Class A Listening fatigue

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rcollege

Member
2010-12-02 5:06 pm
I have made a Class A amp using single mosfet and others using BJT or a Darlington for the only active component.
While it sounds deep and rich...great imaging, transparency and detail...I can't listen long without experiencing listening fatigue...I am not playing at loud volumes. I experience this both when the highs are overpowered by the lows and when the highs are a little bright.
I have been unorthodox in using a switching power supply that switches at a rate well into the GHZ.

Could the switching power supply cause the fatigue?...(the sound of tv's and computer monitors used to drive me crazy)
Or would second order Harmonics play a role in this?
Or both?
I got the THD down to .3% on the simulator ( not the most accurate) and I hear very little distortion...but the ear is not the most accurate for THD...just the most accurate for what sounds right.
 

Root2

Member
2010-11-20 9:21 am
London
I have made a Class A amp using single mosfet and others using BJT or a Darlington for the only active component.
While it sounds deep and rich...great imaging, transparency and detail...I can't listen long without experiencing listening fatigue...I am not playing at loud volumes. I experience this both when the highs are overpowered by the lows and when the highs are a little bright.
I have been unorthodox in using a switching power supply that switches at a rate well into the GHZ.

Could the switching power supply cause the fatigue?...(the sound of tv's and computer monitors used to drive me crazy)
Or would second order Harmonics play a role in this?
Or both?
I got the THD down to .3% on the simulator ( not the most accurate) and I hear very little distortion...but the ear is not the most accurate for THD...just the most accurate for what sounds right.

GHz SMPSU I would love to see that sounds like fun.
 

WuYit

Banned
2010-10-17 3:07 pm
Root2,
just bulk caps will not suffice, either choke regulation or something like this:
 

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I seriously doubt that listening fatigue is down to the amp itself, unless it oscillates or produces extreme amounts of overtones. Listening fatigue in my experience is usually what happens if you listen to a non flat frequency respons, which is usually caused by room influence, or the speakers themselves. Especially, if you have a peak in the region where the human ear is most sensivite, 2-5 kHz, you are very likely to find it fatiguing, even if this initially might be experienced as "great imaging" and detail.

Just my 5 cents worth.......

:)
 

Ian Finch

Member
Paid Member
2010-04-11 4:22 am
Coffs Harbour, NSW
'Seems from your description to be a frequency response or distortion matter.
Have you simmed the THD100 hz. THD10 kHz distortion? Can you post the plots
with your frequency response plot so that we can see what is actually going on?

BTW, this is your own design but what is the schematic so that comparison can
be made to similar types. The speaker types and other load issues are important
in these elemental designs. Of course, you can't see this by simming a simple
resistive load.
 
I have been unorthodox in using a switching power supply that switches at a rate well into the GHZ.

Could the switching power supply cause the fatigue?...(the sound of tv's and computer monitors used to drive me crazy)
You don't say how old you are or what your noise experience is. I was bothered as a child by the horrible howl of the televisions at the department store, but lost all sensitivity to frequencies above 15000 hz at summer camp in 1969. Guns, unmuffled motor vehicles, near lightning strikes, playing an instrument in front of speakers, can destroy hi frequency sensitivity permanently.
You should take a scope and look at your amp output. My mixer was producing 1 Mhz 1.5 V oscillation out as I was "improving" it, and I really couldn't hear the effect in the short term, but it sure was making the fan on the power amp run like crazy. Who knows what it was doing to distortion, I wasn't running a test quality record, just the FM radio.
 
You don't say how old you are or what your noise experience is. I was bothered as a child by the horrible howl of the televisions at the department store, but lost all sensitivity to frequencies above 15000 hz at summer camp in 1969. Guns, unmuffled motor vehicles, near lightning strikes, playing an instrument in front of speakers, can destroy hi frequency sensitivity permanently.
You should take a scope and look at your amp output. My mixer was producing 1 Mhz 1.5 V oscillation out as I was "improving" it, and I really couldn't hear the effect in the short term, but it sure was making the fan on the power amp run like crazy. Who knows what it was doing to distortion, I wasn't running a test quality record, just the FM radio.


Erhm, most poeple above 40 cannot hear 15 kHz anyway.

:)
 
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