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WolfX700 Measurement of Topping L30 Headphone Amp

JohnYang1997

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@WolfX-700 @JohnYang1997 I’m not really familiar with reading graphs, but isn’t there a conflict with the graph for the 50R load? I get that the 3.2W figure came from the X Axis under the Cursors, but the graph itself shows something more like 1.7W at a 50R load.
It seems to be a bug with ap..
 

ichonderoga

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Aboslutely bonkers these numbers!

Futurama-Fry-Shut-Up-And-Take-My-Money.jpg
 
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WolfX-700

WolfX-700

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@WolfX-700 @JohnYang1997 I’m not really familiar with reading graphs, but isn’t there a conflict with the graph for the 50R load? I get that the 3.2W figure came from the X Axis under the Cursors, but the graph itself shows something more like 1.7W at a 50R load.

Thank you for your reminder! I slept for an hour and rushed before I went to work. The measurement results were posted without careful inspection... It seems that the AP's software has a bug?:facepalm:

Anyway, it has been updated. 1.5W@50R
 

half_dog

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I've already have a JDS Atom and it's more than enough for a HD650... But look those numbers!!! And it will stacky really nice with my E30. Thanks @WolfX-700 for the measurements and @JohnYang1997 for this SOTA amp :D
 

mmicko

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Why can't have such a great HP output performance the Dx7 Pro too :(
The price of L30 is perfect, but would be nice to have it in all in one form especially when DAC performance of Dx7 Pro is much better than E30 (which can be the limiting factor when pairing with L30)
 

Veri

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Why can't have such a great HP output performance the Dx7 Pro too :(
The price of L30 is perfect, but would be nice to have it in all in one form especially when DAC performance of Dx7 Pro is much better than E30 (which can be the limiting factor when pairing with L30)
L30 and A90 only just developed, L30 not yet for sale. So it cannot yet be in older products. It will be a thing for future devices.
 

M0du1e

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Why can't have such a great HP output performance the Dx7 Pro too :(
The price of L30 is perfect, but would be nice to have it in all in one form especially when DAC performance of Dx7 Pro is much better than E30 (which can be the limiting factor when pairing with L30)
How can it be E30 is limiting factor when we're see DAC Perfomance Index and it measure very well?
 

niecore

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Does the "L", in "L30" stands for Linear Amplifier?

If yes whats the difference to the "A"-Line of Topping (A30, A50...)?
 
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3125b

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Thats pretty low input impedance. Well, shouldn't make a difference.


How can it be E30 is limiting factor when we're see DAC Perfomance Index and it measure very well?
Limiting factor is not the correct way to put it, noise and distortion of both the DAC and amp just have to be added together. However the E30 would be adding more than the DX7 Pro as DAC.

I think in this case it would be calculated like this:
20 · log10[10^(dB1/20) + 10^(dB2/20)] (with phase angle = 0° (?))
Using that formula I get about -107dB combined for my E30 and Atom amp combo,
DX7 Pro (119dB) and L30 (124dB) best case SINAD would be 115dB,
E30 and L30 would give you 110dB.
 
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odyo

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Why can't have such a great HP output performance the Dx7 Pro too :(
The price of L30 is perfect, but would be nice to have it in all in one form especially when DAC performance of Dx7 Pro is much better than E30 (which can be the limiting factor when pairing with L30)
Yeah i really like DX7 pro box. Even beautiful than Schiit stuff. It would be nice to have E30+L30 inside DX7 Pro box at a cheaper price below $300.
 

Toku

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There is a display of AC15V on the power jack on the back. Is this true? Isn't it a mistake for DC15V?
 

Vini darko

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I have a question about the dynamic range measurements. What rca source puts out 9.5V or even 5V? Would that mean to get max performance out of this amplifier I would need additional voltage gain stage as the majority of rca based devices output 2V? Seems weird that the amp will even accept that voltage without going into protect.
 

JohnYang1997

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I have a question about the dynamic range measurements. What rca source puts out 9.5V or even 5V? Would that mean to get max performance out of this amplifier I would need additional voltage gain stage as the majority of rca based devices output 2V? Seems weird that the amp will even accept that voltage without going into protect.
This is to measuring the device itself. Just like measuring an opamp to meet its specification. It can take in those voltages without any issue.
If you have input of 2V you can use gain +9db which takes you to 6V. In real world use I doubt you will ever need that much output. But you can.

So it cover you all scenarios. 50mV SNR is the real world test. 104dB will give you the best performance at this scenario as you mostly would listen around 50mV (from a few mv to over 100mv). Whether you need it or not is up to you.
 
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