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Topping L30 Headphone Amplifier Review

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amirm

amirm

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It seems from your test that some amplifiers, in that case Benchmark amplifier, do not have this distortion.
That was the kicker: later on I got the benchmark amp and it too had the same distortion in the same test setup!
 

shoto

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What is the name of benchmark amp or can you link the follow up test? thanks
 
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amirm

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What is the name of benchmark amp or can you link the follow up test? thanks
Here you go: https://www.audiosciencereview.com/...ents-of-benchmark-dac3.3545/page-2#post-85580

Dummy load:

index.php


With Sony headphone as the load:

index.php


I should note that multiple designers objected to this type of testing including Andrew Mason of THX and Mathias of RME. They were right. :)

To be clear, if you build a low impedance kelvin type fixture to sample the output and then the problem would not exist. And then if you compare the same setup with a high impedance headphone amp, it would. This is what the original Benchmark paper showed. We (and SBAF) ran foul of building the wrong version of this fixture and thinking that two low very low impedance headphone amps would have the same problem. They do not. This is why I stopped using this setup back in 2018.
 

solderdude

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Again... what is 'measured' is not distortion that supposedly is increased by the amplifier.
It is attenuated back EMF that is added to the test signal.

The proof for that is really easy. Just flip on the measurement device but do not start the test and put the headphone against a speaker making the sweep. You will see the 'distortion'.

It really isn't that hard to figure out the 'distortion' isn't coming from or caused by the amp. It is voltage division of back EMF.
The lower the output R the lower the 'added signals' are.

The reason Marv cannot replicate what JohnYang measured is the test setup (as JohnY already mentioned).
JohnY was smart enough to use the splitter directly at the L30 (and even that adds small resistance). Marv uses a cable that adds output resistance basically and splits after a cable and thus Z2 (in my previous post) is higher so the 'effect' is bigger.

If only he used a speaker amp (a real one with really low output R) and repeated the same measurement but splitted directly at the speaker terminals and then repeat the measurements with small resistors (of different values) between the speaker terminal and the splitting point it would be really easy to verify the cause.

This is basic ohms law stuff with 2 signal generators both 'injecting' their own signals which combine and is what is measured. There is no mystery here. One just has to experiment a bit and stop looking through certain glasses.
 
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amirm

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John was smart enough to use the splitter directly at the L30 (and even that adds small resistance). Marv uses a cable that adds output resistance basically and thus Z2 (in my previous post) is bigger so the 'effect' is bigger.
That was the issue in my original dummy load/test fixture as well.
 

shoto

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Here you go: https://www.audiosciencereview.com/...ents-of-benchmark-dac3.3545/page-2#post-85580

Dummy load:

index.php


With Sony headphone as the load:

index.php


I should note that multiple designers objected to this type of testing including Andrew Mason of THX and Mathias of RME. They were right. :)

To be clear, if you build a low impedance kelvin type fixture to sample the output and then the problem would not exist. And then if you compare the same setup with a high impedance headphone amp, it would. This is what the original Benchmark paper showed. We (and SBAF) ran foul of building the wrong version of this fixture and thinking that two low very low impedance headphone amps would have the same problem. They do not. This is why I stopped using this setup back in 2018.
You say in this test it is Benchmark DAC3 when Benchmark's measurement graphs were for DAC1. Can you give more details about similar claims for DAC3? Did it also have the new measurements graphs showing the effect for DAC3?
If not I don't think that it is fair comparison, but if they have same graphs for DAC3 it will show they are dishonest about the measurements.
 

dmac6419

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Basically, the test setup and the person who performs the test are not good enough for precision analogue measurements.
Marvey trying to make a name for himself,owner on his slong and vice versa,they wanna be big boys,but I have to wonder why they can't hang on their own laurels
 

confucius_zero

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With planar the big difference was in bass, less impactful/loose with quicker roll-off, better amping brought tight/well extended bass.
I felt the same with my L30 I bought within months of interval to make sure I got another batch... that bass rolloff is felt everytime. I wonder if there's an objective measurement that can highlight this glaring deficiency or are the headphones to blame.
 

