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PostPosted: October 27th, 2016, 3:25 pm 
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TubeDriver wrote:
DBerning method of running super high fz AC is interesting in that you might get the sonics of AC with the noise WAY out of audible range but I have 2" space limitation for heater PS so that is a no go.


Hmm....

Audibility of high frequencies by themselves may not be an issue but
what effect will the high frequency contamination of the audio signal will have on the moving elements in the drivers?


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PostPosted: October 27th, 2016, 3:38 pm 
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Joined: March 12th, 2013, 11:12 am
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I think we are talking something like 1.5M Hz (?) so there is not a chance of it getting through my OT. Also IMD should not be an issue as the level is pretty low? I think DB amps have a reputation for long tube life and reliability so I don't think the high freq is in any way harmful to the tubes.


Cogito wrote:
TubeDriver wrote:
DBerning method of running super high fz AC is interesting in that you might get the sonics of AC with the noise WAY out of audible range but I have 2" space limitation for heater PS so that is a no go.


Hmm....

Audibility of high frequencies by themselves may not be an issue but
what effect will the high frequency contamination of the audio signal will have on the moving elements in the drivers?


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PostPosted: October 27th, 2016, 3:55 pm 
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I am referring to the effect on hf noise on the voice coil.

The sensitivity of the voice coil to low level signals makes the speaker more "revealing".

My question is, if the HF frequencies outside the audible range are super imposed on the audio signal, wont they deteriorate the sound reproduction in the audio range? Obviously I am not talking Bose!!


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PostPosted: October 27th, 2016, 4:03 pm 
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I am going to guess that my FS030 OT are about 250K db down at 1.5M Hz so I don't think it would be an issue for me. Perhaps DBerning amps have some sort of low pass filter on output? My OTs probably serve the same purpose.



Cogito wrote:
I am referring to the effect on hf noise on the voice coil.

The sensitivity of the voice coil to low level signals makes the speaker more "revealing".

My question is, if the HF frequencies outside the audible range are super imposed on the audio signal, wont they deteriorate the sound reproduction in the audio range? Obviously I am not talking Bose!!


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PostPosted: October 27th, 2016, 4:23 pm 
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I believe David's HF filament supply operates at 250KHz.

Tom


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PostPosted: October 27th, 2016, 4:24 pm 
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Looking at his patent, it appears his amps do use a 2nd order LC low pass filter on output. This is for the "Output Transformerless Amplifier Impedance Matching Apparatus" but would also work on any heater supply noise.




tomp wrote:
I believe David's HF filament supply operates at 250KHz.

Tom


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