F6 Amplifier

Member
Joined 2009
Paid Member
todays little work....

showing the positive k2 phase with Visual Analyser program.
Botte your hints gave me now a more stable phase picture.....:)
 

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I have had considerable experience using the Visual Analyser and have a few suggestions.

  • In order to measure harmonics at high frequencies, set the sampling rate higher: at least 96kHz. Sometimes the computer audio system sets the soundcard shelf filters to cutoff frequencies above about 20kHz. Be sure to turn off the shelf filters
  • A soundcard with balanced I/O is preferred. See this thread:
  • http://www.diyaudio.com/forums/pass...tortion-measurement.html?highlight=distortion
  • Measure the amplifier output using an oscilloscope or AC voltmeter at 60-100Hz to establish the power level.

todays little work....

showing the positive k2 phase with Visual Analyser program.
Botte your hints gave me now a more stable phase picture.....:)
 
Member
Joined 2009
Paid Member
O.K. Ihquam many thanks for the hints! :)

A problem concerning me and maybe others, my EMU drivers for Mac do not work reliable at 96kHz or my (older Hackintosh) cannot manage it. ARTA is a good recommendation from friends for Windows, but it doesn't accept the Asio driver from EMU it seems and with the Windows driver it is unstable.
Audio Analyser works in my Windows system fairly good but only up to 48kHz/24bit.

Unfortunately my EMU 0204 accepts only unbalanced inputs!

A friend measured with ARTA his J2 clone balanced and unbalanced, there was no difference in the THD.
Did you experiences in the two different setting?

Now I will read your link! :):)

I will try to find the shelf filter... In windows or in the measurement programs?

Yes I measured the output level at 100Hz!




I have had considerable experience using the Visual Analyser and have a few suggestions.

  • In order to measure harmonics at high frequencies, set the sampling rate higher: at least 96kHz. Sometimes the computer audio system sets the soundcard shelf filters to cutoff frequencies above about 20kHz. Be sure to turn off the shelf filters
  • A soundcard with balanced I/O is preferred. See this thread:
  • http://www.diyaudio.com/forums/pass...tortion-measurement.html?highlight=distortion
  • Measure the amplifier output using an oscilloscope or AC voltmeter at 60-100Hz to establish the power level.
 
When running at 48kHz/24bit, don't worry about the shelf filter. You won't get anything above 1/2 the sample-rate.

O.K. Ihquam many thanks for the hints! :)

A problem concerning me and maybe others, my EMU drivers for Mac do not work reliable at 96kHz or my (older Hackintosh) cannot manage it. ARTA is a good recommendation from friends for Windows, but it doesn't accept the Asio driver from EMU it seems and with the Windows driver it is unstable.
Audio Analyser works in my Windows system fairly good but only up to 48kHz/24bit.

Unfortunately my EMU 0204 accepts only unbalanced inputs!

A friend measured with ARTA his J2 clone balanced and unbalanced, there was no difference in the THD.
Did you experiences in the two different setting?

Now I will read your link! :):)

I will try to find the shelf filter... In windows or in the measurement programs?

Yes I measured the output level at 100Hz!
 

ra7

Member
Joined 2009
Paid Member
Too bad your not in NC anymore, you could listen to a whole range of FW clones:D. I could give subjective opinions, with measurements, but who would listen.

I built one or two myself, not FW, but others. Have all the boards, all the parts, but not the time. Hoping to build the F6 and Mike's L'amp soon. Having too much fun with speakers right now.

Did you get a chance to visit Pano?