How do I know if an amp has enough output power for 600ohm ?

[Sharur]

Me, I would replace the DT880 600-Ohm with a Soundmagic HP200 headphone, it's like a combo of the DT880 and DT990.
Seller off your DT880 and use that cash to buy a DAC/amp (Schiit Fulla 3?).

By what metric is the soundmagic hp200 good?

 

[twsecrest]

Does an integrated amp count as a single ended amp in this case? My NAD C 316BEE V2's headphone out gets the DT880 600 ohm ridiculously loud before even reaching half volume.

Your NAD C 316BEE V2 uses the same amplifier(s) to drive the big diaphragms in the speaker, to also drive those little diaphragms in the headphones. A 600-Ohm headphone can be plugged into a headphone jack that has a 68-Ohm output impedance and offer good damping control.

 

[twsecrest]

By what metric is the Soundmagic hp200 good?

I own the DT880 250-Ohm, DT880 600-Ohm, DT990 Pro 250-Ohm and DT990 600-Ohm and the HP200.
I prefer to use the HP200, so the metric is my ears.

 

[ahofer]

Reminds me of a physics professor at college who had a sign on his door that said:

Danger: 10,000Ω

 

[solderdude]

Thanks for the response! I know the 68 ohm output impedance gives a load:source impedance ratio of over 10:1, but does the high output impedance adversely affect things like impulse response and square wave responses?

Not for the DT880

 

[Sharur]

Not for the DT880

Also, I've gotten mixed information about this online, but scientifically, what makes the 600 Ω "sound better" than the 32 Ω and 250 Ω versions?

 

[solderdude]

It is claimed that the 600ohm version has thinner voicecoil wiring and thus is lighter in weight and should be 'faster'.
Those that measured different impedance versions in the past found there are differences but I can't relate those to weight of the moving parts.
Fact is they don't measure and sound the same with just a different impedance.

Below the differences between the stock Superlux HD660Pro in 32 and 150 ohm versions where differences don't appear to be in the treble part but in the lows.

This could lead one to draw the conclusion there is a substantial difference in the impedance part.

below the same HD660Pro but left and right channel of the 32 ohm version.

Differences in a quite similar way can be found here and is all due to production spread (pads/drivers).

On direct comparison the 32 ohm version stands out immediately but this is more because of differences in voltage efficiency than anything else.
105dB/V for 32Ω and 98dB/V for 150Ω

 

[twsecrest]

Also, I've gotten mixed information about this online, but scientifically, what makes the 600 Ω "sound better" than the 32 Ω and 250 Ω versions?

The 600-Ohm version is only very slightly better then the 250-Ohm version, I own both.

 

[Sharur]

It is claimed that the 600ohm version has thinner voicecoil wiring and thus is lighter in weight and should be 'faster'.
Those that measured different impedance versions in the past found there are differences but I can't relate those to weight of the moving parts.
Fact is they don't measure and sound the same with just a different impedance.

Below the differences between the stock Superlux HD660Pro in 32 and 150 ohm versions where differences don't appear to be in the treble part but in the lows.

This could lead one to draw the conclusion there is a substantial difference in the impedance part.

below the same HD660Pro but left and right channel of the 32 ohm version.

Differences in a quite similar way can be found here and is all due to production spread (pads/drivers).

On direct comparison the 32 ohm version stands out immediately but this is more because of differences in voltage efficiency than anything else.
105dB/V for 32Ω and 98dB/V for 150Ω

I was looking at your CSD measurements for the DT880 600 Ω and 250 Ω and wanted to ask which one measures better. Does a smaller amount of "waves" indicate better performance?

600 Ω:

250 Ω:

 

[solderdude]

Both are well damped in the treble. Both have elevated treble. They don't sound very different to me. The 600ohm version is a lot less sensitive though and perhaps a tiny bit 'warmer/fuller' sounding. Treble extension > 20kHz is higher but so is the 'sharpness' which is often mistaken for 'enhanced detail'.

 

[Sharur]

Both are well damped in the treble. Both have elevated treble. They don't sound very different to me. The 600ohm version is a lot less sensitive though and perhaps a tiny bit 'warmer/fuller' sounding. Treble extension > 20kHz is higher but so is the 'sharpness' which is often mistaken for 'enhanced detail'.

what does the difference in number of ridges at, say, 5k mean even if there is no audible difference? There around 40 on the 250 ohm and 30 on the 600

 

[Sharur]

what does the difference in number of ridges at, say, 5k mean even if there is no audible difference? There are around 40 on the 250 ohm and 30 on the 600
View attachment 124923View attachment 124924

 

[solderdude]

You can't say anything more than that there is nothing of any concern seen in these plots.
When there is 'trouble' you will see resonances going on for longer in time.