Vini darko

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I felt the same with my L30 I bought within months of interval to make sure I got another batch... that bass rolloff is felt everytime. I wonder if there's an objective measurement that can highlight this glaring deficiency or are the headphones to blame.
Yeah i kinda agree. My t50rp do very good bass but not sub-bass off the l30. I use my objectively inferior speaker amps if I feel the need for sub-bass from them. The l30 is completely fine with all my dynamic phones though.
 

Jose Hidalgo

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Could somebody please (re)post the power consumption of the L30 in OFF mode? (not 'Idle' - Off !). If I remember well, it was said in this topic that the heavy power brick uses power all the time, even when the amp is turned off, and it's not negligible if the L30 remains plugged 24/7.

Same question for the E30, but in ON and STANDBY modes. In other words :
  • L30 in OFF mode : ??? watts
  • E30 in ON mode : ??? watts
  • E30 in SBY mode : ??? watts
Thank you.
 
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alekksander

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Could somebody please (re)post the power consumption of the L30 in OFF mode? (not 'Idle' - Off !). If I remember well, it was said in this topic that the heavy power brick uses power all the time, even when the amp is turned off, and it's not negligible if the L30 remains plugged 24/7.

Same question for the E30, but in ON and STANDBY modes. In other words :
  • L30 in OFF mode : ??? watts
  • E30 in ON mode : ??? watts
  • E30 in SBY mode : ??? watts
Thank you.

For L30 my measurement tool shows:
6.1 Watt when turned on (0dB, knob at 90%)
2.9 Watt when turned off
2.3 Watt power brick only (not connected to anything at the other end)

This values aren't high, but personally i use remote power switch between my audio components and power applet.
I don't have E30 to check.
 

SergeyPe

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Hello everyone. Been a silent reader of this thread for some time; but as a purchase of E30/ L30 stack is considered now, I have a question to John.
Based on the photos of L30 internals published here, the TPA6120a2 are cooled by the heatsink put on top of the chips. However as it is stated in the datasheet, "The TPA6120A2 incorporates an exposed PowerPAD on the underside of the chip. This acts as a heatsink and must be connected to a
thermally dissipating plane for proper power dissipation. Failure to do so may result in exceeding the maximum junction temperature that
could permanently damage the device.". I'm wondering if this (soldering the PowerPad to the thermally dissipation plane on top of the PCB) is done with L30?
 

JohnYang1997

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Hello everyone. Been a silent reader of this thread for some time; but as a purchase of E30/ L30 stack is considered now, I have a question to John.
Based on the photos of L30 internals published here, the TPA6120a2 are cooled by the heatsink put on top of the chips. However as it is stated in the datasheet, "The TPA6120A2 incorporates an exposed PowerPAD on the underside of the chip. This acts as a heatsink and must be connected to a
thermally dissipating plane for proper power dissipation. Failure to do so may result in exceeding the maximum junction temperature that
could permanently damage the device.". I'm wondering if this (soldering the PowerPad to the thermally dissipation plane on top of the PCB) is done with L30?
The heatsink is extra. The bottom is also soldered.
 

Jose Hidalgo

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For L30 my measurement tool shows:
6.1 Watt when turned on (0dB, knob at 90%)
2.9 Watt when turned off
2.3 Watt power brick only (not connected to anything at the other end)
Thanks :) That doesn't look like much. I thought I had read values up to 20 W or so. I must be mistaken.
I'm surprised by the power consumption when turned off or even power brick only. Wasn't there a way to reduce that to almost 0 ? :oops: The L30 doesn't have a remote sensor or a standby mode, so when it's off it should be... well, really "OFF", lol.
 

