Far from telling him that he's hearing wrong, I said that according to UAC-2's specs, the amplifier is definitely weak to drive the quite hungry Beyerdynamic DT770 80 Ohm, and thus I suggested a variety of much more sensitive headphones with a bassy sound signature.
Source:
here
That's what damping factor means to me.
What I've said, is that the
MAIN and most hearable effect of having a low damping factor is the equalization in the shape of the impedance vs frequency plot.
That's the main effect.
Damping Factor is strongly bounded with what you call Voltage Drop, since higher the Damping Factor means lower the Voltage Drop.
Here's an example:
Let's consider the Beyerdynamic DT880 250 Ohm
+
The Beyerdynamic A20 (output impedance 100 Ohm)
The ratio of the load's impedance to the amp's output impedance is pretty low (Low Damping Factor)
Let's say we have 1V at the Beyerdynamic A20
In the midrange DT880/250 is a 250 Ohm load.
So you have:
1V for the 100 Ohm amplifier impedance + the 250 Ohm headphone.
Then:
350 Ohm .................... 1V
250 Ohm .................... 0.71V
In the Mid-Bass DT880/250 is a 300 Ohm load
So you have:
1V for the 100 Ohm amplifier impedance + the 300 Ohm headphone.
Then:
400 Ohm .................... 1V
300 Ohm .................... 0.75V
In both cases you can see a Voltage Drop, but that's not a problem at all as far as you don't need more voltage than the amplifier can provide.
What's important here is that the amplifier won't be perfectly flat (0.75V at the mid-bass vs 0.71V at the midrange)
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Ok, let's swap the DT880 250 Ohm version for a DT880 600 Ohm version
Now "the ratio of the load's impedance to the amp's output impedance" is higher (OK Damping Factor)
Let's say again that we have 1V at the Beyerdynamic A20
In the midrange DT880/600 is a 600 Ohm load.
So you have:
1V for the 100 Ohm amplifier impedance + the 600 Ohm headphone.
Then:
700 Ohm .................... 1V
600 Ohm .................... 0.86V
In the Mid-Bass DT880/600 is a 700 Ohm load
So you have:
1V for the 100 Ohm amplifier impedance + the 700 Ohm headphone.
Then:
800 Ohm .................... 1V
700 Ohm .................... 0.87V
There's still a Voltage Drop here in both cases (you don't get 1V at the headphone) but again, this is not a problem as far as you don't need more voltage than the amplifier can provide.
What's important here is that the amplifier is now almost perfectly flat (0.87V at the mid-bass and 0.86V at the midrange)
Here we can see how a higher Damping Factor determines how flat the amplifier is when driving a dynamic driver with an impedance that varies with frequency.
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Now we can consider the V-Moda M100 and the UAC-2
The V-Moda is always 35 Ohm
The UAC-2 output impedance is 33Ohm but let's say it's 35 to make this even simpler.
Let's say that we have 1V at the UAC-2
So we have 1V for the 35 Ohm output impedance + the 35 Ohm V-Moda
Then:
70 Ohm ................... 1V
35 Ohm ................... 0.5V
So you'll get 0.5V at the headphone and this is applicable to the whole spectrum since V-Moda M100's impedance doesn't vary with frequency.
Then the amplifier is able to provide a flat frequency response to the headphone.
Here's a 0.5V Voltage Drop, but again, this doesn't matter since the remaining Voltage is more than enough to drive the very sensitive V-Moda.
So you'll hear the M100 as it is, no added coloration.
You'll have the rest of the effects of low damping factor, sure (not uber-ultimate transparency) but this effects are really really subtle with a damping factor equals to 1.