At 5kHz the amplitude drops 40dB in 2ms (250)
At 5kHz the amplitude drops 37dB in about 1.6ms (600)

Then you need to take in consideration that there are filters used in the analysis which may well be a limiting factor.
I would not draw many conclusions on these plots other than both DT880 show no problematic resonances in the time domain.

 

[Sharur]

The output voltage on the HP out with a 600 ohm load = 7.2V peak (88mW) so very loud.
Output R = 68 Ohm. Fine for high impedance headphones can be terrible for certain low impedance headphones.

How was this calculation done? I don't know if I'm doing this correctly, but this would be the voltage and current at a 4 ohm load:
V = sqrt(P×R) = sqrt(40W×4Ω) = 12.6491106V
I = P / V = 40W / 12.649110640673518V = 3.16227766A

Then to find the current and power with the load of my headphones and the headphone out's output impedance (not sure if I am doing this right):
I = V / R = 12.6491106V / 638Ω (570Ω impedance of beyer + 68Ω output impedance of headphone jack) = 0.0198261922A
P = V×I = 12.6491106V×0.019826192163009404A = 0.250783697W

"For short term peaks of 5 milliseconds, the C 316BEE V2’s undistorted peak power is >110W into 8 Ohms, 190W into 4 Ohms and 270W into 2 Ohms." https://nadelectronics.com/wp-content/uploads/2018/05/NAD_C316BEEV2_Data_Sheet.pdf

Peak voltage and current with a 4 ohm load:
V = sqrt(P×R) = sqrt(190W×4Ω) = 27.5680975V
I = P / V = 190W / 27.568097504180443V = 6.89202438A

Peak current and power at a 638 ohm load:
I = V / R = 27.5680975V / 638Ω = 0.0432101842A
P = V×I = 27.5680975V×0.043210184169279A = 1.19122257W

Does this mean I can get 1.191 W of dynamic power at 570Ω?

 

[solderdude]

The 68 ohm is formed by a voltage divider. (100//220=68) so the output voltage is also divided 220 and (100//600) = 0.28 x U speaker (no load)
The current limit of the amp is not important. The max output current is determined by the 220ohm resistor + (100//600)

Based on the schematic:
The amp output stage operates on +/-45V so without a load (300 ohm is no load for a power amp) you can get a voltage swing of about 86Vpp = 30Vrms
30Vrms x 0.28 (the voltage divider) = 8.4Vrms = 106mW in 660 ohm (average over 20-20kHz)

Based on the specs:
90W in 8ohm = 27V x 0.28 = 7.5V
but the power supply voltage will sag under 8ohm load a bit which the headphone doesn't so perhaps the 8.4V is more realistic.

 

[Sharur]

The 68 ohm is formed by a voltage divider. (100//220=68) so the output voltage is also divided 220 and (100//600) = 0.28 x U speaker (no load)
The current limit of the amp is not important. The max output current is determined by the 220ohm resistor + (100//600)

View attachment 131455

Based on the schematic:
The amp output stage operates on +/-45V so without a load (300 ohm is no load for a power amp) you can get a voltage swing of about 86Vpp = 30Vrms
30Vrms x 0.28 (the voltage divider) = 8.4Vrms = 106mW in 660 ohm (average over 20-20kHz)

Based on the specs:
90W in 8ohm = 27V x 0.28 = 7.5V
but the power supply voltage will sag under 8ohm load a bit which the headphone doesn't so perhaps the 8.4V is more realistic.

Thank you for this, it was very informative. I'm just trying to wrap my head around what you meant when you said they have no problem handling 12V continuously. After a very loud volume level (with the headphones off my head) the DT880 starts to massively distort. Would say, 12V out, make them distort less or is that just for unusable headroom?

 

[solderdude]

Beyer drivers tend to distort massively before their electrical power rating is reached. I was talking about the power rating only
Consider that when on the head the driver has acoustical damping and it doesn't when lying on the table.
When one measures the impedance peak lying on a desk or mounted on a fixture the impedance peak differs as well.