp was used as a Driving amp from the picture?

BTW really smart test setup

Last edited by chip_mk; 16th December 2020 at 07:48 AM.
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Old 16th December 2020, 10:18 AM   #507
petr_2009 is offline petr_2009  South Korea
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in fact, the basic version of the Self amplifier does not pull at 150 kHz without distortion, but only 125 kHz. So I repeated the measurements
Attached Images
File Type: png Self-1_FPBW-125kHz.png (82.9 KB, 34 views)
File Type: png Self-1_SR.png (21.1 KB, 32 views)
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Old 16th December 2020, 12:28 PM   #508
scottjoplin is offline scottjoplin  Wales
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Quote:
Originally Posted by petr_2009 View Post
By changing the correction, he managed to reduce the signal transit time by 4 times, which had a positive effect on the sound quality.
What was the nature of that effect and can you explain it?
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Old 16th December 2020, 01:46 PM   #509
petr_2009 is offline petr_2009  South Korea
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Quote:
Originally Posted by jan.didden View Post
Of course it can be done. Pretty much anything can be done - it's just engineering.

By the way can we agree to use 'compensation' for compensation rather than 'correction', and 'square wave' rather than 'meander' for a square wave?
I understand that we are not all native English speakers (I'm not) but a common vocabulary helps understanding. Thanks all.

Jan
Jan, square wave in Russian just "meander"
I don't know much English, I mostly use a translator
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Old 16th December 2020, 01:52 PM   #510
jan.didden is online now jan.didden  Europe
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I understand, just want to help.
I can make the connection from meander to square wave, meander we also know in Dutch.

Jan
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