JohnYang1997

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Thanks :) That doesn't look like much. I thought I had read values up to 20 W or so. I must be mistaken.
I'm surprised by the power consumption when turned off or even power brick only. Wasn't there a way to reduce that to almost 0 ? :oops: The L30 doesn't have a remote sensor or a standby mode, so when it's off it should be... well, really "OFF", lol.
With SMPS it's possible. Not with transformers though. There's always current running through the primary side.
When plugged in there's microcontroller running, detecting supply input voltage, undervolt, overvolt, DC in.
 

raybies

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Loooong time lurker, 1st post.
The L30 went in to my desktop setup PC > miniDSP > SVS 3000 Micro|L30 > Headphones|DIY Class A Amp > DIY speakers.
@JohnYang1997 great little amp; mine has been very transparent, with the only negative a slight physical drag on the pot. Sorry the successful launch turned it to a PitA, but that's just the way things go sometimes.

On the headphone side, I use the Sundara's w/ https://github.com/jaakkopasanen/AutoEq/tree/master/results/innerfidelity/innerfidelity_harman_over-ear_2018/HIFIMAN Sundara PEQ on miniDSP/L30 @ +9dB and it's the only one of my numerous headphone amps that's made me like the Sundara's previously fairly bland experience. Using Qudelix 5K (PEQ) > xDuoo TA20 > Sundara, doesn't exhibit the same <60Hz tightness and airy presence.
My speakers, MDR-Z1R's and Denon AH-D7000's don't show any character development, so transparent.

This is probably the wrong place to ask, audio purests n' all, but just in case @JohnYang1997 is still reading... is there any chance Topping might consider developing a DAC w/ 4ch out + PEQ + Delay + sophisticated DSP algorythms... a miniDSP killer? When I say sophisticated DSP I mean along the lines of psuedo dimentionality, staging, reverb... or if you could implement a DSP design engine like this https://moddevices.com/products/mod-duo-x/ that would be a dream come true, ie open source the DSP effects. The Mod duo x while for music creation has a lot of useful ideas ypu can apply to standalone desktop DACs/Amps, it also rocks my world.
All my DACs ~sound the same, so I only upgrade for DSP.

Anyway L30's a great little clean and transparent amp... great job!
 

JohnYang1997

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Loooong time learker, 1st post.
The L30 went in to my desktop setup PC > miniDSP > SVS 3000 Micro|L30 > Headphones|DIY Class A Amp > DIY speakers.
@JohnYang1997 great little amp; mine has been very transparent, with the only negative a slight physical drag on the pot. Sorry the successful launch turned it to a PitA, but that's just the way things go sometimes.

On the headphone side, I use the Sundara's w/ https://github.com/jaakkopasanen/AutoEq/tree/master/results/innerfidelity/innerfidelity_harman_over-ear_2018/HIFIMAN Sundara PEQ on miniDSP/L30 @ +9dB and it's the only one of my numerous headphone amps that's made me like the Sundara's previously fairly bland experience. Using Qudelix 5K (PEQ) > xDuoo TA20 > Sundara, doesn't exhibit the same <60Hz tightness and airy presence.
My speakers, MDR-Z1R's and Denon AH-D7000's don't show any character development, so transparent.

This is probably the wrong place to ask, audio purests n' all, but just in case @JohnYang1997 is still reading... is there any chance Topping might consider developing a DAC w/ 4ch out + PEQ + Delay + sophisticated DSP algorythms... a miniDSP killer? When I say sophisticated DSP I mean along the lines of psuedo dimentionality, staging, reverb... or if you could implement a DSP design engine like this https://moddevices.com/products/mod-duo-x/ that would be a dream come true, ie open source the DSP effects. The Mod duo x while for music creation has a lot of useful ideas ypu can apply to standalone desktop DACs/Amps, it also rocks my world.
All my DACs ~sound the same, so I only upgrade for DSP.

Anyway L30's a great little clean and transparent amp... great job!
I wouldn't say any about DSP. But I would say there are still a lot more things to be done.
 
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