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gain vs power

Kosta

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apologies if this is a dumb question - I was wondering is there a difference between the underlying power an amp puts out to drive headphones vs its gain .
So say I am using a JDS Atom with 300ohm headphones, does it make a difference to the performance of the headphone if I am listening at low gain with volume at 2pm vs high gain with volume at 11am?
 

JohnYang1997

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Gain = loudness. And it's irrelevant to the power of a amplifier. The power of an amplifier is limited by its circuit and supply rail. If input has high enough level there's no need for gain setting whatsoever.
So use the lowest gain setting possible as long as it's loud enough when volume setting is at max.
 

sergeauckland

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apologies if this is a dumb question - I was wondering is there a difference between the underlying power an amp puts out to drive headphones vs its gain .
So say I am using a JDS Atom with 300ohm headphones, does it make a difference to the performance of the headphone if I am listening at low gain with volume at 2pm vs high gain with volume at 11am?
No audible difference, unless the volume control comes after the gain setting stage, in which case it's possible that the amplifier's front end clips on high level signals. I would expect the volume control to be before the gain setting stage for just this reason.

Gain has nothing to do with loudness or volume, that's to do with power output. Your example of low gain with a 2 setting or high gain at 11 would result in the same power into the load.

S.
 
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Generally, potentiometers track better between L/R sections at higher rotations. In that aspect, it would probably be better to use the lower gain and higher control setting.
However, in the case of the Atom, the sections seem to track pretty well at lower rotations too......at least on mine.
 

JohnYang1997

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No audible difference, unless the volume control comes after the gain setting stage, in which case it's possible that the amplifier's front end clips on high level signals. I would expect the volume control to be before the gain setting stage for just this reason.

Gain has nothing to do with loudness or volume, that's to do with power output. Your example of low gain with a 2 setting or high gain at 11 would result in the same power into the load.

S.
Your explanation is just stiring things up...

1, At same volume setting, higher gain = higher volume.
2, Atom has pot after gain stage to minimize noise. It's the superior way. 10kohm can't clip a opamp output.
3, Voltage gives loudness, power is only required accordingly.
 

sergeauckland

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Your explanation is just stiring things up...

1, At same volume setting, higher gain = higher volume.
2, Atom has pot after gain stage to minimize noise. It's the superior way. 10kohm can't clip a opamp output.
3, Voltage gives loudness, power is only required accordingly.

1) Yes, of course. However, Kosta mentioned that the volume varied between 2 and 11 depending on gain, so the volume setting had changed.
2) Perhaps it is superior, but the gain stage shouldn't be noisy enough for it to matter, and overload performance I think matters more than inaudible noise. That's why I would put the volume control before any gain stage.
3) No, it's power that gives the loudness, but clearly, for a fixed impedance more voltage means more power. For headphones it's even more complicated as impedance and sensitivity both vary depending on the strength of the magnets used and the number of turns on the coils, and the gauge of wire used, which also has an effect on the mass of the diaphragm. All these will affect sensitivity and so just how loud any headphone goes with any specific number of volts and so how much power is needed. I accept, however, that all one can say with any certainty is that for any individual headphone, loudness is proportional to voltage.

Hopefully, things will get unstirred now.

S.
 
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Kosta

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Ok thanks I think I understand now. So assuming my amp has decent power to begin with, as long as I can get enough volume to comfortable listen without needing to go to Max then I needn't worry about using gain
 
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