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RayDunzl

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It cannot give more current?

At the same output voltage, the amp cannot "give more current" unless the load demands it (lower impedance), and the amp can deliver it (not current limited).

There's a 4-way balance of Voltage, Impedance, Current, and Power. Can't change one without changing another.
 
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Doodski

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@AtomAmp do you know the SPL efficiency of your headphones? If you do you can plug in the number into this calculator and the also plug in the resistance. It will output the voltage required to get to different SPL. If you use let's say 50 Ohms and also 300 Ohms and do the 2 calculations using the same efficiency dB rating you'll see how the current and voltage goes up and down depending on the headphone resistances. Print out the 2 screens and then you can compare them side by side.
http://www.digizoid.com/headphones-power.html
 

Doodski

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@AtomAmp if you are unsure of the calculator tell me what headphones you want to calculate for and I'll do the calculations and post the screenshots here.
 

RayDunzl

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4 Volts out with 9dB gains gives

0.3548 x 4 = 1.419 V input

1606292902415.png


http://www.sengpielaudio.com/calculator-db.htm
 

AtomAmp

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@AtomAmp if you are unsure of the calculator tell me what headphones you want to calculate for and I'll do the calculations and post the screenshots here.
Thank you. Those are some useful websites. What I'm really trying to do is compare headphone amplifiers based on specs. Because if one amplifier says max power (balanced) at 500mW at 32 ohms (at +9db gain) and another says 1000mW (single ended) at 32 ohms with no gain adjustment, how do I compare those specs.
 

RayDunzl

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What I'm really trying to do is compare headphone amplifiers based on specs. Because if one amplifier says max power (balanced) at 500mW at 32 ohms (at +9db gain) and another says 1000mW (single ended) at 32 ohms with no gain adjustment, how do I compare those specs.

Carefully.

Guess with what you have to work with.
 

RayDunzl

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AnalogSteph

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The maximum voltage an amplifier can produce undistorted into any given load (and thus also the maximum power) is given by the MINIMUM of the following:
  • the product of input voltage and amplifier gain
  • maximum unloaded output voltage (determined e.g. by power supplies, circuitry)
  • maximum output voltage into given load as determined by unloaded output voltage and the divider ratio of load impedance and output impedance (ignore if output impedance is negligible)
  • the product of maximum output current into given load and load impedance
What happens when this maximum voltage is insufficient wil vary:
  • For the first one, you'll have the volume maxed out and are left wanting more, but it sounds fine.
  • Any of the others means running into clipping, which implies distortion that tends to turn ugly quickly.
 

AtomAmp

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Thank you all for your enlightening explanations. I truly appreciate it.
 

DonH56

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Power P, Voltage V, Current I, Resistance R

x^2 = x * x

P = V * I = (V^2) / R = (I^2) * R

Re-arrange to solve for what you want.
 

AtomAmp

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One positive thing about this hobby is that you get to learn new things, or revisit old interests. Though I had a certain interest in electronics when I was a kid, I was never able to pursue a career in engineering. I never thought I would encounter these again. And what a way to do so.
 
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