Do I need Topping L30 II？

[panyunqi888]

I own a Motu Ultralite AVB and Shure Srh1840 and Sennheiser HD650.I wonder if I should buy Topping L30 II? How much improvement can it bring?

 

[Rja4000]

Loudness.
The Ultralite headphones power is quite limited.
So if you want it louder, yes, you could get benefit from the L30 II.

 

[solderdude]

... or any other amp reaching similar output voltage (power) levels.

The Motu can (I suspect) reach 3.9V on the headphone out (+14dBu)
SRH1840 = 112dB SPL peak
HD650 = 117dB SPL peak.
(assumed SE line out buffered)

more likely to be around 2.8V after further scrutiny (thanks to Rja4000)
SRH1840 = 108dB SPL peak
HD650 = 104dB SPL peak.

The L30-II can make the headphones reach:
SRH1840 = 121dB SPL peak
HD650 = 125dB SPL peak.

 

[Rja4000]

... or any other amp reaching similar output voltage (power) levels.

The Motu can (I suspect) reach 3.9V on the headphone out (+14dBu)
SRH1840 = 112dB SPL peak
HD650 = 117dB SPL peak.

The L30-II can make the headphones reach:
SRH1840 = 121dB SPL peak
HD650 = 125dB SPL peak.

From Amir's measurements, it's rather 2.63V (23mW/300 ohm) or 10.6dBu.
So 114dB SPL max for the HD650

 

[panyunqi888]

Loudness.
The Ultralite headphones power is quite limited.
So if you want it louder, yes, you could get benefit from the L30 II.

Oh……Is Motu enough for 1840 and HD650？Do I need to buy amplier？（I think it is loud enough now）

 

[panyunqi888]

... or any other amp reaching similar output voltage (power) levels.

The Motu can (I suspect) reach 3.9V on the headphone out (+14dBu)
SRH1840 = 112dB SPL peak
HD650 = 117dB SPL peak.

The L30-II can make the headphones reach:
SRH1840 = 121dB SPL peak
HD650 = 125dB SPL peak.

Thanks for reply！Is Motu enough for 1840 and HD650？Do I need to buy amplier？（I think it is loud enough now）

 

[solderdude]

When it is loud enough now and the sound is clean up to those level you do not need another amp, nor will it bring any improvements despite manufacturers, sellers and reviewers claiming this or that amp sounds so much 'better'. Chances are you may perhaps be just about at clipping levels already.

At a bit louder levels you may run into audible clipping.

From Amir's measurements, it's rather 2.63V (23mW/300 ohm) or 10.6dBu.
So 114dB SPL max for the HD650

Looked a little further and found:
max. 80mW but no mention about the impedance for the Motu Ultralite AVB

Looking at the M2 I would think the output stage might well be very similar.
New estimated values are in the edited post ( #3)

 

[Rja4000]

I think it is loud enough now

As @solderdude said, if that's loud enough, that's loud enough.
Then you don't need anything.

 

[usern]

You would need an amplifier with balanced line inputs and because of that Topping L30 II is not suitable for the Motu interface. But as others have said if Motu sounds clean and loud, then there is no need for an amp.

 

[solderdude]

You would need an amplifier with balanced line inputs and because of that Topping L30 II is not suitable for the Motu interface

This could be an option when using the HP out.