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#2,283

At the rated 100-watts output, the distortion was under 0.001 per cent from 20 to 1.000 Hz, and it rose linearly at higher frequencies to the rated 0.005 per cent at 8.000 Hz and 0.01 per cent at 20,000 Hz. At lower power outputs the distortion was still lower. These measurements were made with the amplifier gain set to 20 dB below maximum, in accordance with IHF measurement standards. When the distortion is measured at maximum gain setting, the amplifier meets the published rating of 0.005 per cent at 20,000 Hz.
 
#2,285
bimo said:
At the rated 100-watts output, the distortion was under 0.001 per cent from 20 to 1.000 Hz, and it rose linearly at higher frequencies to the rated 0.005 per cent at 8.000 Hz and 0.01 per cent at 20,000 Hz. At lower power outputs the distortion was still lower. These measurements were made with the amplifier gain set to 20 dB below maximum, in accordance with IHF measurement standards. When the distortion is measured at maximum gain setting, the amplifier meets the published rating of 0.005 per cent at 20,000 Hz.
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and of all 4 amps you chose the only one that's pooreer at 20khz...you friend's amp's distortions are for 1khz not 20khz anyway...
By the way...they made those measurements on an amp after 30 years since it was produced...you can downoad the service manual for youself and see the original measurements from a time when there was no Audio Precision on the market...


https://www.diyaudio.com/forums/sol...dback-huge-benefit-audio-222.html#post6293302
 
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#2,287
dreamth said:
and of all 4 amps you chose the only one that's pooreer at 20khz...you friend's amp's distortions are for 1khz not 20khz anyway...
By the way...they made those measurements on an amp after 30 years since it was produced...you can downoad the service manual for youself and see the original measurements from a time when there was no Audio Precision on the market...


https://www.diyaudio.com/forums/sol...dback-huge-benefit-audio-222.html#post6293302
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Edmond Stuard's amplifier have 0.0001% at 20kHz is poorer? You do not understand math, and now you do not understand number.
 
#2,288
bimo said:
Edmond Stuard's amplifier have 0.0001% at 20kHz is poorer? You do not understand math, and now you do not understand number.
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and now you're insulting too...let me quote again your first statements!


bimo said:
It hard to explain to person who do not understand theoretical knowledge 🙂
You can have amplifier with high slew rate and low distortion in high frequency, example CFA amplifier by Dadod. The measurement by RN Marsh speak it self.
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bimo said:
Of course using VFA can have low distortion also, but using CFA is easier to get higher slew rate.

I doubt any amplifier at 80's can have distortion 0.003% at 20kHz. If distortion 0.003% at 1kHz, I believe it. 20 year ago, I design an amplifier that have distortion 0.003% at 1kHz, 100W rms, 8.2 Ohm dummy load. At that time, I do not use simulation and I do not know Bob Cordell who advocate to get low distortion at 20kHz. So, I do not measure distortion at 20kHz.
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here are the oficial measurements of dados's amp... i only see -90db thd at 1khz...
Lateral CFA 120W - BSA


Engineer's first weapon is caled PRECISION!
 
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#2,291
analog_sa said:
it is perhaps a good time to recall the amazing concept of the Kinergetics amps. They employed "frozen" magnetic pickups in the NFB in order to correct for magnetic hysteresis distortion in recordings. Allegedly JC preceded them by incorporating a tape head in the NFB loop.
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I do not recall the amazing concept of the Kinergetics amps. And, after reading this, to tell you the truth, I am ever so grateful that I didn't ...

Jan
 
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#2,295
dreamth said:
OK...where's that -120db THD at 20khz graph as advertized by your friend?
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If real measurement that will be, probably, the amp with lowest THD20k ever built.
Here is simulated 20k FFT at 50W/8ohm of this amp here: https://www.diyaudio.com/forums/solid-state/253039-unique-cfa-120-230w-amp-25.html#post4665073, but I don't thik it will be so low in real amp.

First FFT was with antisticking diodes connected between VAS output to the VAS enhancement transistor base. Second one is with no diodes.
 

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#2,299
"i have no idea if your name is Stuard but this guy mentioned you first , then he continued with mentioning this stuart to fight my arguments...Now you came into this discussion..."

No, I am not Stuard, and you talked about dadod amps and you can find my name if you are interested. You look quite confused.😱
By the way 0.0001% is -80dB
 
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